Discusses various possible ways by which isolated populations might differentiate into species. The interactions between ecological factors and genes with respect to evolution and the role of genetic polymorphisms and other genetics variation are also discussed. (HM)

Discusses how the nature of the rock and, particularly, its fossils can be used in ecology courses for schools and colleges to help students to deduce the nature of the environment at the time the rock was deposited. A checklist and ways of identifying geological sites and fossils are included. (HM)