So, I’ve decided to try a slightly different approach for the next while—one that has these sorts of folks in mind. From time to time, you can still expect those more in-depth, technical articles, or perhaps a discussion of some new research that makes the popular press, or even an analysis of some new argument from the IDM or RTB. These will be breaks from the new routine, however. For the most part, we’re going to stick to the basics, much like you would if you took an introductory evolution course at a university. Don’t worry, though: this course doesn’t have any prerequisites! All that’s needed is a willingness to learn.

What you can expect

The goal of this course is straightforward: to provide evangelical Christians with a step-by-step introduction to the science of evolutionary biology.  This will provide benefits beyond just the joy of learning more about God’s wonderful creation. An understanding of the basic science of evolution is of great benefit for reflecting on its theological implications, since this reflection can then be done from a scientifically-informed perspective. From time to time we might comment briefly on some issues of theological interest (and suggest resources for those looking to explore those issues further), but for the most part, we’re going to focus on the science. For folks interested in the interaction between science and Christianity, I heartily recommend Ted Davis’ recent series as a fabulous introduction to the topic.

You can also expect a slow, patient pace. Since this course is intended for folks with little or no background in biology, we’re going to take our time to make sure no one gets left behind. This might be frustrating to folks who already know a fair bit about evolution. Hopefully even more knowledgeable readers will learn some new and interesting details along the way—but the goal will primarily be to help folks who are less well versed in evolution increase their understanding.

You can also expect a survey of many different areas that have some bearing on evolution. We’ll examine geology, paleontology, biogeography, genetics, and a host of other topics in order to provide a “big picture” overview. This broad-brush approach means that any given individual post will not necessarily be “convincing” to folks who have doubts about evolution. Think about assembling a large jigsaw puzzle: placing any individual piece, on its own, doesn’t convincingly demonstrate what the overall picture will show. This course will be like that. Each topic we cover will put a few pieces in place here and there, slowly building towards the final overall picture.

Since evolution is an active science, this process will also highlight where there are “missing pieces” that are still being sought by scientists. All of this is well and good, since the purpose of this course is not so much to convince anyone of the validity of evolutionary theory, but rather to inform readers about the nature and scope of evolution as a scientific theory in the present day. My goal is to provide readers with a basic understanding of what evolution is and how it works. Given that as the primary goal, if one finds the scope of the evidence ultimately convincing (or not) is somewhat beside the point. The intent here is to provide readers with information they can use to make their own, informed decision.

How you can help

First and foremost, you can help by spreading the word about this series to folks you think would be interested in learning more about evolution in a non-threatening environment. Secondly, you can help me by asking questions in the comments. One of the challenges of being a specialist is having the ability to put oneself in the shoes of someone just starting out. What might seem obvious to me may not seem obvious to you, and I hope you’ll feel that no question is too basic or too simplistic. If you’re wondering about something, it’s almost guaranteed that other folks are, too! So, please don’t be shy. I’ll do my best to answer questions in the comments, though I hope that some of our more skilled commenters will (respectfully!) help out here, as well. Finally, you can help by letting me know what broader areas of evolution you find confusing. I have my own ideas about what areas of evolution are commonly misunderstood, but I’d love to hear from readers about what areas they find difficult to understand. I’ll use this input to shape the topics I will cover as we go forward.

Getting started

In the next post in this course, we’ll dive into the course content by introducing two key areas: how scientific theories work in general, and how evolution in particular works as the current organizing theory of modern biology. 

Good science has an addiction to theories,¹ and for science to be good science, it must deal with good scientific theories.  What constitutes a good scientific theory?  That is a very involved question, but a user’s view of good scientific theories looks something like this:

1.  A scientific theory is not a guess or suspicion.  For example, “I have a theory about who shot President Kennedy,” reflects the colloquial meaning of the word “theory,” and not the meaning conveyed by scientists when they use the word “theory.”  
2. Scientific theories are convincing explanatory frameworks that efficiently integrate a large body of evidence about the world.  Good scientific theories have the capacity to make sense of a wide range of data that made less sense before the introduction of the theory. 
3. In order to be called a scientific theory, it must have been successfully tested and re-tested many times.²
4. A scientific theory must be falsifiable in order to be truly scientific.  The theory has to live constantly at risk from new data.³ 
5. A theory must have predictive power.⁴  Good theories allow scientists to make predictions based on the theory that, when tested, turn out to be at least roughly correct. 

These are not the only characteristics of a scientific theory, but they probably represent the most important features for practitioners of science. 

If we hold contemporary evolutionary theory to these standards, how well does it do?  Since the inception of evolutionary theory by Charles Darwin in 1859 with the publication of On the Origin of Species, there are four characteristics of evolutionary theory that have endured 150 years of further research:

1. Living species are descendants of other species that lived in the past.
2. These past species lived in populations that underwent gradual transformation so that the individuals in these populations changed their appearance, behaviors, metabolisms, and life histories over long spans of time.⁵
3. New forms of life arose by means of a process called speciation in which one lineage splits into two distinct lineages.  This continual splitting of organismal lineages leads to a nested genealogy of species.  This nested genealogy forms a veritable tree of life, whose root represents the first species to arise and whose twigs represent the millions of species living today.  If you trace back any pair of twigs from the modern species you will find that their histories merge at some node on the tree where the two species share a common ancestor.⁶ 
4. This process of biological change that takes place throughout the advance of geologic time, or evolution, occurs by means of variation in organisms (which we know today is due to genetic mutations) that is acted on by either random genetic drift or natural selection. Those individuals with variations better suited to the current environment leave more offspring, thus changing the average appearance of the population over time and making it a better fit to the environment. This improving fit between organisms and their environment gives the appearance of organisms having been well designed for their milieu.⁷ 

What is the evidence for these aspects of evolutionary theory?  The evidence is actually immense, but I will restrict this discussion to just a few items. 

First there is the fossil record. If life results from a natural process such as biological evolution, then we should observe a progression of fossil organisms that proceed from relatively simple, single-celled organisms in the oldest rocks to more complex, multicellular organisms in younger rocks. When paleontologists examine the geologic column, they perceive that some of the oldest and deepest layers of the geologic column contain fossils of microorganisms, and then marine invertebrates in younger layers above those,⁸ and then much later and higher up in the geologic column fish appear, followed later and higher still by amphibians, and then by reptiles, mammals, and birds.⁹  Thus, the general presentation of the fossil record in the rock record comports exactly with what the theory of evolution predicts. 

However, the fossil story gets even better, because scientists can trace evolutionary trends throughout the fossil record.  For example, horses get bigger, fuse their leg bones and toes into a single bone with a thick hoof and grow the thickness of their tooth enamel;¹⁰ Cenozoic brachiopod shells get narrower, decrease their rib numbers and beak angle;¹¹ diatoms get bigger;¹² and primate fossils reduce the size of their teeth and expand the size of their brains.¹³ 

Additionally, Darwin predicted that there should be organisms preserved in the fossil record that possess features found in two different types of creatures. Such organisms are “transitional forms” that bridge the gap between different types of organisms.¹⁴ However, the fossil record of Darwin’s time provided little evidence of such transitional forms.¹⁵ Therefore, Darwin gambled that future paleontological research would provide sufficient evidence to corroborate his theory. How did this gamble turn out? Since Darwin’s time, paleontologists have discovered transitional fossils that are part fish and tetrapod,¹⁶ part amphibian and part reptile,¹⁷ part dinosaur and part bird,¹⁸ and part reptile and part mammal.¹⁹ Once again, we would predict such paleontological trends and the existence of such transitional fossils if life came about through a process of organic evolution. Clearly paleontological research since Darwin’s time has powerfully vindicated his theory. 

Please join us for part two of this post tomorrow, where we will discuss how signs of evolution can be detected in organisms living today, and how evidence from multifarious scientific fields—not just biology and paleontology—have bolstered the theory of evolution and added to our understanding of how natural selection works.

Notes

1. Ratzsch, Del. The Battle of Beginnings: Why Neither Side Is Winning the Creation-Evolution Debate. Downer’s Grove, WI: Intervarsity Press, 1996. pp. 104–119. 
2. Kitcher, Philip. Abusing Science: The Case Against Creationism. Cambridge, MA: MIT Press, 1983. pp. 45–54.
3. Ibid, 42–48.  .
4. Ratzsch, Del. Science and Its Limits: The Natural Sciences in Christian Perspective. Downer’s Grove, WI: Intervarsity Press, 2000. pp. 21–24. 
5. Hall, Brian K., and Benedikt Hallgrimsson. Strickberger’s Evolution. 5th ed. Burlington, MA: Jones and Bartlett, 2013. pp. 19–68. 
6. Kitcher, Philip. Living With Darwin: Evolution, Design, and the Future of Faith. New York: Oxford University Press, 2009. pp. 43–71. 
7. Futuyma, Douglas J. Evolution. 3rd ed. Sundbury, MA: Sinauer Associates, 2013. pp. 281–343. 
8. Valentine, James W. On the Origin of Phyla. Chicago: University of Chicago Press, 2006. pp. 429–464. 
9. Carroll, Robert L. Vertebrate Paleontology and Evolution. New York: W. H. Freeman and Company, 1990. 
10. MacFadden, “Horses, the Fossil Record, and Evolution,” 131–158; McFadden, Bruce J. “Fossil Horses from "Eohippus" (Hyracotherium) to Equus: Scaling, Cope's Law, and the Evolution of Body Size.” Paleobiology 12, no. 4 (1986): 355–69.; Prothero, Donald R., and R.M. Schoch, eds. The Evolution of Perissodactyls. New York: Clarendon Press, 1989. ; McFadden, Bruce J. Fossil Horses. Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge, Cambridge University Press, 1993. 
11. McNamara, Kenneth J. “Evolutionary Trends.” In Encyclopedia of Life Sciences (New York: Macmillan Publishers Ltd, 2001), pp. 1–7. 
12. Litchman, E., C. A. Klausmeier, and K. Yoshiyama. “Contrasting Size Evolution in Marine and Freshwater Diatoms.” Proceedings of the National Academy of Sciences USA 106, no. 8 (2009): 2665–2670.
13. Tattersall, Ian. The Fossil Trail: How We Know What We Think We Know About Human Evolution. New York: Oxford University Press, 2008. pp. 89–198. 
14. Darwin, Charles. On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. London: Penguin Books, 1985. p. 292.
15. Hunt, Gene. “Evolution in Fossil Lineages: Paleontology and The Origin of Species.” Supplement American Naturalist 176 (2010): S61–S76. 
16. Clack, Jennifer A. Gaining Ground: The Origin and Evolution of Tetrapods. Bloomington, IN: Indiana University Press, 2002; Daeschler, Edward B., Neil H. Shubin, and Farish A. Jenkins, Jr. “A Devonian Tetrapod-Like Fish and the Evolution of the Tetrapod Body Plan,” Nature 440, no. 7085 (2006): 757–63; Shubin, Neil H., Edward B. Daeschler, and Farish A. Jenkins, Jr. “The Pectoral Fin of Tiktaalik roasae and the Origin of the Tetrapod Limb.” Nature 440, no. 7085 (2006).): 764–71; Downs, Jason P., Edward B. Daeschler, Farish A. Jenkins, and Neil H. Shubin. "The Cranial Endoskeleton of Tiktaalik roseae." Nature 455, no. 7215 (2008): 925–9. 
17. Carroll, Robert L. Vertebrate Paleontology and Evolution. New York: W. H. Freeman and Company, 1990. pp. 156–216. 
18. Shipman, Pat. Taking Wing: Archaeopteryx and the Evolution of Bird Flight. New York: Touchstone, 1998. pp. 169–244.  
19. Prothero, Donald R. Evolution: What the Fossils Say and Why It Matters. New York: Columbia University Press, 2007. pp. 271–297. 

A common argument leveled against the theory of evolution is that scientists have not been able to produce the expected transitional fossils that show the change of one species into another. If evolution were true, wouldn’t there be instances of clear intermediary species, like, for example, a species that was half whale and half hippo to show the transition between those two? In this BioLogos podcast, Kelsey Luoma addresses this misconception about what a transitional fossil actually is. Rather than a mix between two related species, transitional fossils point back to the common ancestors that modern species share. The fact is that the number of transitional species is massive and it grows with each passing year. Given the rarity with which organisms are actually fossilized, the amazing thing is actually the completeness of the fossil record, not its incompleteness. The transitional species story strongly supports, and certainly does not disprove, evolutionary theory. ¹

1. To hear the full audio clips which have been referenced go to:

• Rational Response Debate with Kirk Cameron (from Way of the Masters)
• Behind the Scenes with Dr. Neil Shubin (from Cincinnati Museum Center)
• Mark Norell Publishes New Archaeopteryx Findings (from American Museum of Natural Sciences)
• Texas A&M Professor Discusses Findings of Autralopithecus Sediba and its Relationship to Humans (from Texas A&M University)
• Intro/outro music composed by Martin Minor (Minor2Go).

An audio only version of the podcast can be downloaded here.

Evolution and the Problem of Evil

Let me begin by expressing appreciation for the commitment and intent of BioLogos. Francis Collins was speaking at nearby Tulane University a couple of years ago when my son was a senior in high school, and I brought him along to hear this noted Christian biologist’s presentation to help prepare him for challenges he would experience (as he is now) in college. This is a tremendously valuable ministry. However, as a philosopher and a theologian I do have concerns about some of the theological implications of the BioLogos theistic evolution view, particularly regarding the problem of evil.

The problem of evil is one of the most persistent and intuitive challenges to the Christian faith and the existence of God. The classic defenses or theodicies that have been used to answer this challenge include the Freewill Defense (God is not responsible for much of evil because it is caused by the free actions of humans), the Soul Making Defense (God allows or sends some evils or suffering in order to build human character in overcoming adversity), and the Eschatological Defense (although the cause of some suffering may be beyond our understanding, whatever suffering we may experience in this life cannot compare with an eternity of blessing in heaven).

These theodicies or defenses to the problem of evil, however, normally presuppose the standard view of divine creation. Were one to propose creation by means of theistic evolution, some of the presuppositions for these responses to the problem of evil no longer function. Therefore, advocating some form of theistic evolution poses problems for standard explanations of the problem of evil.

Cornelius Hunter has recently published Darwin’s God: Evolution and the Problem of Evil,¹ an excellently researched book which re-examines Darwin’s motives for developing the theory of evolution. Hunter’s main thesis is that Darwin’s intent was not to undermine belief in the existence of God, but to afford a defense of God’s moral nature. The viciousness of nature caused Darwin and some of his contemporaries to desire to disconnect God’s role in creation from this viciousness in nature, and the blind process of natural selection is the vehicle for disassociating God from the vulgarities of nature. In essence, then, Hunter’s argument is that Darwin’s theory was a form of theodicy – sheltering God’s goodness against the accusation that He is the author of the evil in nature.

Hunter’s thesis sounds hauntingly similar to that of the early Gnostics, who sought to insulate God from the evil material world. They therefore proposed intermediary aeons, archetypes, or a demiurge to isolate the purity of God from the evil of nature. The Darwinian account sharply differs from the biblical account in at least three crucial ways:

• The Darwinian account removes God from being directly involved in much of creation by utilizing natural processes instead, while the biblical account presents God as directly involved in the details of creation, both in the beginning and throughout history through his providential care.
• The Darwinian account blurs the distinction between humans and other animals, while in Scripture humans are a distinctive and special creation.
• The Darwinian account presents God as apathetic and disinterested in the moral status of animals, while the scriptural account presents God (though giving primary focus to humans) as vitally interested in the moral status of animals, and indeed for the redemption of the entire created world.

Another problem with Hunter’s thesis is that whatever Darwin’s original motivation might have been, the novelty of Hunter’s thesis underscores the fact that this is not how Darwin’s ideas predominantly have been used and understood. No one (including contemporary evolutionary biologists) seriously believes Darwin’s ideas as he presented them. Darwin’s ideas about evolution have themselves evolved. ( see Falk, Part 2) So even if Hunter’s thesis were correct about Darwin’s original motivation for the problem of natural selection, this has little relevance to contemporary evolutionary biology.

Any such Darwinian evolutionary biology also undermines classical defenses for God’s goodness. For example, the Christian group BioLogos has presented the perspective that God created all living organisms, including humans, through a gradual process that includes natural selection, group selection, genetic drift or other such physical processes, with God possibly intervening at some undefined points. While this BioLogos approach (which might be labeled a variety of “gradualism” with regard to creation) includes a role for God in creation (as opposed to pure Darwinian evolution), some of the same problems involved with the problem of evil pertain to the BioLogos view as well. In fact, the specific role that God plays in evolution remains somewhat vague and ill-defined. (see Falk, Part 1) Without BioLogos providing a clearer and more precise differentiation between itself and Darwinian evolution – and thus building a clear “Chinese wall” between their view and that of Darwinian evolution -- these views appear to be very close, and the problems that pertain to one view pertain to the other view (at least in part) as well. The following problems arise with regard to the problem of evil in relation to forms of creation by gradualism.

The Best of All Possible Worlds

First of all, it is incumbent upon a good God to produce an optimally good world. We could not necessarily expect an evil or morally mixed God to produce a good world, but we have every reason to expect a good and beneficent God (Matt. 5:48; 1 John 1:5, 4:7-8) to produce the “best of all possible worlds” (given human freewill). In the biblical account, therefore, the evil and suffering we witness in nature and in human experience is not accountable to God because of a defective process in creation, but rather it is a result of the moral Fall of the first humans and subsequent sin by their descendents. However, gradualism has no such vehicle to defend God against the accusation of being responsible for natural and physical evil and suffering. (see Applegate, Falk, and Haarsma, Part 2).

Human Distinctiveness

Second, if God created all living species, including humans, through a gradual evolutionary process that includes common descent from nonhuman primates, there is no clear line to draw a moral or spiritual distinction between humans and other living beings. (see Falk, Part 2).. Yet fundamental to any view of a moral universe is the belief that humans are created in the image of God in a way that is uniquely above all other sensate species (Ps. 8:4-8), and included in this image is our soul and our moral capacity. It is difficult to imagine how humans could receive the image of God through some sort of physical process. Instead, the Bible describes God as being directly and personally involved in creating the human soul by breathing it into mankind (Gen. 2:7). (see O’Connor, Part 1). In the specific language of the biblical account (if not to be discounted, allegorized, or completely ignored), God created human souls directly, not indirectly through some impersonal process. Gradualism offers no clear answer as to how a human soul reflecting the image of God could come about; in fact, such a unique thing in all of creation is everything but gradual or natural. (see Bishop, Part 2).

Whence Cometh Freedom?

Thirdly, even if God intervened at various points in theistic evolution to create new forms from which other species evolve, this does not afford a satisfactory account of human freewill. If humans are not a unique and distinct creation (as the biblical account makes quite clear), but are with other apes the product of a single ancestor, from whence did freewill arise? How can we account for some mutations having freewill and others not having it?

Some quasi-materialists propose some form of epiphenomenalism in which the mind emerges somewhat magically from material cells. This proposal is devoid of any convincing scientific evidence, but it is the only alternative left for materialists to espouse in order to account for some of the most basic human intuitions – that our minds are more than merely a physical organ, that our choices are genuine expressions of freewill, and that we are free moral agents who are responsible for our actions.

Evolutionary biology has no scientific evidence to respond to these basic human intuitions other than to assert that “there is no ghost in the machine” and that any apparent choices are actually mechanical outworking of hard determinism predetermined by prior physical causes. (see O’Connor, Part 2). Therefore, if human choices are merely illusions, humans cannot be held morally accountable, all blame and responsibility reverts back to the God who created this world.

The Problem of Pain

Fourth, gradualism has no moral explanation for animal pain. If humans are the product of an earlier ancestor, it may have taken thousands or millions of years for life to evolve to that point, or for humans to evolve from an earlier primate ancestor. How can the pain of these creatures (some of them quasi-human or proto-human) be justified? (see Schloss, Part 2) This is specifically the issue that worries many Christian ethicists about cloning. Each experiment in animal cloning has produced hundreds of “monsters” before the clone is successful. What if we were cloning humans? What would be the moral implications of creating hundreds of “monsters” just to develop one clone?

The unanimous view is that this would be morally unjustifiable, but this is uncannily similar to the notion of creating animals who suffer for millions of years before evolution finally produced humans. (see Schloss, Part 3) In the biblical creation accounts, pain and suffering comes into the world after the Fall and as a result of the Fall of the earliest humans, and thus God is absolved of direct responsibility for this pain. In this gradualist account, pain and suffering precede the Fall. Millions of generations of sensate beings would have suffered and died before the Garden of Eden. Why would God allow this suffering of innocents for millions of years? (see Schloss, Part 3)

Ironically, Hunter’s Darwinian explanation in Darwin’s God doesn’t work for the BioLogos perspective at this point, because God is somewhat more directly involved at several steps in creation than in the purely Darwinian perspective, so it is God who must shoulder the blame for this undeserved pain. (see Schloss, Part 2)

Another attempt to affirm a gradualist view of creation in which pain preceded the creation of humans was by William Dembski, who in his book The End of Christianity: Finding a Good God in an Evil World² proposed that the animal world existed in pain for millennia before the creation of humans, and thus the pain of these animals was applied retroactively from the later Fall (pp. 9-10). This proposal was not well received by many in the evangelical world because it depicts God causing pain to sensate beings even before the cause of the pain took place, and Dembski ultimately felt compelled to post a clarification of his views.³ So, the reality of animal pain before the Fall in the gradualist account of creation heightens the problem of evil rather than resolving it.

Death and the Nature of God

Fifth, in orthodox Christian theology, death is seen as the ultimate punishment for the Fall of Adam and Eve. There was a time of created goodness from when humankind has fallen. All human suffering, animal suffering, natural disasters, and death was ultimately the result of the God’s punishment for human sin, the curse after the Fall as described in Genesis 3. (see Schloss, Part 1)

However, in the gradualist evolutionary account, there is no Fall.(see Applegate, Falk, and Haarsma, Part 2). If anything, there is a “rise,” as human beings “come of age” and become morally responsible at some point in the process of evolution from prehuman primates. There are multiple problems with this proposal from a theological perspective:

• It is one thing to apply symbolic interpretations to the first three chapters of Genesis; it is another to eliminate the historical reality of the Fall altogether.(see Applegate, Falk, and Haarsma, Part 2). .
• In the biblical view of creation, God creates humans in a paradisical Eden, and humans are ejected from Eden after their sin. In the gradualist view,(see Applegate, Falk, and Haarsma, Part 2). there never was an Eden, and humans never enjoyed the kind of original created goodness described in Scripture.
• In the biblical view of creation, separation from God and death are the punishments for human sin. In the gradualist view, there never was an Edenic paradise, and persons were created to die. Sin has no real causal connection with physical death. (see Schloss, Part 1)

As Jeff Schloss reminds us in Part 1 of his paper, "Although commentators differ over whether the Pauline description of death in Romans 5 refers to spiritual and/or physical death, the passage clearly focuses on humans. It identifies humanity as the subject of infection, instigated and promulgated by initial and ongoing human sin: “in this way death came to all people, because all sinned” (Romans 5:12)."

• In the biblical view of creation, humans were created “a little lower than the angels, crowned with glory and honor” (Ps. 8:5). In the gradualist view, humans emerged from previously created nonhuman primates. This is a profound re-envisioning and diminishment of the Christian anthropology found in the Bible. (see Falk, Part 2)

Darrel Falk put it this way: ”Christians recognize that our material ordinariness is radically transformed by the presence and promises of God. Exactly as with the people of Israel among the nations, so humans among the animals: our special identity rests in the free choice of the Creator to give us his himself and his name. If we recognize that human specialness rests on God’s fellowship with and call upon us, and that we—alone of all creatures—are enabled by God to bear his image in the world, then anything Darwin said about the physical continuity between humans and animals is irrelevant."

We think this last significant issue raised by Dr. Lemke shows just how important this Southern Baptist Voices Series has been, because it highlights the fact that many of the theological concerns raised here do not emerge from the scientific data about life's origins or the discipline of evolutionary biology. There are surely theologians who look at creation this way, but to the extent they do so, their views emerge from their own theological considerations; they are not obligatory extrapolations which emerge from the science itself.

• The Bible describes God creating a beautiful paradisicial Eden with sinless humans, which was lost only because of human rebellion and sin. The gradualist account posits God creating a substandard world that had to evolve to reach even the sad levels of contemporary life. This imperfect creation reflects on the nature of God. Why would a perfectly good God create such an imperfect world? Why or how could a moral God create humans to be already fallen? Orthodox Christian theology affirms that God is already perfect in all His attributes, and does not evolve or change in His essence. The theology more apposite to the gradualist account is Process Theology, in which evolution in creation mirrors evolution within God himself, as he moves from a powerful but imperfect being toward a more perfect being. In fact, Process Theology was designed with a view to harmonizing Christian theology with evolutionary presuppositions. But Process Theology is not held to be orthodox by most evangelical Christians, particularly with regard the nature and perfection of God.

At the core of the Christian worldview is the biblical metanarrative of creation, fall, and redemption. The evolutionary gradualist perspective radically rewrites this standard Christian account by essentially merging the creation and fall into a single event. Humans were created as finite and fallen, not placed in a paradise with created righteousness. This gradualist approach squares well with an evolutionary account, but it does not square well with the biblical creation accounts in Scripture.

Notes

1. Cornelius Hunter, Darwin’s God: Evolution and the Problem of Evil (Waco: Brazos Press, 2001).
2. William A. Dembski, The End of Christianity: Finding a Good God in an Evil World (Nashville: B&H Academic, 2009).
3. Tom Nettles, review of The End of Christianity: Finding a Good God in an Evil World, by William Dembski, in Southern Baptist Journal of Theology 13.4 (2009): 80–85. A partial defense and Dembski’s clarification are found in David Allen, “A Reply to Tom Nettles’ Review of William A. Dembski’s The End of Christianity: Finding a Good God in an Evil World,” a white paper at the Center for Theological Research (February 2010), available online (PDF).

My valiant helper, a small-sized tiger
Sleeps sweetly on my desk, by the computer,
Unaware that you insult his tribe.

Cats play with a mouse or
with a half-dead mole.
You are wrong, though: it’s not out of cruelty.
They simply like a thing that moves.

For, after all, we know that only consciousness
Can for a moment move into the Other,
Empathize with the pain and panic of a mouse.

And such as cats are, all of Nature is.
Indifferent, alas, to the good and the evil.
Quite a problem for us, I am afraid.

Natural history has its museums,
But why should our children learn about monsters,
An earth of snakes and reptiles for millions of years?

Nature devouring, nature devoured,
Butchery day and night smoking with blood.

And who created it? Was it the good Lord?

Yes, undoubtedly, they are innocent,
Spiders, mantises, sharks, pythons.

We are the only ones who say: cruelty.

Our consciousness and our conscience
Alone in the pale anthill of galaxies
Put their hope in a humane God.

Who cannot but feel and think,

Who is kindred to us by his warmth and movement,

For we are, as he told us, similar to Him.

Yet if it is so, then He takes pity
On every mauled mouse, every wounded bird.
Then the universe for him is like a Crucifixion.

Such is the outcome of your attack on the cat:
A theological, Augustinian grimace,
Which makes difficult our walking on this earth.

–Czeslaw Milosz,¹
 translated by the author and Robert Hass

The Problem

The poem above communicates in a very poignant and profound way the essence of the theological problem of death, pain, and suffering in the natural world—what has been referred to as “natural evil.” As we will see, it may also point to at least one aspect of a Christian response.

I have become convinced that one of the fundamental issues underlying much of the resistance of many Christians to an ancient, evolving creation is that of the problem of “natural evil.” “Natural evil” is also very often a primary focus of those who reject a personal and compassionate God, as it was for Darwin himself. The issue of theodicy thus seems not only to drive many people of Christian faith away from an acceptance of the conclusions of modern science, but also to drive members of the scientific community away from a serious consideration of the claims of the Christian faith. The topic is important, then not because its solution is central to the validity of the Christian faith, but because it often serves as an unnecessary stumbling block to a productive engagement of both science and faith.

The tension generated by our understanding of God’s character, as revealed in the Bible, and by the reality of the natural world around us has been the focus of much theological and philosophical debate within the Christian church since the first century. This article sets out to examine critically several of the proposed solutions to this problem, viewing them from the perspective of a geologist, paleontologist, and orthodox evangelical Christian.

The theological problem of death and pain emerges from the following propositional statements:

1. Scripture consistently declares the absolute goodness of God and the very goodness of his creation. Furthermore, Scripture declares God’s love and care for creation, and the glory and praise it returns to him.
2. Scripture also confesses a transcendent God who is omnipotent in power, yet immanent in creation as well. God’s creative activity is not described as being confined to some past event at the beginning of time, but as a present and continuing reality. God upholds creation in its being from moment to moment, and is creatively active in its history. This understanding of God’s relationship to creation has been well articulated by Jürgen Moltmann.²
3. In seeming conflict with these confessions of God’s character, we observe death, pain, and suffering as ubiquitous, even integral, aspects of the creation around us.

The apparent conflict between God’s goodness and the presence of pain and suffering is made especially acute when we consider the nonhuman creation.³ How can we accommodate the death and suffering of animals within a theology that declares both God’s omnipotence and goodness? C. S. Lewis forcefully puts the issue before us in his book The Problem of Pain:

The problem of animal suffering is appalling; not because the animals are so numerous ... but because the Christian explanation of human pain cannot be extended to animal pain. So far as we know beasts are incapable either of sin or virtue: therefore they can neither deserve pain nor be improved by it.⁴

Because the issue of animal pain so directly impacts our understanding of the goodness of creation, I will focus particularly on solutions to the problem as posed by Lewis.

How do we then reconcile the goodness of God who is immanent and active in his creation with the death, pain, and suffering we see embedded within it? There seem to be two basic alternative approaches to this dilemma.⁵

1. Natural evil can be attributed to something independent of God and acting against his will. This position threatens to limit God’s power and freedom.
2. Natural evil can be considered a part of God’s good purpose for creation, and either directly willed or permitted by him. Such a view would seem to bring into question God’s goodness and love for his creatures.

The tension between these alternatives—and efforts to avoid their negative theological consequences—surface in many of the proposed solutions to this problem.

In part 2, we start to look at some of the proposed solutions, beginning with the idea that a perfect creation was corrupted by a fall.

Notes

1. This poem was included in a collection of poems that was one of two works by Czeslaw Milosz mentioned in a review article by Michael Ignatieff, “The Art of Witness,” New York Review of Books (March 23, 1995). I thank Carol Regehr for bringing my attention to this work.
2. Moltmann refers to this aspect of God’s creative activity in history as “continuous creation.” Jürgen Moltmann, God in Creation (Minneapolis, MN: Fortress Press, 1993), 206–14.
3. I will not address here arguments concerning the degree to which animals experience pain. This issue is considered by Robert Wennberg in “Animal Suffering and the Problem of Evil,” Christian Scholar’s Review 21 (1991): 120–40. It is obvious to me that, for many animals at least, pain and suffering are a very real conscious experience.
4. C. S. Lewis, The Problem of Pain (New York: Macmillan Publishing, 1962), 129.
5. As stated by John Hick, in Evil and the God of Love, rev. ed. (New York: HarperCollins Publishers, 1977): “For every position that maintains the perfect goodness of God is bound either to let go the absolute divine power and freedom, or else to hold that evil exists ultimately within God’s good purpose” (pp. 149–50).

In 1774, the French chemist Antoine Lavoisier replicated the relevant experiments in more controlled ways to demonstrate that mass was conserved during combustion. He also renamed the part of the air that burned 'oxygène.' English scientists resisted the French scientist's new name, not least because the English Priestly had already published his discovery of the gas. 'Oxygen' nonetheless entered the common English vocabulary in part due to one of the first popular science books, The Botanic Garden (1791), which included a poem praising the gas using the preferred French name. By coincidence, this book also promoted some early ideas about biological evolution (specifically, it suggested that sexual reproduction might be important to evolution, which might help to explain the popularity of a book of poems about science). It was written by Erasmus Darwin, the grandfather of Charles Darwin, who first proposed the modern form of the theory of biological evolution in his 1859 book, On the Origin of Species.

150 years later, we are discovering that the lines connecting evolution and oxygen run deeper than the Darwin family tree. We now know, for instance, that for roughly half of the Earth's 4.6-billion-years of history, there was little to no oxygen in the atmosphere. Instead, oxygen entered the atmosphere in two major pulses, with one between 2.4 and 2.2 billion years ago, and another between 0.8 and 0.54 billion years ago. Recent evidence suggests that the first pulse may have actually been the largest event in a series of fits and starts beginning at around 2.7 billion years ago that finally produced a stable low oxygen atmosphere by around 1.8 billion years ago.

Remarkably, both episodes of atmospheric oxygenation happened just before explosions in biological diversity. We have spotty evidence of unicellular eukaryotes (cells with nuclei) before 2.4 billion years ago, but the first fossil evidence for large, diverse eukaryotic communities comes at 1.5 billion years ago. If you are a human, this is part of your history; humans are multicellular eukaryotes descended from one of these early unicellular pioneers. Multicellular animal life is an innovation that seems to have required more oxygen: animals don't appear in the fossil record until about 0.61 billion years ago, toward the end of the second pulse of oxygen.

It is, perhaps, not surprising that major evolutionary events in the eukaryotic family tree, including the origin and diversification of the animals, would be tied to or even driven by major changes in atmospheric oxygen abundance. Eukaryotes generally, and animals specifically, are oxygen lovers. As the subjects of Mayow and Priestly died to prove, we require oxygen for respiration. In general, the larger and more organizationally complex we are (for instance, a human versus a slime mold), the more oxygen we require.

But where did all the oxygen come from? Ultimately, it was produced by the bacterial equivalents of the plants in Joseph Priestley's experiment, a group of photosynthetic microbes called the cyanobacteria. These bacteria are the first and only organisms to have evolved the ability to produce oxygen by photosynthesis. In fact, plants are able to photosynthesize only because their cells harbor descendants of one of the early cyanobacteria. We call them chloroplasts and think of them as little cellular organs, but they are actually the great-great-great... granddaughters of a cyanobacterium that long ago gave up its independence in exchange for the stable environment inside a eukaryotic cell. In any case, photosynthesis is the only known geological process capable of producing oxygen at the rates required for the two pulses of atmospheric oxygenation. The first pulse was probably largely accomplished by cyanobacteria, while the second pulse was probably mostly associated with the cyanobacterial denizens of eukaryotic algae.

What is remarkable about all of this is the extent to which modern life and the atmosphere are products of each other's evolution. The tiniest of photosynthetic organisms played one of the most important roles in shaping the sky, and the sky helped to usher in the age of animals! As a Christian and a geobiologist, I do not believe that this relationship is anticipated or predicted by the Biblical creation accounts.

But then again, why should it have been? The original audience for these accounts would have found concepts like bacteria or even oxygen incomprehensible. The people for whom the Bible was originally addressed thought about origins primarily in terms of ongoing national conflicts and the current human condition. Faced with a variety of violent creation myths that reinforced national conflicts, Genesis said that the universe was created to be good, peaceful, and orderly by one god. It specifically listed things worshipped by other nations as creatures of that god, and in the climax of the creation account, Abraham was called by the same god to be a blessing to all the nations through Israel.

I am not claiming that the Bible cannot be read in a way that can shape us in real and meaningful ways today. In fact, for those who believe that the Bible is inspired, part of the meaning of inspiration has to be that the Bible is God's powerful word to both those with no concept of modern science (most of the world's population, both today and in the past) and to those deeply engaged in its practice. But, and this is a big but, we contemporary Americans read the Bible best when we are sensitive to the assumptions of the original audience, carefully observe how the Bible transformed those assumptions, and look for opportunities to do the same thing with our thinking.

I think that it is important for Christians to reflect on the view of origins that science has given us in light of the thinking evident in the Biblical creation accounts. We have to do this because science gives us a story that is inherently without philosophical or theological meaning; it is up to us to give it meaning by understanding it in relationship with our beliefs. For instance, some see the evolutionary history of life and the Earth and give that history meaning by elevating chance and necessity to the level of prime actors in their own modern creation account. This meaning is not inherent to the theory of evolution; it is supplied by an atheistic belief system external to the theory. I suggest that this view mistakes created things (chance and necessity) for the Creator.

Others have preferred to see the regularity of the universe as the action of an orderly God. This is an old approach to natural theology that was popular among many early scientists, and saw God as responsible for doing such things as maintaining the planets in consistent paths around the sun. Still others look for God in the unexplained. This is a newer approach that sees God as acting primarily in short bursts not explainable by the regular, orderly function of the universe. Looking for God in these ways is a little like trying to capture him in a bell jar, an approach that worked perfectly well with oxygen for Mayow, Priestley, and Lavoisier, but one that is unlikely to impress the Creator described in the Bible.

I prefer to see the same history in the light of a God who desires to share aspects of his nature with his creation, notably including his creativity. Just as he has made humans to be creators (with a little 'c'), he has given the rest of our world the gift of being instrumental in its own creation through the process of evolution. This surely must have been part of what God saw when he described his creation as good! It is my hope that the modern American church can learn to see the goodness of creation in things like the evolutionary history of life and the atmosphere, as well.

This post first appeared in October 2009

Some implications and conclusions of Theistic Evolution--continued

(4) Several leading TEs have advanced a strongly Christocentric theology of creation—stressing the idea (from the prologue of John’s gospel) that the Maker of heaven and earth is the crucified and resurrected second person of the Trinity. Especially when theodicy is the topic, they like to speak about “the crucified God,” or “the theology of the cross,” or “divine kenosis.”

On first glance, some readers might be a bit perplexed: isn’t this column supposed to be about evolution, not the crucifixion? What could those topics possibly have in common? The answer lies in theodicy, or the problem of evil and suffering in the world. As I stressed in my column about the YEC view, creationism is ultimately about theodicy—it’s not only about theodicy, to be sure, but the belief that animals must not have suffered and died before Adam and Eve committed the first sin is crucial to the “young” in Young Earth Creationism. To a significant degree, Theistic Evolution is also about theodicy. In one of the best books on science and religion that I could name, Catholic theologian John Haught explains the atheist’s view of theodicy (which he does not share) as follows:

“Evolution is incompatible with any and all religious interpretations of the cosmos, not just with Christian fundamentalism. The prevalence of chance variations, which today are called genetic ‘mutations,’ definitively refutes the idea of any ordering deity. The fact of struggle and waste in evolution decisively demonstrates that the cosmos is not cared for by a loving God. And the fact of natural selection is a clear signal of the loveless impersonality of the universe.” (Science and Religion: From Conflict to Conversation, p. 52)

Proponents of TE have responded to the issues raised in the latter two sentences in a variety of ways. I agree with Christopher Southgate’s analysis of the overall situation. Like several of the writers I mention this week, Southgate is a theologian with a doctorate in science; he’s also an accomplished poet. The text he wrote with many others, God, Humanity and the Cosmos: A Textbook in Science and Religion, is really much more than a textbook. I recommend it for anyone seeking a wide-ranging introduction to the principal issues.

Southgate and his collaborators see just two “possible theologies of divine action in respect of evolution,” considering that “the problems of theodicy are severe.” Option ONE: “to posit God merely as the passive, suffering companion of every creature, a view self-consistent but dubiously faithful to the Christian tradition.” Option TWO: “to mount a defence of teleological creation using a combination of [certain] theological resources,” namely these three—

• “we must adopt a very high doctrine of humanity and suppose that indeed humans are of very particular concern to God.” This is linked with the Incarnation.
• “we must take very seriously the cross as costly to God, as part of God’s hugely costly way of taking responsibility for the creative process.”
• “we must give some account of the redemption of the non-human creation …” This is linked with the Trinity. (p. 279 in first edition, 1999)

Given limited space, I’ll focus almost exclusively on the second idea, though we may want to discuss all of them below.

The Crucified God

View of the entrance to the main camp of Auschwitz (May 1945). The gate bears the motto, "Arbeit Macht Frei" (Work makes one free). United States Holocaust Memorial Museum (Source).

We start with something that arose in a context entirely unrelated to evolution, Jürgen Moltmann’s (read more here and here) notion of The Crucified God. The theological point and the emotional impact of Moltmann’s conception is aptly captured in this stark passage, written in response to Elie Wiesel’s dark story of a child who was publicly hanged at Auschwitz: “like the cross of Christ, even Auschwitz is in God himself. Even Auschwitz is taken up into the grief of the Father, the surrender of the Son and the power of the Spirit.” (p. 278) A recent sermon by Matt Bates, pastor of Centenary United Methodist Church in Richmond, fleshes this out for us in a very accessible way; please read the whole sermon before going any further.

Repeat: please read the sermon. It’s a vital part of what I’m trying to say.

Now that you see more clearly what the “Crucified God” is about, let’s see what John Polkinghorne says about it:

“This profound and difficult thought meets the problem of suffering at [the] level which its deep challenge demands. The insight of the Crucified God lies at the very heart of my own Christian belief, indeed of the possibility of such belief in the face of the way the world is. But this can only really be so if God is indeed truly present in that twisted figure on the tree of Calvary. Only an ontological Christology is adequate to the defence of God in the face of human suffering. God must really be there in that darkness.” (Belief in God in an Age of Science, p. 44)

Be sure to notice two things in this passage. First, Polkinghorne confesses that his own Christian faith depends on such a conception of God, but there are only two very brief references to evolution in the entire eloquent chapter from which I’ve quoted. There’s plenty of science there, but almost all of it is modern physics, not biology. (I’ll leave it as an exercise to “students” to get a copy of this excellent little book and fill in the blanks.) In other words, evolution doesn’t shape Polkinghorne’s theology nearly as much as his theology shapes his view of evolution.

The second thing to notice is that in the last three sentences Polkinghorne is doing something subtle, but extremely important—something that I don’t want anyone to miss. Contrary to some of the most influential voices in the science and religion “dialogue” (some examples would be Haught, Ian Barbour, and the late Arthur Peacocke), Polkinghorne affirms the full divinity and humanity of Christ, in a classical Chalcedonian sense. Read those sentences again a couple of times, and you should see what I’m driving at. As he says a bit later on, “Unless there really is a God who really was ‘in Christ reconciling the world to himself’ (2 Cor. 5:19), then the cross is no answer to the bitter problem of the suffering of the world.” (p. 45) In other words, one can only take this approach to theodicy unless one actually believes in the reality of the Incarnation; only an orthodox Christian can speak meaningfully of the “Crucified God.” In the final part of this column, when I’ll present Polkinghorne as a contemporary exemplar of a theologically “orthodox” TE, it’s partly this aspect of his thought that I will have in mind.

Lucas Cranach the Elder

Finally, I should note that the term “crucified God” is not actually modern. Although Moltmann wrote an influential book about it, the language comes from Martin Luther. Another physicist-theologian, George Murphy, writes in a highly Lutheran way about The Cosmos in the Light of the Cross, advancing the view that a “theology of the cross” in which God sets aside power to become a participant in the universe, even to the point of death, takes priority over a “theology of glory,” in which we seek God first in the power behind nature, not in the powerlessness of the cross. For a short version of Murphy’s ideas, go here.

Once again, we need to stop mid-stream. These ideas are deep and perhaps too new for many readers, and it’s best to reflect on them before we go further and even deeper.

In his essay for that series, Jeff Schloss addressed the question of whether animal death is a natural evil, but also noted that such theological considerations aside, death does not actually “drive evolution” in the way most people imagine—especially when they think of violence in the natural world. This more complicated sense of death’s role is partially the result of modern evolutionary science recognizing the importance of cooperation and inter-relation among species, rather than just direct competition. But just as important is the knowledge that evolution is significantly shaped not by the deaths of individual creatures, but by extinction, the loss of species over time. In this post, we explore some aspects of how extinction acts as both a destructive and creative force in evolutionary history, including the evolutionary history of mammals.

Sporadic extinction

Extinction is actually a common feature of life on earth when viewed over long (e.g. geological) timescales. By some estimates, over 99% of the species that have ever lived have gone extinct. One factor that promotes extinction is the fact that evolution does not produce species that are optimally adapted to their environment, but only better adapted than their local competitors. Invasive species testify to this fact: local (endemic) species are not always the best-adapted species for their own environment. Examples abound where species from other environments are actually better-suited to out-compete endemic species. Here in my own province, the invasive Himilayan blackberry (Rubis discolor) easily outcompetes many endemic species. If endemic species were optimally adapted to their environment, this would not be possible, as they would outcompete all exotic species. Instead, exotic species, by chance, might be better adapted to an ecosystem they did not evolve in. These exotics may be capable of eliminating endemic species altogether.

Such an extinction event (of a single species, or perhaps a handful of species) alters the environment of other remaining species in an ecosystem. This, in turn, may influence the ability of some of these remaining species to reproduce compared to other species. For example, the extinction of a competitor might allow a species to increase in population size. Conversely, the extinction of a species that provides a benefit (such as a pollinator) may reduce a species in number. As the ecosystem landscape shifts due to loss of species, new biological opportunities, or niches, might arise. These new niches are then available to support new species to fill them.

Extinction, en masse

One way to appreciate how extinction opens up new niches is to examine mass extinction events – geologically brief periods where large numbers of species go extinct at the same time. Over the history of life on our planet there have been several mass extinction events. The largest such event, at the end of the Permian (~250 million years ago) appears to have been caused, at least in part, by intense volcanic activity over several hundred thousand years. This activity likely shifted CO2 levels and eventually led to a “runaway” greenhouse effect that dramatically raised global temperatures and led to anoxic (i.e. oxygen-depleted) oceans, though the exact contributions of these varied factors remains an area of scientific debate. What appears certain is that during this period environmental changes were too rapid for most species to keep evolutionary pace with, and as a result over 90% of the world’s species alive at that time went extinct. Obviously this represents destruction of biodiversity on an unimaginable scale, and the destructive effects of this event are with us to this day.

Speciation, en masse

This destruction, however, is not the whole story. Following on from the Permian mass extinction, we observe a steady increase in new species. These are species previously unknown in the fossil record. In fact, this pattern (a “radiation” of new species following an extinction event) is the rule, not an exception – we see the same effect after every mass extinction in the fossil record. Extinction is a driving force for novelty.

Perhaps the most famous mass extinction event is the Cretaceous – Paleogene (KPg) extinction, and it too follows this standard pattern. This mass extinction took place 65 million years ago when an asteroid ~10 kilometers in diameter struck the Yucatan peninsula. (Note: this event was formerly known as the Cretaceous – Tertiary (K-T) extinction, but that terminology is in decline within the scientific community). This extinction event is famous since it is the one that eliminated the dinosaurs (with the exception of the ancestors of modern birds). As with the Permian extinction, the elimination of so many species shifted the evolutionary landscape for the remaining species, and the result was a burst of speciation that appears rapid when viewed in geological time. Significantly for our own species, following the KPg extinction event is a burst in mammalian speciation, as small mammals that survived the event diverge and fill niches left empty by the dinosaurs. Without this event, the trajectory of mammalian evolution would certainly look very different.

Clearing the deck, and re-filling the niches

One interesting fact to note is that biological features that make a species resistant to usual, sporadic extinction are not necessarily the same features that will be useful during a mass extinction event. While species are continually under selection at the local level, there is no mechanism for (pre) selection to survive a mass extinction. As such, only species that happen to have the right combination of traits will survive, and often spread widely after a mass extinction. These so-called “disaster species” are usually generalists, and will later be displaced by more specialized species as they arise. As such, where sporadic extinction allows for more gradual turnover in species, mass extinction events are major “resets” of evolution that can radically shift what constitutes “well adapted” in a geological eyeblink. For mammals at the KPg boundary, small body size and an omnivorous diet (including the ability to scavenge detritus) were the “winning” combination of traits that allowed them to survive where larger, more specialized animals (think Tyrannosaurus rex) could not. From this rather humble station, mammals would come to dominate the world’s ecosystems over the coming eons – including a lineage that would someday lead to our own species. Far from only a destructive force, extinction is a powerful mechanism to allow evolutionary innovation, and one that was of significant importance to us.

For further reading:

Meredith, R.W. et al (2011). Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification. Science 334; 521-524.

Fastovsky, D.E. (2005). The Extinction of the Dinosaurs in North America. GSA Today (15); 1052-5173.

Benton, M.J. and Twitchett, R.J. (2003). How to kill (almost) all life: the end-Permian extinction event. TRENDS in Ecology and Evolution (18); 358-365.

In his thoughtful, gracious, and fair-minded essay, Professor John Laing focuses on what many believers and non-believers alike recognize as perhaps the most significant challenge to faith in an all-good, -knowing, and -powerful Creator God: the problem of natural evil, and in particular, the acrid sting of death. While the issue is an ancient one, Laing—and many other contemporary commentators who range from sympathetic to antagonistic toward biblical theism—view evolution as exacerbating the problem to the point that one must choose between the good God of scripture and the truth of evolution. Although the general issue of “evolution and evil” is manifold and beyond the scope of a single essay, John (if I may), zeros in on two ways in which evolution seems to aggravate the particular theological challenge of death. First, in the view of scripture, death is “an invader, disturber of the peace, and a force of evil”; therefore its primordial (as opposed to post hoc) place in the world described by evolution seems incommensurate with an originally good creation. Second, it is not just the primordial place but also the functional role of death that appears to constitute a problem: evolution by natural selection is widely viewed as being driven by death, and more generally by fierce competition, in a way that seems hard to reconcile as a mode of creation that a wise and good God would employ.

I agree with John that these are serious issues. Little is accomplished either by glibly dismissing their prima facie legitimacy or by responding with theological concessions that relinquish core claims of the gospel. In his words: “a fundamental aspect of the good news in the Gospel is the defeat of death – this negative, destroying force – in the resurrection of Christ.” Amen! In what follows I hope to engage sequentially both issues he raises in a way that takes them seriously while avoiding compromised hope.

The Primordial Place of Death

I need to start by acknowledging that these are not just arid intellectual issues but also profoundly personal ones. I have just returned from keeping vigil at the deathbed of my father, and the sting of death is especially acute. The fact that every son sees his father die (or worse, that a parent may see a child die) –that in some sense, universal human death is part of the current “natural order” we all experience – offers no solace for the tearful remonstration of what an awful violation it is. It is a violation not just of our deepest desires, but also of what we construe to be God’s purposes, for the God of scripture is not a mere field of energy or prime mover or initial organizing principle, but is wondrously and clearly portrayed as “the living God” whose explicit purpose is that we “have life, and have it in abundance.” Indeed, in the most extensive section of his essay John cites over 40 scripture passages that affirm life as God’s intention for humanity and death as an intrusive, subverting consequence of sin. I could not be in stronger concord.

Although all Christians have traditionally affirmed resurrection (for both the redeemed and unredeemed), there have been longstanding debates about whether the life that is redemptively restored in Christ and the death that is brought about by sin is “spiritual” (involving the vitality or disruption of communion with God) or “physical” (involving the viability or dissolution of biotic function). Of course these are not mutually exclusive, and perhaps they are not even ultimately distinguishable. But however one understands death to be an incursion upon human telos, it does not answer or even clearly bear upon the evolution-related question of whether other living beings beyond and before humans were created to be immortal. “Violence” in western thought has often been understood as a disruption of natural ends: but do we assume that all creatures share the same “natural end”? For instance, is the nature or telos of worms immortality? Is death a violation of all creaturely natures that was therefore absent from earth prior to initial human intimacy with and subsequent estrangement from God? Significantly, not a single one of the scriptures John cites explicitly refers or even vaguely alludes to the general place of death in the natural order: virtually every one emphatically focuses on death as a consequence of sin for uniquely human moral agents, and—correspondingly—on eternal life as God’s special purpose for supernaturally redeemed humanity.¹ Indeed, I am at a loss to find in the entire Bible a scripture that clearly teaches death across the entire biotic realm postdates and is a consequence of human sin.² Neither is this point affirmed or even mentioned in the most prominent historic creeds of Christian orthodoxy.

Davis Young & Ralph Stearley’s The Bible, Rocks, and Time (2008, Inter Varsity Press) provides an expansive historical survey.

Yet none of this means that there is not an issue here. The view that death in all creation is not endemic but followed from a recent human fall was—with the exception of Aquinas and a few others—the dominant perspective of the church fathers, key reformers, and most Christians through the 17th Century (see sidebar). However, by the same token, so was geocentrism and so was the doctrine of human exceptionalism. Virtually all Christians have relinquished geocentrism in light of utterly compelling scientific evidence along with the recognition—in part motivated but not dictated by findings of science—that no clear and persistent scriptural teaching or core theological doctrine is compromised by this view.³ On the other hand, the claim of exceptionalism continues to be affirmed by many Christians – including myself – in light of important theological commitments and ongoing scientific discussion.

So is the primordial nature of death more like geocentrism, or more like human exceptionalism? Scientifically, there is little question that it is more akin to geocentrism. Over the last three centuries the empirical evidence for and the explanatory fruitfulness of the view that earth’s biota and death’s existence vastly predate the origin of humans have increased explosively—arguably to an extent beyond any other finding of science. Amongst tens of thousands of natural scientists, there is virtually unanimous agreement on this point.⁴ I should be clear that this is not an ad hominem argument: to say the evidential and demographic situation is similar to geocentrism is not in itself to claim that the “recent death” position is wrong. Nor is it an ad populum argument: neither John nor I have space to assess scientific evidence for this claim, and the fact that the overwhelming majority of Christian and non-Christian scientists have for several centuries shared the “primordial death” view does not make it true. But it does mean that if that view is to be rejected for the kinds of theological reasons that John raises, it seems there should be unambiguous scriptural warrant for that rejection. Failing that, then there needs to be a compelling theological rationale and a decided lack of plausible alternatives posited by fellow orthodox Christians.

I have already agreed with John that the Bible persistently presents death as an enemy of God’s purposes for humanity. But I have suggested (perhaps altogether wrongly!) that he does not provide clear scriptural evidence for death being a comparable enemy to and intrusion upon God’s purposes for all creatures. A faithful reading of the Bible does not seem to be incompatible with seeing death as part of the magisterial history of life as depicted by evolution and other natural sciences.

With these considerations of the biblical text as background, tomorrow I’ll describe why I do not believe that John or those with kindred perspectives provide a compelling theological mandate for this view of death, either.

Notes

1. There are a few scriptures not cited by John, which deal with the absence of carnivory (though not death itself) in images of idyllic creation. Genesis 1:30 portrays a world in which every creature with the breath of life had plants for food. And the images of the new earth in Isaiah 11 and 65 paint a renewal of this order in redeemed creation. Interestingly however, they do not portray an elimination of death for animals, or even for humanity. According to Is 65, the passage which presents the beautiful image of the lion and lamb: “ ‘Never again will there be in it an infant who lives but a few days, or an old man who does not live out his years; the one who dies at a hundred will be thought a mere child; the one who fails to reach a hundred will be considered accursed. They will build houses and dwell in them; they will plant vineyards and eat their fruit. No longer will they build houses and others live in them, or plant and others eat. For as the days of a tree, so will be the days of my people… The wolf and the lamb will feed together, and the lion will eat straw like the ox, and dust will be the serpent’s food. They will neither harm nor destroy on all my holy mountain,’ says the LORD.” This and other eschatological passages in scripture have a history of widely varying interpretations, but taken most literally, it describes a world with prolonged life in which there is still death (he who dies a centenarian will be like a child, and most people will live as long as trees), and in which death, however, is not inflicted by one creature upon another.
2. Although commentators differ over whether the Pauline description of death in Romans 5 refers to spiritual and/or physical death, the passage clearly focuses on humans. It identifies humanity as the subject of infection, instigated and promulgated by initial and ongoing human sin: “in this way death came to all people, because all sinned” (Romans 5:12).
3. Not all Christians have relinquished geocentrism. For example, a well-known public advocate is Dr. Gerardus Bouw, who has a Ph.D. in astronomy and until recently taught at Baldwin-Wallace Christian College. He founded the Association for Biblical Astronomy and authored an apologetic monograph for a stationary earth: Geocentricity (1992, Association for Biblical Astronomy). A crucial commitment of Dr. Bouw is that he “assumes that whenever the two [the Bible and astronomy] are at variance, it is always astronomy—that is, our ‘reading’ of the ‘Book of Nature,’ not our reading of the Holy Bible—that is wrong.” (http://www.geocentricity.com/ accessed 8/1/2012). Note that this epistemic framework asserts not just that the Bible is a more perfect witness to theological truth than nature, but that human understanding – “our reading” – of the Bible is somehow more immune to error than our reading of nature. The Bible itself does not clearly teach that humans, in our frailty, are less vulnerable to misunderstanding special than general revelation. The difference between faith in the scriptures and faith in our understanding of the scriptures is important though not always recognized, and underlies much tension in faith-science issues.
4. To his credit, even the most prominent critic of primordial death cited by John acknowledges this evidential and demographic claim. In a moving autobiographical essay, Kurt Wise acknowledges “I accepted the Word of God and rejected all that would ever counter it, including evolution. With that, in great sorrow, I tossed into the fire all my dreams and hopes in science.” Although he believes in the viability of searching for a scientific rationale, he affirms “I am a young-age creationist because that is my understanding of the Scripture. As I shared with my professors years ago when I was in college, if all the evidence in the universe turned against creationism, I would be the first to admit it, but I would still be a creationist because that is what the Word of God seems to indicate.” [Kurt Wise, in John F. Ashton (ed)., In Just Six Days. 2001. Master Books. Page 355.]

When scientists investigate God’s creation, they find that humans appear very late in the history of life. The fossil record shows that many creatures died long before humans appeared. In fact, many entire species went extinct millions of years ago (the dinosaurs are the most famous example), long before humans lived or sinned.

See “What does the Fossil Record Show?” and “How are the ages of the Earth and universe calculated?”

Yet God’s revelation in scripture paints a different picture. Several key scripture passages teach that death is a consequence of sin, including Genesis 2:16-17, Genesis 3:19,22, Romans 5:12-21, and 1 Corinthians 15. How should we think about these passages in light of the scientific evidence? Could animals have died before human sin? Does “death” in these passages refer to physical death, or spiritual death, or sometimes one and sometimes the other? To ponder these questions, we need to consider God’s revelation in scripture and God’s revelation in nature. The scientific evidence is discussed in other Questions, as are the topics of the fall and sin (see sidebars). Here we consider what scripture says about death and how the two revelations might be reconciled.

See “How does original sin fit with evolutionary history?”

Animal Death

The Bible passages that teach about sin and death are clearly referring to the death of humans. Do these passages also refer to animals? Thomas Aquinas (1225-1274) didn’t think so. He believed that God’s original creation included animals that killed each other, writing that “the nature of animals was not changed by man’s sin.”¹ Pastor Daniel Harrell makes a logical argument for animal death, writing that “there had to be death in the Garden, otherwise Adam would have been overrun by bugs and bacteria long before he took that forbidden bite of fruit.”² Animal death is also necessary to maintain population levels in a balanced ecosystem (see below for more). Some Bible passages portray predatory animals as part of God’s original plan for creation (Job 38:39-41, 39:29-30, Psalm 104:21,29). Other passages speak of the “lion laying down with the lamb” instead of killing the lamb (Isaiah 11:6-7, Isaiah 65:25), but these verses refer to the future kingdom of God, not the original creation. While animal death and suffering raises other theological questions (see Sidebar), it does not contradict Biblical teaching about death as a consequence of sin.

See “How does the evil and suffering in the world align with the idea of a loving God?”

Human death: physical or spiritual?

One traditional interpretation of Genesis 2-3 is that sin results in physical death. Humans would have been immortal without sin. In Genesis 2:17, God warns Adam and Eve, “But of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat you shall die.” In Genesis 3:19, God carries out this punishment, cursing Adam with labor and death, “By the sweat of your brow you will eat your food until you return to the ground, since from it you were taken; for dust you are and to dust you will return.” In 1 Corinthians 15 Paul contrasts and compares Christ and Adam, highlighting Adam’s fall as the cause of physical death for the whole human race.

John Calvin, however, suggested that Adam’s sin caused the abrupt painful death that we experience today, a wrenching apart of the physical and spiritual aspects of humans. Calvin seems to have thought that if Adam had not sinned, a more gentle kind of physical death or “passing” from life into life would have occurred: “Truly the first man would have passed to a better life, had he remained upright; but there would have been no separation of the soul from the body, no corruption, no kind of destruction, and, in short, no violent change.”³ In this view, humans were created mortal, but intended for long healthy lives and graceful deaths, such as described in Isaiah 65:20-25. The Old Testament speaks of death at the end of a long life in purely positive terms, such as 1 Chronicles 29:28 where King David “died at a god old age, having enjoyed long life, wealth, and honor.”

Another interpretation of these passages is that the consequence of sin is spiritual death, not physical death. If Adam had not sinned, humans would still have died like we do today, but without “the sense of loss, uncertainty about an afterlife, … and regret for unfinished work” that comes with spiritual death.⁴ Agemir de Carvalho Dias, Presbyterian pastor and teacher of the Evangelical College of Parana, Brazil, writes that “the death that entered the world with Adam is understood as something that takes man apart from God, a spiritual death, in the sense that the access to God is now closed and can be restored only through faith.”⁵ Of course some sins still bring about physical death, such as Abel’s death at Cain’s hand, and the death of King David’s infant son after the king’s adultery (2 Samuel 12:13-14).

The text of Genesis 2-3 can support an interpretation of the curse as spiritual death. In the curse of Genesis 3:19, God tells Adam “for dust you are and to dust you will return,” implying that Adam was created mortal from the dust. God warned Adam and Eve that they would die in the day they ate from the tree, and yet Adam lived to the age of 930 (Genesis 5:5). What did happen on the day they ate from the tree? Adam and Eve felt shame and were expelled from the Garden, breaking their fellowship with God – spiritual death.

Weren’t Adam and Eve immortal, created as perfect ideal human beings? This is a popular idea, but not clear in the Biblical text. The first humans are described as “very good” and pleasing to God (Genesis 1:30-31), but not as perfect or with superhuman abilities. Also, consider the Tree of Life. God planted this tree in the garden before the fall (Genesis 2:9) and it gives immortality to the one who eats it (Genesis 3:22). If God created humans as immortal, what was the purpose of the Tree of Life? It would only be needed if humans were mortal to begin with.⁶

Pastor Stephen Rodeheaver reflects on the two trees of Genesis 2-3 and the implications for us today (blog series)

In the New Testament, Paul writes much on the relationship between sin and death. Sometimes Paul was clearly referring to spiritual death (Romans 6:1-14, 7:11), and other times clearly to physical death (1 Corinthians 15:35-42). Yet even in 1 Corinthians 15, Paul writes of the eternal life in Christ as something much more than the mere earthly life we experience now, implying that “death” also refers to much more than mere physical death. This is more explicit in Romans 5:12-21 where death is contrasted with the gifts of grace, justification, and righteousness, i.e. the new spiritual life provided by Jesus’ victory.

See “Were Adam and Eve Historical Figures?” which discusses the issue of death and the identity of Adam and Eve

For more, be sure to read the full FAQ "Did death occur before the Fall?" in our Questions section!

Notes

1. Saint Thomas Aquinas. Summa Theologica, Part 1, Question 93, Article 1 (web article)
2. Daniel Harrell. “Death’s Resurrection”, BioLogos Forum, December 18, 2009 (blog)
3. John Calvin. Commentaries on the First Book of Moses, called Genesis, trans. by John King. ch3 v19 (p. 97).
4. George Murphy “Human Evolution in Theological Context” BioLogos scholarly essay which includes a discussion of human and animal death (PDF), p. 6
5. Quoted by Marcio Antonio Campos in “Did peace and love reign in the world before the original sin?” BioLogos Forum, March 7, 2011 (blog)
6. See Deborah and Loren Haarsma, “Three interpretations of the Tree of Life”, supplemental material to Origins: Christian Perspectives on Creation, Evolution, and Intelligent Design (Grand Rapids, MI: Faith Alive Christian Resources) 2011 (PDF)
]]> Wed, 08 Aug 12 05:00:49 -0700 http://biologos.org/blog/series/asa-gray-and-charles-darwin-discuss-evolution-and-design?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/series/asa-gray-and-charles-darwin-discuss-evolution-and-design?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication Many Christians believe that they face a painful choice-- either life was designed by God or it is an evolutionary product of natural selection. Charles Darwin himself believed in this dichotomy, and people ever since have felt the need to "choose sides". However, looking back at history, we find that one of Darwin's chief scientific colleagues, Asa Gray, did not share this perspective. In this three-part essay, part 1 charts the relationship of Asa Gray and Charles Darwin. Part 2 describes Darwin's struggle with the problem of natural evil and design in nature, and part 3 explores how Asa Gray was able to embrace evolution without rejecting the idea of design.

Evangelical Christians in the nineteenth century were generally not biblical literalists, nor did they believe in a young earth. In other words, the religious opposition to Darwin did not arise from perceived problems between Darwin's theory and a literal reading of Genesis. Rather, following the publication of Origin of Species, it centered on what seemed to be the randomness of natural selection, the appearance of new organisms by chance, and therefore the exclusion of divine purpose or design in Nature.⁷ It was the teleological question that Gray addressed in his review and about which he and Darwin corresponded over many years.

Darwin responds to Gray's review of Origin of Species

Darwin's response to Gray's review, a copy of which he received prior to its publication, was very positive. Darwin even hoped that it could become a preface in a second American edition of On the Origin of Species on which Gray worked. In a letter later in the year to James Dwight Dana, Darwin said: "No one person understands my views & has defended them so well as A. Gray;--though he does not by any means go all the way with me."⁸ The "all the way" included teleology, and Darwin wrote this to Gray concerning his attempt to retain design:

It has always seemed to me that for an Omnipotent & Omniscient Creator to foresee is the same as to preordain; but then when I come to think over this I get into an uncomfortable puzzle something analogous with "necessity & Free-will" or the "Origin of evil," or other subject quite beyond the scope of the human intellect.⁹

Three months later he picked up the discussion with these comments:

With respect to the theological view of the question; this is always painful to me.--I am bewildered.--I had no intention to write atheistically. But I own that I cannot see, as plainly as others do, & as I should wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice. Not believing this, I see no necessity in the belief that the eye was expressly designed. On the other hand I cannot anyhow be contented to view this wonderful universe & especially the nature of man, & to conclude that everything is the result of brute force. I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we may call chance. Not that this notion at all satisfies me .... But the more I think the more bewildered I become; as indeed I have probably shown by this letter.¹⁰


"I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice." - Charles Darwin

Darwin invokes William Paley

Shortly after this letter to Gray, Darwin wrote Charles Lyell on the same subject and said:

I have said that natural selection is to the structure of organised beings, what the human architect is to a building. The very existence of the human architect shows the existence of more general laws; but no one in giving credit for a building to the human architect, thinks it necessary to refer to the laws by which man has appeared. No astronomer in showing how movements of Planets are due to gravity, thinks it necessary to say that the law of gravity was designed that the planets should pursue the courses which they pursue.--I cannot believe that there is a bit more interference by the Creator in the construction of each species, than in the course of the planets.--It is only owing to Paley & Co, as I believe, that this more special interference is thought necessary with living bodies.¹¹

In mentioning "Paley & Co," Darwin was referring to William Paley and other natural theologians, who had argued that nature--through the organization and adaptations of living organisms--demonstrated the existence of an intelligent creator. Darwin had studied Paley while in university, and Gray had also been influenced by the work of Paley, whose eighteenth-century opus Natural Theology was an important component of nineteenth-century American philosophy and was still used as a text at Harvard when Gray began teaching there in 1842.


William Paley

Paley's Argument from Design ultimately boiled down to this:

Premise 1: God's will is for us to be happy in this life and the next.

Premise 2: We can discover God's will either by consulting Scripture or by consulting "the light of nature." Both ways will lead to the same conclusion.

Premise 3: The will of God with regard to any action can be found by inquiring into its "tendency to promote or diminish the general happiness."

Conclusion 1: God creates to promote the general happiness of all creatures.

Conclusion 2: Organisms are perfectly adapted to their environment by the Creator.

The corollary of this last conclusion was that perfect design, from the structure and functioning of an organ to the structure of the universe, is evidence for God.

Confronting the reality of suffering and death in nature

For Paley, Nature provided the evidence for the existence of God, but Darwin had difficulty with this argument. His difficulty centered on what might best be referred to as issues surrounding theodicy, i.e., are natural selection and its results consistent with design by a benevolent God or do they imply that, if designed, God is capable of malevolent intent. In a July 3, 1860, letter to Gray, Darwin explicitly raises the issue. He writes:

One word more on "designed laws" & "undesigned results." I see a bird which I want for food, take my gun & kill it, I do this designedly.--An innocent & good man stands under tree & is killed by flash of lightning. Do you believe (& I really should like to hear) that God designedly killed this man? Many or most person do believe this; I can't & don't.--If you believe so, do you believe that when a swallow snaps up a gnat that God designed that that particular swallow should snap up that particular gnat at that particular instant? I believe that the man & the gnat are in same predicament.--If the death of neither man or gnat are designed, I see no good reason to believe that their first birth or production should be necessarily designed. Yet, as I said before, I cannot persuade myself that electricity acts, that the tree grows, that man aspires to loftiest conceptions all from blind, brute force.¹²

What Darwin wanted was Design without suffering, teleology without agony, purpose without pain.

Darwin and Gray discuss Design

This issue becomes the focus of discussion following the third article of a series that Gray published in The Atlantic Monthly in July, August, and October of 1860. When these articles were reprinted as a chapter in Gray's Darwiniana, the chapter was titled "Natural Selection not Inconsistent with Natural Theology." The passage that focused the discussion for Darwin was this: "We should advise Mr. Darwin to assume, in the philosophy of his hypothesis, that variation has been led along certain beneficial lines."¹³

After stating that the article was "admirable," Darwin responded to Gray in these words:

But I grieve to say that I cannot honestly go as far as you do about Design .... [Y]ou lead me to infer that you believe "that variation has been led along certain beneficial lines."--I cannot believe this; & I think you would have to believe, that the tail of the fan-tail was led to vary in the number & direction of its feathers in order to gratify the caprice of a few men.¹⁴

In September, Darwin responded to a question from Gray and informed him of his correspondence with Lyell on the subject of Design. In a lengthy passage, he wrote:

Your question of what would convince me of Design is a poser. If I saw an angel come down to teach us good, & I was convinced, from others seeing him, that I was not mad, I should believe in design. If I could be convinced thoroughly that life & mind was in an unknown way a function of other imponderable forces, I should be convinced.... I have lately been corresponding with Lyell, who, I think, adopts your idea of the stream of variation having been led or designed. I have asked him (& he says he will hereafter reflect & answer me) whether he believes that the shape of my nose was designed. If he does, I have nothing more to say. If not, seeing what Fanciers have done by selecting individual differences in the nasal bones of Pigeons, I must think that it is illogical to suppose that the variations, which Nat. Selection preserves for the good of any being, have been designed. But I know that I am in the same sort of muddle (as I have said before) as all the world seems to be in with respect to free will, yet with every supposed to have been foreseen or preordained.¹⁵

Finally, in December, Darwin sent up the white flag, conceding that "if anything is designed, certainly Man must be; one's 'inner consciousness' (though a false guide) tells one so; yet I cannot admit that man's rudimentary mammae ... & pug-nose were designed .... I am in thick mud;--the orthodox would say in fetid abominable mud."¹⁶ From this point on, the topic is not as central in their correspondence.

Following the publication of Darwin's book on orchids, however, he asked Gray to look at the last chapter, since Darwin believed that it bore on the design question. Gray's response was found in both his review of the book and in a letter to Darwin. In his review, he praised Darwin for having "brought back teleological considerations into botany." He concluded:

We faithfully believe that both natural science and natural theology will richly gain, and equally gain, whether we view each varied form as original, or whether we come to conclude, with Mr. Darwin, that they are derived:--the grand and most important inference of design in nature being drawn from the same data, subject to similar difficulties, and enforced by nearly the same considerations, in the one case as in the other.¹⁷

Gray may have believed that Darwin "brought back teleological considerations into botany," and Darwin may have swung that way in his book on orchids, but by 1867 Darwin had definitely swung back to the other side. In his concluding remarks for The Variation of Animals and Plants Under Domestication, he wrote:

However much we may wish it, we can hardly follow Professor Asa Gray in his belief that "variation has been led along certain beneficial lines," like a stream "along definite and useful lines of irrigation." If we assume that each particular variation was from the beginning of all time preordained, then that plasticity of organisation, which leads to many injurious deviations of structure, as well as the redundant power of reproduction which inevitably leads to a struggle for existence, and, as a consequence, to the natural selection or survival of the fittest, must appear to us superfluous laws of nature. On the other hand, an omnipotent and omniscient Creator ordains everything and foresees everything. Thus we are brought face to face with a difficulty as insoluble as is that of free will and predestination.¹⁸

In Part 3, the final post in this series, Dr. Miles will explore how Asa Gray was able to embrace evolution without rejecting the idea of design in nature.

Notes

7. Following the publication of Descent of Man, a second problem arose for evangelicals, centered on how humans could be moral beings, created in the Image of God, if they were continuous with the animal kingdom. I will not be addressing that issue in this paper.
8. Charles Darwin, The Correspondence of Charles Darwin 8, 1860 (Cambridge: Cambridge University Press, 1993), 303.
9. Ibid., 106.
10. Ibid., 224.
11. Ibid., 258.
12. Ibid., 275.
13. Asa Gray, "Natural Selection not Inconsistent with Natural Theology" in Darwiniana (Cambridge, MA: The Belknap Press of Harvard University, 1963), 121-2.
14. Darwin, The Correspondence of Charles Darwin 8, 496.
15. Charles Darwin, The Correspondence of Charles Darwin 9, 1861 (Cambridge: Cambridge University Press, 1994), 267-8.
16. Darwin, The Correspondence of Charles Darwin 9, 369.
17. Cited in Darwin, The Correspondence of Charles Darwin 9, note 11, 430.
18. Charles Darwin, The Variation of Animals and Plants Under Domestication (New York: D. Appleton and Company, 1896), 428.

]]> Sat, 04 Aug 12 07:21:11 -0700 Sara Joan Miles http://biologos.org/questions/what-evidence-do-we-have-for-evolution-besides-fossils-and-genes?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/questions/what-evidence-do-we-have-for-evolution-besides-fossils-and-genes?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication Scientists have found multiple lines of evidence for evolution, not just one or two. These types of evidence are independent of each other, coming from sources as different as ancient fossils and modern genetics labs. Evidence also comes from comparing the anatomy of creatures living today. All creatures with four limbs (whether mammals, birds, or reptiles) have the same bone structure in each limb, pointing to their descent from a common ancestor. More evidence comes from biogeography. Isolated islands are missing common species found on the mainland, but are filled with many unique species that can be related by a common ancestor. Finally, evidence comes from embryonic development. As an embryo of a mammal grows, its heart develops through stages similar to fish, amphibians, and reptiles. God’s creation declares the history of life in many different ways. All these ways are pointing to a consistent picture of God creating through evolution. Coming soon.]]> Fri, 13 Jul 12 13:25:46 -0700 http://biologos.org/blog/the-fossil-record?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/the-fossil-record?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication There are two opposite errors which need to be countered about the fossil record: 1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and 2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within all or most lineages. The Fossil Record: Is there enough evidence ?

There are two opposite errors which need to be countered about the fossil record: 1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and 2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within all or most lineages.

What then is the quality of the fossil record? It can be confidently stated that only a very small fraction of the species that once lived on Earth have been preserved in the rock record and subsequently discovered and described by science.

A more expanded discussion of this topic can be found in Miller, K.B., 2003, “Common descent, transitional forms, and the fossil record,” IN, K.B. Miller (ed.), Perspectives on an Evolving Crreation, Wm. B. Eerdmans, Grand Rapids.

There is an entire field of scientific research referred to as "taphonomy" -- literally, "the study of death." Taphonomic research includes investigating those processes active from the time of death of an organism until its final burial by sediment. These processes include decomposition, scavenging, mechanical destruction, transportation, and chemical dissolution and alteration. The ways in which the remains of organisms are subsequently mechanically and chemically altered after burial are also examined -- including the various processes of fossilization. Burial and "fossilization" of an organism's remains in no way guarantees its ultimate preservation as a fossil. Processes such as dissolution and recrystallization can remove all record of fossils from the rock. What we collect as fossils are thus the "lucky" organisms that have avoided the wide spectrum of destructive pre- and post-depositional processes arrayed against them.

Soft-bodied organisms, and organisms with non-mineralized skeletons have very little chance of preservation under most environmental conditions. Until the Cambrian nearly all organisms were soft-bodied, and even today the majority of species in marine communities are soft-bodied. The discovery of new soft-bodied fossil localities is always met with great enthusiasm. These localities typically turn up new species with unusual morphologies, and new higher taxa can be erected on the basis of a few specimens! Such localities are also erratically and widely spaced geographically and in geologic time.

Even those organisms with preservable hard parts are unlikely to be preserved under "normal" conditions. Studies of the fate of clam shells in shallow coastal waters reveal that shells are rapidly destroyed by scavenging, boring, chemical dissolution and breakage. Occasional burial during major storm events is one process that favors the incorporation of shells into the sedimentary record, and their ultimate preservation as fossils. Getting terrestrial vertebrate material into the fossil record is even more difficult. The terrestrial environment is a very destructive one: with decomposition and scavenging together with physical and chemical destruction by weathering.

The potential for fossil preservation varies dramatically from environment to environment. Preservation is enhanced under conditions that limit destructive physical and biological processes. Thus marine and fresh water environments with low oxygen levels, high salinities, or relatively high rates of sediment deposition favor preservation. Similarly, in some environments biochemical conditions can favor the early mineralization of skeletons and even soft tissues by a variety of compounds (eg. carbonate, silica, pyrite, and phosphate). The likelihood of preservation is thus highly variable. As a result, the fossil record is biased toward sampling the biota of certain types of environments, and against sampling the biota of others.

In addition to these preservational biases, the erosion, deformation and metamorphism of originally fossiliferous sedimentary rock have eliminated significant portions of the fossil record over geologic time. Furthermore, much of the fossil-bearing sedimentary record is hidden in the subsurface, or located in poorly accessible or little studied geographic areas. For these reasons, of those once-living species actually preserved in the fossil record, only a small portion have been discovered and described by science. However, there is also the promise of continued new and important discovery.

The forces arrayed against fossil preservation also guarantee that the earliest fossils known for a given animal group will always date to some time after that group first evolved. The fossil record always provides only minimum ages for the first appearance of organisms.

Because of the biases of the fossil record, the most abundant and geographically widespread species of hardpart-bearing organisms would tend to be best represented. Also, short-lived species that belonged to rapidly evolving lines of descent are less likely to be preserved than long-lived stable species. Because evolutionary change is probably most rapid within small isolated populations, a detailed species-by-species record of such evolutionary transitions is unlikely to be preserved. Furthermore, capturing such evolutionary events in the fossil record requires the fortuitous sampling of the particular geographic locality where the changes occurred.

Using the model of a branching tree of life, the expectation is for the preservation of isolated branches on an originally very bushy evolutionary tree. A few of these branches (lines of descent) would be fairly complete, while most are reconstructed with only very fragmentary evidence. As a result, the large-scale patterns of evolutionary history can generally be better discerned than the population-by-population or species-by-species transitions. Evolutionary trends over longer periods of time and across greater anatomical transitions can be followed by reconstructing the sequences in which anatomical features were acquired within an evolving branch of the tree of life.

]]> Fri, 13 Jul 12 05:00:15 -0700 Keith Miller http://biologos.org/blog/understanding-evolution-theory-prediction-and-evidence-1?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/understanding-evolution-theory-prediction-and-evidence-1?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication In science, we don’t really know the true way things actually work. What we have are theories—broad explanatory frameworks supported by experimentation, which we can use to make testable predictions about the natural world. One of the challenges for discussing evolution within evangelical Christian circles is that there is widespread confusion about how evolution actually works. In this (intermittent) series, I discuss aspects of evolution that are commonly misunderstood in the Christian community. In this post, we explore how evolution is a theory in the scientific sense, how it is supported by converging lines of evidence, and how it can make accurate predictions about the natural world, using whale evolution as an example.

Evolution: just a theory

One game that my (young) children like to play is a guessing game where both players select a character from among many choices, and by process of elimination, tries to guess the character the other has selected. Questions like “does your character have red hair? glasses?” etc., are used to narrow down the possibilities. Once you have guessed correctly which character your opponent has selected, you can perfectly predict the answer to every question thereafter (and a good many parents likely prolong the questioning to keep the hopes of victory alive for their children). When considered separately, the individual features of each character—glasses, brown hair, purple hat, and so on—mean almost nothing, since they could be features shared with other characters in the game. Only the convergence of multiple features is indicative of a good guess, and the accuracy of that guess is put to the test every time a new question is asked.

A good theory is something like this: an educated guess, based on and consistent with all past work on the topic to date. It allows you to predict how future tests should pan out. In the guessing game, there are limited options to choose from (so the analogy, like all analogies, eventually breaks down). In science, we don’t really know the true way things actually work. What we have are theories—broad explanatory frameworks supported by experimentation, that make sense of our current collection of facts—that we can use to make testable predictions about the natural world. All theories in science are provisional in that they are not complete descriptions of how the world actually works and are subject to future revision; but at the same time they are robust frameworks that can be used to predict how experiments should behave with almost boring regularity. So, far from the colloquial usage of “theory” as speculation, “just a theory” is high praise in science.

The current understanding of evolutionary theory in all its scope and diversity is far more complex than Darwin himself could have ever envisaged. (As a geneticist, I’ve often wished I could have a cup of tea with him to show him how far his theory has grown, especially given his confusion about how heredity worked.) Our understanding of how evolution works has grown by leaps and bounds since the 1850s. What is remarkable is just how much Darwin got “right” given his time and place. His main hypotheses—that species descend from ancestral forms through descent with modification, that and natural selection acting on heritable variation is a significant force in that process—remains the core of modern evolutionary theory. We’ve added a lot of detail since then (population genetics, kin selection, neutral evolution/genetic drift, symbiosis, horizontal gene transfer, molecular exaptation, and so on), but Darwin’s core ideas have produced a wealth of successful predictions. They were a very good “guess” that continues to pay rich scientific dividends.



Whale evolution: an example of converging lines of evidence

One of the things I personally find quite enjoyable about evolutionary theory is the counter-intuitiveness of some of the predictions it makes. One example that is a personal favorite, and one I often use to illustrate how evolution makes sense of converging lines of evidence, is cetacean (whale) evolution. Let’s set up the “problem” that evolutionary biology forces upon us:

• Modern cetaceans are mammals – they nourish their young in utero through a placenta, give birth to live young, and feed newborns with milk – all features of standard mammalian biology.
• Mammals are tetrapods – organisms with four limbs. Mammalian life shows up in the fossil record as an innovation within tetrapods, so mammals are “nested within the set” of tetrapod forms. Not all tetrapods are mammals (amphibians, for example) but all mammals are tetrapods.
• Tetrapods are by and large terrestrial creatures. Having four limbs for locomotion is a distinctly land-based adaptation.

The “problem”, of course, is that modern whales are emphatically not terrestrial, nor do they have four limbs – they have two front flippers and a tail, with no hind limbs in sight. Yet they are mammals, which forces evolution’s hand as it were. Evolution thus is dragged, under protest, to the prediction that modern whales, as mammals, are descended, with modification, from ancestral terrestrial, tetrapod ancestors. Instantly this prediction raises a host of uncomfortable questions: where did their hind limbs go? How did they acquire a blowhole on the top of their heads when other mammals have two nostrils on the front of their faces? How did they transition to giving birth in the water? What happened to the teeth of the baleen whales? What happened to the hair characteristic of mammals? and so on. In some ways, evolutionary thinking about whales creates more difficulties than it appears to solve.

And yet, these difficulties are the stuff of science. If indeed our “educated guess” of terrestrial, tetrapod ancestry for whales is correct, the evidence will show that these transitions, challenging though they may seem, did indeed occur on the road to becoming “truly cetacean”.

Going out on a limb

Anyone who has seen a modern whale skeleton in a museum and noted it carefully may have noticed that though whales lack hind limbs, they do have a bit of bone back there where the hind limbs ought to be. While this is suggestive of a vestigial characteristic (a feature in a modern organism that has a reduced role relative to the role the structure played in an ancestral species), it’s hardly a smoking gun for evolution. Still, it’s consistent with the idea.

When we look at the cetacean fossil record, we also see forms suggestive of a progressive loss of hind limb function and structure over time, as David Kerk and Darrel Falk have elegantly explained before. Again, if one were resistant to evolutionary explanations, it would be possible (if a bit strained) to interpret these creatures as having been created directly as we find them in the fossil record. The facts that we do not see these forms in the present day, and that they seem to blur the distinctions between terrestrial tetrapods and whales might make one a bit uncomfortable, however.

Recent work on cetacean embryogenesis (how whales and their relatives develop from fertilized eggs into fully-formed baby whales) has shed even more light on the issue for modern species, however. Dolphin embryos actually have four limbs early in their development, as well as a few facial hairs, just as any good mammal should have. The hind limbs and hairs are lost later in development, and work on the molecular signaling events that halt hind limb growth and cause the limb bud to regress into the body wall have now been worked out in some detail. Moreover, early in dolphin development the nostrils are distinct and on the front of the face, and only fuse into a blowhole and migrate to the top of the head later in development. Early dolphin embryogenesis is distinctly mammalian and uncannily tetrapod-like.

… and passing the test

Taken in isolation, these facts about whales are interesting trivia. Taken together, however, they begin to form a picture entirely consistent with the prediction that modern whales are derived from terrestrial ancestors. The true strength of evolution as a scientific theory for the origin of whales is this: not that we can prove it, (for no theory is ever proven in science due to its permanently provisional nature), nor that we have full access to every bit of data we would like (consider how fragmentary the fossil record is, for example), but rather that we haven’t been able to disprove it yet, despite our best efforts. Descent with modification remains a productive educated guess that grows stronger with each investigation.

In the next post in this series, we’ll explore some additional lines of evidence for cetacean evolution that further illustrate the predictive power of evolutionary theory.

For further reading

Evidences for Evolution, Part 2a: The Whale's Tale


Evidences for Evolution, Part 2b: The Whale's Tale
J. G. M. Thewissen, M. J. Cohn, L. S. Stevens, S. Bajpai, J. Heyning, and W. E. Horton, Jr. (2006). Developmental basis for hind-limb loss in dolphins and origin of the cetacean bodyplan. Proceedings of the National Academy of Sciences 103 (22), 8414–8418. available freely online.

]]> Thu, 05 Apr 12 05:15:22 -0700 Dennis Venema http://biologos.org/blog/speciation-and-macroevolution?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/speciation-and-macroevolution?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication A common challenge to evolutionary theory is that while life does indeed change over time (what is known as microevolution), no one has ever seen one species evolve into another species (macroevolution).

In our last two BioLogos podcasts, we looked at the question of transitional fossils and the genetic evidence for evolution. In our final installment of this three part series, we move on to the question of speciation and macroevolution. A common challenge to evolutionary theory is that while life does indeed change over time (what is known as microevolution), no one has ever seen one species evolve into another species (macroevolution). For example, no one has seen a dog evolve into something other than a dog. Because speciation has never been observed, and because science is based on observation, evolution cannot be considered scientific.

In fact, examples of speciation have been observed by scientists. We must also remember that we are able to observe just a tiny window of the long history of life on Earth, and the fact that any speciation has been noted at all is impressive indeed.

Transcript

It’s pretty clear to most of us that life can change over time. For those who aren’t convinced, just take a quick trip to your local animal shelter. Each of the dog breeds there, from the Great Dane to the Chihuahua, descended from a single ancestral population. As you probably already know, that ancestral group was a wolf-like species. -How did these drastic changes take place? Well, basically, genetic variation within that original population was acted upon by selective forces. Now, just to be clear, the selection at work here wasn’t natural. It was the result of breeding done over hundreds of years. But the basic principle is the same. Genetic variation plus some sort of selection results in genetic change. This is evolution.

For the most part we are ok with accepting this. Yet many people still have a problem with the Theory of Evolution. Those suspicious of evolutionary Theory generally split evolution into two categories. Instead of arguing that evolution is completely impossible, they will say something like, “I know microevolution is real, but I just can’t accept macroevolution.”

Kent Hovind, an especially outspoken opponent of evolutionary theory, often makes this argument in his presentations:

“Maybe you’re talking about macroevolution. That’s where an animal changes into a different kind of animal. Nobody’s ever seen that. Nobody’s seen a dog produce a non-dog. I mean you may get a big dog or a little dog, I understand, but you’re going to get a dog, okay?” (source)

But what does this mean? What is the difference between micro and macroevolution anyway, and why is one of them ok while the other is condemned?

Well, like many terms used in the evolution debate, the definitions tend to differ depending on who you talk to. This can make rational discussion difficult. Most opponents of evolution, like Kent Hovind, say that macroevolution refers to one “type” or “kind” of organism evolving into another “kind”. Microevolution, they might say, is evolution within a “kind”. Evolution of one dog breed into another, they would say, is microevolution. Evolution of a “dog into a non-dog”, as Hovind puts it, would be “macroevolution.”’

One big problem with this argument is that “kind” is not clearly defined. It is a subjective term referring to organisms that seem similar to each other. Now, this is a definition that can easily be manipulated. And it doesn’t work very well when asking scientific questions. Because there is disagreement about what they actually mean, the terms micro and macroevolution aren’t often used in scientific literature. But when biologists do refer to “macroevolution”, most define it as “evolution above the species level”.

(Sources: http://ib.berkeley.edu/courses/ib200a/lect/ib200a_lect26_Lindberg_macroevolution.pdf, http://www.nescent.org/media/NABT/, http://evolution.berkeley.edu/evosite/evo101/VIADefinition.shtml, http://www.nhm.ac.uk/hosted_sites/paleonet/paleo21/mevolution.html)

In other words, at the smallest scale, macroevolution is the development of a new species. This definition is more useful because you can objectively determine whether two organisms are members the same species, but “kind” has no specific definition.

So what does “species” mean anyway? How is it different from “kind?” Well, the term species can be hard to define. Life is complex, and categorizing it into clear groups can be tricky. The currently accepted definition of species comes from what we call the “biological species concept.” Basically, the biological species concept says that a species is made of populations that actually or potentially interbreed in nature.

So, two populations that cannot mate to produce successful offspring are by definition separate species. Now, this definition doesn’t always work. For example, when you have a species that reproduces asexually, finding the boundaries between species can be a little tricky. But in most cases it does a pretty good job. It’s a good way to objectively determine where one species stops and another one begins.

The Biological Species Concept is especially useful when you have two species that look and act very similar. Eastern and Western Meadowlarks are a good example of this. They look almost exactly the same. But they cannot interbreed successfully. Therefore, they are separate species. This definition also helps when we study evolution. Where can we draw the line between microevolution and macroevolution? Well, it’s never easy, but having a working definition of this thing called a species helps out a lot. When enough genetic changes accumulate in a population, eventually it loses the ability to mate with others of its species. Then, by definition, it becomes a new species. In other words, macroevolution has occurred.

As we just discussed, many critics claim that macroevolution can never happen—one species can never cross over to become another one. This statement might sound valid, but a little bit of investigation shows that it is not well supported by evidence. For one thing, the only difference between micro and macroevolution is scope. When enough micro changes accumulate, a population will eventually lose its ability to interbreed with other members of its species. At this point, we say that macroevolution has occurred.

The same processes—random mutation and natural selection—cause both micro and macro evolution. There are no invisible boundaries that prevent organisms from evolving into new species. It just takes time. Usually, the amount time required for macroevolution to occur is significant—on the order of thousands or millions of years. That’s why you don’t normally see brand new forms of life appear every time you step out your front door. And that’s also why some people think that speciation never happens at all.

But sometimes macroevolution doesn’t take that much time. In fact, the evolution of new species sometimes happens so quickly that we can actually see it take place! Let’s look at a few recent examples.

Biologists Peter and Rosemary Grant had been studying finches since 1973. They lived on an island called Daphne Major in the Galapagos. It was here that they conducted their studies. When they first began their studies, only two species of Finch lived on Daphne Major: the medium ground finch and the cactus finch. But, in 1981, Peter and Rosemary noticed that an odd new finch had immigrated to the island. It was a hybrid, a mix between a cactus finch and a medium ground finch. It didn’t quite fit in with the other birds. The odd misfit had an extra large beak, an unusual hybrid genome, and a new kind of song. But somehow he was still able to find a mate. The female was also a bit of a misfit and had some hybrid chromosomes of her own. So their offspring were very different from the other birds on the island.

Rosemary and Peter continued to carefully watch the odd hybrid line. They wondered if the birds would become isolated from the other finch species on the island or if they would eventually re-assimilate. After four finch generations, a drought killed off many of the birds on Daphne Major. In fact, almost the entire hybrid line was exterminated. Only a brother and sister pair remained. The two family members mated with each other, producing offspring that were even more unique than their parent line. From that point on, as far as biologists Peter and Rosemary could tell, the odd population of finches mated only with each other. They were never seen to breed with the cactus finches or the medium ground finches on the island. The finches with the strange song had become a brand new species.

(Source: http://www.pnas.org/content/106/48/20141.full)

Another example of speciation, or macroevolution, also took place on an island—this time, on the beautiful Portuguese island of Madeira. According to history books, the Island of Madeira was colonized by the Portuguese about 600 years ago. The colonizers brought with them a few unassuming European House Mice, which they accidentally left on the island. It’s also possible that a group of Portuguese House Mice was dropped off later on.

Recently, Britton-Davidian, an evolutionary biologist at University Montpellier 2 in France, decided to collect samples of the Madeira mice and see how those original populations had changed over time. What she found was surprising. Rather than just one or two species of mouse, she found several. In only a few hundred years, the original populations of Mice had separated into six genetically unique species. The first mouse populations had 40 chromosomes altogether. But the new ones were quite different. Each new variety had its own unique combination of chromosomes, which ranged in number from 22 to 30.

What seems to have happened is that, over time, the mice spread out across the island and split into separate groups. Madeira is a rugged volcanic island with crags and cliffs. So it makes sense that this would have been easy to do. There were many isolated corners for the mice to occupy. Over time, random mutations occurred—some chromosomes became fused together.

Now, In order to reproduce successfully, both parents must have the same number of chromosomes. So when a population develops a chromosome fusion, suddenly that group cannot mate with the other members of its species. It becomes a brand new species. That’s exactly what happened on Madeira. And because of this phenomenon, 6 new species evolved from just 1 or 2 in an extremely short amount of time.

(Sources: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2009.04345.x/full, http://www.genomenewsnetwork.org/articles/04_00/island_mice.shtml, http://www.nature.com/hdy/journal/v99/n4/full/6801021a.html)

Another fascinating example of macroevolution was recently observed by researchers at Pennsylvania State University. This time, two species combined to make a single new one. In 1997, researchers at Penn State noticed a fruit maggot infestation on some recently introduced Asian Honeysuckle bushes. They decided to investigate the Honeysuckle fly population and determine how it was related to the other flies nearby. When they examined the honeysuckle fly’s genes, the researchers discovered something interesting. The fly appeared to be a hybrid of two native species—the blueberry fly and the snowberry fly.

But the honeysuckle fly’s genetic material was not an exact balance between that of the two parent species. The ratios of DNA varied from fly to fly. This showed the researchers that the honeysuckle flies had been breeding amongst themselves for many generations—probably at least 100. Also, they found that the Honeysuckle Flies were very unlikely to breed with any other species. They bred only on their host Honeysuckle plants. So they weren’t likely to mix with flies that lived on a different host.

According to Dr. Dietmar Schwarz, post-doctoral researcher in entomology, as far as the researchers can tell, “The new species is already reproductively isolated. They seem to be in a niche on the brushy honeysuckle where the parent species cannot compete."

(Source: http://www.psiee.psu.edu/news/2005_news/july_2005/hybrid_insects.asp)

While this kind of speciation—two species hybridizing to create a new one—seems odd, it is a significant mechanism of macroevolution. And it’s especially common in plants. In fact, a new species of weed recently arose this way in Great Britain. In 1991, Richard Abbot, a plant evolutionary biologist from St. Andrews University, noticed an unusual weed growing next to a car park in York. He discovered that the species, an unassuming scruffy weed, was a natural hybrid between the common groundsel and the Oxford ragwort, a plant that was introduced to Britain only 300 years ago. The York Groundsel lives in a different niche, or microenvironment, than either of its parent species. It is able to breed and reproduce, but only with other York Groundsel plants. It cannot successfully reproduce with any other species, including either of its parent plants. Thus, by definition, the York Groundsel is its own new species.

(Sources: http://www.nerc.ac.uk/publications/planetearth/2003/summer/sum03-evolution.pdf, http://www.nature.com/hdy/journal/v69/n5/abs/hdy1992147a.html)

So, as we have seen, macroevolution is an established process. Usually it takes thousands of years to occur, but sometimes we get lucky and catch it in the act. When Kent Hovind said that, “no one has ever seen a dog produce a non-dog” he was technically quite correct. But this statement infers that macroevolution means a drastic and obvious change from one type of organism into another. Those who think this way believe that macroevolution is something like two dogs breeding to suddenly produce a cat, or two guinea pigs mating to produce a mouse.

But this is not how evolution works at all. Over millions of years, a dog-like animal may indeed evolve into a something that looks completely unlike a dog. However, this is not something that we would expect to be able to observe. It just takes too much time. To put the scale of evolution into perspective, consider this. If the average lifespan of a United Stated citizen, 78 years, were a single minute, then single-celled life has been around for nearly 100 years. On this scale, all we get to see is one minute. And even in that time frame we sometimes see new species forming. God’s time is not our time and we tend to forget this. What we do expect to observe is a very slow step-by-step accumulation of tiny genetic changes that eventually result in speciation. And indeed, as we discussed today, this is exactly the sort of evidence revealed in nature.

So, macroevolution is not a “myth” by any means. It is supported by a vast amount of evidence. That evidence includes the fossil record and genetics, as discussed in previous BioLogos podcasts, and, when we get lucky, direct observation of speciation. God, being who God is, could conceivably have created species out of thin air in a single instant. But what if instead if God created and sustained the process by which new species are created? Does that make him less powerful or less "god-like"? Is it somehow more God’s process if it happened in an instant, than it is if it happened over a long period of time? Presumably even if it happened in an instant, it would still happen by some sort of process—only faster.

God’s time is not our time, and perhaps it’s a good idea for all of us to simply stand back in amazement while God does God’s work in God’s time through God’s process.

]]> Thu, 23 Feb 12 03:59:24 -0800 Kelsey Luoma http://biologos.org/blog/beauty-from-the-bleak?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/beauty-from-the-bleak?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication Physical death is a necessary and, perhaps, disconcerting element of the evolutionary process for many Christians. It is difficult to imagine a perfect and loving God designing such a universe where forces such as natural death and entropy operate.

Though some may believe that moving the science/faith dialogue forward is best left to scientists, scholars, and theologians, we at BioLogos recognize that our pastors play an invaluable role in the conversation. Across the globe, pastors are helping their congregations work through difficult issues of science and faith with honesty, insight, and a gentle spirit. To this end we present an ongoing series recognizing sermons (and the pastors who give them) that are helping to promote the harmony of science and faith. Today's sermon comes from Michael Gungor, a musician, founder of the musical group Gungor, and a pastor at the Bloom Church in Denver, Colorado.

Gungor’s song “Beautiful Things” emphasizes the liberating truth that God has wonderfully made beautiful things “out of the dust,” just as God makes beautiful things out of a life fully surrendered to him and buried in his love.

Beautiful Things

All this pain
I wonder if I’ll ever find my way
I wonder if my life could really change at all
All this earth
Could all that is lost ever be found
Could a garden come up from this ground at all

You make beautiful things
You make beautiful things out of the dust
You make beautiful things
You make beautiful things out of us

All around
Hope is springing up from this old ground
Out of chaos life is being found in You

You make beautiful things
You make beautiful things out of the dust
You make beautiful things
You make beautiful things out of us

Physical death is a necessary and, perhaps, disconcerting element of the evolutionary process for many Christians. It is difficult to imagine a perfect and loving God designing such a universe where forces such as natural death and entropy operated. Michael Gungor of Bloom Church in Colorado addresses this idea and offers wisdom on such a complex issue.

He highlights the words of Jesus in John 12:24 (NIV): “Very truly I tell you, unless a kernel of wheat falls to the ground and dies, it remains only a single seed. But if it dies, it produces many seeds. Anyone who loves their life will lose it, while anyone who hates their life in this world will keep it for eternal life.” In other words, death precedes true life. This statement appears self-contradictory, but there is evidence of this truth in the world around us. Gungor points to the death of cells in a human body. The death of worn-out cells makes room for new cells, keeping the body healthy. In fact, humans necessarily consume plants and animals in their diet to bring nourishment and support life. He also discusses the second law of thermodynamics: entropy. In accordance with this law, the sun continually burns itself out as it produces light and energy that supports life on earth. Thus, there is a place for natural death on this earth as it allows for the continuation of life.

In light of the New Testament and the testament of science, Gungor proposes that perhaps God is not as afraid of physical death as humans are. God is not fearful of death, knowing full well that it will not remain. It allows for growth in the present, but God has spoken of the day when all death will be destroyed forever. Revelation 21:4(NIV) affirms this truth: “He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away.” Chapter eight of Romans also speaks about the time when all things will be brought into the glorious freedom of the children of God—that is all things will be made new. Ultimately, life will swallow up death forever, but the current “messiness” of the process of becoming is part of God’s plan too.

(To hear the entire sermon go to this link and scroll to the sermon —“What Can We Learn About Jesus from Science? Part 2”)

]]> Sat, 04 Feb 12 07:00:37 -0800 Michael Gungor http://biologos.org/blog/series/evidences-for-evolution?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/series/evidences-for-evolution?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication This technical series, co-written by Darrel Falk and David Kerk, looks into the evidence for evolution in order to dispel doubts that people may have about this well-supported theory. They look at three things specifically: the separate methods which reveal of the age of the earth, the unfolding history of whale evolution, and finally the common trends of heart development in vertebrates. A literalistic view of Genesis causes many evangelicals to believe that the earth is less than ten thousand years old. Christian children and young people frequently grow up being told that the earth is young and that evolution is a lie. The most popular science/religion web-site by far according to Alexa ratings is “Answers in Genesis”, and its museum, dedicated to a young earth perspective has attracted over 1 million visitors since its opening two years ago. Since evangelicals, we believe, are correct about so many other all-important issues, how can we be so certain that so many are so wrong about this one? Consider sending this link to a young earth friend or pastor. Some think that the science behind this matter can’t be trusted. Nothing could be further than the truth.

The beauty of the scientific process is its inherent scepticism. (See "What Scientists Do" by Steven Benner). If there is only one way of reaching a conclusion, the scientific process requires the scientist to remain highly sceptical. The only conclusions in science which are widely accepted are those which are supported by multiple, reinforcing lines of evidence – “all roads must lead to Rome”. If there is even one scientific trajectory that seems to clearly lead off to Peoria instead of Rome (to use a recent analogy of Francisco Ayala), the scientific process demands that the scientist find out why. The scientist who does not retain an attitude of scepticism when there is only a single line of evidence, and particularly one who ignores other, conflicting lines of evidence, is on a stubborn trajectory of his own—a trajectory to failure. If the only reason for following the directions which “lead away from Rome” is a particular view of Scripture, then it is important to consider the possibility of human error. Biblical hermeneutics, after all, is a human enterprise just as science itself is. For example, John MacArthur in his current series on Genesis is human and is interpreting Genesis in his way just like the rest of us. He, wonderful pastor and shepherd that he is, interprets Scripture too. There is good reason to be quite certain that the interpretation he subscribes to is mistaken.

As Christians, we are called to follow Jesus. In so doing, Jesus said we are to love the Lord our God with all our heart, soul and mind—not just our heart and soul. Indeed if we close our mind, we are actually disobeying what Jesus said was the greatest commandment of all. So let’s not be shy about using those minds. Are there multiple independent ways of keeping track of time since the creation of the earth? If so, do each of those ways point to the same conclusion?

The best known method of calculating the age of material on earth depends on the well-established fact that certain elements in the earth’s crust are unstable and decay at a fixed rate that can be measured. (For an introduction to this topic see this BioLogos FAQ.) This instability functions sort of like a set of clocks that have been ticking through the eons of time. Indeed there are many types of unstable elements; there are many ticking clocks. Each of the various clocks tick at a different rate. The rate of each can be calibrated, and, with an amazing degree of consistency, all “clocks” point back to the same starting point: an ancient earth with rocks that are hundreds of millions and even billions of years old. This “ticking clock” technique is known as radiometric dating.^1,2

There are other totally independent ways of estimating the age of material on earth. To appreciate how these work, perhaps we should start with shorter spans of time, which for human beings are much more readily comprehensible. Some of the fondest boyhood memories of one of us (DK) come from visits to the majestic California redwood forests. He especially remembers an exhibit of a section from a giant tree which showed the pattern of growth rings within it. It turns out that these rings accumulate in response to seasonal differences in rainfall and temperature, which in turn produces differences in growth rate. Fastened within this huge slab of wood was a series of tags, proceeding from the surface inward, demonstrating the dates of major historical events: the landing of the Pilgrims on Plymouth Rock; Columbus’ discovery of the New World; the Norman conquest of England, and so forth. It was possible to see in the yearly growth rings a history of what seemed then to be the very distant past!³

Growth layering processes are not restricted to trees. Many species of marine invertebrates accumulate calcium carbonate from their watery environment and incorporate it into some form of shell. Examples would be clams and corals. In fact, for these species, the variation in shell deposition occurs on a both a daily and a yearly basis, so an even finer counting of time periods is possible.⁴

Just as it is possible to count the rings in trees and correlate their age to known historical events in the past, it is also possible to count the banding patterns preserved in the fossils of marine organisms, and use this as a method to estimate their ages. Let’s see how it works.

Astronomical data, developed and analyzed over the past couple of centuries, has revealed that the rotation of the earth is gradually slowing down. This is due to the friction created daily by the moving tides on the earth’s surface, produced by the gravitational pull of the moon and sun. Furthermore, as the earth slows down slightly, some rotational energy is transferred to the moon, which alters its orbit slightly (its orbit is moving slowly away from the earth). The data leading to these conclusions range from analysis of ancient solar eclipses (whose dating allows the precise position of the earth, sun and moon to be determined) to bouncing laser beams off mirrors placed on the surface of the moon by the Apollo astronauts. For our purposes, what will be important is the slowing of the earth’s rotation. This predicts that the length of each day has been slowly increasing since the formation of the earth/moon system. The average increase in the day length is estimated at 2.3 milliseconds (.0023 seconds) per century.^5,6 Hence as we examine events in the past, day length was shorter, by an amount that can be calculated. Ten thousand years ago, a day would have been .23 seconds shorter than it is today. If direct experimental estimates of day length can be obtained, they allow an estimate of the age of the material.

One way that such experimental estimates of day length can be obtained is through the periodic growth rings deposited in the shells of marine invertebrate organisms. Take for example a clam living in an intertidal environment. If the tide is in and the shell is open, it can readily absorb oxygen from water, use aerobic metabolism, and incorporate calcium carbonate into its shells. When the tide is out and the shells are closed, however, little oxygen can be absorbed, anaerobic metabolism is used, shell decalcification occurs, and organic rich material accumulates in the shell. This alternating pattern of shell deposition occurs on a daily basis, and is clearly visible in both shells from living and fossil clam species by microscopic examination. Furthermore, shells contain an identifiable mark resulting from the first freezing day of winter, and from the first really hot day of summer. Hence a yearly growth interval can be readily determined.⁷

When such data are analyzed for a number of fossil species, it is clear that the number of days these organisms experienced each year was higher than today. Given that, we have another clock - a totally independent way of measuring the age of certain fossils. So how well do clocks based upon radiometric dating agree with those based on measuring rings in certain sea shells?

As already mentioned, organisms living 10,000 years ago would have experienced shorter days, but they would only have been shorter by 0.2 seconds. Organisms living 1 million years ago would have experienced a day length that was 20 seconds shorter. If the earth really is very, very old, organisms living 465 million years ago, for example, would have experienced approximately 416 days per year, each day being about 21 hours long.⁷ Amazingly, shelled fossils in formations dated by radiometric clocks to be about 465 million years old show, by their banding patterns, that the days really were three hours shorter. In fact the two sets of clocks agree within 1 percent!

Another way such estimates of ancient day length can be derived is to look at the periodic patterns formed in fine silts in ancient river estuaries. The daily tides produce shifts in the mud, leaving a fine layering pattern, which is recorded in rock as these sediments transform into materials such as sandstone (such deposits are called “rhythmites”). Other shifts in the mud are produced over longer time intervals, including seasonal and yearly shifts. By counting the number of daily depositional layers per year, in a similar fashion to work with marine organism shells cited above, an estimate of ancient day length can be derived. One advantage of the rhythmite analysis method is that it can be applied to more ancient materials, in eras of the earth’s history when organisms suitable for shell analysis were scarce or non-existent. For example, radiometric analysis of certain rock formations in South Australia dated them at 620 million years of age. On this basis one would predict that the day/night cycles should have been about 20 hours long in these formations. Actual measurements of day length from the preserved mud banding patterns, although off from the expected by ten percent (estimated day length is 22 hours) is again consistent with the formation being hundreds of millions of years old just as the radiometric dating has predicted.⁸

In conclusion, there is data derived from three independent sources: the decay of radioisotopes, the growth patterns recorded in fossilized shells of marine organisms, and rocks containing tidal depositional material from river estuaries, which all agree on an ancient age for the earth. Furthermore, by a totally independent method it is also possible to measure the age of the universe as a whole and again it is billions, not thousands of years.

All of the roads in God’s book of Nature “lead to Rome” (i.e an ancient earth) - it is only mistaken human interpretation of Scripture that causes some of our precious brothers and sisters in Christ to end up in Peoria.

The next blog in this series can be found here.

Editor's Note: Dr. Kerk offers a further discussion of the age of the earth in the comment section of this post, beginning here. Dr. Kerk has also included the following graph:



References

1: Elementary principles of radiometric dating are discussed by Richard Dawkins. Dawkins, R. 2009. The Greatest Show on Earth: The Evidence for Evolution. Free Press, New York Pgs. 91-98.

2: Wiens, R.C. 2002. Radiometric Dating: A Christian Perspective. This is a more detailed but still highly readable account of radiometric dating, written by a well-qualified physicist who is also a professing Christian. It can be obtained from the web site of the American Scientific Affiliation: http://www.asa3.org/ASA/resources/Wiens.html

3: Tree ring dating (“dendrochronology”) is discussed by Dawkins, pgs. 88-91.

4: Dating using coral skeletal deposition is discussed by Jerry Coyne: Coyne, J.A. 2009. Why Evolution is True. Viking Penguin, New York. Pgs. 24-25.

5: “Tidal Acceleration”, Wikipedia: http://en.wikipedia.org/wiki/Tidal_acceleration

6: Stephenson, F.R. 2003. Historical Eclipses and Earth’s Rotation. Astronomy and Geophysics 44:2.22-2.27.

7: Zhenyu, Z., Yaoqi Z., Guosheng J. 2007. The periodic growth increments of biological shells and the orbital parameters of Earth-Moon system. Environmental Geology 51: 1271–1277.

8: Williams, G.E. 2000. Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit. Reviews of Geophysics 38(1):37-59.

]]> Sun, 27 Nov 11 23:31:20 -0800 David Kerk, Darrel Falk, Falk, Darrel, Kerk, David http://biologos.org/blog/misconceptions-about-evolution-part-2?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/misconceptions-about-evolution-part-2?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication Evolutionary theory is not in crisis; scientists accept evolution as the best explanation for life's diversity because of the multiple lines of evidence supporting it, its broad power to explain biological phenomena, and its ability to make accurate predictions in a wide variety of situations. The website Understanding Evolution, hosted by The University of California Museum of Paleontology, Berkeley, offers its readers numerous helpful resources regarding the science and history of evolutionary biology. The site’s stated goal is to “help you understand what evolution is, how it works, how it factors into your life, how research in evolutionary biology is performed, and how ideas in this area have changed over time.” Among its resources is a list of popular misconceptions about evolutionary theory. In this two part series, we’d like to highlight some of the site’s most helpful responses to these misconceptions. The full list, and many other wonderful resources, can be found at Understanding Evolution.

Misconceptions about Evolution and the Nature of Science

“Evolution is not science because it is not observable or testable.”

This misconception encompasses two incorrect ideas: (1) that all science depends on controlled laboratory experiments, and (2) that evolution cannot be studied with such experiments. First, many scientific investigations do not involve experiments or direct observation. Astronomers cannot hold stars in their hands and geologists cannot go back in time, but both scientists can learn a great deal about the universe through observation and comparison. In the same way, evolutionary biologists can test their ideas about the history of life on Earth by making observations in the real world. Second, though we can't run an experiment that will tell us how the dinosaur lineage radiated, we can study many aspects of evolution with controlled experiments in a laboratory setting. In organisms with short generation times (e.g., bacteria or fruit flies), we can actually observe evolution in action over the course of an experiment. And in some cases, biologists have observed evolution occurring in the wild.

"Evolution is 'just' a theory."

This misconception stems from a mix-up between casual and scientific use of the word theory. In everyday language, theory is often used to mean a hunch with little evidential support. Scientific theories, on the other hand, are broad explanations for a wide range of phenomena. In order to be accepted by the scientific community, a theory must be strongly supported by many different lines of evidence. Evolution is a well-supported and broadly accepted scientific theory; it is not ‘just' a hunch.

For more, see the question "What is evolution?"

"Evolutionary theory is invalid because it is incomplete and cannot give a total explanation for the biodiversity we see around us."

This misconception stems from a misunderstanding of the nature of scientific theories. All scientific theories (from evolutionary theory to atomic theory) are works in progress. As new evidence is discovered and new ideas are developed, our understanding of how the world works changes and so too do scientific theories. While we don't know everything there is to know about evolution (or any other scientific discipline, for that matter), we do know a great deal about the history of life, the pattern of lineage-splitting through time, and the mechanisms that have caused these changes. And more will be learned in the future. Evolutionary theory, like any scientific theory, does not yet explain everything we observe in the natural world. However, evolutionary theory does help us understand a wide range of observations (from the rise of antibiotic-resistant bacteria to the physical match between pollinators and their preferred flowers), does make accurate predictions in new situations (e.g., that treating AIDS patients with a cocktail of medications should slow the evolution of the virus), and has proven itself time and time again in thousands of experiments and observational studies.

For more, see the questions "How can evolution account for the complexity of life on earth today?" and "How can evolution account for the complexity of life on earth today?"

"Gaps in the fossil record disprove evolution."

While it's true that there are gaps in the fossil record, this does not constitute evidence against evolutionary theory. Scientists evaluate hypotheses and theories by figuring out what we would expect to observe if a particular idea were true and then seeing if those expectations are borne out. If evolutionary theory were true, then we'd expect there to have been transitional forms connecting ancient species with their ancestors and descendents. This expectation has been borne out. Paleontologists have found many fossils with transitional features, and new fossils are discovered all the time. However, if evolutionary theory were true, we would not expect all of these forms to be preserved in the fossil record. Many organisms don't have any body parts that fossilize well, the environmental conditions for forming good fossils are rare, and of course, we've only discovered a small percentage of the fossils that might be preserved somewhere on Earth. So scientists expect that for many evolutionary transitions, there will be gaps in the fossil record.

For more see out question "What does the fossil record show?"

Misconceptions about the Acceptance and Implications of Evolution

“Evolution is a theory in crisis and is collapsing as scientists lose confidence in it.”

Evolutionary theory is not in crisis; scientists accept evolution as the best explanation for life's diversity because of the multiple lines of evidence supporting it, its broad power to explain biological phenomena, and its ability to make accurate predictions in a wide variety of situations. The vast majority of scientists do not debate whether evolution took place, but they do debate many details of how evolution occurred and occurs in different circumstances. Antievolutionists may hear the debates about how evolution occurs and misinterpret them as debates about whether evolution occurs. Evolution is sound science and is treated accordingly by scientists and scholars worldwide.

For more see the questions "Does thermodynamics disprove evolution?", "How can evolution account for the complexity of life on earth today?" and "How can evolution account for the complexity of life on earth today?"

"Evolution supports the idea that 'might makes right' and rationalizes the oppression of some people by others."

In the nineteenth and early twentieth centuries, a philosophy called Social Darwinism arose from a misguided effort to apply lessons from biological evolution to society. Social Darwinism suggests that society should allow the weak and less fit to fail and die and that this is good policy and morally right. Supposedly, evolution by natural selection provided support for these ideas. Pre-existing prejudices were rationalized by the notion that colonized nations, poor people, or disadvantaged minorities must have deserved their situations because they were "less fit" than those who were better off. In this case, science was misapplied to promote a social and political agenda. While Social Darwinism as a political and social orientation has been broadly rejected, the scientific idea of biological evolution has stood the test of time.

"Evolution and religion are incompatible."

Because of some individuals and groups stridently declaring their beliefs, it's easy to get the impression that science (which includes evolution) and religion are at war; however, the idea that one always has to choose between science and religion is incorrect. People of many different faiths and levels of scientific expertise see no contradiction at all between science and religion.

In fact, science and religion can have a constructive relationship. The majority of scientists during the emergence of modern science in medieval Europe, for example, were devout or conventionally religious. Religious belief, then, can function as a framework within which scientific progress flourishes. Religious belief can also be influenced by science. In the Galileo Affair, scientific evidence of a heliocentric universe caused the church to revisit its interpretation of a part of Scripture.

Oddly enough, some people argue that God’s existence is actually a scientific claim and should be tested like any other. However, God’s existence is not something that can be tested by the scientific method in the same way the existence of postulated new elementary particles are tested in supercolliders. Because science provides knowledge about the natural world, no amount of testing or theorizing could prove or disprove the existence of a supernatural creator. Rather than an empirical claim about nature or its laws, the claim that God exists is a metaphysical one, a statement about what there is, whether it be natural or supernatural.

For more see the questions "What is the proper relationship between science and religion?", "Can scientific and scriptural truth be reconciled?", "What were the initial Christian responses to Darwin?", and "What role could God have in evolution?"

]]> Tue, 22 Nov 11 04:00:56 -0800 http://biologos.org/blog/misconceptions-about-evolution-part-1?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/misconceptions-about-evolution-part-1?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication The website Understanding Evolution, hosted by The University of California Museum of Paleontology, Berkeley, offers its readers numerous helpful resources regarding the science and history of evolutionary biology. The website Understanding Evolution, hosted by The University of California Museum of Paleontology, Berkeley, offers its readers numerous helpful resources regarding the science and history of evolutionary biology. The site’s stated goal is to “help you understand what evolution is, how it works, how it factors into your life, how research in evolutionary biology is performed, and how ideas in this area have changed over time.” Among its resources is a list of popular misconceptions about evolutionary theory. In this two part series, we’d like to highlight some of the site’s most helpful responses to these misconceptions. The full list, and many other wonderful resources, can be found at Understanding Evolution.

Misconceptions about Evolutionary Theory and Process

"Evolution is a theory about the origin of life."

Evolutionary theory does encompass ideas and evidence regarding life's origins (e.g., whether or not it happened near a deep-sea vent, which organic molecules came first, etc.), but this is not the central focus of evolutionary theory. Most of evolutionary biology deals with how life changed after its origin. Regardless of how life started, afterwards it branched and diversified, and most studies of evolution are focused on those processes.

For more, see our questions on "What is Evolution?" and "Isn't the Origin of Life Highly Improbable?".

"Evolution is like a climb up a ladder of progress; organisms are always getting better."

One important mechanism of evolution, natural selection, does result in the evolution of improved abilities to survive and reproduce; however, this does not mean that evolution is progressive — for several reasons. First, natural selection does not produce organisms perfectly suited to their environments. It often allows the survival of individuals with a range of traits — individuals that are "good enough" to survive. Hence, evolutionary change is not always necessary for species to persist. Many taxa (like some mosses, fungi, sharks, opossums, and crayfish) have changed little physically over great expanses of time. Second, there are other mechanisms of evolution that don't cause adaptive change. Mutation, migration and genetic drift may cause populations to evolve in ways that are actually harmful overall or make them less suitable for their environments. For example, the Afrikaner population of South Africa has an unusually high frequency of the gene responsible for Huntington's disease because the gene version drifted to high frequency as the population grew from a small starting population. Finally, the whole idea of "progress" doesn't make sense when it comes to evolution. Climates change, rivers shift course, new competitors invade — and an organism with traits that are beneficial in one situation may be poorly equipped for survival when the environment changes. And even if we focus on a single environment and habitat, the idea of how to measure "progress" is skewed by the perspective of the observer. From a plant's perspective, the best measure of progress might be photosynthetic ability; from a spider's it might be the efficiency of a venom delivery system; from a human's, cognitive ability. It is tempting to see evolution as a grand progressive ladder with Homo sapiens emerging at the top. But evolution produces a tree, not a ladder — and we are just one of many twigs on the tree.

For more, see our questions "What is Evolution?" and "Did Evolution Have to Result in Human Beings?".

"Evolution means that life changed 'by chance.'"

Chance and randomness do factor into evolution and the history of life in many different ways; however, some important mechanisms of evolution are non-random and these make the overall process non-random. For example, consider the process of natural selection, which results in adaptations — features of organisms that appear to suit the environment in which the organisms live (e.g., the fit between a flower and its pollinator, the coordinated response of the immune system to pathogens, and the ability of bats to echolocate). Such amazing adaptations clearly did not come about "by chance." They evolved via a combination of random and non-random processes. The process of mutation, which generates genetic variation, is random, but selection is non-random. Selection favored variants that were better able to survive and reproduce (e.g., to be pollinated, to fend off pathogens, or to navigate in the dark). Over many generations of random mutation and non-random selection, complex adaptations evolved. To say that evolution happens "by chance" ignores half of the picture.

For more see our questions on "What is Evolution?" and "How do randomness and chance align with belief in God’s sovereignty and purpose?".

“Humans are not currently evolving”

Humans are now able to modify our environments with technology. We have invented medical treatments, agricultural practices, and economic structures that significantly alter the challenges to reproduction and survival faced by modern humans. So, for example, because we can now treat diabetes with insulin, the gene versions that contribute to juvenile diabetes are no longer strongly selected against in developed countries. Some have argued that such technological advances mean that we've opted out of the evolutionary game and set ourselves beyond the reach of natural selection — essentially, that we've stopped evolving. However, this is not the case. Humans still face challenges to survival and reproduction, just not the same ones that we did 20,000 years ago. The direction, but not the fact of our evolution has changed. For example, modern humans living in densely populated areas face greater risks of epidemic diseases than did our hunter-gatherer ancestors (who did not come into close contact with so many people on a daily basis) — and this situation favors the spread of gene versions that protect against these diseases.

For more see our question "Did evolution have to result in human beings?".

"Species are distinct natural entities, with a clear definition, that can be easily recognized by anyone."

Many of us are familiar with the biological species concept, which defines a species as a group of individuals that actually or potentially interbreed in nature. That definition of a species might seem cut and dried — and for many organisms (e.g., mammals), it works well — but in many other cases, this definition is difficult to apply. For example, many bacteria reproduce mainly asexually. How can the biological species concept be applied to them? Many plants and some animals form hybrids in nature, even if they largely mate within their own groups. Should groups that occasionally hybridize in selected areas be considered the same species or separate species? The concept of a species is a fuzzy one because humans invented the concept to help get a grasp on the diversity of the natural world. It is difficult to apply because the term species reflects our attempts to give discrete names to different parts of the tree of life — which is not discrete at all, but a continuous web of life, connected from its roots to its leaves.

Misconceptions about Natural Selection and Adaptation

“Natural selection involves organisms trying to adapt”.

Natural selection leads to the adaptation of species over time, but the process does not involve effort, trying, or wanting. Natural selection naturally results from genetic variation in a population and the fact that some of those variants may be able to leave more offspring in the next generation than other variants. That genetic variation is generated by random mutation — a process that is unaffected by what organisms in the population want or what they are "trying" to do. Either an individual has genes that are good enough to survive and reproduce, or it does not; it can't get the right genes by "trying." For example bacteria do not evolve resistance to our antibiotics because they "try" so hard. Instead, resistance evolves because random mutation happens to generate some individuals that are better able to survive the antibiotic, and these individuals can reproduce more than other, leaving behind more resistant bacteria.

“The fittest organisms in a population are those that are strongest, healthiest, fastest, and/or largest.”

In evolutionary terms, fitness has a very different meaning than the everyday meaning of the word. An organism's evolutionary fitness does not indicate its health, but rather its ability to get its genes into the next generation. The more fertile offspring an organism leaves in the next generation, the fitter it is. This doesn't always correlate with strength, speed, or size. For example, a puny male bird with bright tail feathers might leave behind more offspring than a stronger, duller male, and a spindly plant with big seed pods may leave behind more offspring than a larger specimen — meaning that the puny bird and the spindly plant have higher evolutionary fitness than their stronger, larger counterparts.

“Natural selection produces organisms perfectly suited to their environments.”

Natural selection is not all-powerful. There are many reasons that natural selection cannot produce "perfectly-engineered" traits. For example, living things are made up of traits resulting from a complicated set of trade-offs — changing one feature for the better may mean changing another for the worse (e.g., a bird with the "perfect" tail plumage to attract mates maybe be particularly vulnerable to predators because of its long tail). And of course, because organisms have arisen through complex evolutionary histories (not a design process), their future evolution is often constrained by traits they have already evolved. For example, even if it were advantageous for an insect to grow in some way other than molting, this switch simply could not happen because molting is embedded in the genetic makeup of insects at many levels.

]]> Mon, 21 Nov 11 04:00:31 -0800 http://biologos.org/blog/what-does-the-fossil-record-show?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication http://biologos.org/blog/what-does-the-fossil-record-show?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication Organisms have changed significantly over time. In rocks more than 1 billion years old, only fossils of single-celled organisms are found. Moving to rocks that are about 550 million years old, fossils of simple, multicellular animals can be found. Yesterday, in our BioLogos podcast, we looked at the question of transitional fossils. Today, to follow-up, we’d like to repost our recently revised FAQ on the fossil record – one of ten Questions we’ve updated. We’ve also edited how the Questions are organized, to help readers more easily find answers to the topics they care about, from explaining the BioLogos view to responding to arguments against God and Christianity. If you haven’t yet, we encourage you to take a look at the changes!

Evidence of Gradual Change

Organisms have changed significantly over time. In rocks more than 1 billion years old, only fossils of single-celled organisms are found. Moving to rocks that are about 550 million years old, fossils of simple, multicellular animals can be found. At 500 million years ago, ancient fish without jawbones surface; and at 400 million years ago, fish with jaws are found. Gradually, new animals appear: amphibians at 350 million years ago, reptiles at 300 million years ago, mammals at 230 million years ago, and birds at 150 million years ago.¹ As the rocks become more and more recent, the fossils look increasingly like the animals we observe today.

The Transition to Land: Sea Creatures to Land Animals

Fossils of land animals, or tetrapods, first appear in rocks that are about 370 million years old. In older rocks, only sea creatures are found. But in 1998, scientists found a fossilized fin, 370 million years old, with eight digits similar to the five fingers humans have on their hands, as shown in Figure 1. However, the fin was undoubtedly that of a fish, which means this fossil is strong evidence of a transitional form.

Figure 1:An Illustration of the fossilized fin found in 1998. Its resemblance to a tetrapod is an indication of gradual evolutionary change from sea creatures to land animals. Source: Image is used by permission from Falk, Coming to Peace, 113.

One of the great success stories in the examination of the fossil record was the finding of a near-perfect fossilized transition between a vertebrate adapted for water and one adapted for land. Evolutionary biologist Neal Shubin set out to find a more complete transitional specimen than the 1998 fin. He determined the exact age of rock that he expected would yield a transitional land/water animal, and then he and his team spent four summers in the Arctic scouring rocks of that age to find one. The results (see Figure 2 below) were spectacular.²



From Reptiles to Mammals

Mammals first appeared in the fossil record about 230 million years ago, nearly 70 million years after reptiles first appeared. One group of reptiles, the cynodonts, first appeared about 260 million years ago and became increasingly mammal-like in more recent fossils—circa 245 million years ago. This change can be seen most clearly in the bone structure of the ear, as illustrated in Figure 3.



Figure 3: As shown in the image above, transitional fossils of cynodonts had two jaw hinges. These fossils date from a time when the dentary and squamosal bones were beginning to take over the role of jaw hinge (hinge #2). This allowed the articular and quadrate bones to evolve into the second and third bones of the mammalian ear, as shown on the right. Source: Image used by permission from Falk, Coming to Peace, 119. Originally from F. H. Pough, J. B. Heiser, and W. N. McFarland, Vertebrate Life, 4th ed. (Upper Saddle River, NJ: Prentice Hall, 1996), 607.

Scientists found a species of cynodonts, dating to just before the emergence of mammals, that had a double jaw hinge like that of a mammal. A pair of bones found in even earlier cynodont fossils seems to have transitioned slowly into the ear. No other fossils have been found that share a similar structure to the transitional cynodonts and date back before the time of mammals. Likewise, soon after mammals appeared, these cynodonts became extinct. This timing implies that the cynodont fossils record the transition from reptiles to mammals.³

Transitional Forms: Few and Far Between

Transitional forms occur just when one might expect to see a change from one body type to another. However, a common objection is that few transitional fossils have been discovered; thus many lineages cannot be traced smoothly.

There are several reason for these gaps in the fossil record. First, fossilization is a very rare event. Plus, transitional species tend to appear in small populations, where rapid changes in the environment can provide a stronger evolutionary drive. Finally, because fossilization itself is a rare event, smaller populations are sure to produce fewer fossils. The fact that transitional species have been found at all is remarkable, and it offers further support of gradual, evolutionary change.

Notes

1. Darrel Falk, Coming to Peace with Science, 83-84.
2. For a discussion of the science and the story of the discovery, see Darrel Falk, “In the Bones” (July 29, 2009), (accessed 10/21/2011) and Stephen Matheson, “New Limbs from Old Fins, Part 2” (Sept 16, 2011), (accessed 10/21/2011). Shubin’s 2008 book Your Inner Fish (Pantheon) is also very good.
3. Falk, Coming to Peace, 115–120; F. H. Pough, J. B. Heiser, and W. N. McFarland, Vertebrate Life, 4th ed. (Upper Saddle River, NJ: Prentice Hall, 1996), 607; M. J. Benton, Vertebrate Palaeontology: Biology and Evolution (London: Unwin Hyman, 1990), 228–231; E. H. Colbert, M. Morales, and E. C. Minkoff, Colbert’s Evolution of the Vertebrates: A History of the Backboned Animals Through Time (New York: Wiley-Liss, 2001), 274–277; T. S. Kemp, The Origin and Evolution of Mammals (New York: Oxford University Press, 2005), 75–78.
• Back to Top
]]> Fri, 11 Nov 11 06:13:26 -0800