The Origin of Life
Natural Selection Directs Evolution
Genetic Factors in Evolution
Rates of Evolutionary Change
Fossils clearly show that various living things once existed that no longer do. Fossils of animals that no longer exist puzzled the early 19th-century naturalists. Georges Cuvier, a French scientist, believed that the fossil sequence resulted from a series of recurring catastrophes, followed by creation of new plants and animals. Charles Lyell, an English geologist, saw instead that the fossil sequences in progressively younger rock layers substantiated the notion that living things experience gradual…