11 lecture feb 21

11 lecture feb 21 - Evolutionary Biology Tree of Life...

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1 Evolutionary Biology Tree of Life Theory Natural Selection Theory Testing the theory Misunderstandings about theory Using the theory to explain puzzling traits Speciation Theory See “Course Documents” for information on Undergraduate Research Experiences in SOLS Long-tailed widowbird male (above) and female (on right) Misconception: “Selection cannot favor traits that reduce the chances of survival” Another Misconception - An adaptation is a hereditary trait that helps a species survive. A Species Benefit Hypothesis: “Lemmings disperse at high population densities in order to commit suicide, which will reduce their numbers and thereby help preserve the species.” Group benefit hypotheses are based on group selection theory (not natural selection theory) If groups vary in their composition, and if the variation is hereditary, and if the variation affects group survival , then groups good at survival will replace other groups.
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2 Imagine 2 hereditarily different kinds of lemmings. One type commits suicide for the benefit of the group; the other type lives to reproduce. Whose genes will spread through the species? Which process (natural selection or group selection) is more likely to cause evolution? Which of the following hypotheses for lemming dispersal
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This note was uploaded on 04/02/2008 for the course BIO 187 taught by Professor Douglasgreen during the Spring '07 term at ASU.

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11 lecture feb 21 - Evolutionary Biology Tree of Life...

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