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Sunday, January 16, 2011

SciAm: Dawn of the Deed: the Origin of Sex

Just read the full article in my print version of the magazine.  This blurb and video link to the cover story.  Sadly, it's things like this that lead the ignorant and deluded to proclaim that because we learn more, the whole structure of the theory is falling apart.  How little they actually understand science:

Dawn of the Deed: the Origin of Sex [Video]

Evidence of reproduction by internal fertilization has been discovered in a large group of ancient jawed fish. Embryos discovered within fossils of these animals confirm that live birth in prehistoric times was much more widespread than previously thought. Watch the researchers talk about the fossils and techniques used to find them.

Scientists used to think that, among backboned animals, internal fertilization and carrying the young inside the mother's body originated in sharks and their kin some 350 million years ago. Before then, sexual reproduction in fish consisted of spawning, wherein females deposit eggs in the water, the males fertilize them, and the embryos then develop out in the open. Or so the story went.

As the cover story of the January 2011 Scientific American explains, recent analyses of fossils found in a remote locale in northwestern Australia and elsewhere have shown that intercourse and live birth actually arose millions of years earlier than previously believed—and in a more primitive group of fish than the one to which sharks belong. These fish—called placoderms—reside on the long line of animals leading us, and their sexual equipment gave rise to our own reproductive system and other parts of our anatomy.

In this video paleontologist John A. Long of the Natural History Museum of Los Angeles County, author of the cover story, discusses a fossil central to this new view of the origin of copulation and live birth: a 375-million-year-old expectant mother fish dubbed Materpiscis attenboroughi.




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