01:013:143 Lecture Notes - Lecture 11: Mutation, Darwinism, Ethology
21 Nov 2017
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Giraffes- they acquired longer necks to reach higher in trees to get food. Catastophism- species are extinguished periodically by sudden catastrophes, such as meteorites, and then replaced by different species. All originated from the same place but varied because of different ecological conditions on the islands. Malthus said organisms exist in numbers far greater than can survive and reproduce. Darwin determined there must be a "struggle for existence" where favorable variations tend to be preserved. Once the process is repeated several generations is forms an adaptation. Species vary in terms of wing length, bone mass, etc. This variability leads to the selection of the best characteristics which leads to inheritance of the best. Brought about by possession of heritable variants that increase or decrease an individuals chances of surviving and reproducing. Defined by comparison of reproductive success or failure of others. Intrasexual competition- competition of organisms of the same gender and species (bulls locking horns).
