Darwinism Recitation Paper Week 11

Darwinism Recitation Paper Week 11 - Andra Stanley Systma,...

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Andra Stanley Recitation Paper 11 April 4 th , 2006 Systma, Rec. Tuesdays 3:00-3:50 Young Ch. 8 R.C. Punnett intended to show how mimetic resemblances in butterflies couldn’t have been created through natural selection (but through a single stem mutation), but his appendix led people to believe otherwise. Two alleles will remain in the same proportions throughout the generations unless something disturbs the equilibrium (i.e. natural selection). Ronald Fisher was able to show how the Mendelian pattern of inheritance is consistent with the theory of gradual evolution based on the natural selection of small genetic differences, the most effective means to change the frequency of the occurrence of alternative genes. Fisher also showed how selection could maintain a balance between two alternative alleles under certain circumstances in a population, explaining polymorphism (where two or more discontinuous forms of a species occur together in the same region). William Castle provided evidence for the efficacy of selection and gene interactions through experiments with rats of different coat colors. Gene interactions are important contributors to the final appearance of the phenotype; the effects of a single gene can be modified by the actions of other genes and can exert influence eon more than one aspect of the phenotype. Sewall Wright believed that natural selection was most effective with groups of interacting genes, which are an important part of hereditary make-up, and also with smaller populations. Fisher,
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This note was uploaded on 04/07/2008 for the course HPS 0437 taught by Professor Sandramitchell during the Fall '06 term at Pittsburgh.

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Darwinism Recitation Paper Week 11 - Andra Stanley Systma,...

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