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Population Genetics and evolution. Population Genetics and microevolution. Darwin developed his theory of _____________ evolve , not ______________ An organism is born with Evolution occurs as a Gene Pool : Allelic Frequency :
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Population Genetics and microevolution • Darwin developed his theory of • _____________evolve, not ______________ • An organism is born with • Evolution occurs as a • Gene Pool: • Allelic Frequency: • A population of organisms in which the allelic frequency remains the same over generations is said to have reached _______________________________
Changes in Genetic Equlibrium • Mutations • . • most • some may • Genetic Drift • change in • affects • is responsible for • Movement of individuals
Natural Selection acts on variations • Stabilizing Selection • favors • reduces • Directional Selection • nature • ex: • Disruptive Selection • nature favors • complete opposite of
Evolution of Species (macroevolution) • Speciation: evolution of • Can be caused by: • Geographic Isolation • when a • over time, • Reproductive Isolation (two types) • genetic material • behavioral changes • Change in Chromosomal Number • caused by • polyploid: • results in immediate
How quickly does speciation occur? • 2 Views • Gradualism: • Punctuated Equilibrium: • Biologists tend to agree that both occur depending on the circumstances
Patterns of Evolution • Divergent Evolution • Pattern of evolution • Occurs when Convergent Evolution • Pattern of evolution • Occurs due to • Ex: dolphins and sharks or euphorbs and cacti