June 18, 2002


15 Answers to Creationist Nonsense (John Rennie, June 17, 2002, Scientific American)
12. Nobody has ever seen a new species evolve.

Speciation is probably fairly rare and in many cases might take centuries. Furthermore, recognizing a new species during a formative stage can be difficult, because biologists sometimes disagree about how best to define a species. The most widely used definition, Mayr's Biological Species Concept, recognizes a species as a distinct community of reproductively isolated populations--sets of organisms that normally do not or cannot breed outside their community. In practice, this standard can be difficult to apply to organisms isolated by distance or terrain or to plants (and, of course, fossils do not breed). Biologists therefore usually use organisms' physical and behavioral traits as clues to their species membership.

Nevertheless, the scientific literature does contain reports of apparent speciation events in plants, insects and worms. In most of these experiments, researchers subjected organisms to various types of selection--for anatomical differences, mating behaviors, habitat preferences and other traits--and found that they had created populations of organisms that did not breed with outsiders. For example, William R. Rice of the University of New Mexico and George W. Salt of the University of California at Davis demonstrated that if they sorted a group of fruit flies by their preference for certain environments and bred those flies separately over 35 generations, the resulting flies would refuse to breed with those from a very different environment.

Yet, they'd still be fruit flies.

When he's not knocking down pure straw men, Mr. Rennie's responses are pretty much all this woefully inadequate. We can break this answer down this way :

(1) Well, no, they haven't.

(2) Or, they might have and we just don't know it.

(3) But suppose we take an absurdly cramped definition of speciation, one based on behavior rather than biology. If we use that as our standard, then scientists have been able to force some organisms to speciate. Which proves that evolution is a naturally occurring process, not guided by an intelligent being or beings.

He, of course, finishes his essay by saying that creationism and intelligent design aren't sciences. There at least he's correct. Unfortunately for him, neither is evolution.

Posted by Orrin Judd at June 18, 2002 9:31 PM
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