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

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

Transcript

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Beautiful Things

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

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

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

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

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

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

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

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

The opening chapters in Genesis omit seemingly important details, leaving one with an incomplete understanding of the situation at hand. Dr. Keller explains that ancient Biblical writers sought to convey certain truths, and, therefore, would only include facts relevant to the point of the narrative. This is true of Cain’s exile in Genesis 4: 11-26. As he explores this story, he highlights the crucial insights that the passage means to offer.

Foremost, he exposes the cause of Cain’s ruin. When Cain murders Abel, God questions him saying “Where is Abel your brother?” and “What have you done? The voice of your brother’s blood is crying to me from the ground.” God is not seeking information, but rather creating an opportunity for Cain to repent of his sin. Why is this so? Dr. Keller explains that sin results when one is self-focused, rather than God- focused. Repentance, however, goes to the root of this problem by turning one’s attention to God and others once again. It is the action of removing oneself from the center that heals the hardness and pride of the heart.

However, Cain does not repent. Instead, he complains to God that his “punishment is more than he can bear.” In other words, he is sorry for the consequences of his sin, not the sin itself. This leads to his exile from the presence of God, which is the ultimate downfall of Cain.

Next, there is evidence that Cain’s city is a “culture of death.” From the line of Cain comes a civilization marked by animal husbandry, technology, and music. In these “gardening” activities, the people indeed reflect God’s image as they creatively order the surrounding materials. However, rather than a Garden of Eden through love and service, it becomes a place marked by oppression and violence. For example, one descendant of Cain called Lamech is polygamous, having two wives. Furthermore, this man boasts saying, “I have killed a man for wounding me, a young man for injuring me—If Cain is avenged seven times, then Lamech seventy-seven times.” Their culture is now about power and exploitation. In spite of the death cultivated in this city, Dr. Keller clarifies that cities are not the issue. It is human sin alone that corrupts the city.

Finally, the scriptures point to a coming city of grace. When Cain establishes his city, he names it after himself. Without God’s presence and love, his work becomes a means of making a name for himself. However, cities are supposed to be a place where people selflessly give to one another in response to the Lord. This text shows the beginning of one such city that comes through the line of Seth, Eve’s third son. The passage states that this city is filled with a people who “call on the name of the Lord.” Thus, it is a place where people lift high the name of God. Dr. Keller explains that the Body of Christ is called to be this city of grace within the city of death. Ultimately, this power comes through the Lord Jesus Christ alone, who has poured out endless love and forgiveness and grace upon all who believe in his name.

Exactly one decade ago today, the September Eleventh terrorist attacks shocked Americans beyond belief as they watched airplanes crash into the mighty Twin Towers and Pentagon. The hearts of the people filled with grief at the aftermath of the tragedy. The Twin Towers were reduced to rubble, thousands of dearly loved individuals died, and all were crushed with heartache. In the midst of this death arose a beautiful sight and sound: millions bowing their heads in prayer, speaking words of comfort, and coming to the aid of one another. In spite of the physical deaths, New York City and the U.S. as a whole were transformed from death to life as people joined hand in hand to mourn the loss and move forward into the healing process. The pain of the losses was raw and real, but so was the love and grace that swept through, causing our divided nation to unite in unbelievable strength.

This sermon is a clear reminder that we each have a choice. We can work to build cities that celebrate God’s love for us (the lineage of Seth), or we can live in the destructive lineage of Cain. May the spirit of prayer, humility, and love characterize the world’s cities on this the tenth anniversary of America’s most stark example of “The Tale of Two Cities.”

Many scientists think that evolution is a directionless process, one in which humans are merely an accidental byproduct. In a recent episode of the award-winning radio program “To the Best of Our Knowledge” (produced by Wisconsin Public Radio, and reposted above, with permission), however, esteemed paleontologist Simon Conway Morris of Cambridge University explains a different view of evolution. Conway Morris has catalogued plentiful examples of evolutionary convergence, in which different organisms arrive at the same function through different evolutionary pathways, including the trait of intelligence. He examines the ability of the octopus to gaze, learn and play, and compares it to the intelligent behaviors of dolphins and the tool making ability of certain crows. Given enough time and resources, he says, every ecological niche will be filled up by some kind of life form. One of these niches is that for highly intelligent life, a niche occupied by us, Homo sapiens. If the tape was rewound and evolution started over from scratch, Conway Morris says, the evolutionary details would be different, but the end result would be similar: a species characterized by intelligence and complex civilization.

While several esteemed scientists, including atheist Richard Dawkins, and Brown University cell biologist, Kenneth Miller, agree with Simon Conway Morris, most (according to Dawkins) do not accept that evolution can have this sort of directionality. Sean Carroll, leading evolutionary biologist and Vice-President of the Howard Hughes Medical Institute, says that animals merely “exploit what’s available,” with no necessary end. Little, he believes, is inevitable. “With a few other rolls of the dice”, he says, evolution would have resulted in a significantly different assortment of organisms. Noted philosopher of science, Daniel Dennett, agrees with Carroll. Just as the origin and wide-spread diversity of creatures like marsupials (mammals with a pouch) was not inevitable, he says, so the evolution of intelligent human-like beings was not inevitable either. Dennett goes on to say:

The idea that this whole great universe was in some sense designed or intended for us strikes me as just bizarrely self-involved (chuckles)—one of the most stunningly narcissistic visions that I’ve ever encountered. It seems unlikely, don’t you think?

In complete contrast Conway Morris says:

The universe from a theistic viewpoint, from a Christian viewpoint, is utterly contingent. It needn’t exist at all, more particularly it could be anything which God so chose. Science is an open-ended adventure; we don’t know where it’s going to end. People who think religion is simply a set of answers to keep you comfortable are, I’m afraid, sadly mistaken—it is an open-ended adventure. We don’t know, really, what the nature of the universe is. We don’t know why we have our moral, ethical, intellectual and poetic capacities. I know they come from an evolutionary basis, I have no quarrel with that. But so far as I’m concerned, we are going on to completely new territory and my view would be that in fact the religious instincts and the religious teachings actually tell us something real about the world. They’re not simply fairy stories.

So is the near-certainty of human life front-loaded from the beginning? Was it predetermined from the Big Bang that human beings would eventually arise? Was it predetermined that God’s natural activity—that activity which upholds the universe and maintains all that is within it—would be sufficient for the eventual development of humans? Alternatively, was supernatural activity required for the creation of the human body? Does the Bible dictate one way or the other? Is it somehow less God’s creation if it took place through God’s natural activity? Is it somehow more God’s creation if supernatural activity was required? These are questions for theologians. Science is taking us up to edge as Conway Morris brilliantly shows. There, we meet the theologians, and there, we begin the journey’s next phase.

I encourage you to listen to the above recording. The deeper we explore creation, the more we see and appreciate its beauty. So also, and even more significant, the deeper we embed ourselves in God's written and Living Word, the more confident we become of “Romans 8:26-39”. We are loved. More than we can possibly imagine, we are deeply embedded in the love of God. This, truly, is "Life's Solution."

]]> Thu, 11 Aug 11 02:15:51 -0700 Darrel Falk