8/16/2007

VOX DE BAIT #4

More provocative questions from Vox....

Is it correct to say that "we just don't see clear evidence of speciation in the fossil record"? This appears to contradict what I have been taught about evolution since elementary school.

I can't really answer that, Vox, unless I know the context of the quote. We can certainly infer speciation in the fossil record, and there really are transitional forms.

This provides, by the way, a great opportunity to present a test case of a pair of competing predictions----one, from Darwin; the other, from the authors of the notorious textbook Of Pandas and People.

In the first edition of the Origin (1859), Darwin received a lot of criticism for one of his more 'far-out' suggestions, which appeared in Chapter 6 ("Difficulties On Theory"):

"... I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale."

Now this quote clearly predicts the possible existence of intermediate forms between a carnivore that lived on land and a modern whale. Again, pretty far out for Darwin's day, and when Darwin made a number of changes in the second edition in an attempt to placate the sensibilities of his comtemporaries, he leaves this speculation entirely out. Writing nearly 130 years later, the authors (Kenyon and Davis) of Of Pandas and People (1989) remark:

"The absence of unambiguous transitional fossils is illustrate
d by the fossil record of whales. The earliest forms of whales occur in rocks of Eocene age, dated some 50 million years ago, but little is known of their possible ancestors. By and large, Darwinists believe that whales evolved from a land mammal. The problems is that there are no clear transitional fossils linking land mammals to whales. If whales did have land-dwelling ancestors, it is reasonable to expect to find some transitional fossils. Why? Because the anatomical differences between the two are so great that innumerable in-between stages must have paddled and swam the ancient seas."



In other words, clearly implying such 'transitional fossils' would not be found, because they don't exist. This is also a prediction, and we can now test it, along with Darwin's prediction: Hello, Phil Gingerich! Click on this fabulous link, and see the truly wonderful work of this scientist, who starting in 1981 (with Pakicetus) helped uncover many new fossils with transitional features between a land-based carnivore and modern whales . . . .

Now, do these examples, are they fulfillment of exhaustively precise scenarios, as in 'you're gonna find such-and-such a fossil in such-and-such strata at such-and-such a location, of such-and-such an age?' Of course not, but their existence, unknown both to Charles Darwin and the Panda authors, constitutes a test of their respective predictions.

And...as you can see....one fella's speculation is pretty robustly corroborated, whereas the claim that no transitional forms between land animals and
whales has been pretty much----you should pardon the expression----blown out of the water:




I would be remiss if I did not also provide a link to this incredibly detailed, illustration-rich exploration of this topic by E. Babinski. And clicking here or on any of the whale fossil illustrations will take you to the UC Berkeley Museum of Paleontology's 'Understanding Evolution', a wonderful resource to which both Babinksi and myself are indebted.





2 comments:

Kseniya said...

Fascinating stuff! I love this! But Scott, don't you see what's happening? Each discovery of a transitional form only creates another new gap in the fossil record!

Heh.

(I guess the heavy-duty commenting is going on over at Vox's place, huh?)

Pieter said...

Actually, each discovery of a transitional form creates TWO gaps in the fossil record.