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→Darwin's idea: evolution by natural selection: an amazingly complex and awkward sentence . |
→Comparative anatomy: redundant informtion --- already stated in prior section on Drwin |
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;Taxonomy
[[Alpha taxonomy|Taxonomy]] is the branch of biology that names and classifies all living things. Scientists use morphological and genetic similarities to assist them in categorizing life forms based on ancestral relationships. For example, [[orangutan]]s, [[gorilla]]s, [[chimpanzee]]s, and [[human]]s all belong to the same taxonomic grouping referred to as a family – in this case the family called ''[[Hominidae]]''. These animals are grouped together because of similarities in morphology that come from common ancestry (called ''homology'').<ref>{{Harv |Diamond|1992| pp=16}}</ref>
Strong evidence for evolution comes from the analysis of ''homologous'' structures in different species that no longer perform the same task.<ref name= PBS>{{citation| year =2001 | publication-date = | contribution =Glossary | contribution-url = http://www.pbs.org/wgbh/evolution/library/glossary/index.html| title =Evolution Library| publisher =WGBH Educational Foundation| url =http://www.pbs.org/wgbh/evolution/library/faq/cat03.html|format = web resource|accessdate=2008-01-23 }}.</ref> Such is the case of the forelimbs of mammals. The forelimbs of a human, cat, whale, and bat all have strikingly similar bone structures. However, each of these four species' forelimbs performs a different task. The same bones that construct a bird's wings, which are used for flight, also construct a whale's flippers, which are used for swimming. Such a "design" makes little sense if they are unrelated and uniquely constructed for their particular tasks. The theory of evolution explains these homologous structures: all four animals shared a common ancestor, and each has undergone change over many generations. These changes in structure have produced forelimbs adapted for different tasks.
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