Bio171-F11-Lec 23(1)

Bio171-F11-Lec 23(1) - Biology 171 Monday Lecture 23...

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Biology 171 Monday, October 31, 2011 Lecture 23: Evolutionary Processes I Announcements Text Reading Lecture 23 : 4 th : Chapter 25 (440-443) Lecture 24: 4 th : Chapter 25 (452-455) Modern Synthesis Different Types of Selection Heterozygote Advantage Directional/Disruptive/Stabilizing Reductive Evolution This Week in Discussion: Population Genetics/ Evolution Simulations
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+ The modern evolutionary synthesis represents the combination of Darwin & Wallace's theory of the evolution of species by natural selection, Gregor Mendel's theory of genetics as the basis for biological inheritance, and mathematical population genetics. The Modern Synthesis
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According to the modern synthesis, genetic variation in populations arises spontaneously through random mutation and is constantly reshuffled into new allelic combinations by meiosis & random fertilization. Evolution consists primarily of changes in the frequencies of alleles between one generation and another as a result of genetic drift, gene flow, natural selection and other processes. Speciation is usually due to the gradual accumulation of small genetic changes and most easily occurs when populations are reproductively isolated, e.g. by geographic barriers. The modern evolutionary synthesis represents the combination of Charles Darwin's theory of the evolution of species by natural selection, Gregor Mendel's theory of genetics as the basis for biological inheritance, and mathematical population genetics. The Modern Synthesis
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Natural selection occurs when individuals with certain heritable phenotypes survive and reproduce better than others. The alleles responsible for the increased reproduction then increase in frequency. Different patterns of natural selection exist, each with its own
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Bio171-F11-Lec 23(1) - Biology 171 Monday Lecture 23...

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