EEB 2245 Chapter 17: The History of Life 1
30 Jan 2019
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The history of evolution can be inferred in two ways that complement each other. Phylogenetic inferences from living organisms can tell a lot about when some lineages evolved and about patterns of change in their characters. Fossils tell us of the existence of innumerable creatures that have left no living descendants, of great episodes of extinction and diversification, and of the movements of continents and organisms that explain their present distributions. The fossil record allows us to obtain an absolute time scale for evolutionary events or evidence of the environmental conditions in which they transpired. Living things have profoundly affected the atmosphere and other physical aspects of. At several times, extinction rates have been particularly high; especially after these mass extinctions, the diversification of higher taxa has sometimes been rapid. Sedimentary rock is formed by the deposition and solidification of sediments; most fossils are found in sedimentary rocks; a few fossils are found in other situations.
