Re: [asa] Rejoinder 3B: Reply to David Opderbeck

From: David Campbell <>
Date: Tue Sep 30 2008 - 18:16:48 EDT

Denton himself accepts evolution as credible in his more recent work,
though I don't think he has explicitly commented on the change from
his previous work. At any rate, I don't know of any specific
critcisms of evolution in his first book that hold up. Any particular
arguments that you are interested in?

Taking another example, Wells' slander of the peppered moth example is
inexcusable. Although some technical details have been revised by
more recent studies, it is clear that
1) the proportion of moths that were mostly or all dark changed from
nearly zero to nearly 100% in some populations, and back again
2) light moths were better camoflaged on tree bark in places with less pollution
3) dark moths were better camoflaged on tree bark in places with more pollution
4) birds were better at spotting the moths that didn't match

Evolution at work! Incidentally, this qualifies as microevolution by
anyone's definition, yet Wells still wastes time attacking it.

The standard photos most often used with discussion of this example
are posed. Especially given photographic technology available several
decades ago, it's not too practical to search the woods for two moths
side by side, one well-hidden and one conspicuous and appealing to
birds, in a spot amenable to a good picture. However, there's a big
difference between posed and faked.

The selective pattern affecting color banding in Cepaea nemoralis (a
European snail, invasive in many other parts of the world) provides a
similar story and the photographic advantage of a slow-moving subject.
 However, the story is a bit more complex. Birds learn to look for
the most common color pattern. Heavier predation makes it less common
and other color patterns more common. Birds change search image to
new common form. Net result: a mix of color patterns.

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
To unsubscribe, send a message to with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Tue Sep 30 18:17:34 2008

This archive was generated by hypermail 2.1.8 : Tue Sep 30 2008 - 18:17:34 EDT