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33 Cards in this Set
- Front
- Back
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Define gene pool |
Total of all the alleles for all the genes of allthe individuals in a population |
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Define genotype frequency |
proportion of members of apopulation with a particular genotype; usuallyexpressed as a decimal |
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Define phenotype frequency |
proportion of members of apopulation with a particular phenotype; usuallyexpressed as a decimal |
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Population genetics is based upon finding |
gene frequencies within a population |
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Allele frequency |
rate of occurrence of a particular allele in a population with respect to a particular gene |
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Population |
group of organisms of the same species living in the same area at a specific time |
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Population Sampling |
technique in which gene frequencies for a particular trait are determine in a small sample of population |
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According to Hardy Weinberg the allele frequency will remain the same from one generation to then next as long as five conditions are met |
1. populations are big enough that chance events will not alter allele frequency 2. mates chosen on random basis 3. no net mutations 4. there is no migration 5. no natural selection against any phenotypes |
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Define mutation |
permanent change in a cell's DNA - [inheritable mutation has the potential to affect an entire gene pool] |
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Define genetic diversity |
degree of genetic variation within a species or population |
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5 agents of evolutionary change? |
1. mutation 2. gene flow 3. non-random mating 4. genetic drift 5. natural selection for favourable variations |
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Genetic equilibrium |
Condition of a gene pool in which allele frequencies remain constant over time constant over time (not changing or evolving) |
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Micro evolution |
Gradual change in allele frequency in a population over time |
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Example of microevolution |
Development of DDT- reinsurance in mosquito populations |
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Define mutation |
Permanent change in DNA (can be neutral, harmful or beneficial) |
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What is a back mutation? |
Mutation that reverses effects of former mutations |
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Gene flow |
New movement of alleles from one population to another due to migration and interbreeding |
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Non-random mating |
Matin between individuals on the basis of mate selection for a particular phenotype or due to inbreeding |
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Example of non-random mating |
Caribou males compete for mates using their antlers to spar |
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Genetic drift |
Change in allele frequencies due to chance events in a small breeding population |
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Why are large populations not affected by genetic drift? |
Because chance events are unlikely to affect overall allele frequency |
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Two types of genetic drift |
Founder effect and bottleneck effect |
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Founder effect |
Gene lool change that occurs when a few individuals start a new, isolated population ex: islands |
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Bottleneck effect |
Gene pool change that results from a RAPID decrease in population size, gene pool loses diversity (ex:starvation) |
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Natural selection |
Characteristics of a population of organisms change over time because individuals with certain heritable traits survive environmental conditions and pass on their traits |
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Selective advantage |
Characteristic that improves chance of survival in a changing environment |
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Sexual selection |
Natural selection that results from non-random mating |
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What is speciation |
Formation of a new species due to geographical or reproductive isolation |
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Two methods of speciation |
1. Geographic isolation 2. Reproductive isolation |
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Habitat fragmentation |
Human-made barriers may prevent gene flow |
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Unregulated hunting can cause (2) |
1. Can cause bottleneck effect followed by genetic drift 2. Sudden large scale loss can cause inbreeding which decreases fertility rates |
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Populations that lack genetic diversity are more vulnerable to new |
Diseases |
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How can cloning save species |
Creating clones of endangered species can reverse threat of extinction |
