My question is: how does one explain the cambrian explosion of life?
http://www.time.com/time/magazine/article/0,9171,983789,00.html
I did not read the NYT article, but I am familiar with the premise. It usualy is based upon a couple of ideas:
1. Wow there are suddenly all these life forms , where did they come from?
2.The Cambrian creatures have some sort of feature that was never seen before, where did it come from?
3. The cambrian creatures don't have something, it appears later, where did it come from?
To question 1,2 and 3. First off, the Cambrian explosion is a misnomer, it is a sound byte, something to grab the attention. What is the cambrian explosion, so called, it is the first evidence of a variety of multicellur life forms of some complexity. But what do fossils, like the Burgess shale represent? They represent a preservation event. Fossilization is a crap shoot, you have to have certain conditions for the objects to be preserved. So the Cambrian explosion is more like the Cambrian death events leading to preservation. Just like the alleged CroMagnon or Magdelenian explosion of human culture, there are no artifacts of humans making tools out of anything other than rock prior to 10,000-14,000 BCE, suddenly there are all these cool bone, wooden and clay objects, why? Because the europeans were so smart that they just invented them all! Wrong, they are there because that is the preservation window.
1. The diversity of life forms, we don't know how long life existed prior to the cambrian fossilization, we have some soft body preservation from the Burgess shale, but it is like trying to recreate any creature after it has been mixed in with a lot of other creatures and placed in a car crusher, then baked and set in cement. We have a vauge idea of what that particular sample of creatures might have looked like. It could be a sample of all the life at that time, it could be a fractional sample, we don't know. So we don't actualy know anything other than that these life forms got preserved.
It is likely that life existed long before these creatures were preserved.
2.Sampling, we don't have intermediate life forms, and things can also evolve through jumps starts and slow changes.
3. Same as above.
I will look through the article and see what it says.