ANT 301 � PHYSICAL ANTHRO

ANT 301 â�� - ANT 301 – PHYSICAL ANTHRO test 1 notes 15:03:00 ← Jan 16 ← ← Evolution and Natural Selection Intro and History ← ←

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Unformatted text preview: ANT 301 – PHYSICAL ANTHRO test 1 notes 16/01/2008 15:03:00 ← Jan 16 ← ← Evolution and Natural Selection: Intro and History ← ← Overview • introduce evolution • introduce natural selection • illustrative example of natural selection • history of evolutionary thought ← ← What is evolution? • Survival of the fittest – this variation in populations is heritable and has benefits as it’s passed down. Talking about a process • The pattern of things we observe in the fossil record and the process that creates this pattern. • Change over time. – change in gene frequencies in a population over time. – change in morphology over time. • Darwin made his name by coming up with a process that explains evolution – Natural selection ← ← Darwin’s postulates • Limited resources. The ability of a population to expand is infinite but the resources to support populations is finite. Biological competition is a zero sum game. Darwin called this the “struggle for existence”, a phrase he borrowed from Thomas Malthus • Variation and differential reproduction. organisms vary, and this variation affects the ability of individuals to survive and reproduce. • Heritability. Useful variations are transmitted from parents to offspring. ← ← Process of Natural selection • 1. Populations with variation – causes… • 2. Differential reproduction (not survival and death) – creates a zero sum phenomena-- – traits that are responsible for this variation must be heritable which results in… • 3. Inheritance of useful traits (heritability) ← ← Galapagos finches an example of natural selection • Darwin cited the many different species of finches in a Galapagos islands as an example of new species arising from a common ancestor • More recently, Peter and Rosemary Grant have concluded detailed studies on the medium ground finch. Their data reveal much about the basic process of natural selection in a wild population. ← ← Variation • There is variation in beak size between individuals within the species • Individuals with deeper beaks can more easily eat larger, harder seeds • However, individuals with smaller beaks suffer less juvenile mortality than individuals with large beaks. (Trade offs.) ← ← Resource limitation • Drought – trees produce the seeds died off, all the small soft seeds were eaten quickly leaving only large hard seeds ← ← differential reproductive success • during the drought, birds with deeper beaks were better able to process the larger, harder seeds and were more likely to survive and produce more...
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This note was uploaded on 03/25/2008 for the course ANT 301 taught by Professor Reed during the Spring '08 term at University of Texas at Austin.

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ANT 301 â�� - ANT 301 – PHYSICAL ANTHRO test 1 notes 15:03:00 ← Jan 16 ← ← Evolution and Natural Selection Intro and History ← ←

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