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Definition
| The study of genetic change in populations; the study of micorevolutionary changes in populations |
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| A localized group of individuals of the same species |
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| A reproductively isolated group of individuals who have the potential to interbreed |
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| Total aggregate of genes in a population at any one time |
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Definition
| States the the frequencies of alleles and genotypes in a particular gene pool remain constant over the generations unless acted upon by agents other than Mendelian segregation and recombination of alleles. |
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Term
| Hardy-Weinberg equillibrium |
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Definition
| The condition describing a non-evolving population |
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Definition
| The fraction of all the alleles in a population's gene pool that are the allele in question. For example if all the individuals in a population have genotype Aa, then the frequency of allele A is .5 or 50% |
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Term
What does
p + q = 1
represent? |
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Definition
| In situations wehre there are only two alleles at a locus and one is dominant & the other recessive, "p" represents the frequency of the dominant allele, while "q" represents the frequency of the recessive allele. These frequencies should add up to 1. |
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Term
| Conditions that must be met to achieve Hardy-Weinberg equilibrium |
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Definition
1) Very large population
2) No migration in or out of the population (no gene flow)
3) No mutations
4) Random mating
5) No natural selection |
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Term
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Definition
The fraction of a population that is a particular genotype. For example, if a population is 20% AA, 20% Aa and 60% aa, the genotypic frequencies are:
.2 AA
.2 Aa
.6 aa
Genotypic frequencies of a population in H-W equilibrium should equal 1. |
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Term
| When is it possible to compute allelic freqencies? |
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Definition
| If you have a complete list of genotypic frequencies, regardless of wheterh the population is in H-W equillibrium. |
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| When is it possible to compute genotypic frequencies? |
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Definition
| Only if we assume Hardy-Weinberg equillibrium |
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Term
| In the Hardy-Weinberg equation, what does 2pq represent? |
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Definition
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Term
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Definition
| A change in the gene pool of a population from generation to generation |
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Definition
| The change in allelic frequencies of a small population that results from the random outcome of matings, or chance. |
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Definition
| The founder effect occurs when a subset of a population migrates or becomes geographically isolated from the original population. The gene pool will differ from the parent population because of it's small size and for the same reason changes in allelic frequencies will have a greater effect on the population as a whole. |
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Definition
| Genetic drift due to a drastic reduction in population. Often due to natural disaster. The remaining members of the population do not fully represent the original gene pool. |
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Definition
| Genetic exchange (loss or gain of alleles) due to migration of fertile individuals or gametes bewteen populations. |
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Definition
| A change in an organism's DNA |
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Definition
| A population is said to be polymorphic for a characteristic if two or more distinct forms of the characteristic are each represented in high enough frequencies to be readily noticable. For example, a population of flowers in which half have red petals and half have white petals. |
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Definition
| Differences in genetic structure between populations |
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Definition
| Graded variation in some traits of individuals that parallels a gradient in the environment. For example, the average body size of many North American birds and mammals increases gradually with increasing latitudes. |
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Definition
| The ability of natural selection to maintain stable frequencies of two or more forms of a characteristic in a population |
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Definition
| One of the two mechanisms by which natural selection preserves variation. If individuals who are heterozygous for a trait have greater survivorship and reproductive sucess than a homozygote, then both alleles will be preserved and passed on. |
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Term
| Frequency-dependent Selection |
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Definition
| One of the two mechanisms by which natural selection preserves variation. The survival and reproduction of any one trait declines if that trait becomes too common in the population. |
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Definition
| A variation which seems to convey no selective advantage. Example: fingerprints |
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Definition
| Having atributes that facilitate reproduction/mating. The contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals |
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Definition
| Shifts the overall makeup of the poulation by favoring variants of one extreme. For example, favoring darker colored mice and weeding out the lighter and mid-colored ones. |
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Definition
| Favors variants of opposite extremes. For example, favoring both light and dark mice, and weeding out the mid-colored ones. |
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Definition
| Weeding out of extremes. For example, weeding out both light and dark mice, leaving the mid-colored ones |
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Definition
| Phenotypic distinction between the sexes. Secondary sex characteristics |
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Definition
| Direct competition among individuals of one sex for mates of the opposite sex |
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Definition
| Choosiness among members of one sex in selecting mates of the opposte sex. For example, peahens tend to chose peacocks with the most impressive tail span |
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