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21 Cards in this Set
- Front
- Back
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Causes of change in Allele Frequency |
1.Natural Selection 2.Gene Flow 3.Genetic Drift 4.Mutation |
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NATURAL SELECTION |
Occurs when phenotype has higher fitness |
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4 TYPES OF NATURAL SELECTION |
Directional Selection Stabilizing Selection Disruptive Selection Sexual Selection |
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2 types of Sexual Selection |
Female Choice Male-Male Competition |
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Balancing Polymorphism |
Maintains less fit alleles in a population via 1.Heterozygote Advantage 2. Negative Frequency Dependent Selection |
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GENETIC DRIFT |
natural selection driven via the environment (RANDOM CHANCE) via 1.Founder Effect 2.Genetic Bottleneck |
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GENE FLOW |
Movement of alleles from one population to another via 1.Immigration/Emigration 2.Propagules *tries to equalize population |
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MUTATION |
Production of a new allele that increases genetic diversity |
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SPECIATION |
formation of new species from ancestral species via 1.Genetic (reproductive) Isolation 2.Genetic Divergence |
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BIOLOGICAL SPECIES |
Reproductively isolated but are members of the same species 1.can interbreed & make viable offspring 2.cant apply to fossils/asexuals/geographically isolated pops |
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MORPHOLOGICAL SPECIES |
based on differences in morphology 1.applicable to fossils/asexuals 2.criteria subjective(intra >vs. inter species variation) |
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PHYLOGENETIC (LINEAGE) SPECIES |
based on ancestral analysis: phylogeny smallest identifiable group assigned to species status: Monophyletic group |
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ECOLOGICAL SPECIES |
based on environmental context |
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ALLOPATRY |
Speciation via populations physically separated |
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SYMPATRY |
Speciation via co-occurring populations become reproductively isolated |
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2 Types of Reproduction Isolation |
1. Prezygotic (zygote never formed) 2. Postzygotic (zygote is not viable) |
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PREZYGOTIC ISOLATION causes |
Disruptions (1.temporal 2.spatial 3.behavioral) Gametic Barriers Mechanical Incompatibilities |
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POSTZYGOTIC ISOLATION causes |
-Divergence of isolated populations occurs -Hybrid viability -Hybrid sterility |
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2 Mechanism for Speciation |
1.Allopatric Speciation -dispersal/colonization -vicariance 2.Sympatric Speciation -spatial, temporal, behavioral -polyploidy |
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Anagenesis |
one species gradually transforms into another |
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Cladogenesis |
One species gives rise to two or more species |
