4c+Evolutionary+processes

4c+Evolutionary+processes - 10/1/09 MACRO EVOLUTION:...

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10/1/09 1 MACRO EVOLUTION: CRITERIA FOR TRACING THE PATH OF EVOLUTION I. Working Defnitions II. Mechanisms oF Macro-evolution III. Evidence oF Macro-evolution IV. Mode oF Macro-evolution V. Tempo oF Macro-evolution VI. MACROEVOLUTION: WORKING DEFINITIONS EVOLUTION: Accumulation of small genetic changes, guided by natural MACROEVOLUTION : Lo ng-term patterns of genetic change over millions of years that accounts for the formation & disappearance of new species. MICRO EVOLUTION: Changes in gene frequency leading to changes in morphology . MACROEVOLUTION: WORKING DEFINITIONS SPECIES: Members of a population that can GENUS: a group of species composed of members more closely related to each other than they are to species from any other genus. Moreover, members of a genus often share similar environments, .
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10/1/09 2 MACROEVOLUTION: WORKING DEFINITIONS SPECIES: Members of a population that can SPECIATION: The process of a single species becoming two or more species. MECHANISM OF MACROEVOLUTION CAUSES OF OR CONDITIONS FOR SPECIATION 1. Reproductive Isolation = Reduction of Gene Flow a. Geographic Isolation - when two populations are separated by a physical barrier b. Behavioral Isolation - gene fow cut oFF by diFFerences in behavior e.g. Feeding practices oF diurnal vs. nocturnal organisms. MECHANISM OF MACROEVOLUTION 2. REPRODUCTIVE ISOLATION: a. isolated populations of species accumulated different changes b. Some changes could create reproductive barriers: Mating time, mating rituals, physical barriers. C. Once isolated, species continue to diverge, innovate, even if mixed together.
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10/1/09 3 MECHANISM OF MACROEVOLUTION CAUSES OF OR CONDITIONS FOR SPECIATION 2. Genetic Divergence Once reproductive isolation has occurred & gene fow has been eliminated there is an opportunity For speciation. At this point other evolutionary Forces such as mutation or genetic driFt must act upon this isolation to make Fertile interbreeding between the 2 original populations impossible. MECHANISM OF MACROEVOLUTION SPECIATION: The process by which one species evolves into a new one or evolve to into two different ones MICROEVOLUTION VERSUS MACROEVOLUTION 1. TRANSPECIFIC EVOLUTION : is an extrapolation & magnification of events that take place within
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This note was uploaded on 11/18/2009 for the course ANTHRBIO 161 taught by Professor Mitani during the Spring '08 term at University of Michigan.

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4c+Evolutionary+processes - 10/1/09 MACRO EVOLUTION:...

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