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lecture 13
| Term | Definition |
|---|---|
| genetic drift | mechanism of evolution, specially in small populations |
| genetic drift results from | random sampling error |
| sampling error is higher with a | small sample |
| drift reduces | genetic variation in population |
| some alleles become | fixed in the population, while others disappear |
| bottlenecks reduce | genetic variation |
| bottleneck results in a | nonrepresentative set of alleles for subsequent populations |
| rare alleles are most likely to be | lost during a bottleneck |
| the probability of an allele making it through a bottleneck depends on | frequency of the allele before the bottleneck and the severity of the bottleneck |
| founder effect | type of bottleneck resulting from small number of individuals colonizing a new, islotated habitat |
| fitness | survival and reproductive success of an individual w a particular phenotype |
| relative fitness (w) | contribution of individuals w one genotype compared w the average contribution of all individuals in the population |
| components of fitness | survival to reproduce age, mating success, fecundity (offspring by females) |
| average excess fitness | diff between relative contribution with one genotype and the avg fitness of population as a whole (remember formula) |
| natural selection is more effective in | large population in bringing about change |
| pleitropy | may constrain evolution, mutation in a single gene affects more than one phenotype trait |
| antagonistic pleitropy | beneficial effects for one trait but detrimental effects for other traits |
| experimental studies provide | important insights about selection |
| negative selection | alleles that lower fitness experience |
| positive selection | alleles that increases fitness experience |
| some mutations increased and became fixed, while others | disappeared from the population |
| additive alleles | homozygous conditions yields twice the phenotypic effect for the gene as compared with heterozygotes |
| dominance | dominant alleles masks presence of recessive in heterozygote |
| mutation rates | for any given gene are low |
| many new mutations arise each | generation |
| equilibrium frequency | reached thru a tug of war between negative selection s on alleles and new mutations, explains deleterious mutations in populations |
| balancing selection | describes type of selection that favors more than one allele |
| negative frequency-dependent selection | common phenotypes are selected against, rare phenotypes are favored |
| heterozygote advantage | confers greater fitness than homozygotes |
| heterozygote advantage and | sickle cell anemia |
| inbreeding and the | hapsburg dynasty |
| inbreeding coefficient | expected from a brother and sister |
| inbreeding depression results in | reduced fitness |
| high inbreeding tend sot be associated with | low infant survival rates |
| rare recessive alleles are expressed in | homozygous state |
| many organisms occupy ranges that | are discontinuous |
| population subdivision (metapopulation) | depends on landscape and relative degree of individuals in the population (depending in population size) |
| genetic drift creates | genetic distance between populations |
| subdivision population show | distinct genetic structure |
| Fst | is a measure of genetic distance between subpopulations |
| gene flow can counteract the | loss of alleles due to drift |
| amount of gene flow varies with the | range of movement of the organism |
| humans alter population structure by constructing | barriers between populations |
Created by:
jcava141
Popular Ecology sets