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47 Cards in this Set

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  • Back
balanced polymorphism
The ability of natural selection to maintain diversity in a population.
bottleneck effect
Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.

Graded variation in some traits of individuals that parallels a gradient in the environment.
Darwinian fitness
The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals.
founder effect
founder effect

Genetic drift attributable to colonization by a limited number of individuals from a parent population.
frequency-dependant selection
A decline in the reproductive success of a morph resulting from the morph's phenotype becoming too common in a population; a cause of balanced polymorphism in populations.
gene flow
The loss or gain of alleles in a population due to the migration of fertile individuals or gametes between populations.
gene pool
The total aggregate of genes in a population at any one time.
genetic drift
Changes in the gene pool of a small population due to chance.
geographic variation
Differences in genetic structure between populations.
Hardy-Weinberg formula
A formula for calculating the frequencies of genotypes in a gene pool from the frequencies of alleles, and vice versa.
Hardy-Weinberg equilibrium
The condition describing a non-evolving population (one that is in genetic equilibrium).
Hardy-Weinberg theorem
An axiom maintaining that the sexual shuffling of genes alone cannot alter the overall genetic makeup of a population.
heterozygote advantage
Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools.
intersexual selection
Individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex, also called mate choice.
intrasexual selection
A direct competition among individuals of one sex (usually the males in vertebrates) for mates of the opposite sex.
A change in the gene pool of a population from generation to generation.
modern synthesis
A comprehensive theory of evolution emphasizing natural selection, gradualism, and populations as the fundamental units of evolutionary change; also called neo-Darwinism.
A rare change in the DNA of a gene ultimately creating genetic diversity.
natural selection
Differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool.
neutral variation
Genetic diversity that confers no apparent selective advantage.
The coexistence of two or more distinct forms of individuals (polymorphic characters) in the same population.
population genetics
population genetics

The study of genetic changes in populations; the science of microevolutionary changes in populations.
A group of individuals of one species that live in a particular geographic area.
relative fitness
The contribution of one genotype to the next generation compared to that of alternative genotypes for the same locus.
sexual dimorphism
A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.

A group whose members possess similar anatomical characteristics and have the ability to interbreed.
adaptive radiation
adaptive radiation

The emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems.
allometric growth
allometric growth

The variation in the relative rates of growth of various parts of the body, which helps shape the organism.
allopatric speciation
A mode of speciation induced when the ancestral population becomes segregated by a geographic barrier.
A common type of polyploid species resulting from two different species interbreeding and combining their chromosomes.
A pattern of evolutionary change involving the transformation of an entire population, sometimes to a state different enough from the ancestral population to justify renaming it as a separate species; also called phyletic evolution.

A type of polyploid species resulting from one species doubling its chromosome number to become tetraploid, which may self-fertilize or mate with other tetraploids.
biological species concept
biological species concept

The definition of a species as a population or group of populations whose members have the potential in nature to interbreed and produce fertile offspring; a biological species is also called a sexual species.
A pattern of evolutionary change that produces biological diversity by budding one or more new species from a parent species that continues to exist; also called branching evolution.
exological species concept
The idea that ecological roles (niches) define species.
Evolutionary change in the timing or rate of development.

Evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction.
morphological species concept
The idea that species are defined by measurable anatomical criteria.
The retention in an adult organism of the juvenile features of its evolutionary ancestors.
pluralistic species concept
pluralistic species concept

The idea that there is no universal explanation for the cohesion of individuals that make up species.

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.
postzygotic barrier
Any of several species-isolating mechanisms that prevent hybrids produced by two different species from developing into viable, fertile adults.
punctuated equilibrium
punctuated equilibrium

A theory of evolution advocating spurts of relatively rapid change followed by long periods of stasis.
The origin of new species in evolution.
species selction
A theory maintaining that species living the longest and generating the greatest number of species determine the direction of major evolutionary trends.
sympatric speciation
sympatric speciation

A mode of speciation occurring as a result of a radical change in the genome of a subpopulation, reproductively isolating the subpopulation from the parent population.