Wednesday, October 01, 2008

New evidence supports fascinating dinosaur evolution twist

Last year, Pound360 wrote about a theory (by University of Washington paleontologist Peter Ward) explaining how rising/falling oxygen levels have been quietly guiding the evolution of life on earth. When it came to dinosaurs, a respiratory innovation 150 million years ago allowed them to improve breathing efficiency 30 percent at a time when other species were being wiped out by plummeting oxygen levels.

That innovation: air sacks attached to conventional lungs. By the way, modern birds (not lizards) happen to have air sacks, too.

This week, paleontologists have unearthed the remains of a 33-foot-long predator showing strong evidence that it had air sacks,
reports Reuters. The creature likely was feathered (not scaled, like a lizard).

Conventional wisdom suggests birds evolved from scrappy little dinosaurs, but the size of the recently discovered monster (named Aerosteon riocoloradensis, or "air bones from the Rio Colorado," where it was discovered) suggests birds are linked to more than the little guys.

In the Reuters piece, experts suggests the air sacks developed to help cool dinosaurs, which many suspect now were warm blooded (unlike lizards) and had feathers. Warm blood and feathers means they would have warmed up pretty quick during summer months and needed a way to cool off.

So, let's take stock here. Dinosaurs seem to have had feathers, air sacks and warm blood. Pound360 has
said it before, dinosaurs seem to be getting less like lizards every year.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.