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Microevolution In Action

Casey Luskin

The journal Science has a large piece on “Evolution in Action” (see the cool video at http://www.biocompare.com/science/btoy2005) or read the article at http://www.sciencemag.org/cgi/content/full/310/5756/1878). While the pieces did indeed cite examples of evolution, these did not present evidence that Neo-Darwinism can account for things like new body plans, novel biological functions, and real biological novelty. I found the examples interesting, but unimpressive as data supporting the grander claims of Darwin’s theory. Here’s the evidence they cited.

1) Genetic similarities between humans and chimps:
This isn’t a new “breakthrough”–we’ve known about close genetic similarities between humans and chimps for over a decade. Sure, they just finished decoding the chimp genome but it actually lessened our knowledge of human/chimp similarities rather than upping it. Similarities could easily be the result of “common design” rather than common descent–where a designer wanted to design organisms on a similar blueprint and thus used similar genes in both organisms. This doesn’t challenge ID.

But it turns out that similarities depend on how you measure them. One study which considered insertions and deletions realized that “our perceived sequence divergence of only 1% between these two species [humans and chimps] appears to be erroneous, because this work […] puts both species much further apart.” (see “Driving man and chimp apart” by Cathy Holding in The Scientist, June 26, 2003; “Comparative sequencing of human and chimpanzee MHC class I regions unveils insertions/deletions as the major path to genomic divergence” by T. Anzai et al. in PNAS 100:7708-7713 (June 24, 2003)). Those interested in an analysis of the many differences between humans and chimps from a pro-ID perspective should read Reflections on Human Origins by William Dembski. (PCID, Volume 4.1, July 2005)

2) Evidence of speciation for birds:
In college I learned quite a bit about speciation in various evolutionary biology courses. The problem is, as this indicates, speciation just means reproductive isolation (“a population stop mating with others”). This doesn’t mean you have observed the origin of something truly new. All they observed was that two bird populations migrated at different times so they didn’t mate anymore. No big deal. They also observed that fish populations can be split up into different lakes and grow different over time. I did a paper on cichlid speciation for an evolutionary biology course in college and was struck at how these small scale changes, even after long periods of time, wrongly excite evolutionists into thinking they can extrapolate to believe that new body plans and functions can arise due to Neo-Darwinian processes. These are very small changes in fish populations, and extended reproductive isolation often results merely in different coloring patterns and feeding habits.

Incidentally, one part of this article notes that noncoding DNA in fruit flies probably has a function–something which is a prediction of intelligent design, not evolution!

3) Avian flu evolution:
I previsouly wrote a post explaining why viral evolution doesn’t entail the origin of any new genetic information, and why it really isn’t an impressive example of evolution! The feared evolution of the Avian flu essentially entails the swapping of pre-existing genes to produce a new virus composed of pre-existing genes. This is not the origin of new genetic material but simply genetic “reassortment.” This is evolution, but not a very impressive example of such. Also, a response to some critics of the original post is found here.

In the end, this evidence reminds me of an insightful comment from Ernst Mayr when he noted that examples of changing gene frequencies or reproductive isolation causing speciation do little to explain the origin of true biological novelty. It’s all about how you define “evolution”:

“The definition widely adopted in recent decades-“Evolution is the change of gene frequencies in populations”-refers only to the transformational component. It tells us nothing about the multiplication of species nor, more broadly, about the origin of organic diversity. A broader definition is needed which would include both transformation and diversification.”

(Mayr, Ernst, “The Growth of Biological Thought: Diversity, Evolution, and Inheritance,” Belknap Press: Cambridge MA, 1982, p400)

In conclusion, the evidence presented in this article supports microevolution–a process denied by no design theorist. My college biology text, Campbell’s Biology defines macroevolution as, “Evolutionary change on a grand scale, encompassing the origin of novel designs, evolutionary trends, adaptive radiation, and mass extinction.” (Campbell, N. A., Reece, J. B., Mitchell, L. G., Biology 4th Ed, 1999) To extrapolate this evidence to such grand claims of macroevolution is highly questionable.


Casey Luskin

Associate Director, Center for Science and Culture
Casey Luskin is a geologist and an attorney with graduate degrees in science and law, giving him expertise in both the scientific and legal dimensions of the debate over evolution. He earned his PhD in Geology from the University of Johannesburg, and BS and MS degrees in Earth Sciences from the University of California, San Diego, where he studied evolution extensively at both the graduate and undergraduate levels. His law degree is from the University of San Diego, where he focused his studies on First Amendment law, education law, and environmental law.