BIO 200 Lecture Notes - Lecture 4: Medium Ground Finch, Daphne Major, Transitional Fossil
1 Nov 2017
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Three parts of natural selection: variation of population, must lead to differences among individuals in lifetime reproductive success, variation must be transmitted to the next generation. Rosemary and peter grant: galapagos finches in daphne major (large ground finches, La nina years very dry years extreme drought in 1977 -> extreme mortality: small soft seeds quickly eaten, large and hard seeds remain -> birds with large beaks survive because they can consume hard/large seeds. Example: chewing large seeds -> acquire longer/deeper beaks -> acquired traits are not heritable however, large beaks during drought were acquired by offspring -> increase in average beak size. Why isn"t everyone satisfied: earth must be old enough for evolution to have occurred. Hutton/lyell: depth of canyons/thickness of rock strata -> indicated very long natural process (age of fossil samples) 4. 6 bya (earth), 3. 8 bya (first life: fossils should show evidence of change through time. > megatheriums (1. 1m tall, up to 6,000 lbs) closely related to.
