Proving common descent (Introduction)

by David Turell , Tuesday, November 06, 2012, 18:26 (4401 days ago) @ dhw

dhw: 4) The Cambrian explosion was the result of cell communities (organisms) responding to new environmental conditions (perhaps an increase in oxygen) which permitted a whole range of inventions that would not have been possible in the old environment.-This is a key problem. There is a huge jump in the Cambrian. These animals have legs, jaws, brains(!) and for all the world look like animals today, because some of our existing species came directly from 520 mya, and are little changed today. In the preceding pre-Cambrain, nothing like this is found. Simple worms, sheet of cells, some hollow sack-like characters. This whole period looks like a second creation of life. We have no idea why. Yes, more oxygen, but remember oxygen is dangerous stuff. Things burn because of oxygen. Using oxygen as fuel has to be done very carefully by biologic organisms. Why are humans told to use antioxident foods, etc? The two miracles are the origin of life and then the two explosions, the Cambrian and later the 'plant bloom', just as dramatic as the animal bloom which preceded. Deus ex machina?