Abnormal Interests

It is reasonable to argue, as I have, that these arguing points come about as the result of a conflict between religious dogma and scientific method. If the dogma is strongly held, there is no reason to go forward with the debate. But I believe there are people, with weak allegiances to dogma, who would give up their dogmatic position if they could see simple examples of "macro-evolution" that were easy to understand and evaluate.

To be most persuasive these examples should be of animals, alive today, and of complete animals not parts like eyes or wings. The individual organ examples are good if one already gets it.

There are exactly these kinds of examples readily available in the literature: ring species. As Darren E. Irwin told the BBC,

Ring species are unique because they present all levels of variation, from small differences between neighbouring populations to species-level differences in a single group of organisms.

The ring species salamander, Ensatina escholtzii, of the US Pacific Coast is one example. Dave Wake explained, "All of the intermediate steps, normally missing, have been preserved, and that is what makes it so fascinating."

For a layman, some of the most interesting material on Ensatina escholtzii can be found on the web site of the Department of Life Sciences at Santa Rosa Junior College. They provide a large bibliography on these salamanders. It is likely that the can observe the Ensatina escholtzii oregonensis within a few miles of their campus.

Another good example of a ring species is the Greenish warblers found in parts of Asia and Eastern Europe and studied by Darren E. Irwin who reports,

In Siberia, two distinct forms of greenish warblers coexist, one in the west and one in the east, their distributions narrowly overlapping in central Siberia, where they do not interbreed. These forms differ in color patterns, the songs that males sing to attract mates, and genetic characteristics. Also, males of each form usually do not recognize the song of the other form, but respond strongly to their own.

The traits that differ between the two Siberian forms change gradually through the chain of populations encircling the Tibetan Plateau to the south.

Thus two distinct species are connected by gradual variation in morphological, behavioral, and genetic traits.

What's great about these examples is that they are simple, easy to understand and involve whole animals that are alive today. In addition, the evidence for evolution can be presented graphically. I think these examples, and others like them, should be brought up in every context in which they are at all relevant. The undecided can simply evaluate how the examples are explained by scientists and how they are explained by evolutionists and decide who has the best explanation. I'm not claiming that this is a new idea, only that it is a good idea.

I agree with PZ Myers that evolutionists should never be debated on evolutionists terms but I do think scientists should put their most pedagogically persuasive stuff up front. Ring species are certainly among the most pedagogically persuasive things going.

At least when it comes to the Greenish warblers, Answers in Genesis has the creationist explanation. Their explanation relies, in part, on an erroneous understanding of the increase in generic information,

Creation as described in the book of Genesis implies that virtually all the genetic information in today’s world was present in the beginning, contained in separate populations (the original created kinds).

This information would not be expected to increase, but could decrease with time—in other words, any genetic changes would be expected to be informationally downhill.

I don't remember an implication concerning genetic information in Genesis. Perhaps they are using a different translation. The only way these creationists can explain the phenomenon is by claiming that all the variation in genetic information seen in Greenish warblers was "present at the beginning" and it could not have been otherwise. Their argument does show how it is possible to get off on a strange tangent when the evidence is against your position. That they had to go to this argument to explain ring species is somewhat pathetic but the authors of Answers in Genesis are not interested in promoting science. They are interested in promoting a certain dogmatic religious position. As far as I can find, they do not discuss the ring salamander species. (By the way, is "informationally" an English word?)

On the other hand, Talk Origins uses ring species to illustrate the "Stages of Speciation." Check out both Talk Origins and Answers in Genesis and decide which explanation is the most parsimonious or even the most understandable. Also, check out the paragraph entitled "Falsification" in the Talk Origins discussion. I looked, in vane, for such a paragraph on the Answers in Genesis page.

References (in addition to the links in the text):

Irwin, D.E., Irwin, J.H., and Price, T.D. (2001) "Ring species as bridges between microevolution and speciation." Genetica. 112-113: 223-243.

Moritz, C., C. J. Schneider, et al. (1982) "Evolutionary relationships within the Ensatina eschscholtzii complex confirm the ring species interpretation." Systematic Biology 41: 273-291.

PhatNav's Encyclopedia

Ridley, M, Evolution, Blackwell 3rd edition