Sexual Reproduction and Evolutionary Change

Sexual Reproduction and Evolutionary Change - environment...

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Sexual Reproduction and Evolutionary Change Variation Later in this course, we will discuss how sexual reproduction acts to increase variation in populations by shuffling genes. Offspring have some genes from each of two different parents and therefore are not identical clones of their parents. The increased variation due to sexual reproduction allows natural selection (and thus evolution) to produce changes in populations as described above. Fluctuating environments Evolutionary change due to natural selection would not be necessary if the environment never changed and the organisms within the environment were optimally adapted to the environment. For example, imagine a plant that is adapted to an
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Unformatted text preview: environment that has an average annual rainfall of 100 cm. If the climate were to change so that the amount of rainfall decreased, individuals that could tolerate less rain would survive and reproduce better, thus establishing their drought-tolerant genes in subsequent generations. If there was no variation in the plant population, there would not be any drought-tolerant individuals and the species would likely go extinct in areas of decreased rainfall. Sexual reproduction therefore, enables species to survive in fluctuating or changing environments because it promotes variation, which in turn allows natural selection....
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