Chapter 15 PDF

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Chapter 15 - BIO101...

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Chapter 15      

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Evolution – the change in characteristics of a given population Population – consists of all individuals of one species in a particular area Pre-Darwinian – religion influenced science Modern biology is based on how life has evolved Aristotle’s ladder of life – places us as humans at the top of the ladder, human matter is at the bottom Exploration of land revealed diversity of life o Buffon – species create and evolved and changed w geological changes o Hutton – geological changes o Lamarck – mechanisms of species change o Cuvier – catastrophes affect species o Smith – sequence of fossils – note changes of species over time o Lyell – very old earth o Darwin & Wallace – evolutionary theory, and natural selection Fossils provide strong evidence in changes of species over time Fossil distribution of several species – something happened within a given environment that caused this Lyell – no need to invoke catastrophes to explain the findings of geology o Uniformitarianism – the earth is ancient Darwin & Wallace – evolutionary changes between a species and their adaptive traits o 4 Postulates:  Individual members of a population differ from one another in many aspects  At least some of the differences among members of a population are due to characteristics that may be passed from parent to offspring  In each generation, some individuals in a population survive and reproduce successfully but others do not  The fate of individuals is not determined by luck or chance; instead, the likelihood of survival and reproduction depends on its characteristics  Natural selection – individuals w advantageous traits survive longest and leave the most offspring Evidence that supports theory of evolution o Fossils o Comparative anatomy – homologous structures provide evidence of common ancestry o Embryology o Biochemistry

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o Genetics Vestigial structures – no apparent essential function o Ex. Appendix, wisdom teeth Convergent evolution – process which natural selection causes non-homologous structures that serve similar functions to resemble one another Analogous structures – structures that are outwardly similar in appearance, but differ In their evolutionary origin o Typically very different in internal anatomy because the parts are not derived from common ancestral structures...