what is the cambrian radiation and when did it occur
The Cambrian explosion, or less commonly Cambrian radiation, was the relatively short evolutionary event, beginning around 542 million years ago in the Cambrian Period, during which most major animal phyla appeared, as indicated by the fossil record.he Cambrian explosion has generated extensive scientific debate. The seemingly rapid appearance of fossils in the âPrimordial Strataâ was noted as early as the 1840s, and in 1859 Charles Darwin discussed it as one of the main objections that could be made against the theory of evolution by natural selection.