BIOLOGY 1M03 Lecture : 1MO3_Chapter 27.docx
11 Jun 2013
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Phylogenies and the fossil record are 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. They rapidly eliminate most of the species alive in a relatively unbiased manner. In biology we must consider profound changes in the nature of life on earth over immense periods of time. (now looking at macro evolutionary process). Let"s first look at two major analytical tools that biologists use to reconstruct the history of life: phylogenetic tress and the fossil record. The evolutionary history of a group of organisms is called o phylogeny. A phylogenetic tree shows ancestor-descendants relationships among populations or species. The diagram provides an extremely effective way to summarise data (according to criteria such as distance, parsimony, likelihood, bayesianism) and may be interpreted as depicting the evolutionary history for the group.
