Wednesday, June 26, 2013
What caused the Cambrian explosion?
The “Cambrian explosion” marked the rapid appearance of many animal phyla that persist today, and began about 570 million years ago (mya). Life itself appeared in the fossil record as simple cyanobacteria—”blue green algae”—about 3.6 billion years ago (bya); the first “true” cell with a nucleus probably arose about 2 bya; and the first multicellular organism between 1 and 2 bya.
The “explosion”, contrary to some creationists, wasn’t instantaneous, so it couldn’t have marked a single creation “event” at one time. Rather, the origination of many (but not all) modern phyla occurred between 570 and 540 mya. So the “explosion” took at least thirty million years.