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Download Genetics and Evolution Ch. 2
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Evolution • Selection Natural vs. artificial Fitness Galapagos Finch Directional, Stabilizing, Disruptive Selection Polymorphism = several forms of a species in same habitat • Microevolution vs. Macroevolution Microevolution: change in allele frequency Macroevolution: formation of new species Field Assistants Chesapeake Bay Retrievers= + English Peppered Moth Example English Peppered Moth Example Before industrial revolution After industrial revolution Darwin’s 2 Major Ideas • Variation within an species (organisms of the same species do not look exactly alike) • Not all the offspring produced survive (there is a struggle for existence) Macroevolution: formation of new species • Allopatric Speciation: formation of new species due to geographic (physical) barrier • Sympatric Speciation: formation of new species due to genetic mutation or reproductive isolation (although they occur together) • Adaptive Radiation: formation of new species due to new opportunities (niches) i.e. islands
