BIO152H5 Chapter Notes - Chapter 27: Shocked Quartz, Genetic Drift, Cyanobacteria
Document Summary
Phylogenies and the fossil record are the major tools that biologists use to study the history of life. The cambrian explosion was the rapid morphological and ecological diversification of animals that occurred during the cambrian period. Adaptive radiations are a major pattern in the history of life. They are instances of rapid diversification associated with new ecological opportunities and new morphological innovations. Mass extinctions have occurred repeatedly throughout the history of life. They rapidly eliminate most of the species alive in a more or less random manner. In biology we must consider profound changes in the nature of life on earth over immense periods of time. Let"s first look at two major analytical tools that biologists use to reconstruct the history of life: phylogenetic trees and the fossil record. Phylogeny the evolutionary history of a group of organisms. Phylogenetic tree shows ancestor-descendant relationships among populations or species.
