Oxygen Brought Earliest Carnivores to Life
by Becky Oskin
Without oxygen, there would be no carnivores. Without carnivores, there would be no Cambrian explosion, the stunning evolutionary burst of diversity in species and body forms that began 540 million years ago.
Those are the findings of a new study that stitches together competing models for why meat-eating appeared simultaneously with the Cambrian explosion. Previously, one camp of scientists had proposed that rising oxygen levels gave animals the extra power to evolve complex body forms. Another school of thought said that competition among animals drove the sudden appearance of new species, such as the weird and wild life forms found in the Burgess Shale, a rock formation in Canada that has been an amazing source of fossils.
"There’s always been this tension," said lead author Erik Sperling, a postdoc at Harvard University. “Each side is looking at their own data, which is often common in science.”…
(read more: Live Science)
illustration - Orthrozanclus reburrus, by Marianne Collins (C) AAAS/Science-2007