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Unformatted text preview: TEST 1: Chapters 22, 23, 24, 25, 26 17:04 Chapter 22: Descent with Modification: A Darwinian View of Life Wednesday, January 20, 2010 12:06 PM What is Evolution and Adaptation?? Two Main Ideas 1. Change over time of the genetic composition of a population 2. Decent of modern organisms with modification from preexisting organisms Evolutionary Adaptation Accumulation of inherited characteristics that enhance organism's ability to survive in specific environments Pre-Darwinian Theory of Evolution o Lamarck: proposed the inheritance of "acquired characteristics" famous for incorrect mechanism for how evolution occurs explained through 2 principles: o 1. Use and Disuse: the idea that parts of the body that are used extensively become larger and stronger and those that are not, detoriate. Ex/ giraffes neck o 2 . Inheritance of acquired characteristics: an organism could pass these modifications to its offspring. Ex/ neck evolved Inherititance of acquired characteristics Bodies of living organisms are modified through the use or disuse of parts These modifications are inherited by offspring This idea turned out to be wrong: o ACQUIRED TRAITS CANNOT BE INHERITED Evolution by Natural Selection o Darwin and Wallace developed the theory independently Darwin-voyage of the Beagle o Studied animals, plants, and geology in South American coastline o Galpagos= studied birds; found resemblances to other continents Hypothesized that the Galapagos had been colonized by organisms that had strayed from South America and then diversified, giving rise to new species. Adaptations: characteristics of organisms that enhance their survival and reproduction in specific environments Natural Selection: a process by which individuals with certain inherited traits leave more offspring than individuals with other traits o Developed the book: On the Origin of Species by Means of Natural Selection Descent with modification: NOT EVOLUTION Wallace-Naturalist in Indonesia o Developed a hypothesis of natural selection similar to Darwins o Natural Selection The unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations Process "selects" from what is available in the gene pool New characteristics are not created on demand SUMMARY: Individuals that have certain heritable characteristics survive and reproduce at a higher rate than other individuals Over time, natural selection can increase the match btw organisms and their environment If an environment changes, or if the individuals move to a new...
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