Friday, August 29, 2014
Inquirer Daily News

Creationists and Their Debunkers Back by Popular Demand

Some creationists say it's okay for microbes to evolve, but not for new species to evolve from earlier ones. Scientists disagree.

Creationists and Their Debunkers Back by Popular Demand

Starting today, this blog will update much more often, and will begin to include new features as well as more regular discussion among readers. Today I'd like to post some back-and-forth generated by the column on evolving e-coli. Here's one of the responses: 

Faye's column was informative. However, the whole column could have been written without ever using the word evolution or any derivative of this word. Certainly we are not talking about random mutations here or natural selection (the essence of neo-Darwinism). Evolution is forced onto the narrative because real examples of evolution (species to species transitions)is MIA. Evolutionists are mystics -- they believe in this mysterious force by which they explain everything. Give me an example of something about evolution that you know with certainty, and not just "evolution happened."

David Sanders, a biologist at Purdue University, says that accepting so-called microevolution, especially as it refers to microbes, but denying larger-scale "macroevolution", is like saying there's gravity in America but not in Asia.

Another reader kindly sent along this following response, which made some very good points:

Scientists know a great deal about evolution with certainty.  The very structure of your arm gives evidence. You have a  single large bone (humerus) in the upper arm, two thinner long bones (radius and ulna) in the forearm, several small bones (carpals and metacarpals) at the wrist and multiple bones (phalanges) supporting five digits (fingers).  So do whales, birds, lizards, dinosaurs, fossil amphibians and ancient lobefin fishes (all of which are certainly different species).  The same basic structure has been modified through time by natural selection and adaptation in the course of evolution. The underlying similarity exists because evolutionary change is constrained by existing anatomy. New species are not “built from scratch” but have changed gradually from a common ancestor. (Donald Prothero, “Evolution: What the Fossils Say and Why It Matters”, pp. 105-107).

There is more evidence for evolution in your own chromosomes. You have forty-six chromosomes in twenty-three pairs. Chimpanzees (and all the great apes) have forty-eight in twenty-four pairs.  Why? If humans and chimpanzees share a common ancestor then two chimp chromosomes must have been accidentally fused to form a single human chromosome. We should find that one of our chromosomes has had its two halves pasted together. Simply losing a pair of chromosomes would have been fatal to any primate. Chromosomes have a centromere in the middle and telomeres at either end. A chromosome that had fused would have two extra telomeres stuck together right in the middle and two centromeres instead of one. We have such a chromosome (#2) and its genes are almost an exact match for corresponding genes on chimp chromosomes 12 and 13, so close that scientists have now relabeled them 2A and 2B.  This could not occur because of chance (unique DNA sequences are involved) but only because of shared common ancestry. It is proof that one species evolved into two species: chimpanzees and humans. (Kenneth R. Miller, “Only a Theory: Evolution and the Battle for America’s Soul”, pp. 103-110).

Perhaps the clearest example we have of a sequence of transitions from one species to another is the fossil and genetic record of the history of whales. From early terrestrial artiodactyls living 55 million years ago scientists can trace a detailed succession of species, each linked one to another by clear anatomical transitions that can be observed in the fossil record, supported by genetic analysis. One key piece of evidence was the discovery of a unique ankle structure, the “double-pulley” astragalus in early whales, exactly like their land-based hooved ancestors. And some of today’s whales still possess vestigial hind limbs, although they are concealed beneath their blubber. (Prothero, op. cit., pp. 318-322).

I urge you to read these two books as well as Jerry Coyne’s “Why Evolution is True”, Cameron M. Smith’s “The Fact of Evolution” and Alan R. Rogers’s “The Evidence for Evolution.”  You will see that evolution is not a mystic belief but is both a proven fact and a powerful theory that not only underlies all of modern biology but is the basis for modern medicine, agriculture, criminal forensics and a dozen other fields as well.

“Theory: In science, a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.” (National Academy of Sciences).

You can scorn evolution but you cannot avoid it.

The word "theory" is indeed often misconstrued, which is a great frustration to many of the biologists I interview for these columns. Another word that's causing confusion and frustration is "belief". For more on the power of words, as well as Miss USA and Chris Christie, read Monday's column and blog post.

About this blog
Faye Flam - writer
In pursuit of her stories, writer Faye Flam has weathered storms in Greenland, gotten frost nip at the South Pole, and floated weightless aboard NASA’s zero-g plane. She has a degree in geophysics from the California Institute of Technology and started her writing career with the Economist. She later took on the particle physics and cosmology beat at Science Magazine before coming to the Inquirer in 1995. Her previous science column, “Carnal Knowledge,” ran from 2005 to 2008. Her new column and blog, Planet of the Apes, explores the topic of evolution and runs here and in the Inquirer’s health section each Monday. Email Faye at fflam@phillynews.com. Reach Planet of the at fflam@phillynews.com.

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