Originally Posted by: sgreggLord of the Strings appears to be the only informed person here. I earned a degree in biology in 2000. During college I took plenty of earth sciences courses and chemistry. ....

I'll take that as a personal compliment, but you really should take a closer look at your surroundings here. Specifically, you should get to know more about Dr_simon of the University of Iowa, who I daresay knows a thing or two about biology himself. :o