lecture 2-3 evolution theories

lecture 2-3 evolution theories - Chapter 22: Descent with...

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Unformatted text preview: Chapter 22: Descent with modification Evolution Learning objectives Describe the theories of catastrophism, gradualism, and uniformitarianism Explain the mechanism for evolutionary change proposed by Jean-Baptiste de Lamarck Describe the three inferences Darwin made from his observations that led him to propose natural selection as a mechanism for evolutionary change Distinguish between artificial selection and natural selection Recognize that selection of favorable traits involves a balancing of risks to survival and reproduction Paleontology, the study of fossils Was largely developed by French scientist Georges Cuvier (1769-1832) Cuvier opposed the idea of gradual evolutionary change And instead advocated catastrophism , speculating that each boundary between strata represents a catastrophe Gradualism Hutton (1795) Is the idea that profound change can take place through the cumulative effect of slow but continuous processes Uniformitarianism Lyell (1830)- The same geologic processes are operating today as in the past, and at the same rate. On The Origin of Species by Means of Natural Selection Darwin, 1859 Natural Selection in Action Two examples Provide evidence for natural selection Study with guppies Study of evolving HIV resistance to drugs Differential Predation in Guppy Populations Researchers have observed natural selection Leading to adaptive evolution in guppy populations Reznick and Endler transplanted guppies from pike-cichlid pools to killifish pools and measured the average age and size of guppies at maturity over an 11-year period (30 to 60 generations). EXPERIMENT Pools with killifish, but not guppies prior to transplant Experimental transplant of guppies Predator: Killifish; preys mainly on small guppies Guppies: Larger at sexual maturity than those in pike-cichlid pools Predator: Pike-cichlid; preys mainly on large guppies Guppies: Smaller at sexual maturity than those in killifish pools Figure 22.12 RESULTS After 11 years, the average size and age at maturity of guppies in the transplanted populations increased compared to those of guppies in control populations....
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This note was uploaded on 03/19/2008 for the course BIO 311D taught by Professor Reichler during the Spring '08 term at University of Texas at Austin.

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lecture 2-3 evolution theories - Chapter 22: Descent with...

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