ANTH 1 Lecture Notes - Lecture 4: Thomas Robert Malthus, Heritability, Phenotype
13 Oct 2020
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Thomas malthus: population growth is exponential (geometric); food supply increase is linear. People who can get resources will survive and reproduce. Galapagos: some varieties of traits help food gathering, survival, reproduction. Variation some trait variants increase chance of survival or reproduction. Selection more individuals are born than can survive to reproduce. Differential reproduction trait variant helps parents survive and reproduce and more the next generation carries the trait variant, etc. Variants that help survival or reproduction become more frequent in the population. Frequency in population must increase over time. Provides a benefit in a certain environment. Darwin"s finches have different adaptations that match their different environments. Fitness = average # of offspring from a parent with a given trait variant. Adaptations spread because they increase a parent"s fitness (offspring) Adaptation = longer neck; fitness = # offspring of long necked giraffe compared to short neck. Sexual selection: a special case of natural selection.
