Bio_Lecture_10 - Evolution&NaturalSelection...

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The theory of evolution Evolution sometimes characterized as “just a theory” That puts it on the same level as o Atomic structure Cubic model (e- in block around nucleus) Rutherford/Bohr model (e- spin around) Quantum mechanics o The attraction of large bodies in space Gravitation General Relativity Confusion of evolution There has been a confusion of ideas o Evolution o The Origin of life o Religion Origin of life is not known o We have ideas, some data, but no solid conclusions The supposed conflict between religion and evolution Two ideas of evolution Evolution really consists of two ideas o Evolution (change) has occurred Change in organisms is well documented o Natural selection is a mechanism that can drive evolution The theory of natural selection is well supported The poster boys of evolution Alfred Wallace Charles Darwin Evolution Idea of evolution actually predates Darwin and Wallace
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Ancient Greek philosophers ~520 B.C. de Buffon suggested evolution occurred o Said that the environment was the agent of change Proposed no mechanism, only an agent Provided no facts or experimentation o The idea suffered for a lack of support and clarity Influences on Charles Darwin Influences on Darwin and his proposed mechanism of evolution Lyell’s Principles of Geology o Catastrophism vs uniformitarianism o The steady accumulation of very small changes Artificial selection     o Rapid change in animals/plants over generations T.      Malthus : observation of excess reproduction Journey on the H.M.S. Beagle  (1831) o Observations of variation in the Galapagos o Darwin’s finches The Galapagos Islands A series of small islands 600 miles off the coast of Ecuador, South  America Darwin’s Finches Galapagos birds had differences in their beaks, food sources, and habitat Figure 1.7 Significance of Galapagos Darwin observed many birds o Thought to be finches, wrens, blackbirds, jays, etc. o Each exhibited differences in beak shape and “ecological niche” He later found that these were in fact 14 species of finches What could lead to this pattern of species diversity? Species and preexisting species
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Only one or a few species successfully migrate o Successful migrants are reproductively isolated Can diverge from their mainland relatives based on lack of  competitors, resources, environment Eat seeds/cactus o The diversity of birds arose from a single migrating ancestor 
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This note was uploaded on 04/11/2011 for the course BIO 111 taught by Professor Dr. bos during the Winter '10 term at Purdue University-West Lafayette.

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Bio_Lecture_10 - Evolution&NaturalSelection...

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