The cambrian explosion

[polar bear]

Short answer: No
Long answer: Our understanding of evolution is vastly better then it was 150 years ago, and we now have enough of the fossil record to see something called punctuated equaliburium which shows that some organisms will keep the same form for a long time then change relatively quickly. This depends on both species and environment and we see a change in the environment in the Cambrian that opened up a lot of ecological niches, strongly encouraging evolutionary diversification. So no.

Lemon, thanks for this fact!

What proof do we have that the environment changed?

I run up against this stupid shit a lot, and if I can point to this fact, it will shut some people up at least for awhile.

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The important factor is the emergence of free oxygen in the atmosphere, in the first great pollution event. Oxygen is basically rocket fuel for multicellular life.

Thanks Stimbo...should have read further