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33 Cards in this Set

  • Front
  • Back
gene flow
Genetic additions to or substractions from a population resulting from the movement of fertile individuals or gametes.
The study of the past and present distribution of species.
The hypothesis by Georges Cuvier that each boundary between strata corresponded in time to a catastrophe, such as a flood or drought, that had destroyed many of the species living there at that time.
descent with modification
Darwin’s initial phrase for the general process of evolution.
A view of Earth’s history that attributes profound change to the cumulative product of slow but continuous processes.
homologous structures
Structures in different species that are similar because of common ancestry.
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.
A set of characteristics used to assess the similarities and differences between various species, leading to a classification scheme; the branch of biology concerned with naming and classifying the diverse forms of life.
Charles Lyell’s idea that geologic processes have not changed throughout Earth’s history.
vestigial organ
A structure of marginal, if any, importance to an organism. Vestigial organs are historical remnants of structures that had important functions in ancestors.
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.
A graded variation in a trait that parallels a gradient in the environment.
directional selection
Natural selection that favors individuals at one end of the phenotypic range.
evolutionary fitness
The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals.
founder effect
Genetic drift that occurs when a few individuals become isolated from a larger population, with the result that the new population’s gene pool is not reflective of the original population.
frequency-dependent 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 pool
The total aggregate of genes in a population at any one time.
genetic drift
Unpredictable fluctuations in allele frequencies from one generation to the next because of a population’s finite size.
geographic variation
Differences between the gene pools of separate populations or population subgroups.
Evolutionary change below the species level; change in the genetic makeup of a population from generation to generation.
neutral variation
Genetic diversity that confers no apparent selective advantage.
The evolutionary history of a species or group of related species.
point mutation
A change in a gene at a single nucleotide pair.
The coexistence of two or more distinct forms in the same population.
A localized group of individuals that belong to the same biological species (that are capable of interbreeding and producing fertile offspring).
sexual dimorphism
A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.
stabilizing selection
Natural selection that favors intermediate variants by acting against extreme phenotypes.
allele frequency
the frequency of occurrence or proportions of different alleles of a particular gene in a given population.
ananlogous structures
Structures that evolve separately to perform a similar function are analogous.
The wings of birds, bats, and insects, for example,
assortative mating
In population genetics, selective mating in a population between individuals that
are genetically related or have similar characteristics.
diversifying selection
Natural selection that favors individuals on both extremes of a phenotypic range over intermediate phenotypes.
The origin and development of an individual organism from embryo to adult.