Chapter 23: The Evolution of Populations
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| Evolutionary change below the species level. Change in the allele frequecies in popuations over generations | ||
| The average percent of loci that are heterozygous. | ||
| Differences in the genetic composition of separate populations | ||
| Another way geographic variation occurs. A graded change in a trait along a geographic axis | ||
| A change in the nucleotide sequence of an organism's DNA | ||
| A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. | ||
| Derived in 1908, this principle states that the frequencie sof all alleles and genotypes in a population will remain constant form generation to generation, provided that only Mendelian segregation and rocombination of alleles are at work. | ||
| The condition describing a non-evolving population that is in genetic balance | ||
| A process in which chance events cause cause unpredictable fluctuation in allele frequencies from on generation to the next. Its effects are most pronounced in small populations | ||
| Genetic drift that ocurs when a few individuals become isolated form a larger poplualtion and form a new population whose gene pool composisition is not relective of that of the original population. | ||
| Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Usually, the surviving population is no longer genetically representive of the original population. | ||
| The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes | ||
| Natural selection in which individuals at one end of the phenotypic range survive and reproduce more sucessfully than the other individuals | ||
| Natural selection in which intermediate phenotypes survive and reproduce more successfully than extreme phenotypes | ||
| Natural selection in which individuals on both extremes of a phenotypic range survive and reproduce more sucessfully than the other idividuals with intermediate phenotypes | ||
| A form of natural selection in which individuals with certain inherited chracteristics are more likely than other individuals to obtain mates | ||
| Marked differences between the two sexes in secondary sexual characteristics, which are not directly associated with reproduction or survival. May include differences in color, size, ornementation, and behavior | ||
| Selection within the same sex where individuals directly compete for mates of the opposite sex | ||
| (mate choice) Individuals of one sex (usually the females) are choosy in selecting thier mates from the other sex | ||
| Natural selection that maintains two or more phenotypic forms in a population | ||
| Greater reproductive success of heterozygous individuals compared with homozygotes. Tends to preserve variatin in gene pool | ||
| A decline in the reproductive success of individuals that have phenotype that has become too common in a population | ||
| Genetic variation that does not appear to provide a selective advantage or disadvantage. | ||
| the contribution an individual makes to the gene pool of the next generation, relative to the contribution of other organisms |