Saturday, January 23, 2010

Thinking about evolution today... the BIG controversy is the WHALE's evolution from land to sea as a mammal... current belief is based upon ear bones.

"One particularly baffling fossil was the back part of a 50-million-year-old skull. It was about the size of a coyote's and had a high ridge running like a mohawk over the top of its head, where muscles could attach and give the mammal a powerful bite. When Gingerich looked underneath the skull, he saw ear bones. They were two shells shaped like a pair of grapes and were anchored to the skull by bones in the shape of an S. For a paleontologist like Gingrich, these ear bones were a shock. Only the ear bones of whales have such a structure; no other vertebrate possesses them."
- Carl Zimmer

Thanks to Professor Hans Thewissen, Ph.D. for his insightful comments on the featured graphic above.

I like the ideal that todays oceans are full of mammals that were once "wolf like" creatures that ran in packs, not pods, on the land. However, this theory is not fully proven by the bone evidence alone. But, this was the missing piece of the puzzle for most scientists in the study of evolution- a middle ear bone.



The attack is given in this reading:

However, National Geographic continues the battle for their concept:

The Evolution of Whales, Adapted from National Geographic, November 2001:

"The Evolution of Whales Based on November 2001 National Geographic Magazine, 'The Evolution of Whales'. Covering the Evolutionary Origins of Modern Whales and Dolphins. Reviewed, with some edits by Northeastern Ohio Universities College of Medicine, Dr. J.G.M. Thewissen, with additional comments by Edward T. Babinski, and revised text and art by Sharon Mooney.

All images reconstructed from National Geographic, are public access, though source and appropriate credits must be left intact.

The Whale's Tale - research on whale evolution Science News, Nov 6, 1999 by Richard Monastersky
Only 24 years after Charles Darwin rewrote the book of life with his theory of natural selection, a fellow Victorian scientist named William Flower trained this powerful new idea on one of the toughest problems in zoology: the whale. Natural historians had long before recognized that whales are mammals, but that was about as far as they had come in understanding the origins of cetaceans. How evolution had managed to craft such a unique beast presented a mystery as vast as the creature itself."

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