BS 110 Notes 9-22-2010

BS 110 Notes 9-22-2010 - produce more surviving offspring,...

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BS 110 Notes 9-22-2010 Mutations, Heredity and Natural Selection Mutations are basis and source of hereditary variability Fusion possibilities of gametes and crossing over Variations provide a species population with a means of adapting Natural selection: environment selects those characteristics (individuals) that function most efficiently for survival of organism o Explains mechanism how new structures/traits are produced and appear, and through which change occurs Modern Theory of Natural Selection 1. Natural variation in populations – all naturally occurring populations include individuals with a wide variety of different genetically determined traits 2. Presence of Adaptive traits – individuals with certain traits are better adapted to their particular environment and ecological niche 3. Differential reproduction – the better adapted individuals tend to survive and
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Unformatted text preview: produce more surviving offspring, so their traits are more common in the next generation. 4. Continuing change through random mutation occasional mutations give rise to new traits which may be adaptive and start the process over again Alternative Theory (Relating to Giraffes) Giraffes spend most time feeding at 60% of height Males among themselves mate by swinging necks and hitting with their heads Knocked unconscious and died Longer necked individuals strike harder blows than short necked Therefore longer neck individuals survive, reproduce, and pass on genes more often than short necked individuals o Sexual Competition Theory First Exam Content Above Chapters 1,16,17,12,13,14, and 22...
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This note was uploaded on 01/31/2011 for the course BS 110 taught by Professor S.lawrence during the Fall '07 term at Michigan State University.

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BS 110 Notes 9-22-2010 - produce more surviving offspring,...

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