Tag Archives: Macro-Evolution

New study: natural selection can act to impede speciation

Australian Walking Stick
Australian Walking Stick

My friend KL sent me this press release from the University of Colorado at Boulder.

It says:

An intriguing study involving walking stick insects led by the University of Sheffield in England and the University of Colorado Boulder shows how natural selection, the engine of evolution, can also impede the formation of new species.

The team studied a plant-eating stick insect species from California called Timema cristinae known for its cryptic camouflage that allows it to hide from hungry birds, said CU-Boulder Assistant Professor Samuel Flaxman. T. cristinae comes in several different types — one is green and blends in with the broad green leaves of a particular shrub species, while a second green variant sports a white, vertical stripe that helps disguise it on a different species of shrub with narrow, needle-like leaves.

While Darwinian natural selection has begun pushing the two green forms of walking sticks down separate paths that could lead to the formation of two new species, the team found that a third melanistic, or brown variation of T. cristinae appears to be thwarting the process, said Flaxman. The brown version is known to successfully camouflage itself among the stems of both shrub species inhabited by its green brethren, he said.

Using field investigations, laboratory genetics, modern genome sequencing and computer simulations, the team concluded the brown version of T. cristinae is shuttling enough genes between the green stick insects living on different shrubs to prevent strong divergent adaptation and speciation. The brown variant of the walking stick species also is favored by natural selection because it has a slight advantage in mate selection and a stronger resistance to fungal infections than its green counterparts.

“This is one of the best demonstrations we know of regarding the counteractive effects of natural selection on speciation,” said Flaxman of CU-Boulder’s Department of Ecology and Evolutionary Biology, second author on the new study. “We show how the brown population essentially carries genes back and forth between the green populations, acting as a genetic bridge that causes a slowdown in divergence.”

A paper on the subject appeared in a recent issue of the journal Current Biology. 

[…]“This movement of genes between environments slows down the genetic divergence of these stick insect populations, impeding the formation of new species,” said Aaron Comeault, a former CU-Boulder graduate student and lead study author who conducted the research while at the University of Sheffield.

So, in the past I had read that natural selection can act as a stabilizing force in nature – keeping the organism operating within a type. This study seems to be confirmation of that. But there are other problems with generating macro-evolutionary change.

Also related to the problem raised by the study is this problem of genetic drift, which also works against the preservation of beneficial mutations.

Evolution News explains the genetic drift problem:

Evolutionary biologists often assume that once mutations produce a functionally advantageous trait, it will easily spread (become “fixed”) throughout a population by natural selection. For example, imagine a population of brown-haired foxes that lives in a snowy region. One fox is born with a mutation that turns its fur coat white, rather than brown. This fox now has an advantage in hunting prey and escaping predators, because its white fur provides it with camouflage. The white fox survives, passing its genes on to its offspring, which are also adept at surviving and reproducing. Over time, the white-haired trait spreads throughout the population.

This is how it’s supposed to work — in theory. In the real world, however, merely generating a functionally advantageous trait does not guarantee it will persist, or become fixed. For example, what if by chance the white fox trips, breaks a leg, and gets eaten by a predator — never passing on its genes? Random forces or events can prevent a trait from spreading through a population, even if it provides an advantage. These random forces are lumped together under the name “genetic drift.” When biologists run the mathematics of natural selection, they find that unless a trait gives an extremely strong selective advantage, genetic drift will tend to overwhelm the force of selection and prevent adaptations from gaining a foothold in a population.

This underappreciated problem has been recognized by some evolutionary scientists who are skeptical of the ability of natural selection to drive the evolutionary process. One of those scientists is Michael Lynch, an evolutionary biologist at Indiana University, who writes that “random genetic drift can impose a strong barrier to the advancement of molecular refinements by adaptive processes.”2 He notes that the effect of drift is “encouraging the fixation of mildly deleterious mutations and discouraging the promotion of beneficial mutations.”3

I guess the point of this is that if someone wants to convince you that macro-evolution is possible through the mechanisms of random mutation and natural selection, then they have some work to do. And it’s more work than just asserting that it happened.

People who are technical may benefit from reading Michael Behe’s book “The Edge of Evolution”, which studies how likely it is to get several positive adaptations in a row within a reasonable period of time.

UPDATE: A biologist friend tells me that “whether natural selection is driving speciation or preventing it, in neither case is it explaining how these organisms came to be in the first place. It only explains how existing organisms interact with their environment. And this can be explained at least as well through intelligent design as through naturalistic processes.” She also says that natural selection can drive speciation, but still within a kind.

Did your science textbook teach that peppered moths prove evolution?

Here’s a post by Jonathan Wells at Evolution News, which re-caps the history of the peppered moths experiment.

Excerpt: (links removed)

The peppered moth story is familiar — even overly familiar — to most readers of ENV, so I will summarize it only briefly here. Before the industrial revolution, most peppered moths in England were light-colored; but after tree trunks around cities were darkened by pollution, a dark-colored (“melanic”) variety became much more common (a phenomenon known as “industrial melanism”). In the 1950s, British physician Bernard Kettlewell performed some experiments that seemed to show that the proportion of melanic moths had increased because they were better camouflaged on darkened tree trunks and thus less likely to be eaten by predatory birds.

Kettlewell’s evidence soon became the classic textbook demonstration of natural selection in action — commonly illustrated with photos of peppered moths resting on light- and dark-colored tree trunks.

By the 1990s, however, biologists had discovered several discrepancies in the classic story– not the least of which was that peppered moths in the wild do not usually rest on tree trunks. Most of the textbook photos had been staged.

In the 2000s the story began disappearing from the textbooks. British biologist Michael Majerus then did some studies that he felt supported the camouflage-predation explanation. But before he died of cancer in 2009, he only managed to publish a report of his study in the Darwin lobby’s in-house magazine Evolution: Education and Outreach. Now four other British biologists have presented his results posthumously in the Royal Society’s peer-reviewed Biology Letters. In an accompanying supplement, the authors presented their version of what they call “the peppered moth debacle.” And a debacle it certainly is, but not in the way they think.

According to Charles Darwin, natural selection has been “the most important” factor in the descent with modification of all living things from one or a few common ancestors, yet he had no actual evidence for it. All he could offer in The Origin of Species were “one or two imaginary illustrations.” It wasn’t until almost a century later that Kettlewell seemed to provide “Darwin’s missing evidence” by marking and releasing light- and dark-colored moths in polluted and unpolluted woodlands and recovering some of them the next day. Consistent with the camouflage-predation explanation, the proportion of better-camouflaged moths increased between their release and recapture.

Throughout the 1970s and 1980s, however, researchers reported various problems with the camouflage-predation explanation, and in 1998 University of Massachusetts biologist Theodore Sargent and two colleagues published an article in volume 30 of Evolutionary Biology concluding “there is little persuasive evidence, in the form of rigorous and replicated observations and experiments, to support this explanation at the present time.” (p. 318)

The same year, Michael Majerus published a book in which he concluded that evidence gathered in the forty years since Kettlewell’s work showed that “the basic peppered moth story is wrong, inaccurate, or incomplete, with respect to most of the story’s component parts.” (p. 116) In a review of Majerus’s book published in Nature, University of Chicago evolutionary biologist Jerry Coyne wrote: “From time to time, evolutionists re-examine a classic experimental study and find, to their horror, that it is flawed or downright wrong.” According to Coyne, the fact that peppered moths in the wild rarely rest on tree trunks “alone invalidates Kettlewell’s release-and-recapture experiments, as moths were released by placing them directly onto tree trunks.”

In 1999, I published an article in The Scientist summarizing these and other criticisms of the peppered moth story, and in 2000 I included a chapter on peppered moths in my book Icons of Evolution. Then, in 2002, journalist Judith Hooper published a book about the controversy titled Of Moths and Men. Hooper accused Kettlewell of fraud, though I never did; my criticism was directed primarily at textbook writers who ignored problems with the story and continued to use staged photos even after they were known to misrepresent natural conditions.

Jonathan has actually written about a number of  misleading things that you may mind in Biology textbooks.

Here are the sections in his book “Icons of Evolution“:

  • The Miller-Urey Experiment
  • Darwin’s Tree of Life
  • Homology in Vertebrate Limbs
  • Haeckel’s Embroys
  • Archaeopteryx–The Missing Link
  • Peppered Moths
  • Darwin’s Finches
  • Four-Winged Fruit Flies
  • Fossil Horses and Directed Evolution
  • From Ape to Human: The Ultimate Icon

Dr. Wells holds a Ph.D in Molecular and Cell Biology from the University of California at Berkeley.

Is there a smooth pathway from micro-evolution to macro-evolution?

From Luke Nix who blogs at Faithful Thinkers.


Macroevolutionary changes are a lot of microevolutionary changes, but they are in a specific series that follow a specific pathway. The missing premise in this argument is that the pathway from ancestor to claimed offspring (many generations down the road) is clear of obstacles.

In his book, “The Edge of Evolution” Michael Behe shows that scientists have observed such an obstacle in the lab. The obstacle was not time, it is in the genetic pathway that must be traversed if macroevolutionary changes are to take place in reality. Since an obstacle has been observed, we now have a false premise in the argument. Since there is a false premise, the argument fails. There is a difference between micro- and macro-evolutionary changes. A lot of microevolutionary changes are necessary for macroevolution, but they are not sufficient. The other sufficient condition (a clear genetic pathway) still has yet to be met. Since both sufficient conditions for macroevolution have not been met, it has not been demonstrated. And since changes over time has been demonstrated, there is a need to distinguish between the two. To prevent confusion about what we know to be true and what we don’t, this distinction must be made.

There is only one way that this can be overcome by the naturalist: find a pathway that would be clear by default in nature. Notice that I have added one more piece to the missing premise above: “…clear by default in nature“. I have to add that last qualification because as scientists are looking for a way to overcome this obstacle, they are introducing their own intelligence- fine-tuning the process, then “allowing nature to take its course”. Their conclusion of naturalistic macroevolution will depend on a premise that is founded on intelligence. That would undermine the whole argument for naturalistic (macro)evolution.

This is one of the ways to show that evolution is true – by showing a pathway to macro-evolutionary change in the lab. If people expect me to believe in the grandiose claims of fully naturalistic evolution through a stepwise process, then why can’t I see the pathway myself? If you make the claim that it happened, then I want to see the evidence for the claim.

Related posts

The Talk Origins speciation FAQ and the problem of citation-bluffing

The thing to be explained by Darwinism (in addition to the origin of life) is how can you get new, different body plans and organ types by the mechanisms of mutation and selection. Everyone admits that you can get cases where animal A mutates in a small way so that it can no longer breed with animal B. That is speciation of a sort, because the animals can no longer breed. But the real question is whether we can generate species with different body plans using these naturalistic Darwinian mechanisms of mutation and selection.

Here are two podcasts featuring Casey Luskin that discuss how much morphological change has really been observed according to research.

Here is the MP3 file from part one. (14 minutes)


On this episode of ID The Future, Casey Luskin discusses Talk Origins, a resource often used by supporters of Darwinian evolution to refute arguments made by proponents of intelligent design. After taking a closer look, Luskin found FAQs on Talk Origins guilty of citation bluffing, overstated claims, and other misleading tactics. In particular, the Talk Origins FAQ on speciation claims to provide evidence of “observed instances” of new species. On further review, this turns out to be far from the case. Tune in to Luskin as he explains why.

Here is the MP3 file from part two. (21 minutes)


On this episode of ID The Future, Casey Luskin continues his discussion about Talk Origins, a resource often used by supporters of Darwinian evolution to refute arguments made by proponents of intelligent design. After taking a closer look, Luskin found FAQs onTalk Origins guilty of citation bluffing, overstated claims, and other misleading tactics. In particular, the Talk Origins FAQ on speciation claims to provide evidence of “observed instances” of new species. On further review, this turns out to be far from the case. Tune in to Luskin as he explains why in this conclusion to a two-part series.

Basically, he takes a look at the details of cases of “speciation” claimed in the Talk Origins FAQ, and finds that the changes are minor changes, and not changes in morphology. This is not the change that we are looking for to support the hypothesis of macro-evolution. In order to become Darwinists, we need to observe change driven by mutations that leads to changes in body plans. And the mutations have to be heritable.

Highly recommended. You’ve got to love the directness of Casey Luskin explaining what needs to be proved and what has been proved. By the way, here is a more detailed written assessment of speciation claims of the Darwinists.

In Asia, questioning Darwinism on scientific grounds is no problem

From Evolution News.


In Korea, a mainstream publisher of popular and science texts, Book 21 Publishing Group, has brought out an edition of Explore Evolution, a textbook presenting both sides of the evolution debate. The translation was done by a pair of Korean academics, Seung Yup Lee and Eung Bin Kim, whose scientific specialties are respectively in biomimetics and environmental microbiology. Both teach at universities, Sogang and Yonsei, ranked in Korea’s top ten.

Dr. Lee’s research fuels his questions about macroevolution. His work on the amazing “natural design” of the South American Hercules beetle and its humidity-sensing shell was highlighted in Nature. In the Preface to the Korean Explore Evolution, Lee advocates investigating “alternative theories” to undirected Darwinian evolution.

Korea also has its own Research Association for Intelligent Design, with an impressive masthead of biologists, chemists and other scientists at top research institutions. Sogang University in Seoul hosts an Annual Symposium on Intelligent Design. The event has included presentations on William Dembski and Robert Marks’s Law of Conservation of Information and on protein translation as evidence of intelligent design.

China, of course, is Asia’s biggest market for ideas. Illustra Media has had considerable success distributing DVDs of prime ID-related titles there.

[…]Producer and director Lad Allen had Unlocking the Mystery of Life and Privileged Planet dubbed into Cantonese and Mandarin, moving a hundred thousand copies into China via Hong Kong. He estimates that three or four times that many DVDs were illegally pirated and copied.

[…]Illustra has completed a Japanese translation of The Privileged Planet, lip-synced by Japanese actors in Tokyo. But Unlocking the Mystery of Life is Illustra’s most-translated film, with editions in Khmer (Cambodian), Thai, Sri Lankan, and Mongolian as well as a variety of European languages.

On the book-publishing side, Center for Science & Culture senior fellow Paul Chien has been largely responsible for introducing intelligent design to China. A biologist at the University of San Francisco, Chien has translated Phil Johnston’sDarwin on Trial and Michael Behe’s Darwin’s Black Box among other titles.

He recently finished work on Denyse O’Leary’s By Design Or By Chance?, to be followed by Stephen Meyer’s Signature in the Cell.

It’s good that there are still some places left where a person can ask questions about what natural causes can do and what intelligent causes can do.