Like any theory, Darwin’s idea that evolution proceeds through natural selection was once merely a hypothesis. In this post, we’ll look at some of the early observations Darwin made on biogeography: the study of where species are distributed across the globe. These lines of evidence would later prod him to consider the possibility that species arise through a natural process of gradual change over time, rather than being independently created in each location where they are found.

The curious case of the missing mammals

As a widely-travelled naturalist on the HMS Beagle, Darwin studied a large number of different environments and documented the species he found in each. The Beagle, engaged as it was in an effort to map the coastline of South America, naturally paid call to numerous island groups along the way, including islands at a great distance from a continent (i.e.oceanic islands). One observation that Darwin made about oceanic islands is that none that he studied had terrestrial mammals on them. Later work, after his voyage, would confirm that this was a general rule. Oceanic islands lack terrestrial mammal species, except for small species that were introduced by humans. In contrast, flying mammals (i.e. bats) were found on oceanic islands, and often these species were endemic (i.e. found nowhere else in the world but the island in question).

Darwin found these observations difficult to square with his (then) working assumption that species were independently created in (and specifically created for) the locations in which they are found across the globe. He discusses these observations, and the questions they raised in his mind, in two chapters entitled “Geographical Distribution” in his Origin of Species. After discussing the similar case that amphibians (such as frogs, newts, and so on) are also not to be found on oceanic islands, he turns his attention to the missing mammals:

Mammals offer another and similar case. I have carefully searched the oldest voyages, but have not finished my search; as yet I have not found a single instance, free from doubt, of a terrestrial mammal (excluding domesticated animals kept by the natives) inhabiting an island situated above 300 miles from a continent or great continental island.... It cannot be said, on the ordinary view of creation, that there has not been time for the creation of mammals; many volcanic islands are sufficiently ancient, as shown by the stupendous degradation which they have suffered and by their tertiary strata: there has also been time for the production of endemic species belonging to other classes; and on continents it is thought that mammals appear and disappear at a quicker rate than other and lower animals. Though terrestrial mammals do not occur on oceanic islands, aërial mammals do occur on almost every island. New Zealand possesses two bats found nowhere else in the world: Norfolk Island, the Viti Archipelago, the Bonin Islands, the Caroline and Marianne Archipelagoes, and Mauritius, all possess their peculiar bats. Why, it may be asked, has the supposed creative force produced bats and no other mammals on remote islands? On my view this question can easily be answered; for no terrestrial mammal can be transported across a wide space of sea, but bats can fly across. Bats have been seen wandering by day far over the Atlantic Ocean; and two North American species either regularly or occasionally visit Bermuda, at the distance of 600 miles from the mainland. I hear from Mr. Tomes, who has specially studied this family, that many of the same species have enormous ranges, and are found on continents and on far distant islands. Hence we have only to suppose that such wandering species have been modified through natural selection in their new homes in relation to their new position, and we can understand the presence of endemic bats on islands, with the absence of all terrestrial mammals.

(As an aside, it’s important to note that Darwin, when he discusses the “supposed creative force” is not here arguing against the existence of God as creator in general, but rather against the “ordinary view of creation” common at the time: that God had episodically created species at specific geographical locations (what were called “centers of creation”) and that biogeographical patterns could be explained with limited dispersal from those centers. Darwin himself held to this common view at the start of his voyage on the Beagle, and that is the model he is attempting to refute in Origin, since it was a prevailing view among scientists at the time. Darwin and many of his scientific contemporaries also had no difficulty viewing natural processes as part of God’s regular action in the world, as is evident in Darwin’s correspondence with American botanist Asa Gray, among others.)

So, for Darwin, his biogeographical observations sat at ease with his (later) ideas of colonization and subsequent species change through natural selection, but made no sense to him if one held to an independent creation model. Many oceanic islands were very old, yet no mammals had been created there. Many oceanic islands had habitat suitable for mammals (or, indeed, for amphibians, as he notes) yet no such species had been created for that suitable habitat.

Island endemics and their continental “allied species”

Darwin noticed more than the absence of certain species groups on oceanic islands. He also noticed an interesting feature of the species that were present: an endemic species on an oceanic island would often have strong similarities with a species on the mainland closest to the island in question. Additionally, the pairing of oceanic endemic species with continental species often seemed to override expectations that species found in similar environments would be more similar to each other. These observations prompted him to reflect further on the possible means by which these “closely allied species” arose. As Darwin would write in his Origin this repeated pattern made a significant impression on him, and further caused him to doubt that endemic species had been individually created for each oceanic island. His visit to the Galapagos would prove instrumental on this point:

The most striking and important fact for us in regard to the inhabitants of islands, is their affinity to those of the nearest mainland, without being actually the same species. Numerous instances could be given of this fact. I will give only one, that of the Galapagos Archipelago, situated under the equator, between 500 and 600 miles from the shores of South America. Here almost every product of the land and water bears the unmistakeable stamp of the American continent. There are twenty-six land birds, and twenty-five of these are ranked by Mr. Gould as distinct species, supposed to have been created here; yet the close affinity of most of these birds to American species in every character, in their habits, gestures, and tones of voice, was manifest. So it is with the other animals, and with nearly all the plants, as shown by Dr. Hooker in his admirable memoir on the Flora of this archipelago. The naturalist, looking at the inhabitants of these volcanic islands in the Pacific, distant several hundred miles from the continent, yet feels that he is standing on American land. Why should this be so? why should the species which are supposed to have been created in the Galapagos Archipelago, and nowhere else, bear so plain a stamp of affinity to those created in America? There is nothing in the conditions of life, in the geological nature of the islands, in their height or climate, or in the proportions in which the several classes are associated together, which resembles closely the conditions of the South American coast: in fact there is a considerable dissimilarity in all these respects. On the other hand, there is a considerable degree of resemblance in the volcanic nature of the soil, in climate, height, and size of the islands, between the Galapagos and Cape de Verde Archipelagos: but what an entire and absolute difference in their inhabitants! The inhabitants of the Cape de Verde Islands are related to those of Africa, like those of the Galapagos to America. I believe this grand fact can receive no sort of explanation on the ordinary view of independent creation; whereas on the view here maintained, it is obvious that the Galapagos Islands would be likely to receive colonists, whether by occasional means of transport or by formerly continuous land, from America; and the Cape de Verde Islands from Africa; and that such colonists would be liable to modification;—the principle of inheritance still betraying their original birthplace.

Many analogous facts could be given: indeed it is an almost universal rule that the endemic productions of islands are related to those of the nearest continent, or of other near islands.

Rethinking independent creation

For Darwin, both of these observations (that oceanic islands lacked terrestrial mammals, and that endemic species on islands were most similar to a species on the closest mainland) had the same explanation: his hypothesis that endemic, oceanic species were the modified descendants of a colonizing species from the nearest continent. This also explained the lack of amphibians and terrestrial mammals (but allowed for bats) - simply based on the ability of these classes of life to disperse across large expanses of ocean. Those that could disperse and colonize oceanic islands would experience modification in the new environment, and species unable to colonize these islands would never appear. To Darwin’s thinking, this explanation was wholly more satisfactory than the assumption that God had independently created every endemic species in its place, and arbitrarily chosen that oceanic islands did not need terrestrial mammals and amphibians.

Despite Darwin’s musing on the biogeographical patterns he observed, and the strong suggestion these patterns made of species change over time, a mechanism for that change would take some time for him to imagine. In our next post, we’ll look at that mechanism: Darwin’s idea of natural selection, and the evidence he assembled in its support prior to publishing the Origin.

Grantees will benefit from in-person interaction through a series of summer workshops in 2013, 2014, and 2015. These meetings will not only foster a broader knowledge base, but will build a sustained network of scholars and church leaders, both young and seasoned, who are serious about addressing the concerns of the church about evolution. Also in 2015, in connection with the third summer workshop, BioLogos will host a large conference open to scientists, scholars, and church leaders from around the world.

ECF History

In January 2012, BioLogos was awarded a multi-million dollar grant from the John Templeton Foundation to fund the work of scholars and church leaders on evolution and Christian faith. In spring 2012 we worked hard to get the word out. You may have seen announcements on the BioLogos website, in our newsletters, on the Books & Culture, Leadership Journal, or First Things websites, on your professional society’s listserv, or perhaps on your friend’s blog.

The response was overwhelming: we received 225 letters of intent for a total request of $21 million—about seven times the amount we had to offer. We needed to invite the most promising applicants to submit a full proposal, but recognizing the projects with highest potential would require broad expertise. From the beginning, we envisioned that a panel of scientists, pastors, and scholars would oversee the application and review process as well as play key advisory roles throughout the project. A team of eight highly qualified individuals came on board in the early months of the project. They reviewed each proposal and together recommended that BioLogos invite 86 applicants to submit full applications.

The deadline for submissions was October 1, 2012. As in the previous round, the ECF panel evaluated each proposal. In addition, we asked 55 other experts to participate, so that each proposal received 3-4 scores. Criteria for the decision included significance of topic, project design, creativity and innovation, long-term impact potential, feasibility, and budget.

The panel then met together November 29-30, 2012, to make the final funding decisions. In the end, they recommended that BioLogos give 37 awards, ranging from $23,000 to $300,000. BioLogos staff notified applicants of their awards on December 14, 2013.

The Grantees

As part of our objective to create a network of scholars and leaders, we awarded grants to organizations across the U.S. and the world. Thirty of the 37 grantees are domestic; seven are international, hailing from Canada, France, Great Britain, Netherlands, and Spain.

Two-thirds of the accepted projects will be led by teams—some with three or more Project Leaders. We expect that the teamwork and time spent together at our summer workshops will be the start of a long-lasting network of people dedicated to helping the church think carefully about origins.

Applicants chose to apply under one of three program tracks: interdisciplinary scholarship (Track 1), intra-disciplinary scholarship (Track 2), and translational projects (Track 3). Track 1 projects focus on both the collaboration between individuals in different disciplines and the development of projects at the interface of different content areas. Track 2 projects focus on work done within a specific discipline. Track 3 focuses on projects that encourage Christians, especially those within more conservative traditions, to engage in meaningful and productive dialogue to reduce tensions between mainstream science and the Christian faith. The numbers of grantees in Tracks 1, 2, and 3 are 6, 8, and 23, respectively.

Many of the scholarly projects tackle questions about Adam and Eve, the Fall, human identity, and Original Sin—some of the most critical interpretive issues for evangelical theology.  Some examples: 

• Theologian Oliver Crisp of Fuller Seminary will take an analytic theology approach to ask to what extent a theological account of the origin of human sin depends upon the evolution of modern humans from one and only one ancestral pair—especially if that pair does not appear to correspond to what we would think of as modern human beings. 

• Pastor Michael Gulker and philosopher James Smith, leading a large team from The Colossian Forum, ask a related question: if humanity emerged from non-human primates—as genetic, biological, and archaeological evidence seems to suggest—then what are the implications for Christian theology’s traditional account of origins, including both the origin of humanity and the origin of sin? 

• Biologist Dennis Venema of Trinity Western University and New Testament scholar Scot McKnight of Northern Seminary will write a book on the evidence for evolution and population genetics, with informed theological reflection on how these issues interact with orthodox Christianity.

• Biologist David Wilcox of Eastern University will develop an updated model of human identity which reflects the complex recent scientific advances in genetics and paleoanthropology and yet is sensitive to theological concerns.  

These are just a few of the scholarly awards; check out the Grantees page for full descriptions of all Track 1 and Track 2 projects.

All projects have translational potential, but Track 3 projects are designed to meet the needs of a particular constituency within the evangelical church. These projects run the gamut from ethics to education to media production to ministry resources.  Some examples include:

• Theologian Lee Camp of Lipscomb University will produce “The Questions in Monkey Town,” an episode of Tokens, a live variety show that features musical performances, comedic sketches, brief interpretive monologues, and dialog with authors and scholars. The episode will be performed and filmed on the site of the famous Scopes Trial in Dayton, Tennessee.

• Chaplain Joshua Hayashi and Educator Diane Sweeney of the Punahou School in Hawaii will lead a team to produce multimedia curricula aimed at helping high school students connect with their biology curricula and, at the same time, deepen their Christian faith.

• Physics teacher and pastor Benoît Hébert of Science et Foi Chrétienne in France will lead an international, multi-denominational team of French speaking Evangelical scientists, pastors and church leaders to produce a large number of resources on evolutionary creation.

• Pastor Seung-Hwan Kim of Grace Truth Community Church, a Southern Baptist church in Cambridge, Massachusetts, will produce teaching and preaching materials about evolution for church leaders.

• President Gregory Wolfe and Director of Resource Development for IMAGE will gather artists and writers of faith whose work explores the dialogue between evolutionary science and faith practice, convening a conversation between them and scientists, theologians, and church leaders in private and public conferences.

Again, this is just a taste of the diversity of Track 3 projects. Read more about each project on the Grantees page. You can look forward to an incredible variety of resources coming out of the ECF program, many of which will be featured right here on the BioLogos Forum.

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.

For more than a century, evangelicals and fundamentalists have typically rejected both evolution and higher biblical criticism. Sometimes there are good reasons: the claims of some biblical scholars are so outrageous and the claims of some scientists so anti-religious, that a strongly negative response is entirely appropriate. Too often, however, the evangelical encounter with modern science conforms to what historian Mark Noll has called “the scandal of the evangelical mind”—namely, “that there is not much of an evangelical mind.” Attitudes toward science have been crucial to this analysis. As Noll says, “since 1960 creationism has done more than any other issue except abortion to inflame the cultural warfare in American public life.” (p. 192)

Readers who want to know more about Noll’s book and its reception should go here and here. His conclusions about evangelicals and science are fully consistent with those I am about to present.

Evangelicals in Tension with Science

Evangelicals exhibit considerable tension and ambivalence when it comes to science, especially human evolution. On the one hand, evangelicals enthusiastically embrace the findings of science, when it comes to most applications in medicine and engineering. They also accept the experimental sciences, such as physics, chemistry, physiology, or thermodynamics. They have no problems with gravitation, the periodic table, the circulation of the blood, or the law of entropy. Here, their attitude is highly empirical: if it can be shown from repeatable experiments and observations, it’s true and presents no challenge whatsoever to religious belief.

On the other hand, evangelicals are quite hesitant to accept some conclusions of the so-called historical sciences, such as geology, cosmology, and evolutionary biology. Fundamentalists reject the very legitimacy of those sciences, and have created their own alternative explanation, “creation science,” which comports with their particular views of biblical authority and hermeneutics. Evangelicals are more ambivalent. As we’ve seen, many evangelicals accept the big bang and modern geology, with a 4.65 billion-year-old earth and the enormously long history of living things before humans arrived on the planet. But evolution–understood here to mean the common descent of humans and other organisms–presents very serious problems for many, perhaps most, evangelicals. This motivates them to look for alternative views.

The alternatives evangelicals embrace are precisely those we have studied in this series. Some eagerly support the YEC view. Others prefer one of the many varieties of the OEC view. Many like the strident tone of the ID movement, with its vigorous assault on biological and cultural “Darwinism” and its near-universal rejection of human evolution. For most evangelicals, however, TE is probably not a viable option at present, for biblical and theological reasons.

Reconciling Evolution with Scripture

Most evangelicals do not see any reasonable way to combine human evolution with the following beliefs:

• the uniqueness of humans, who alone bear the “image of God”
• the fall of Adam and Eve, the original parents of all humans, from a sinless state, by their own free choices to disobey God
• the responsibility of each person for their own actions and beliefs, within a universe that is not fully deterministic
• the redemption of individual persons by the atoning sacrifice of Christ.

Evangelicals cannot and must not be separated from these crucial beliefs about human dignity, freedom, responsibility, sin, and redemption. The 64-dollar question is: can these beliefs be maintained without simultaneously affirming the necessity of an historical, separately created first human pair? The answer is probably in the hands of evangelical academics, especially theologians and biblical scholars. Can they be persuaded that the scientific evidence for evolution is sufficiently strong to warrant a re-examination of the traditional view? Can a credible gospel and credible science be harmonized?

There exists an enormous gap between popular conceptions of science–conclusions, methods, and attitudes–and those of scientists themselves. This gap is not unique to science among practitioners of specialized knowledge, and it is not unique to evangelicals among the lay public. But it is real and very significant, and it affects theologians and biblical scholars no less than anyone else. Those who try to bridge this gap are mostly scientists (in their role as educators at colleges and universities and insofar as they write books for lay readers) and science journalists. Many influential members of those professional communities are skeptical or even strongly hostile toward Christian beliefs, and this can exacerbate an already difficult state of affairs. If ways can be found to popularize good science, while showing appropriate sensitivity to the concerns of evangelicals, it would be a very good thing.

Signs of Hope

Certainly there are reasons to hope. The conversation about science and religion is considerably broader now than it was at the time of the Scopes trial in 1925. Back then, many Protestants faced a very grim choice. On the one hand, they could follow politician William Jennings Bryan and the fundamentalists, rejecting modern science in the name of biblical authority and orthodox beliefs. On the other hand, they could follow theologian Shailer Mathews and the modernists, rejecting biblical authority and orthodox beliefs in the name of modern science. There was no one out there like John Polkinghorne, Francis Collins, Joan Centrella, Owen Gingerich, Simon Conway Morris, William Phillips, or Ian Hutchinson—to name just a few of the many top scientists today who accept evolution while affirming the divinity of Jesus, the bodily resurrection, and the actual divine creation of the universe. But they are all scientists, not theologians (except for Polkinghorne, who is both). In Galileo’s day, it was the scientists who eventually convinced the theologians and biblical scholars to accept Copernicus’ theory of the earth’s motion around the sun. But, it took a long time, and the process was difficult and often painful. Thus far, the biblical scholars and theologians who have tried to move the conversation forward have not been very well received, as Richard Ostling has so capably reported. I suspect we are in for more of the same.

It’s Your Turn to Talk

That’s what I think. What do you think? I’ll mainly be listening quietly, since I’ve now said all I wanted to say. Thank you all for hanging in there for ten months—far longer than I had originally anticipated. After a short respite I’ll return with a new series, but I’ll keep the topic under wraps for the time being.

According to Merriam Webster, the term “intelligent design” has been used since at least 1847, in reference to “the theory that matter, the various forms of life, and the world were created by a designing intelligence.” That’s a decent definition, also consistent with those offered by today’s proponents of intelligent design (ID). For example, the leading ID think tank, The Discovery Institute (Seattle), has this:

Intelligent design refers to a scientific research program as well as a community of scientists, philosophers and other scholars who seek evidence of design in nature. The theory of intelligent design holds that certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection.

And in the opening sentence of a book he edited with philosopher Michael Ruse, ID theorist William Dembski said, “Intelligent Design is the hypothesis that in order to explain life it is necessary to suppose the action of an unevolved intelligence.” (Debating Design, p. 3)

On the other hand, while a recent contest on a prominent intelligent design (ID) website uncovered several other early uses of the term, it is important to note that it does not always mean exactly the same thing in each reference. The term itself has an interesting history, and while ID authors obviously did not invent the term “intelligent design,” they have given it specific content in recent years. Indeed, they have even removed content in some cases: a point I will return to later is that, though it seems the only viable candidate for such an “unevolved intelligence” is God, ID proponents sometimes seem to do cartwheels to avoid saying as much. When a term has such a complicated past, there simply is no substitute for looking at specific references in their own contexts as we move to seeing how ID plays out today as one of the 5 ways of relating science and the Bible.

Interestingly, many Protestant “modernist” scientists and theologians from William Jennings Bryan’s day (see my previous column) unhesitatingly endorsed the idea that a designing intelligence lay behind nature. At least one such person, Nobel prize-winning physicist Arthur Holly Compton, even used the very term “intelligent design” in an address he gave at a Unitarian church in 1940: “The chance of a world such as ours occurring without intelligent design becomes more and more remote as we learn of its wonders.” (Quoting his pamphlet from 1940, The Idea of God as Affected by Modern Knowledge, p. 13. For more about this aspect of Compton’s views, click here.) However, Compton regarded design as a philosophical and theological inference from science, not an explanation within science to be invoked when other explanations fail. He also accepted the common ancestry of humans and other organisms. This is a significant difference from the ID movement today, which offers ID as a scientific alternative to Darwinian evolution and (at least in many cases) seeks to undermine public confidence in common ancestry (even though ID per se is not actually opposed to it).

If any ID proponents are sympathetic to the type of religious modernism that Compton and his friends embraced, I cannot tell you who they are. In a curious, ironic twist, ID is often used by conservative Christian apologists partly to defend a cluster of traditional theological and hermeneutical positions that none of the modernists would have defended. A further irony: the intellectual descendants of the modernists—those scientists and theologians who occupy the left wing of the modern “dialogue” of science and religion—exhibit a studied avoidance of the term “design,” disconnecting them on that score from the modernists of the 1920s.

Many other contemporary writers, including some evangelical TEs, are also reluctant to use the word “design,” precisely because in their view it has been co-opted by ID proponents and they do not want readers to misunderstand their position(s). They may agree with ID proponents that certain features of the universe reflect divine design, but because they do not see design as a scientific explanation they employ other language. (Likewise, the YECs have co-opted the word “creationism” to mean just one specific understanding of God’s creative activity, leading most advocates of other views either to provide their own definitions of the word or else to avoid using it altogether. Politics dogs this conversation at every turn.)

Core Tenets or Assumptions of Intelligent Design

With that bit of historical context for the term “Intelligent Design,” let’s now look at the first of the Core Tenets of this perspective in its current state, and as it is most often used by those associated with the Intelligent Design movement.

(1) The Bible is NOT to be mentioned (at least for now); ditto for “God” and “theology” as far as possible.

This is a deliberate strategy, adopted for political reasons to keep arguments at the level of philosophy and science. Here, “political” refers to the American political system, with its constitutional disestablishment of religion, not to partisan politics. Since the 1980s, federal courts have consistently ruled that “creationism” (which was specifically of the YEC variety in the relevant cases) is sectarian religion, not science, and therefore it cannot be taught in public school science classes. Anxious to avoid a similar fate, proponents of ID always want to ensure that they are not perceived as advocates of “creationism.” The less they mention God and the Bible, the reasoning goes, the less likely they are to fall afoul of those decisions.

The First Amendment to the U.S. Constitution, pertaining to the freedom of religion and the freedom of the press.
Source: http://www.rochester.edu/college/psc/images/Courses/Spring2008/FirstAmendment.png

Phillip Johnson, the former law professor who effectively began the ID movement some twenty years ago, has put it bluntly: “To put things on a more rational basis, the first thing that has to be done is to get the Bible out of the discussion.” He quickly adds, “This is not to say that the biblical issues are unimportant; the point is rather that the time to address them will be after we have separated materialist prejudice from scientific fact.” (“The Wedge: Breaking the Modernist Monopoly on Science,” Touchstone: A Journal of Mere Christianity, July/August 1999, p. 22.)

If God and the Bible are really to be left out for the time being, then why am I discussing ID in a series on “Science and the Bible”? It’s a fair question. I simply don’t see any way meaningfully to avoid talking about ID apart from the culture wars in which it is embedded (I’ll say more about this in a subsequent column), and the Bible is never far from the surface when the battle being fought involves origins. Conservative Christians sense that ID really is about God—Dembski’s “unevolved intelligence”. As Dembski himself has said, “no intelligent agent who is strictly physical could have presided over the origin of the universe or the origin of life”, and there aren’t a lot of candidates for that job. Many Christians also identify strongly with the ways in which ID seeks to confront the secular establishment, in an explicitly-stated effort to combat what Johnson calls “the modernist scientific and intellectual world, with its materialist assumptions.” (“The Wedge,” p. 23.) They see it as a way of getting traditional theistic perspectives and Christian values back into the academy, once “design” has become an acceptable academic talking point—and it isn’t very far from there to conversations about “science and the Bible.” If this were not so, then why would so much ID literature be published by Christian presses? Indeed, when I tell church audiences with a straight face that ID purports not to be about the Bible at all, I’m usually met with considerable skepticism.

When I’m back in about two weeks, we’ll look at further Core Tenets of ID—the ones that have even less to do with the Bible, explicitly, and more to do with the way we approach the study of the natural world.

With his compelling personal story of becoming England’s “most reluctant convert,” his towering intellect, and his inimitable eloquence, American evangelicals’ lionization of Lewis is certainly understandable.² But when we attempt to lionize people we often ironically end up taming them, paring their claws so that our heroes and our preconceptions can safely cohabitate in our imaginations. But Lewis is no safer a lion than Aslan, and he will not go quietly into our tidy evangelical boxes. To be frank, American Evangelicalism’s infatuation with Lewis is in many respects somewhat odd. For here is a pathologically populist movement with a penchant for Big Tent Revivalism, an obsession with liturgical innovation, a deep-seated suspicion of ecclesiastical tradition, and a raw nerve about the doctrine of justification, falling head-over-heels for a tweed-jacketed, Anglo-Catholic Oxford don—a curmudgeonly liturgical traditionalist who was fuzzy on the atonement, a believer in purgatory, and, as we shall see, whose views on Scripture, Genesis, and evolution position him well outside of American Evangelicalism’s standard theological paradigms. All of that is to say that Lewis was not “just like us”—any of us—and if we would do him justice, we must be prepared to be surprised by Jack.

In what follows, I would like to look at three areas relevant to faith and science discussions where Lewis’s stated views might be surprising for his American Evangelical admirers—namely, his views on Scripture generally and Genesis in particular, his views on Adam and the doctrine of the Fall, and his views on evolutionary science and the myth of ‘Evolutionism.’

Reflections on the Scriptures: Lewis on the Bible, Myth, & Fact

Lewis derived his theological understanding of the Bible from his reading of Scripture, his intimate knowledge of the Church Fathers and the Medieval Doctors, and also from his awareness of modern biblical scholarship. While Lewis was regularly critical of Modernist biblical scholarship’s naturalistic dismissal of the miraculous, its pedantry, literary tin-ear, and over-eagerness to conflate Jesus’ story with the stories of pagan mythologies (he had precious little patience for Rudolf Bultmann, for instance ), he was not at all given to the knee-jerk reactionary Fundamentalism which has held so much sway in American Evangelical culture. In fact, Lewis incorporated many of the more well-supported conclusions of modern biblical criticism into his theology of Scripture, not least critical opinions about the historicity of much of the Old Testament. In good Anglican fashion, Lewis creatively drew upon the deep resources of the Church’s grand Tradition in order to think through the contemporary problems posed by modern critical scholarship. Here I wish to focus on three features of Lewis’s theological conception of Scripture—his understanding of the Bible as being incarnational and sacramental in character, and Christotelic in focus—before turning to his theological reading of Genesis 1-3.⁴

Inspiration and Incarnation

According to Lewis, the Bible is both a vessel of the divine Word and also a profoundly human collection of documents. In his longest, most substantive piece on Scripture, chapter XI of Reflections on the Psalms, Lewis frames a thoroughly incarnational understanding of the Bible:

The human qualities of the raw materials show through. Naïvety, error, contradiction, even (as in the cursing Psalms) wickedness are not removed. The total result is not “the Word of God” in the sense that every passage, in itself, gives impeccable science or history. It carries the Word of God; and we (under grace, with attention to tradition and to interpreters wiser than ourselves, and with the use of such intelligence and learning as we may have) receive that word from it not by using it as an encyclopedia or an encyclical but by steeping ourselves in its tone or temper and so learning its overall message.⁵

Lewis’s reference to “[the] human qualities” of the Bible’s “raw materials” is suggestive. As Peter Enns puts it in his book Inspiration & Incarnation: Evangelicals and the Problem of the Old Testament, the Incarnation of the Son and the inspiration of Scripture are “analogous.”⁶ Lewis clearly agrees. He goes on in the chapter to articulate a theology of Scripture precisely in incarnational terms:

For we are taught that the Incarnation itself proceeded “not by the conversion of the godhead into flesh, but by taking of (the) manhood into God”; in it human life becomes the vehicle of Divine life. If the Scriptures proceed not by conversion of God’s word into literature but by taking up of a literature to be the vehicle of God’s word, this is not anomalous.⁷

According to Lewis, the means whereby God gives us Scripture is not by faxing us transcripts of inner-Trinitarian dialogue direct from Heaven, but rather, on analogy with the Incarnation, by taking up very human literature and utilizing it to communicate His Divine life to us.

“We might have expected, we may think we should have preferred, an unrefracted light giving us ultimate truth in systematic form—something we could have tabulated and memorised and relied on like the multiplication table.”⁸ But God has instead deigned to give us a very human book, just as He deigned to send us a fully human Savior. Lewis makes this point most poignantly in his Introduction to J.B. Phillips’s Letters to Young Churches where he writes:

The same divine humility which decreed that God should become a baby at a peasant-woman’s breast, and later an arrested field-preacher in the hands of the Roman police, decreed also that He should be preached in a vulgar, prosaic and unliterary language. If you can stomach the one, you can stomach the other. The Incarnation is in that sense an irreverent doctrine: Christianity, in that sense, an incurably irreverent religion. When we expect that it should have come before the World in all the beauty that we now feel in the Authorised Version we are as wide of the mark as the Jews were in expecting that the Messiah would come as a great earthly King.⁹

For Lewis, God’s work in the inspiration of Scripture not only communicates but also emulates God’s humble, self-effacing work in the Incarnation. If the heart of Christianity, “an incurably irreverent religion,” should be the Incarnation, “an irreverent doctrine,” then it ought to come as no surprise that that doctrine should be most fundamentally communicated via an irreverent book.

A corollary of Lewis’ incarnational and sacramental view of Scripture is that when it comes to studying the Scriptures we must be prepared to be surprised. Lewis warns against “the Fundamentalist’s” procedure of attempting to frame our ideas of Scripture a priori, deducing parameters for what the Scriptures can and cannot be from our preconceptions about God. Lewis thinks such an approach to be a nonstarter:

[There] is one argument which we should beware of using…: God must have done what is best, this is best, therefore God has done this. For we are mortals and do not know what is best for us, and it is dangerous to prescribe what God must have done–especially when we cannot, for the life of us, see that He has after all done it.¹⁰

Instead, says Lewis, we should take a humble, a posteriori approach, looking and seeing just what kind of book it is that God has actually given us before making grand doctrinal declarations. “To a human mind,” Lewis recognizes, an incarnational Bible “seems, no doubt, an untidy and leaky vehicle.”¹¹ But it appears that this is what God has given us, and we must trust that God knows what He is doing. As Lewis says, “Since this is what God has done, this, we must conclude, was best.”¹²

Myth Became Fact

For Lewis, the Word is also like the sacrament. Just as ordinary water, bread, and wine are taken up into and become conduits for and communicators of the Divine life that we so desperately need, so, also, all-too-ordinary human writings are taken up into and become conduits for and communicators of the Divine life and word. In Lewis’s view, we must receive the Divine word by approaching Scripture in a sacramental manner. We “receive that word,” as Lewis says, again, “not by using [Scripture] as an encyclopedia or an encyclical but by steeping ourselves in its tone or temper and so learning its overall message.”¹³ For Lewis, at least when it comes to the Old Testament, receiving the Word means more than simply paying critical attention to the surface meaning of the text, the sensus literalis. Instead, we must press beyond the surface to the sensus plenior, to the “second sense” of the Old Testament, namely, Christ Himself. “It is Christ Himself, not the Bible, who is the true word of God,” Lewis once wrote in a private letter. “The Bible, read in the right spirit and with the guidance of good teachers, will bring us to Him.”¹⁴ While such Christological sensus plenior interpretation may have fallen out of favor with many Protestants (to say nothing of thoroughgoing Modernist historical-critics), Lewis believes that “[we] are committed to it in principle by Our Lord Himself.”¹⁵ Citing Jesus’ words to His disciples on the road to Emmaus, Lewis argues that Christ “accepted—indeed He claimed to be—the second meaning of Scripture.” Citing a litany of Dominical sayings and New Testament texts, Lewis is clear that Christ is mysteriously the true spiritual center, climax, coherence, sum, and substance of the Old Testament Scriptures.¹⁶

Lewis stands in good company in thinking along these lines. The “good teachers” from which Lewis learned this hermeneutic are undoubtedly Aquinas, Bernard of Clairveaux, Augustine, Origen, and Irenaeus, not to mention the Apostles and Christ Himself. In short, Lewis is standing within the mainstream tradition of pre-Reformation theological interpretation. But Lewis is not simply striking a traditionalist posture. Like a scribe trained for the Kingdom, he is prepared to bring forth treasures new and old. By positioning himself within the grand tradition of pre-modern theological interpretation, Lewis frees himself to follow his highly-attuned modern literary-critical instincts regarding the historicity of much of the Old Testament while simultaneously upholding both a robust belief in the historicity of the Incarnation and a vital theological hermeneutic. He writes:

The earliest stratum of the Old Testament contains many truths in a form which I take to be legendary, or even mythical—hanging in the clouds, but gradually the truth condenses, becomes more and more historical. From things like Noah’s Ark or the sun standing still upon Ajalon, you come down to the court memoirs of King David. Finally you reach the New Testament and history reigns supreme, and the Truth is incarnate. And “incarnate” here is more than a metaphor. It is not an accidental resemblance that what, from the point of view of being, is stated in the form “God became Man,” should involve, from the point of view of human knowledge, the statement “Myth became Fact.”¹⁷

He sets up the above paragraph by saying, “[The Christian story] is like watching something come gradually into focus; first it hangs in the clouds of myth and ritual, vast and vague, then it condenses, grows hard and in a sense small, as a historical event in first century Palestine.”¹⁸ Apart from the Incarnation, then, much of the Old Testament would be but “myth,” “ritual,” and “legend.” These elements of the Old Testament only become tangible historical “Fact,” for Lewis, in the person and work of Christ.

Next time, Williams looks at how this understanding of Scripture framed Lewis' reading of Genesis 1-3.

Note

1. C.S. Lewis, A Grief Observed, (San Francisco: Harper Collins, 2001), 66
2. See Smietana, Bob, “C.S. Lewis Superstar: How a reserved British intellectual with a checkered pedigree became a rockstar for evangelicals,” http://www.christianitytoday.com/ct/2005/december/9.28.html
3. “Through what strange process has this learned German gone in order to make himself blind to what all men except him see?,” wrote Lewis in “Modern Theology and Biblical Criticism,” in Walter Hooper, ed., Christian Reflections (Grand Rapids: Eerdmans, 1995), 156
4. I owe the word “christotelic” to my teachers at Westminster. See especially the discussion in Peter Enns’ Inspiration and Incarnation: Evangelicals and the Problem of the Old Testament, (Grand Rapids: Baker Academic, 2005)
5. Lewis, Reflections on the Psalms, (San Diego: Harcourt Inc., 1986), 111-12
6. See note xii above.
7. Lewis, Reflections on the Psalms, 116
8. Ibid, 112
9. Lewis, “Modern Translations,” in God in the Dock, (Grand Rapids: Eerdmans, 1970), 230
10. Lewis, Reflections on the Psalms, 112
11. Ibid
12. Ibid, 113
13. Ibid, 112
14. Lewis in a letter, 8 November, 1952, in W.H. Lewis, ed., Letters of C.S. Lewis, (New York: Harcourt Brace Jovanovich, 1966), 247 cited in Martindale and Root, The Quotable Lewis, 72
15. Lewis, Reflections on the Psalms, 117
16. Ibid, 117-19
17. Lewis, “Is Theology Poetry?,” in The Weight of Glory and Other Essays, (New York: Harper Collins, 2001), 129
18. Ibid

Introduction

One of the reasons that some of us are hesitant to accept evolutionary creation is that it seems to make God responsible for the suffering and death of innumerable creatures over millions of years—before humans ever existed or sinned against their creator. Since we believe in and worship a God who is loving, benevolent, and all-powerful, it sounds quite implausible that our God would have created a world like that; therefore, any scientific evidence for evolution must be incorrect.

Other people look at the scientific evidence for evolution and find a compelling case that it has taken place during our earth's history. On this basis they may conclude that if evolution is true, then the belief in an all-powerful, perfectly good God must be false!

The trouble with both of these views is that they tend to invoke a completely abstract, philosophical god, not the living God of the Bible—the God who became a human being, experienced unimaginable suffering, and died in a grotesque and humiliating public display. The death of Jesus completely defied the expectations (and common sense) of his followers, as well as the expectations of any “rational” understanding of the way the Creator of the universe should act in the world. On the cross, in the person of Jesus, God took upon himself far more suffering than any creature has ever experienced.

If God himself is willing to die, particularly in such a gruesome way, then perhaps we should at least consider the possibility of God allowing the death of other creatures, too. But would this really be compatible with what we know of God through Scripture? In this essay, we will explore this quandary through a “theology of the cross”, a concept articulated by pastor George Murphy in his book Cosmos in the Light of the Cross.¹

Theology of the cross

Before we jump into the theological problems associated with evolution, let’s take a look at how we understand Christian theology itself. For the reformer Martin Luther, any theology (or science) that tries to reach knowledge of God apart from the cross is bad theology.² Instead, Luther pointed to a theologia crucis, in which the true God is seen first and foremost “through suffering and the cross”. To make his point even clearer, Luther insisted that “the CROSS alone is our theology”.³ It is the lens through which we view everything.

Of course Martin Luther, having lived in the 16th century, was not aware of the vast history of life on our planet (or any other aspect of modern science, for that matter), but George Murphy draws from Luther’s teachings the foundation that all human knowledge begins with the Word made flesh and crucified.⁴ With the cross of Christ as the ultimate framework through which we view reality, we are bound to view the processes of nature quite differently. As Murphy explains it,

A theology of the cross is an explication of belief in a God who becomes a participant in the history of the universe and thereby shares in the suffering, loss, and death that are part of worldly experience.⁵

God does not sit idly by and watch unaffected as his creatures suffer, but neither does he swoop in and make everything completely effortless and easy. Instead he chose another way, the crucifixion of Jesus—certainly not the approach that we would have preferred! The apostle Peter went so far as to try to talk Jesus out of it, but he was met with a stern rebuke (Matthew 16:21-23).

Why is evolution so disconcerting to Christians?

The problem of suffering throughout all of human history is troubling enough for us to reconcile with a loving, personal God. But in addition to that, the discovery of vast numbers of fossils reveals that death has taken place on a far greater scale than we had ever imagined. Both the wide variety of extinct creatures and their sheer numbers is quite staggering, and it raises questions about our Creator:

The picture of a God who is immune from suffering and death but who forces organisms through millions of generations and extinction is disturbing to those who believe in a God of love.⁷

The mass extinction of life on earth was already well established by the early 19th century—decades before Darwin’s research—and extinction can be empirically verified independent of any theory of evolution.⁸ The fact that the earth’s crust is a veritable graveyard of long-lost creatures is deeply troubling, and as late as the 1790’s, distinguished intellectuals such as Thomas Jefferson denied the very possibility of extinction.⁹

But in addition to the reality of species extinction, the theory of evolution by natural selection proposes that new species also arise in an environment containing widespread pain and death. Both the creatures that are now living and those that are gone are tainted by an “acrid smell of death”.¹⁰ It makes us wonder, if our Creator is not the God of the dead, but of the living (Mk. 12:27), where is God’s presence in the evolutionary picture?

In all honesty, creation through evolution is not what we would expect from God, but Scripture is full of examples in which God acts in unexpected ways. After all, God’s choosing to undergo an agonizing death on a cross is not what we would expect from the all-powerful Creator of the universe, either. In both cases, new life comes about through pain, suffering, and death. As George Murphy puts it,

A priori ideas about God have to be overcome, and God's character has to be learned from God's self-revelation.¹¹

God’s fullest self-expression is in Jesus Christ himself, one who is intimately familiar with and personally endured creaturely pain and death. The theology of the cross reveals that God's self-revelation takes place in situations of suffering, loss, and apparent hopelessness, much like situations that occur through natural selection.¹²

The crucifixion is disconcerting too

Not only is creation through evolution an unexpected and unsettling process, but so is the crucifixion of Jesus! Killing someone by hanging them on a cross is an unbearably painful, prolonged, humiliating form of death. It was such a horrific type of public execution that it wasn't until after the Roman Empire stopped the practice of crucifixion—and people no longer witnessed it personally—did the cross become a visual object of devotion.¹³ Our culture is sufficiently removed from crucifixion that we are desensitized to its original significance, but to connect it to our current context, imagine the reaction you would get by wearing jewelry designed to look like an electric chair.¹⁴

Once we are more attuned to the brutality of crucifixion, it seems all the more striking that the cross is the sign of God’s work, what George Murphy calls “the trademark of God”.¹⁵ The suffering and death of Jesus is featured prominently in the Gospels, but the crucifixion-resurrection pattern is strongly resonant within the Old Testament, too. Israel suffered and toiled as slaves in Egypt for centuries before they were rescued in the Exodus, bringing life to a people who were spiritually dead. Centuries later, the nation of Israel would experience death again when the Babylonians destroyed the Davidic monarchy, burned their Temple, killed their people, and sent many into exile.¹⁶ Neither Israel (God’s chosen people) nor Jesus (God’s own son) were spared from death and suffering; rather, suffering seems to have been the way in which God re-forms and renews humanity to fully bear His own image.

Redemption extends to all of creation

Fortunately, God’s story does not end with death. God gives new life after his creatures have been subjected to terrible circumstances. Redemption was promised to Israel itself—Ezekiel’s vision of the valley of dry bones describes how God would renew His chosen people (Ezek 37:1-14). Later, the astonishing resurrection of Jesus made salvation possible not only for Jews, but for all people in Christ (Gal 3:26-29). Ultimately, the New Testament makes it clear that God’s renewal will encompass the entire Creation:

For God was pleased to have all his fullness dwell in him, and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross. (Colossians 1:19-20)

With all wisdom and understanding, he made known to us the mystery of his will according to his good pleasure, which he purposed in Christ, to be put into effect when the times reach their fulfillment—to bring unity to all things in heaven and on earth under Christ. (Ephesians 1:8-10)

Christians are accustomed to thinking of the death of Christ in regard to humans, but our culture rarely acknowledges God plan for the redemption of His entire creation. This is partly attributable to the fact that discussions of creation and origins are often separated from the topic of salvation.¹⁷ In doing so we tend to marginalize Jesus as we argue about Genesis. Rather than fall into this trap, if we view nature through a theology of the cross, we will see Christ as both the alpha and the omega point in discussions of life’s history and life’s future. With this perspective, we are more apt to sense our solidarity with the rest of creation as we wait in eager anticipation of a glorious future:

The creation waits in eager expectation for the children of God to be revealed. For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope that the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God. (Romans 8:19-21)

Conclusion

As part of the Church’s conversation about the problem of natural evil, this essay is meant to be a brief introduction to a “theology of the cross”. One can explore this concept in greater detail in Murphy’s book The Cosmos in the Light of the Cross. While there is a lot more to be said, let me conclude with the following observation: though evolution may not be compatible with some interpretations of Christianity, evolutionary creation is certainly compatible with the crucified Christ and the theology of the cross. In the person of Jesus, God suffers with the world and ultimately redeems it. As George Murphy puts in, “The world's pains are God's stigmata.”¹⁸

Explore this Topic Further

• Miller, Keith. “And God saw that it was good”: Death and Pain in the Created Order. BioLogos series
• Murphy, George L. The Cosmos in the Light of the Cross. Harrisburg, PA: Trinity Press, 2003.
• Murphy, George L. “Cross, Evolution, and Theodicy: Telling It Like It Is”. In The Evolution of Evil. Edited by G. Bennett, M.J. Hewlett, T. Peters, and R.J. Russell. Göttingen: Vandenhoeck & Ruprecht, 2008.
• Southgate, Christopher. The Groaning of Creation: God, Evolution, and the Problem of Evil. Louisville, KY: Westminister John Knox Press, 2008.

Notes

1. Murphy, George L. The Cosmos in the Light of the Cross. Harrisburg, PA: Trinity Press, 2003.
2. Murphy, p34
3. “CRUX Sola Est Nostra Theologia,” in D. Martin Luthers Werke, Kritische Gesammtausgabe (Weimar: Hermann Boehlau, 1892), 5:172. The captitalization is in the original. Cited in Murphy, p26.
4. Murphy, p108
5. Murphy, p4
6. Murphy, p43
7. Murphy, p3
8. Some Christians ascribe animal death to some combination of Adam’s fall and Noah’s flood, but this does not resolve the problem that the animals are still suffering and dying through no fault of their own. See Keith Miller’s BioLogos series Death and Pain in the Created Order for the limitations inherent in a fall-based theodicy.
9. Rudwick, Martin. The meaning of fossils: Episodes in the history of paleontology. Chicago, University of Chicago Press, 1985.
10. See Jeff Schloss’ BioLogos essay Evolution, Creation, and the Sting of Death
11. Murphy, p63
12. Murphy, p122
13. Murphy, p27
14. This example is drawn from an evangelical outreach event held by a Christian student group in Innsbruck, Austria. On campus one day, they started conversations with their classmates by asking the question, “Would you wear an electric chair on your neck?”
15. Murphy, George L. The Trademark of God: A Christian Course in Creation, Evolution, and Salvation. Wilton, Conn.: Morehouse-Barlow, 1986.
16. Murphy, Cosmos in the Light of the Cross, p 31-32.
17. Murphy, p35
18. Murphy, p87

Behe and IC

Since we have previously explored Behe’s idea of irreducible complexity in an entire series, we will not revisit it here in great detail. It is important, however, to reemphasize how Behe defines irreducible complexity (IC). As we noted in the first part of that series, Behe frames his ideas on IC as a counter to Darwin’s ideas of gradualism.

For Behe, the argument for IC is a critique of gradual evolutionary processes, of the kind that Darwin saw as necessary for his theory to hold. When Behe introduces and defines IC in his book Darwin’s Black Box, he has a key quote from Darwin on gradualism explicitly in view:

Darwin knew that his theory of gradual evolution by natural selection carried a heavy burden: "If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down."

It is safe to say the most of the scientific skepticism about Darwinism in the past century has centered on this requirement… critics of Darwin have suspected that his criterion of failure had been met. But how can we be confident? What type of biological system could not be formed by “numerous, successive, slight modifications”?

Well, for starters, a system that is irreducibly complex. By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution.

(Darwin’s Black Box, p. 39)

The definition of an IC system is thus straightforward: it is a matched group of components, where all the components are necessary for the function of the system. The necessity of each component can be demonstrated by attempting to remove it – if the system no longer works if even one component is removed, it is by definition IC.

Behe and exaptation

The standard response to Behe’s argument from IC is to discuss the evolutionary concept of exaptation: that new systems and functions are cobbled together from components that have functional roles in other systems already present in the cell. Behe discusses, and ultimately dismisses this idea in Darwin’s Black Box as follows:

In Chapter 2 I noted that one couldn’t take specialized parts of other complex systems (such as the spring from a grandfather clock) and use them directly as specialized parts of a second irreducible system (like a mousetrap) unless the parts were first extensively modified. Analogous parts playing roles in other systems cannot relieve the irreducible complexity of a new system; the focus simply shifts from “making” the components to “modifying” them. In either case, there is no new function unless an intelligent agent guides the setup.

So for Behe, two points are clear: parts selected for function in one system cannot be exapted for use in other systems since they would require too many modifications; and the emergence of a new function is the indication that an intelligent agent is guiding the process.

Behe has responded to my previous posts to claim that the tandem duplication event that brought about the Cit+ actualization event should not be considered a gain-of-FCT mutation under his criteria:

The gene duplication which brought an oxygen-tolerant promoter near to the citT gene did not make any new functional element. Rather, it simply duplicated existing features. The two FCTs comprising the oxygen tolerant citrate transporter locus -- the promoter and the gene -- were functional before the duplication and functional after. I had written in my review that one type of mutation that could be categorized as a gain-of-FCT was gene duplication with subsequent sequence modification, to allow the gene to specialize in some task. Venema thinks the mutation observed by Lenski is such an event. He has overlooked the fact that there was no subsequent sequence modification; a segment of DNA simply tandemly duplicated, bringing together two pre-existing FCTs.

As an aside, quibbling over whether this mutation constitutes a “genuine gain-of-FCT” mutation is not my purpose here, since the definition is Behe’s to define, and I am not aware of anyone else in the scientific literature who uses Behe’s definitions. That said, I consider it passing strange to claim that a series of events that produced a gene that has a new sequence and functional properties distinct from either of its component parts does not constitute the production of a new “functional coded element.” If nothing else, it is a functional coded element that has not previously existed, cobbled together from parts of other functional coded elements, displaying new, adaptive properties. If according to Behe’s definition that’s not “new” or a “gain” then I guess it’s not, but that seems to me to torture the words “new” and “gain” beyond recognition. But I digress.

The important point for our purposes, however, lies elsewhere. Note carefully how Behe describes the Cit+ actualization event. By dividing the new aerobic citrate transporter gene into two previously existing FCTs, Behe is describing an exaptation event. The one FCT (the aerobic promoter) starts off as a necessary component of a gene transcribed when oxygen is present. As such it is under selection for that function, which has nothing to do with expressing a citrate transporter. The second FCT (the citrate transporter amino acid coding sequence) is under selection to be a citrate transporter, which has nothing to do with the function of the gene the promoter comes from. The Cit+ actualization event, then, exapts these two FCTs by placing them together to create a new function (which Behe does not mention).

And here’s the kicker: the new system (expression of the citrate transporter when oxygen is present) requires both FCTs in order to work. It has become a system of “well matched, interacting parts that contribute to the basic function” (i.e. transporting citrate in the presence of oxygen) “wherein the removal of any one of the parts causes the system to effectively cease functioning.”

In other words, it is a new IC system – a small and relatively simple system, yes, but nonetheless IC. Now, I’m fairly sure that Behe would not define this system as IC, since the documentation of an IC system evolving would seriously undermine his thesis. I am interested, however, in how he will handle this development, on two fronts. First, he would need to explain specifically why two exapted FCTs that are required together for a basic function does not constitute an IC system (if indeed he wishes to preserve his definition). Secondly, given that he allows for exaptation in this case, he needs to explain how exaptation is not a threat to IC in general. In Darwin’s Black Box he disallows exaptation altogether, but that option is no longer on the table.

In the next post in this series, we’ll continue to explore the evidence for exaptation as a means to build new FCTs, and go on to examine the implications of this evidence for Douglas Axe’s proposed limit to evolutionary mechanisms.

For further reading:

Blount, Z.D., Barrick, J.E., Davidson, C.J. and Lenski, R.E. (2012). Genomic analysis of a key innovation in an experimental Escherichia coli population. Nature 489; 513- 518.

Michael J. Behe, Darwin’s Black Box: The Search for the Limits of Darwinism (New York: Free Press, 2006).

Michael J. Behe, The Edge of Evolution: The Search for the Limits of Darwinism (New York: Free Press, 2007).

Michael J. Behe (2010). Experimental evolution, loss-of-function mutations, and “The first rule of adaptive evolution”. The Quarterly Review of Biology 85(4); 419-445.

Genesis is one of my favorite books of the Bible. I read through it probably once every few months and repeatedly grind my Hebrew language skills on its opening chapters. Unlike Leviticus (at least in the opinion of most people I know), the Genesis narrative is exciting and adventurous. Some of our favorite stories come out of the book: Noah and the Ark, The Tower of Babel, Abraham and Isaac, Joseph and the Coat of Many Colors, and so on.

But no story is perhaps as infamous and well known as the creation account (or accounts) as presented in Genesis 1-2. Almost every Christian or Jew, even those less than devout, know the opening words to the tale: “In the beginning, God created the heavens and the earth.” We know that God created the earth in six days. We know Eve was taken from Adam's rib for a companion. We know that God called the general creation “good”, the special creation of man “very good” and, at the very end of it all, took a day of rest (which I'm sure most of us would call “very good.”)

Of course, we know all of this. Yet we challenge it (and are challenged by it), continually, when we consider the variety of interpretations of how this story intersects the world as described by science. With Genesis, are we dealing with a literal scientific account, where “day” means 24-hours; are we dealing with metaphorical “days” in which epochs or periods of time or even processes are being described; or are we readers of a creation mythology from the Ancient Near East that doesn’t have anything directly to do with material origins? Interpretations go on and on, as anyone who has spent any time at all studying the creation debate knows. By and large, however, we can probably categorize Genesis interpreters into three camps: the Young Earth Creationists, the Old Earth Creationists, and the Theistic Evolutionists.

Now, I have the unique benefit of falling into all of these individual camps at one point or another in my life, sometimes even mixing them up. I have made a strong transition from being a die-hard Young Earth Creationist to being convinced that the evolutionary story is, in fact, the more substantiated and evidenced position. I say this with no pride, since my own transition involved many agonizing questions, a whole lot of reading, and a significant internal spiritual battle: what I believed about when and how the earth was created would not only change the way I read Scripture, it would also change certain aspects of how I viewed the Creator.

While I've certainly learned a lot of information on my journey, it was not an accumulation of facts that has kept me following Christ through all the ups and downs, but Jesus himself, and the knowledge that truth is not something which the Christian should find spiritually threatening. Nevertheless, those same ups and downs—and my internalization of each of these views on creation in turn—has provided me with one simple realization about the debate over scripture and evolution: most of us are not so committed to finding the truth about Genesis and creation as we are to sustaining and maintaining our own interpretive boundaries and the boundaries of the communities which influence us. In other words, the debate is often not so much over Genesis—or even over whether we can all follow the same God when we believe different things about how he created—it's over our own ability to be right. I know this because admitting that I was wrong was the most difficult part of my own transition.

Interpretive communities

While I am pretty convinced of the truth of an evolutionary portrait of reality and an ANE reading of Genesis similar to that espoused by scholars like Peter Enns or Bruce Waltke, I can still make this claim about interpretive communities because my intention is not to dissuade others from debating the issues involved, but to ask that we simply recognize our own limits and check them as often as possible. This is part of following Jesus, is it not? Unfortunately, vigorous debate often deteriorates quickly into screaming matches where proponents of one position or another simply are talking heads, speaking past each other and forgetting our fellowship in Christ. We play into the same interpretive competition that the Pharisee and Sadducee scribes were well known for, each claiming to have a proper interpretation of the Scriptures, but all the while forgetting that interpretive arguments matter exceptionally little if a genuine search for God is not at the forefront. This is certainly not to insist that the discussions cease, but rather, to insist that these discussions can only be propelled forward if individuals—of whatever stripe—step outside of their own interpretive boundaries and communities and humbly present themselves before God, seeking His truth alone. It is to insist that “system maintenance” must die along with the self, because only then can we allow Scripture to interpret itself. Unfortunately (and this is an issue that goes way beyond the Genesis text), too many of us are more committed to a specific model than we are committed to seeking God’s truth, whatever inconvenience to us that truth proves to be.

In 2006, for instance, I heard a popular and well-trained Young Earth paleontologist make the following statement: “If all the evidence turns against young earth creationism, I will still believe it because that's what the Bible says.” I followed up with him in a conversation a year later over lunch and quickly realized that I did not misunderstand his statement. For him, the parameters of his convictions were set in concrete and the truth of the overarching story of Christianity rested on these parameters not being crossed. In his view, the Bible absolutely and fundamentally teaches a universe which came into existence 6,000-10,000 years ago; to deny that is to deny Scripture, and if evidence turned up to the contrary one must not alter those parameters but, instead, search (perhaps in vain) for counter-evidence or be willing to live in blind faith. For this paleontologist, confident Christianity hinged on the stability of those borders of interpretation. Transition wasn't allowed.

But I have heard and read statements coming out of the two other camps of thought that share this kind of certainty over interpretation, too. There is a sense of doing injustice to scripture, thereby doing an injustice to Christianity, and, thereby again, doing an injustice to God if one strays from the preferred reading. One Old Earth Creationist remarked in a popular book that an interpretation of Genesis that allows for evolution is a “contradiction in terms” and it's an unfortunate thing to “blame God for it.” Genesis, in the mind of this thinker, specifically precludes any interpretation which leads to the sort of story evolution tells. To think otherwise is to “blame” God for something which he intentionally tells us is otherwise against his nature.

I have equally heard some theistic evolutionists deride—in a very spiritually shallow and personally offensive way—those who do not accept an evolutionary viewpoint. As one who went through an interpretive evolution on biological evolution, I can say confidently that I believe my own transition would have been much easier both intellectually and spiritually if not for feeling as if certain theistic evolutionists accused me of intentionally lying or being mentally ignorant. It seems that all three camps are at least sometimes plagued by the issue of pride—especially in the cases of a few strong advocates. But pride is nothing less than the cement by which interpretive barriers are built, helping them become unmovable walls that protect the interpretive communities within.¹

On the other hand, one of the great benefits of the fall of positivism (or verificationism) and the rise of postmodernism was the realization that total objectivity among individuals is a false conception. And, since individuals make up communities, neither are camps of thought above error and immune from being wrong. Yet way too many Christians continue to approach Genesis as if we can interpret it on its own terms, completely and totally, without reference to our own location in history and culture. We're still functionally positivists. But it is an illusion that we’re above the interpretive fray, and we must realize time and again that we are subjective individuals, affected by a number of factors and people. We are deeply influenced by those that speak into us, those that we trust, and those that we find credible. As W. Randolph Tate writes,

Interpretations...must be consistent with the established interpretive framework of the interpretive community. The worldview of the interpretive community sets the parameters within which interpretations are accepted or rejected.²

The Bible takes a slightly different angle and puts it this way: “for all have sinned and fall short of the glory of God.” In other words, we are not objective data-interpreting individuals but fallen men and women, even as followers of Jesus.

So it’s when groups of folks line up on either side of an issue and make their positions part of their identity that the debate over interpreting Genesis reaches a near stalemate. It's communities against communities, PhDs against PhDs, experts against experts, and—perhaps more internally—interpretive parameters against interpretive parameters. The truth is that as long as we are first and foremost committed to maintaining the community in which we are involved, there will be very little chance of us getting at the real issues and the best conclusions, much less giving an adequate witness to our God, both Creator and Redeemer.

New eyes, fresh air

I mentioned earlier that I spent time in all three major camps of thought on this issue. I was a hard-lined Young Earth Creationist, debating on forums and writing creationist papers in college. I argued for the existence of modern-day dinosaurs, major flood geology, and so on. I was convinced I was right, that defending the truth meant digging my heels deeper into the sand. But two questions plagued my thoughts: first, I asked whether Christianity fell to pieces if I was wrong. Second, I asked whether I was committed to Christ or, rather, to myself and my interpretations. With that as my first major paradigm shift, I eventually came to accept an Old Earth view. I sat comfortably within the Old Earth view for several years, but the Lord was still at work in me, and, once again, brought those two questions to my mind. Back to the books I went, back to the Bible I went, and back to prayer I went.

Through months of extremely difficult and heart-rending transition, I found myself considering a particular reading of Genesis that I would have regarded as unacceptable as a YEC. But then I was confronted with this even more important point about Christianity: often God finds what is unacceptable to us very acceptable to Him! That included me, personally, and I felt the warmth of God’s grace flow over me. In the wake of that change of heart, people accused me of rejecting my background, my Christian education, and my interpretive communities. And, yet—whether I was right or wrong—I knew God accepted my path towards this new reading of Creation as a genuine search for Him. My spiritual struggle—contrary to what I thought while it was happening—was not a struggle to reject bad data and exegesis, it was a struggle to reject myself.

While the “facts” were important, that spiritual struggle was even more so for me. What was God showing me in the midst of it all? Was thinking differently about the creation making me appreciate the Creator less, or more? Did reading Genesis differently mean only that I had been wrong, or that it was somehow less true? What did any of this have to do with my sense of calling to love and serve God and my fellow men? In a way, I’m still figuring this out. But I can absolutely testify that the struggle transformed every single one of these questions. Indeed, for the first time, I believe I saw God as much this-worldly as other-worldly. I saw nature as intimately intertwined with itself, still being woven together by God’s hand. I saw Scripture as a beautiful expression of God’s desire that man should participate in creation. I saw that my fellow men and my fellow Christians were all on a journey, much the way I was. And I saw myself as a flawed, stubborn, and prideful man, yet forgiven for the times I’ve pitted myself and my presuppositions about Scripture against God, its author.

As settled as I am now, I have not forgotten that the common ribbon which ties together all of these transitions is my commitment to keep asking questions within my own circle, too—realizing that God still has much to teach all of us. I have learned the continuing importance of stepping outside of my camp and making sure I haven’t become merely a product of or a willing prisoner to thinking a certain way, unwilling to consider that it and I might be incorrect. I came to realize that everyone (including myself, of course) has stories and life experiences that become the framework in which they read Genesis 1-2. And if I stopped pretending that I, myself, could be perfectly objective, then I also had to stop pretending that those in the community that I trusted were necessarily objective, themselves.

Ultimately, I had to be willing to be wrong and to see that my friends might be wrong, too. That’s not something that any of us are “naturally” very good at, but it is possible when we realize that the world does not depend on us being right, but upon Jesus being right. For me, seeking truth rather than presupposition requires that we all be able to approach the communities that have influenced us deeply, and ask not just “what” they say but “why” they say it. We all have to guard our hearts even more than our heads. Frequently reminding myself to walk back to the edge of my own camp—to follow Jesus’ example and withdraw to a solitary place—has shown me that there is room to breathe outside our familiar interpretive parameters. At certain times, I have found it to be the most refreshing air I've ever tasted.

Notes

1. Though, admittedly, the theistic evolutionists tend to have a greater sense of leeway when it comes to how the claims of Genesis 1-2 affect Christianity as a whole. It would be an odd thing to say that to not interpret Genesis 1-2 as an evolutionary metaphor is to reject Christianity. As far as I know, most Christian evolutionists are very much willing to acknowledge that Young and Old Earth Creationists are still within appropriate spiritual bounds, even if not scientific ones. It seems to me that if individual theistic evolutionists choose an issue about which to be rigid, it’s the Fall and the existence of Adam.
2. Tate, W. Randolpy. Biblical Interpretation: An Integrated Approach. Peabody, MA: Hendrickson, 2008, p 222.

With the complete genome sequence in hand, we knew the sequence and location of our genes, but what we didn’t know was how all those genes are regulated: how do the trillions of cells in our bodies know when to turn on or off all those genes? How do the hundreds of distinct cell types develop and function together, when they are all running on the same DNA “operating system?”

That’s where the ENCODE (short for Encyclopedia of DNA Elements) project comes in. Launched in September 2003, shortly after the announced completion of the Human Genome Project, the goal of the ENCODE project is “to build a comprehensive parts list of functional elements in the human genome, including elements that act at the protein and RNA levels, and regulatory elements that control cells and circumstances in which a gene is active.” In other words, the project seeks to understand how the genome “works.”

Early this month, researchers from ENCODE released more than thirty papers presenting their findings. During a Science magazine online chat, the project’s data coordinator, Ewan Birney, explained the outcome:

The ENCODE project aimed to start our understanding of how the human genome works. We know that (nearly) all the information that determines a human is in the genome, as we all start off as single cell with this DNA. However, we had a patchy understanding of how it works, in particular away from protein coding genes.

To work out how the genome works, we used the fact there are many tiny machines (proteins and RNA - RNA is very like DNA) in each of our cells which know how to "read" parts of the genome. By monitoring where these little molecular machines are on the genome, or how parts of the DNA are copied into RNA (there are quite a few different types of RNA as well), we start to gain some insight into the genome.

We did many such experiments, across different cell types (eg, one cell type was very similar to a liver cell type; another was very similar to a white blood cell). This way not only can we see what is similar, we can also see differences between these cell types.

There is a lot more to get to know and understand here - this is definitely closer to the start than the end. But it is a substantial amount of data, and analysis, to start on this journey.

According to the abstract of one of the lead papers from Nature, this extraordinary glut of data “enabled us to assign biochemical functions for 80% of the genome, in particular outside of the well-studied protein-coding regions.” Only 2% of the genome codes for proteins, but 80% or more has some biochemical function. As a Science news article put it, these 30 papers “sound the death knell for the idea that our DNA is mostly littered with useless bases.”

The pro-Intelligent Design organization The Discovery Institute has heralded the discovery as the “demise of junk DNA.” Casey Luskin writes for their blog Evolution News:

Let's simply observe that it provides a stunning vindication of the prediction of intelligent design that the genome will turn out to have mass functionality for so-called "junk" DNA. ENCODE researchers use words like "surprising" or "unprecedented." They talk about of how "human DNA is a lot more active than we expected." But under an intelligent design paradigm, none of this is surprising. In fact, it is exactly what ID predicted.

The extent to which the ENCODE project been able to identify function has been surprising—even exhilarating—though scientists have for some time been getting glimpses of the many ways in which segments of DNA can be “active.” Even in 1970 biologists knew that some non-coding DNA had function, and by 2003 there was a large body of work demonstrating that many non-coding elements acted as promoters, enhancers, insulators, and so on. Indeed, in recent years many have come to appreciate the fact that “junk” was never really an appropriate metaphor in the first place. Still, because sequencing of multiple genomes has shed such extraordinary light on key evolutionary mechanisms, many geneticists have focused on function primarily in terms of which regions do or do not contribute to the evolutionary fitness of their host, rather than whether they were merely "doing something" biochemically. What the impressive ENCODE project has done is open a treasure trove of new information that can only accelerate the pace at which researchers are able to explore the incredible subtlety and complexity of DNA, and refine the very concept of “functionality.”

So with all this in mind, is ENCODE a stunning victory for ID, as Luskin believes? Bryan College biologist Todd Wood thinks not. He writes, “I don't think that function equates to design, nor do I think that design requires or predicts function. They're not the same thing… my understanding of function does not require me to hypothesize God (or an anonymous designer, if you must) as the proximal cause.”

We agree. Indeed we would go on to say that evolution and design are not mutually exclusive. So while finding function is not sufficient to prove design, recognizing that function has arisen by way of evolution does not indicate that God was not at work. We at BioLogos believe God providentially works out his purposes—his designs—through the elegant processes of evolution, not in opposition to them.

Amazing as the new data are, it only strengthens and enhances our evidence for evolution. While much of the genome is “doing something” biochemically, it is still likely that the majority of the sequence is evolutionarily neutral (Senior Fellow Dennis Venema discusses the evidence for this “neutrality” in a post on our site, including a striking comparison between 29 different mammal genomes and the human genome). In fact, another ENCODE researcher participating in the Science magazine chat, John A. Stamatoyannopoulos of the University of Washington School of Medicine, thinks the findings align beautifully with evolutionary theory:

ENCODE's data provide a unique and powerful window through which to view evolutionary change. We can see those changes directly by lining up the genome sequences of many different organisms -- these line-ups have revealed millions of regions where all the genomes agree, indicating sequences that have been specially preserved by evolution while others have decayed away (ie freely changed their letter codes). We now see that a large proportion of these 'conserved' regions are lighted up by ENCODE annotations, indicating that they are marking spots in the genome that contain important instructions for cell function.

We’ve discussed “junk” DNA previously, including a multi-part series by Dennis Venema, and we’ve received many emails over the past few days asking for our comments on the ENCODE findings. On Monday and Tuesday, Dr. Venema will begin to offer his own thoughts on ENCODE.

A special thanks goes to Darrel Falk, Mark Sprinkle, Kathryn Applegate, Dennis Venema, and Tom Burnett for their contributions to this post.

The Denisovans, an extinct hominid group that interbred with modern humans, made the news again lately with the publication of a more detailed study of their genome. One of the many interesting findings was that the Denisovans share the same chromosome 2 fusion that modern humans have. In this post, I review what we know about the origins of human chromosome 2, and then discuss the new Denisovan findings and their implications.

The origins of human chromosome 2: a brief review

Though I have discussed the evidence for a fusion event leading to human chromosome 2 before, perhaps a brief review of the evidence is in order. The human genome is made up of 23 pairs of chromosomes (for a total of 46 chromosomes). This makes us something of an oddity among living great apes, all the rest of whom have 24 pairs of chromosomes (for a total of 48). Given that there are many independent lines of evidence that support the conclusion that we share a common ancestor with other great apes, this poses something of a conundrum: how is it that our species arrived at this specific chromosome number? If we were to represent this “problem” on a phylogeny, or tree of relatedness, it would look something like this (not to scale):

Our closest living relatives, chimpanzees and bonobos, both have 48 chromosomes, as do all other great apes such as gorillas and orangutans. This pattern has one of two explanations, one of which is much more likely than the other. Either the common ancestor to these species had 48 chromosomes, and there was an event that reduced that number to 46 specifically on the lineage leading to humans (option A), or the common ancestor species had 46 chromosomes, and there were independent, repeated events that increased chromosome number in all other great ape species (option B). We can compare these options by placing the required event(s) on the phylogeny (again, not to scale):

It should be obvious that the option that requires the fewest events is the more likely one – in this case option A with an event that reduces chromosome number in the lineage leading to humans. The other option, that of repeated, independent events to increase chromosome number, remains a formal, but unlikely, possibility. Events that reduce chromosome number are not frequent occurrences, so Option A is more likely than Option B.

We can also find further support for Option A, because it predicts a specific type of event, namely one that reduces chromosome number. Since loss of a large amount of chromosomal material is almost always detrimental, we need an event that reduces chromosome number without losing information. One way for this to happen is for two chromosomes to fuse together and become one. Initially, this event would produce an individual with 47 chromosomes, where two different chromosomes get stuck together. Contrary to what is often assumed, this individual would be fertile and able to interbreed with the others in his or her population (who continue to have 48 chromosomes). In a small population, over time, two relatives who both have one copy of the fusion chromosome may mate and produce some progeny with two copies of the fused chromosome, or the first individuals with 46 chromosomes. Since either a 48-pair set or a 46-pair set is preferable for ease of cell division, this population will either eventually get rid of the fusion variant (the most likely outcome), or by chance will switch over completely to the “new” form, with everyone bearing 46 chromosome pairs. While not overly likely, this type of event is not especially rare in mammals, and we have observed this sort of thing happening within recorded human history in other species. Some mammalian species even maintain distinct populations in the wild with differing chromosome numbers due to fusions, and these populations retain the ability to interbreed.

Further evidence for a fusion event in the lineage leading to modern humans comes from comparing synteny, or gene locations and orders on chromosomes within modern great apes – an issue we have discussed here before. In brief, what we see in human chromosome 2 is exactly what we would predict for a fusion event. When compared to other great apes, we see the genes on human chromosome 2 match up, in order, with two smaller ape chromosomes. We also see that sequences used at the tips of chromosomes are present at the proposed fusion site, and that human chromosome 2 has not one but two sites for the cell cytoskeleton to attach to for cell division – but that one of the sites is mutated and not functional, though it lines up precisely with the location of this site on the appropriate ape chromosome. Together, this evidence consistently supports both common ancestry for humans and great apes, and specifically that the difference we see in our chromosome numbers arose due to a single fusion event. I briefly discussed this evidence in my last post where I describe how I teach some of this material and the compelling impact it has on students exploring the evolution question for the first time.

Enter the Denisovans

With that as background, we are now prepared to appreciate a new finding that comes from genomics work done on the Denisovan hominids, an archaic species that is more closely related to Neanderthals than to us, but that nonetheless interbred with some anatomically modern humans as they migrated out of Africa and populated the globe. (For those not familiar with the Denisovans, or the evidence for our interbreeding with them, both Darrel Falk and I have written on this previously, here and here). Recently, a more detailed understanding of the Denisovan genome was published, and nested in the new information is the discovery that the Denisovans share the 46 chromosome set with the same fusion that we have. This strongly supports the hypothesis that the fusion event predates the separation of our species. If we were to represent this on a phylogeny, we can now place this event with more accuracy than before (as before, the phylogeny is not to scale):

Despite this new information, one obvious question remains. Did the Neanderthals also have the 46-pair set? From looking at the phylogeny above, we can see that the most likely answer is that they did, since the fact that the Denisovans had it strongly implies that the last common ancestor of humans and Neanderthals / Denisovans had it as well, and the Neanderthal-Denisovan split comes later. While the Denisovan DNA samples are of high enough quality to make this assessment, we do not yet have Neanderthal DNA of high enough quality to do the same analysis with current methods (though one additional feature of the new work on the Denisovan genome is developing more sensitive DNA sequencing techniques that may resolve this question in the future).

In other words, this fusion seems to be an ancient one, predating our species by several hundred thousand years. Present estimates of the last common ancestor between humans and Neanderthals / Denisovans range at about 800,000 years ago.

Implications for understanding our “becoming human”

The main implication from this work is that it places the fusion event well before the advent of our species. I’ve often chatted informally with Christians about evolution, and at times some have thought that this fusion event was what “started” our species, or made our species unable to interbreed with other groups. Some have even suggested that perhaps the fusion event was what produced the first human (i.e. Adam).

Note that thinking this way suggests a misunderstanding of how chromosome fusions occur and what effect they have on their hosts. A fusion does not precipitate a speciation event, but rather the individual with the fusion remains a part of his or her population, and able to interbreed, even if with reduced fertility. Also, there is no necessary biological effect or change that the fusion produces on the appearance of the organism. These misunderstandings aside, however,what this new evidence shows is that this fusion event took place long before modern humans arose at around 200,000 years ago. Indeed, the 800,000 years ago date for the last human - Denisovan common ancestor means that this is the most recent date possible for the fusion. While it is an interesting piece of our evolutionary history, it doesn’t seem to have much to do with how we came to acquire the traits that set us apart from, and ultimately outcompete, other similar species.

In Tennessee and across the country, many others weighed in on the subject over the next few weeks, including two essays (here and here) on the BioLogos Forum. But soon after that, other issues crowded that story off the front page. Now, though, teachers and students across my state are returning to science classrooms, and we will all get to see what effect the law has in practice. Again speaking as a Christian, a biologist, and educator and drawing on all three of those perspectives, I’d like to offer my own reflections on the bill’s likely effect on Tennessee teachers and students, beginning with this excerpt from the bill itself:

The teaching of some scientific subjects, including, but not limited to, biological evolution, the chemical origins of life, global warming, and human cloning, can cause controversy . . . The state board of education, public elementary and secondary school governing authorities, directors of schools, school system administrators, and public elementary and secondary school principals and administrators shall endeavor to assist teachers to find effective ways to present the science curriculum as it addresses scientific controversies. (Tennessee HB368 / SB893)

As an evangelical, I think this bill could be more detrimental than helpful to Christian teenagers’ faith. Many students who are particularly interested in the sciences and theory of evolution are already in the uncomfortable position of hearing pro-Intelligent Design doctrine from the pulpit on Sunday and then listening to their science teacher’s evolution instruction on Monday. I was one of those students—sitting in more than one congregation under pastors who were particularly antagonistic to the theory of evolution, and who made not-so-subtle comments that it cannot co-exist with authentic Christian faith. Having a keen interest in the sciences and wanting to explore the data so widely accepted by the scientific community, I felt confused and ostracized in my church. I wondered if I would have to choose between my faith and intellectual integrity. The church family I trusted clashed with the science that I also trusted, causing a near catastrophe for my faith. I am thankful to the few people who offered me grace, allowing for my questioning of some of what I heard in church without labeling me a heretic.

Though the conservative Christian community may view this bill as a “win for the faith,” it is actually a loss if it reinforces the idea that this is simply an issue of science vs. scripture. Evolution is central to modern biology; trust in the authority of the Scriptures is central to Christian faith. But this fight mentality between the two established communities is detrimental to our young teenagers who are seeking to grow in faith, but who cannot seem to reconcile scripture and scientific data. We need them to seek after that reconciliation, not be told it can’t be done. Whatever they are hearing from the pulpit, the science classroom should be the one place that students can learn science. Students may well emerge with bitterness towards the church for dismissing the evidence of evolution not only so quickly, but in what is so often a haughty and condescending manner. Worse yet, students may emerge with bitterness that they were forced to choose between faith and intellectual integrity. Is this really an all or nothing argument? Are the two truly diametrically opposed?

In my world, these two have reconciled, and they now co-exist in peace. It has been a very long road to get there and I could not have done it without both access to good data and the freedom to explore it. Having taught teenagers in an evangelical church for years and having observed in many biology classrooms as well, I know that many students are still struggling for this same reconciliation. That reconciliation is perhaps most easily attained when the seeking student is able investigate evolution in the science classroom without harassment from opposing religious forces. With this freedom, the student may very well realize that the fear that he/she may have regarding evolution is really just a fear of the unknown, and that it is possible to have intellectual integrity and to praise God for initiating and sustaining the evolutionary process.

In Tennessee’s science classrooms there are surely many teachers who begrudge being told that they must teach evolution, and who are relieved that they can now present it as a controversy and/or allow Intelligent Design as an alternative. They, too, will likely see this law as a “win.” But isn’t public science education is about giving students an accurate picture of the state of science, not about teachers’ philosophical opinions? As has been pointed out before, most Tennessee science teachers have not had the training to teach about religion or philosophy; they have been trained to teach about the basic principles of the biological world.

This bill may be particularly frustrating, then, to teachers who do simply want to teach science. From the many hours I’ve spent in secondary biology classrooms this year, I can say for sure that time is of the essence. Tennessee teachers have barely enough instructional time to cover what students must know to pass the end-of-course biology test required for graduation; they do not have extra time to spend covering material that is not science. I have seen classroom arguments over evolution’s feasibility that ate away precious instruction time and only left a greater rift between the two camps and no doubt, a frustrated teacher. News of the Intelligent Design movement’s success in creating political and legal controversy is misplaced content in the secondary biology classroom.

Furthermore, as it allows teachers to frame biological evolution in terms of “controversy”— something that is a topic for debate—this law will likely not result in students who are more engaged in understanding science, but instead, only in more confusion (and possibly antagonism) in the classroom. Educators welcome debate in many cases because debate encourages critical thinking that leads to “formal thought,” the Holy Grail of Piaget’s Theory of Cognitive Development. But the practice of science is about proposing hypotheses and testing the data, not primarily argumentation. And if the science community is not “debating” evolution, why should high school science students be debating evolution as part of their biology curriculum?

The bill is correct in stating that the purpose of science education is to “inform students about scientific evidence” and “help students develop critical thinking skills necessary to becoming intelligent, productive, and scientifically informed citizens.” I certainly agree, though I question whether it needed to be legislated. Rather, my answer is: “Let’s actually do it!” Before bringing “debate” and “controversy” about scientific theories into the classroom, let’s instead teach our students about sound scientific practice; let’s give them opportunities to learn how to research and to employ the scientific method in everyday life. Let’s focus on teaching them about observing the indicators of climate change, the intricacies of DNA, conservation of ecosystems, and the principles of molecular and cell biology. Let’s give them the tools—specific to science— that help them think critically and work out problems, rather than undermining faith in those very practices and the community of people that uses them every day. Let’s not teach them to live in denial of the ordinary dependability of science, let’s not teach them to distrust scientists who have no interest in “debate,” but want to understand the world God made.

In Tennessee and elsewhere, let’s give both our students and those scientists the grace and support they need to merge authentic faith and intellectual integrity.

Asa Gray

If Thomas Huxley earned the title of "Darwin's bulldog," then Asa Gray should be remembered as "Darwin's dove." Whereas Huxley enjoyed a good fight in his defense of Darwin's theory, Gray sought to mediate and bring sides together around a common understanding of "good science." As Darwin's strongest and most vocal scientific ally in the United States, Gray recognized the scientific importance of Darwin's efforts for the growing professionalism of biological researchers.

But as an orthodox Christian, a Presbyterian firmly devoted to the faith expressed in the Nicene Creed, Gray saw in Darwin's theory both evidence for his philosophical commitment to natural theology and support for his opposition to the idealism advocated by Louis Agassiz and the Naturphilosophen in both Europe and America. Indeed, Agassiz's advocacy of Platonic forms as a basis of biological understanding (e.g., "A species is a thought of the creator")¹ would be a major source of American opposition to Darwin's theory.

Professor of botany at Harvard during most of the middle half of the nineteenth century, Gray was one of the few members of the scientific community to whom Darwin revealed his theory before the publication of On the Origin of Species, and, from what I can tell, the only American. Gray and Darwin met briefly in January 1839 during one of Gray's visits to England. Later, during the 1850s, Darwin wrote Gray on several occasions requesting information--a practice that Darwin frequently employed. In 1854, Darwin's friend and confidant, Joseph Hooker, showed Darwin Gray's review of Hooker's Flora of New Zealand, in which Gray had argued strongly against Louis Agassiz's idealism and had raised questions from his own work on the stability of species. Gray was not yet ready to deny their permanence, but hybrids and other observations were beginning to trouble him.

The next year Gray wrote a lucid and penetrating positive evaluation of Alphonse De Candolle's two-volume Géographie botanique raisonnée, a pioneering work dealing with plant geography and distribution from a statistical perspective. Hooker had sneeringly dismissed the work. In A. Hunter Dupree's authoritative biography of Gray, he describes Gray's puzzlement at Hooker's response in these terms:

Although in the long view Gray's evaluation of the epoch-making nature of De Candolle's book was more justified than Hooker's sneers, [Gray was confused by his response, for] Hooker seemed to be talking with a more comprehensive theory definitely in mind, some reason for taking his position, which he did not divulge and which his friend [Gray] did not possess.²

Darwin, however, saw in both Gray's review of Hooker's book and in his comments on De Candolle's tome that Gray was troubled by some of the same empirical data that had been bothering him. In April 1855, Darwin wrote Gray to urge that Gray update his Manual of the Botany of the Northern United States first published in 1848, and especially to address the issue of the range of Alpine plants in the United States. Specifically, he said: "Now I would say it is your duty to generalise as far as you safely can from your as yet completed work."³

Behind this request was Darwin's desire to test his impression that Gray could make a good ally. Gray passed the test, and finally, in July 1857, Darwin let Gray in on his theory of the transmutation of species. Gray was never an uncritical supporter, and there are many evidences in the correspondence between these two scientists that Gray was willing to challenge Darwin and disagree with some of his conclusions. Nevertheless, Gray saw the importance of Darwin's work and the ways in which it provided answers to the troublesome issues that he had confronted in his own botanical efforts.

Gray responds to Darwin's theory

After considerable interchange--one might even say debate--among Gray, Darwin, and Hooker, Gray wrote to Hooker in October 1859 (one month before the publication of On the Origin of Species) saying that he had absolutely no problem with cognate species arising by variation. He did, however, raise a concern that would be the source of much future discussion. He wondered about Darwin's "carry[ing] out this view to its ultimate and legitimate results,--how [do] you connect the philosophy of religion with the philosophy of your science." He added: "I should feel uneasy if I could not connect them into a consistent whole--i.e., fundamental principles of science should not be in conflict."⁴

When Origins was published, Gray wrote a clear, positive, yet critical review in The American Journal of Science. Aware of mounting religious opposition, he ended his review by arguing that whereas one could use Darwin's theory in support of an atheistic view of Nature, one could use any scientific theory in that way. He wrote: "The theory of gravitation and ... the nebular hypothesis assume a universal and ultimate physical cause, from which the effects in nature must necessarily have resulted."⁵ He did not see the physicists and astronomers who adopted Newton's theories as atheists or pantheists, though Leibniz earlier had raised such reservations. And a similar situation existed with the origin of species by natural selection. Darwin, Gray continued: "merely takes up a particular, proximate cause, or set of such causes, from which, it is argued, the present diversity of species has or may have contingently resulted. The author does not say necessarily resulted."⁶

This far Gray could go with Darwin. But there was a point at which he parted company, and that was the fortuitous randomness of the process that Darwin's theory seemed to imply.

In part 2, Dr. Miles describes Darwin's struggle with the problem of natural evil and design in nature.

Notes

1. Cited in A. Hunter Dupree, Asa Gray: American Botanist, Friend of Darwin (Baltimore: The Johns Hopkins Press, 1959), 151. 2. Ibid., 236.
3. Charles Darwin, More Letters of Charles Darwin, ed. Francis Darwin, (New York: D. Appleton and Company, 1903), 252.
4. Dupree, Asa Gray, 266.
5. Asa Gray, "The Origin of Species" in Darwiniana (Cambridge, MA: The Belknap Press of Harvard University, 1963), 44.
6. Ibid.

Darwin’s finches are some of the most visible and recognizable symbols of evolution in the world today. Biology textbooks feature them prominently, and the National Academy of Sciences has enshrined them in the entrance of their headquarters in Washington, DC. Surely the finches that Darwin collected on the Galápagos islands were a central feature of his evolutionary theory, right?

Lobby of The National Academies Building. Courtesy of CPNAS. Photo by Robert Lautman

Actually, the Galápagos finches are never even mentioned in Darwin’s famous work On the Origin of Species. Nor do they appear in Darwin’s famous notebooks on “Transmutation of Species”, in which he formulated the idea of evolution by natural selection.¹ Even Darwin’s private diary of his voyage on the HMS Beagle only mentions the Galápagos finches briefly in passing.²

It was only in 1845, in the second edition of The Voyage of the Beagle, that Darwin included a tantalizing sentence about the Galápagos finches:

Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends.³

However insightful this statement may have been, Darwin never published anything else about the Galápagos finches for the rest of his life. Nor did he publically present these birds as direct evidence for this theory of evolution.⁴

If these finches were so important to Darwin’s evolutionary theory, why did he remain silent about them? One of his comments in The Voyage of the Beagle provides us with a clue:

Unfortunately most of the specimens of the finch tribe were mingled together; but I have strong reasons to suspect that some of the species of the subgroup Geospiza are confined to separate islands.⁵

When Darwin was exploring the Galápagos himself in 1835, he had not formulated his theory of evolution yet, and thus he did know what data would be necessary to make definitive conclusions about finch evolution. In particular, he did not keep careful track of which of his specimens came from which islands. Moreover, as was customary among naturalists at that time, Darwin only collected a small number specimens—he brought home only 31 finches and 64 total birds from the Galápagos.⁶

Though Darwin sensed that these birds were truly special, he lacked sufficient evidence to reach any specific conclusions about their evolutionary origins. It would be up to the rest of the scientific community to carry out the necessary empirical research. Subsequent expeditions in 1868, 1891, 1897, and 1905 brought back thousands of Galápagos finch specimens, but instead of unlocking the mysteries of evolutionary theory, the Galápagos finches became a great enigma.⁷

A century after Darwin's voyage, scientists still struggled to explain the staggering variety of finches on this tiny, remote archipelago. By the mid-1930’s, British Museum ornithologist Percy Lowe argued that the finches presented a "biological problem of first class importance", and he told the British Association for the Advancement of Science that the finches displayed a "bewildering diversity, intergradation, and distribution".⁸ Who would be up to the challenge of making sense of such tremendous biological complexity? It was David Lack.

David Lack

Ornithologist David Lack

David Lack had an exceptionally keen eye for bird-watching, and he possessed a passion to match it. By age 15, he had already observed 100 distinct species of birds, and before entering college, authored his first scientific paper. At Cambridge University in the early 1930’s, Lack was disappointed to find that his zoology professors taught “nothing about evolution, ecology, behavior or genetics, and of course nothing about birds.”⁹ In fact, at that time, there were only two professional ornithologists in all of Britain!

Thus David Lack took it upon himself to create his own learning opportunities. As an undergraduate, he became the president of the Cambridge Ornithological Club, traveled to Greenland for a bird-watching expedition, and cultivated a relationship with the prominent biologist Julian Huxley (grandson of Thomas Henry Huxley). Huxley was an inspiring mentor and encouraged Lack to expand his research further by studying tropical birds.¹⁰ Following this advice, Lack embarked on a research trip to Tanzania in the summer of 1934, but his greatest adventure was yet to come.

In 1937, Lack became fascinated by the scientific mysteries surrounding the Galápagos finches. But in order to study their behavior, Lack would need to travel to remote islands halfway around the world. How could he possibly get there? Once again, Julian Huxley was tremendously supportive and raised funds from two prominent scientific societies to pay for his expedition. After a long delay, David Lack and five companions finally set off on their journey.

Instead of residing in comfortable quarters aboard a royal naval ship, Lack’s group subsisted on a shoestring budget, traveled on commercial steamers, and stayed with local settlers. Their experience was definitely not a romantic tale of imperial expedition:

The Galápagos are interesting, but scarcely a residential paradise. The biological peculiarities are offset by an enervating climate, monotonous scenery, dense thorn scrub, cactus spines, loose sharp lava, food deficiencies, water shortage, black rats, fleas, jiggers, ants, mosquitoes, scorpions, Ecuadorian Indians of doubtful honesty, and dejected, disillusioned European settlers.¹¹

Whereas Charles Darwin spent only nineteen days on the shores of the Galápagos, Lack and his crew conducted more than five months of meticulous and exhausting study in the harsh climate. At that time, even the finches themselves provided little solace. Lack wrote,

Darwin’s finches are dull to look at, not only in their orderly ranks in museum trays, but also when they hop about the ground or perch in the trees of the Galápagos, making dull unmusical noises. Only the variety of their beaks and the number of their species excite attention.¹²

Large Cactus Finch on Española Island in the Galápagos Islands

The repetitive tedium requisite for important scientific discoveries is rarely discussed in public, and even today many bright-eyed science students become disillusioned by the painstaking work demanded by their Ph.D. programs. But one of the things that distinguishes great scientists is their unwavering commitment and tenacity in completing major projects. David Lack's efforts were not in vain:

"Despite his personal discomforts (or perhaps because of them), Lack did see something on the Galápagos that no one had ever seen before—natural selection at work among its finches through interspecies competition." ¹³

When the birds’ breeding season ended in 1939, Lack was ready to return to his home in England. But the captive finches that he had brought with him fared so badly on the voyage home that he detoured to San Francisco and put them in the care of the California Academy of Sciences. Turning this mishap into an opportunity, Lack stayed there for five additional months to study the Academy’s enormous collection of Galápagos finch specimens.¹⁴

To complete his systematic research, Lack then travelled across the United States to study the Galápagos finch collection housed at the American Museum in New York.¹⁵ Altogether, Lack examined more than 8000 specimens and specifically measured the length, width, and depth of all their beaks.¹⁶

Lack’s final obstacle was in getting his research published. Though he completed his academic manuscript “The Galápagos Finches—A Study in Variation” in 1940, paper shortages during World War II delayed its publication by the California Academy of Sciences until 1945. Were he only interested in making an original contribution to science, Lack could have stopped here and congratulated himself on a job well-done. However, his motivation sprung from a deeper source:

David Lack's drawing of 14 species of Galápagos finches, p. 19 of Darwin’s Finches

"I did not watch birds primarily for scientific reasons but for sheer enjoyment, and from the age of 15 onward returned day after day in a glow of excitement after seeing a new bird or a new habit." ¹⁷

Lack’s joyful fascination with the Galápagos finches inspired him to continue developing his conclusions long after returning from his expedition. While waiting for his academic paper to be published, he began writing a book that would enable students and the general public to share his excitement about these remarkable birds and the evolutionary processes that shaped them.

First published in 1947, Lack’s book became tremendously influential. Before this time, biology textbooks had never even mentioned the Galápagos finches. But after David Lack’s study, the finches became a primary example of evolution by natural selection, specifically adaptive radiation. Not only did textbooks fully rely on Lack’s findings, they also followed his lead in calling them “Darwin’s finches”, the title of Lack’s famous book.¹⁸

Iconic Finches

What was it about these birds that made them such a prominent symbol of evolution? As Darwin himself pointed out, the numerous Galápagos finch populations each have distinctive beaks, and he speculated that they could have evolved from an ancestral species that came to the islands. But a complete picture of finch evolution would have to wait another hundred years, when David Lack arrived.

During his five months on the Galápagos, including both the rainy and dry seasons, Lack observed that these beak differences enable the finches to subsist on different kinds of food:

The beak differences between most of the genera and subgenera of Darwin's finches are clearly correlated with differences in feeding methods. This is well borne out by the heavy, finch-like beak of the seed-eating Geospiza, the long beak of the flower-probing Cactornis, the somewhat parrot-like beak of the leaf, bud, and fruit-eating Platyspiza, the woodpecker-like beak of the woodboring Catcospiza, and the warbler-like beaks of the insect-eating certhidea and Pinaroloxias.¹⁹

Lack's image of beak adaptations from Darwin’s Finches

Specializing in such different sources of food enables these finches to live in close proximity without directly competing with each other or driving populations to extinction. The fact that so many of these closely related finches are able to co-exist is a remarkable fact in itself. As Lack himself put it, “It is not only the origin, but also the persistence, of new species which require explanation.”²⁰

But it is also fascinating to consider how these birds got to be so different in the first place. How did a finch come to have a beak like a “parrot”, “woodpecker”, or “warbler”? The answer lies in the distinct characteristics of the Galápagos. Because the islands are so remote, no actual parrots, woodpeckers, or warblers ever settled on it. In the absence of these species, the Galápagos finches were able to adopt feeding habits and forms that they would never have taken on a large continent full of other birds competing for food. The isolation of these islands offered just the right conditions for us to see living examples of adaptive radiation.²¹

Conclusion

Considering the immense popularity of the Galápagos finches, it is quite surprising to learn that Charles Darwin himself had so little to say about them. In fact, it was actually David Lack, one century later, who conducted the critical research that immortalized the finches in biology textbooks and popular lore. By naming his landmark book Darwin’s Finches,²² Lack paid homage to the man whose voyage on the HMS Beagle helped transform the study of natural history. But at the same time, Lack also obscured the fact that evolutionary biology is an enterprise conducted by a large community of brilliant scholars, not just the product of one man’s efforts.

This tendency to immortalize “great men of science” has also led many people to refer to modern evolutionary theory as Darwinism, despite the fact that it has substantially changed and developed over the past 150 years. It is important to give credit where credit is due, and if that’s the case, we should seriously reconsider how we refer to the Galapagos finches. Evolutionary biologist Dolph Schluter, who studied the finches several decades after David Lack, had this to say:

I find Lack's intuition really stunning given how little information he had. He's my hero actually… They should be called Lack's finches.²³

In the second part of this series, we’ll explore the fact that David Lack, in addition to being a world-renowned evolutionary biologist, was also a devout Christian. His study of evolutionary theory did not cause him to lose his faith; in fact, he actually converted to Christianity after completing his Galápagos finch research.

For Discussion

Further Reading

• Grant, Peter R.; Grant, B. Rosemary. How and Why Species Multiply: The Radiation of Darwin's Finches, Princeton University Press, 2008.
• Sulloway, Frank J. (Spring 1982), "Darwin and His Finches: The Evolution of a Legend" (PDF), Journal of the History of Biology 15 (1): 1–53.
• Weiner, Jonathon. The Beak of the Finch: A Story of Evolution in Our Time. Vintage Books, 1995.

Notes

1. Sulloway, F. (1983). "Darwin and his finches: The evolution of a legend." Journal of the history of biology 15(1): 32. Darwin’s notebooks on transmutation mentioned Galapagos tortoises and mockingbirds, not finches.
2. Lack, David. Darwin’s Finches. Cambridge University Press, 1947: 9. Confirmed by Sulloway (1983), p5.
3. Darwin, Charles. Journal of researches into the natural history and geology of the countries visited during the voyage of H.M.S. Beagle round the world. London: John Murray. 2d ed. 1845: 379-80. This edition of the book also contained the drawings of four different finches that have become enshrined in biology textbooks and on the walls of the National Academy of Sciences in Washington, DC.
4. Sulloway, p35. Sulloway points out that the first published evolutionary account of the Galapagos finches was not until 1876, by Osbert Salvin: "On the Avifauna of the Galapagos Archipelago." Trans. Zool. Soc. London, 9:447-51.
5. Darwin (1845), p395.
6. Sulloway, p40.
7. Sulloway, p40.
8. Larson, E. J. Evolution's Workshop: God and Science on the Galapagos Islands. New York, Basic Books, 2001: 166-67.
9. Lack, David. (1973) “My life as an amateur ornithologist.” Ibis: 424.
10. Lack (1973), 425-27.
11. Lack (1947), p1.
12. Lack (1947), p11.
13. Larson, 167-68.
14. The California Academy of Sciences sponsored an expedition to the Galapagos in 1905-06 and collected nearly 9000 Galapagos finch specimens (Sulloway, p40).
15. In New York, Lack roomed with the curator of the finch collection—German émigré zoologist Ernst Mayr. By developing this relationship, Lack had close ties with two of the biggest figures in the neo-Darwinian synthesis, Julian Huxley and Ernst Mayr (Larson, 168).
16. Larson, p168.
17. Lack (1973), p424.
18. Larson, p198.
19. Lack (1947), p60.
20. Lack (1947), p158.
21. See Lack’s concluding chapter on “Adaptive Radiation”, pp146-159 of Darwin’s Finches (1947).
22. British ornithologist Percy Lowe originally proposed the name “Darwin’s finches” in 1935, but the name did not catch on until Lack used it in his book. See P.R. Lowe, (1936) "The Finches of the Galapagos in Relation to Darwin's Conception of Species." Ibis, 13th ser., 6:310-321. (Cited in Larson, p287)
23. Schluter, in an interview with Edward Larson, 16 March 2000.

Transitional Fossils

Some time ago, the Discovery Institute’s Casey Luskin commented on the human origins exhibit at the Smithsonian Institution, suggesting that palaeoanthropologists use evolutionary theory to describe the progression of the human lineage even when they don’t have transitional fossils with which to work. He writes:

What's ironic, however, is that if you ask the question How Do We Know Humans Evolved? the answer you’re given is, “Fossils like the ones shown in our Human Fossils Gallery provide evidence that modern humans evolved from earlier humans.” So whether you find fossils or you don’t, that’s evidence for evolution.

Indeed, it has become an article of faith for those espousing both the young earth creation (hereafter YEC) model and many who hold to the intelligent design model that transitional fossils do not exist and therefore evolution has not taken place. Support for this position usually entails attacking the weak areas of the fossil record, where burial processes have left us little with which to work, or the creation of straw men arguments in which transitional fossils are defined in such a way that none could ever be found. Often this centers on the concept of “missing link,” a term that is habitually used in the popular press and young earth creation and intelligent design literature when referring to fossil remains but which has little to no meaning for biologists or palaeontologists. As Ahlberg and Clack (Ahlberg and Clack 2006) write:

But the concept has become freighted with unfounded notions of evolutionary ‘progress’ and with a mistaken emphasis on the single intermediate fossil as the key to understanding evolutionary transitions. Much of the importance of transitional fossils actually lies in how they resemble and differ from their nearest neighbours in the phylogenetic tree, and in the picture of change that emerges from this pattern.

Contrary to common misconceptions, the fossil record does not record one single lineage for any family of organisms but rather a series of branches, with many related species coexisting synchronously. Darwin hypothesized that the evolutionary record reflected this bushiness and drew such a diagram in his journal. At the time, though, he had little in the way of fossil evidence to back up this position. Much has changed since his day.

An analogy for understanding this “bushiness” was best described by Prothero and Buell (Prothero and Buell 2007). They suggest that the reader consider his or her own genealogy. You and your siblings are the direct descendents of your parents and, while you are similar to them, each of you has different characteristics not shared with them as well as characteristics that you do share. Your parents have siblings as well (your aunts and uncles), and your grandparents are their last common ancestors. These siblings have their own children (your cousins), who have different and similar traits relative to their parents. They are broadly recognizable as being related to you (“oh, I see you have Aunt Edna’s nose”) but three or four generations out, they will become less and less so. These are the “nearest neighbours” that Ahlberg and Clack describe. In this analogy, each of these cousins represents a transitional form from what was (your grandparents) to what will be down the road.

For example, no one would confuse a frog with a salamander but if you trace the fossil record of each back in time, eventually you encounter a fossil, Gerobatrachus hottoni which was recently discovered (Anderson et al. 2008) that is best described as a “frogamander,” having the basal characteristics of both frogs and salamanders. Had we seen such an animal at the time, it is likely we would not have found it remarkable because it would have resembled the species around it. One lineage eventually diverged into frogs, salamanders and other amphibians. Most (just like Darwin proposed in his tree diagram with the little hatch marks at the tip of many branches) went extinct.

Taxonomy and the Beginnings of Human Origins

All life is classified based on a system devised by Carolus Linneaus in 1735 in his remarkable work Systema Naturae. This system gives all recognized species an individual place based on a system of hierarchy. The study of classification is known as taxonomy. A taxonomic ranking for humans would be this:

When a fossil is excavated, the first thing that the palaeontologist does is make a taxonomic assessment of where it fits in a sequence of known fossils. Traits that are shared with other like species or genera are referred to as primitive traits. Examples of this in humans are five fingers and the presence of three arm bones. We share this with all mammals. Traits that are new or are not shared with other like species are referred to as derived traits. Examples of this in humans are the skeletal changes in the pelvis and the foot to allow for walking upright. We do not share these with any other primates.

Transitional fossils in the human fossil record are distinguished at both the genus and species level. This group includes the extinct genera Ardipithecus and Australopithecus and the current genus Homo. All species except Homo sapiens are extinct. Much of the recent study of early humans focuses on the transition from Ardipithecus (‘Ardi’) to Australopithecus (‘Lucy’ and similar fossils) and from Australopithecus to Homo, the genus that led eventually to us. While each of the australopithecine species identified in the fossil record has derived characteristics that separate them from their ancestors and from each other, only one led to the genus Homo.

In future posts, I will describe the evidence for human evolution and why this evidence is compelling. It suggests that we have had a long, varied history filled with great leaps of change, crushing defeat, and eventual expansion into all areas of the globe.

Notes

Ahlberg, P. & J. Clack (2006) A firm step from water to land. Nature, 440.

Anderson, J. S., R. R. Reisz, D. Scott, N. B. Frobisch & S. S. Sumida (2008) A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature, 453, 515-518.

Prothero, D. & C. Buell. 2007. Evolution: What the fossils say and why it matters. Columbia Univ Pr.

But it is also important that we engage believers who disagree with us (on human origins, especially) with charity and humility as a witness to our common identity in Christ—that we may be known by our love for each other in tandem with our demonstrated love for the secular world that does not yet claim Christ as Lord and Savior.

While the BioLogos Foundation is committed to both of these aspects, we are especially pleased that our desire to engage in gracious dialogue with fellow believers who reject biological evolution has been receiving increased and very favorable attention in both the Christian and secular press. More importantly, we are being joined in that reconciling project by those who have often been defined primarily as our “opponents,” rather than as brothers and sisters in Christ.

First, A Tale of Two Scientists, the cover story of Christianity Today’s July-August 2012 issue, featured the accounts of BioLogos Foundation President Darrel Falk and Todd Wood, Director of the Center for Creation Research at Bryan University. Though Wood does not accept biological evolution on theological grounds, both men recognize its strength and explanatory power. But more importantly, both reject the warfare model between science and faith (and between Christians who think differently) as being, in Wood’s words, “detrimental to the Church.”

Second, our Southern Baptist Voices series has become a model for how such dialogue can be pursued, even in the sometimes no-holds-barred context of the web. Several installments in our ongoing dialogue with Southern Baptist theologians have been covered by the Erin Roach of the Baptist Press (on May 25th , June 6th, and July 3rd) and on on July 19th by Lillian Kwan of the Christian Post. And just this past week, Associated Press reporter Travis Loller highlighted the series in an article picked up by the Huffington Post, the Washington Post, and many other news outlets across the country.

To make it easier for readers to find the entire Southern Baptist Voices series and join in the conversation themselves, we’ve launched a new landing page here: Southern Baptist Voices. It is our hope and prayer that this initiative will set the stage for future dialogue between evolutionary creationists and those who hold other perspectives, as well.

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.

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.

In the last post in this series, we introduced a paper by Chen and colleagues that sought to identify new genes in various Drosophila (fruit fly) species. The youngest (i.e. the most recently evolved) gene they found is one specific to Drosophila melanogaster, the species of fruit fly beloved by geneticists as a model organism. The gene is named “p24-2” (not the most imaginative name, but it serves its purpose) and the gene it is duplicated from is called “Éclair”. The Éclair gene is found in a number of Drosophila species. A simplified “family tree” of three Drosophila species (D. melanogaster, D. simulans and D. erecta) is shown below. The duplication event that generated the p24-2 gene happened within the lineage leading to D. melanogaster, but after D. melanogaster and D. simulans separated as distinct species:

Since the entire genomes of these species are now sequenced and available online, it is possible to look at the chromosome region where the Éclair gene is found in all three. By looking at this region in D. melanogaster, we see that the brand-new p24-2 gene is almost right next door to its “parent” gene, Éclair. Below is a screen shot taken when looking at this region using a Drosophila “genome browser” that is freely available online. The red arrow indicates the Éclair gene, and we can see p24-2 is just one gene over, and seems to be nested within another gene called “Unc-115b”. The green arrows are pointing to two different “versions” of how p24-2 is made into an mRNA working copy. The Unc-115b gene (blue arrow) has five different mRNA versions. (One of the p24-2 mRNA versions has a lot of Unc-115b sequence that is not used when the p24-2 protein is made).

(Click Image to Enlarge)

Finding a duplicated gene next door to the sequence it is copied from is pretty common in genomes – when chromosomes are copied or recombined during cell division, side-by-side copies of parts of chromosomes show up every now and then. It’s also not surprising to see a new gene cobbled together with another gene. In this case, Unc-115b and p24-2 are overlapping but separate functional entities: they each have their own protein sequences, but each includes the code of the other as a sequence that does not actually translate into protein. The details of how this “cobbling” happens aren’t important for this discussion, other than to note that the mechanisms are known and not rare. In the chart above, then, the orange sections indicate the active parts of the transcribed sequence, while the gray are sections that are included in the RNA molecule, but do not get used directly to code for the new protein.

When we look at this same chromosome region in D. simulans and D. erecta, however, p24-2 is missing. Éclair and Unc-115b are there, but p24-2 is not, since it arose after D. melanogaster separated from its common ancestors with the other species. (Note: this entire region is a mirror image in D. simulans and D. erecta when compared to D. melanogaster due to a large scale chromosome inversion that covers this whole area. So, while it looks “backwards” compared to the image above, that is not surprising, it’s expected):

(Click Image to Enlarge)

So, with the p24-2 gene in D. melanogaster, we have a bona-fide, recent gene duplication event. This gene is brand new, evolutionarily speaking (less than 3 million years old, given the calculated speciation times of D. melanogaster and D. simulans). Not only is it brand new, it is also essential for survival in D. melanogaster: if you remove it, the fly dies. Obviously, since every other Drosophila species lacks p24-2, this gene is not essential for survival for any other species. It’s new, and now it’s necessary.

Do new, essential genes refute the Intelligent Design (ID) argument from Irreducible Complexity (IC)?

So far, nothing we have discussed explicitly threatens the ID argument from IC, though it does threaten the ID argument that new information cannot arise through evolution, a topic we have discussed in detail before. Michael Behe, the main ID proponent of the argument from IC, has commented on this research by Chen and colleagues (thanks to commenter “Bilbo” for pointing this out). Behe’s rejoinder was to a blog post by biologist and atheist blogger Jerry Coyne, who used the paper by Chen and colleagues to attack Behe’s ideas. Since Behe’s reply deals with his understanding of how gene duplication relates to his argument from IC, I will quote it here at length:

I have never stated, nor do I think, that gene duplication and diversification cannot happen by Darwinian mechanisms, or that “they play almost no role at all” in the unfolding of life. (As a matter of fact, I discussed several examples of that in my 2007 book The Edge of Evolution. That would be silly — why would anyone with knowledge of basic biochemical mechanisms deny that, say, the two gamma-globin coding regions on human chromosome 11 resulted from the duplication of a single gamma-globin gene and then the alteration of a single codon? What I don’t think can happen is that duplication/ divergence by Darwinian mechanisms can build new, complex interactive molecular machines or pathways. Assuming (since he is in fact critiquing them) Professor Coyne has been attentive to my arguments, one background assumption that he may have left unexpressed is that he thinks the newer duplicated genes discovered by Professor Long’s excellent work represent such complex entities, or parts of them.

There is no reason to think so. A gene can duplicate and diversify without building a new machine or network, or even changing function much. The above example of the two gamma-globin genes shows that duplication does not necessarily result in change in function. The examples of delta- and epsilon-globin, which, like gamma-globin, presumably also resulted from the duplication of an ancestral beta-like globin gene, show that sequence can diversify further, but function remain very similar. Even myoglobin, which shares rather little sequence homology with the other globins, has not diverged much in biochemical function.

In his recent work Professor Long discovered that many of the new genes were essential for the viability of the organism — without the gene product, the fruitflies would die before maturity. Perhaps Professor Coyne thinks that that means the genes necessarily are parts of complex systems, or at least do something fundamentally new. Again, however, there is no reason to think so. The notion of “essential” genes is at best ambiguous. We know of examples of proteins that surely appear necessary, but whose genes are dispensable. The classic example is myoglobin. It is also easy to conceive of a simple route to an “essential” duplicate gene that does little new. Suppose, for example, that some gene was duplicated. Although the duplication caused the organism to express more of the protein than was optimum, subsequent mutations in the promoter or protein sequence of one or both of the copies decreased the total activity of the protein to pre-duplication levels. Now, however, if one of the copies is deleted, there is not enough residual protein activity for the organism to survive. The new copy is now “essential”, although it does nothing that the original did not do.

The main points of Behe’s reply can be summarized as follows:

1. Gene duplications and subsequent changes to the copies (diversification) can and do happen, but the results are nothing really “new”— no new molecular machines or pathways (nor parts of such pathways), nor much in the way of new functions.
2. Duplicated genes can become essential simply by “sharing” the original function, and then reducing their share to a minimum, perhaps through the amount of protein that each copy makes. Again, this is not anything really new, since the copy doesn’t do anything that the original didn’t do already. So, the finding that some gene copies are essential genes is not a threat to the IC argument.

Note that Behe’s reply makes predictions that can be tested with further research. These predictions might be summarized in this way:

1. If IC is correct, duplicated genes will not be part of new, complex molecular pathways or machines.
2. If IC is correct, duplicated genes that are both essential should “share” the original function.

Testing IC with new research

Behe’s reply to the Chen paper is of course hypothetical and speculative – as demonstrated by his own comment that “there is no reason to think” that the duplicated genes are components of new complex pathways or systems. Accordingly, the validity of Behe’s reply depends on its ability to hold up over time as more work is done. Of note, the functions of p24-2 and its parent gene Éclair have been studied intensively since 2010. These studies, as we shall see in the next post in this series, shed quite a bit of light on these questions.

For further reading:

Behe, M.J. Darwin’s Black Box: the Biochemical Challenge to Evolution. Free Press, New York, 1996.

Behe, M.J. The Edge of Evolution: the Search for the Limits of Darwinism. Free Press, New York, 2007.

Chen, S., Zhang, Y, and Long, M (2010). New genes in Drosophila quickly become essential. Science 330; 1682-1685.