lecture 2

This view explains the hierarchical relationships in

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Unformatted text preview: ancestor that lived in the remote past –  Defines what Evolution is, heritable change through time. 13 9/30/12 Sirenia Hyracoidea (Manatees (Hyraxes) and rela:ves) Stegodon Platybelodon Mammuthus Mammut Loxodonta cyclo=s (Africa) Barytherium Deinotherium Elephas Loxodonta maximus africana (Africa) (Asia) Moeritherium Millions of years ago Years ago •  In the Darwinian view, the history of life is like a tree with multiple branchings from a common trunk to the tips of the youngest twigs that represent the diversity of living organisms. •  This view explains the hierarchical relationships in Linnaean classification. Figure 22.7 Natural Selection •  Descent with modification, or evolution, describes the changes of organisms through time. •  Natural Selection is one mechanism of change •  Natural Selection is the process that leads to adaptation 14 9/30/12 Deductive reasoning for evolution by natural selection •  Observation #1: For any species, population sizes would increase exponentially –  If all individuals that are born reproduced successfully –  This is the argument of ? •  •  •  •  •  A Lyell B Cuvier C Copernicus D Malthus E Darwin Figure 22.8 •  Observation #2: Nonetheless, populations tend to be stable in size •  Observation #3: Resources are limited –  Inference #1: Production of more individuals than the environment can support •  Leads to a struggle for existence among individuals of a population, with only a fraction of their offspring surviving •  This is the inference Darwin arrived at afte...
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This note was uploaded on 02/06/2014 for the course BILD 3 taught by Professor Wills during the Fall '07 term at UCSD.

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