Chapter 10 Definitions Flashcards
The process by which, as a result of natural selection, a population’s organisms become better matched to their environment. Also, a specific feature, such as the quills of a porcupine, that makes an organism more fit.
adaptation
A special case of natural selection; the three necessary and sufficient conditions for natural selection are satisfied, but the differential reproductive success is determined by humans rather than by nature and so is typically goal-oriented.
artificial selection
The study and interpretation of distribution patterns of living organisms around the world.
biogeography
A phenomenon through which genetic drift can occur; a sudden reduction in population size (often due to famine, disease, or rapid environmental disturbance) that can lead to changes in the allele frequencies of a population.
bottleneck effect
A process of natural selection in which features of organisms not closely related come to resemble each other as a consequence of similar selective forces.
convergent evolution
The situation in which some individuals have greater reproductive success than other individuals in a population. Along with variation and heritability, it is one of the three conditions necessary for evolution by natural selection.
differential reproductive success
Selection that, for a given trait, increases fitness at one extreme of the phenotype and reduces fitness at the other, leading to an increase or decrease in the mean value of the trait.
directional selection
Selection that, for a given trait, increases fitness at both extremes of the phenotype distribution and reduces fitness at middle values.
disruptive selection
A change in allele frequencies of a population.
evolution
A relative measure of the reproductive output of an individual with a given phenotype compared with the reproductive output of individuals with alternative phenotypes.
fitness
In genetics, the point at which the frequency of an allele in a population is 100%, and thus there is no more variation in the population for this gene.
fixation
The remains of an organism, usually its hard parts such as shell, bones, or teeth, that have been naturally preserved; also, traces of such an organism, such as footprints.
fossil
A phenomenon by which genetic drift can occur. The isolation of a small subgroup of a larger population can lead to changes in the allele frequencies of the isolated population, because all the descendants of the smaller group will reflect the allele frequencies of the subgroup, which may differ from those of the larger source population.
founder effect
A change in the allele frequencies of a population due to movement of some individuals of a species from one population to another, changing the allele frequencies of the population they join; also known as migration.
gene flow
A random change in allele frequencies over successive generations; a cause of evolution.
genetic drift
The transmission of traits from parents to offspring via genetic information; also known as inheritance.
heritability
Body structures in different organisms that, although they may have been modified over time to serve different functions in different species, are derived through inheritance from a common evolutionary ancestor.
homologous structure
The transmission of traits from parents to offspring via genetic information; also known as heritability.
inheritance
In populations, a change in allele frequencies due to the movement of some individuals from one population to another; an agent of evolutionary change caused by the movement of individuals into or out of a population.
migration
An alteration in the base-pair sequence of an individual’s DNA; may arise spontaneously or following exposure to a mutagen.
mutation
A mechanism of evolution that occurs when, for a heritable variation of a trait, individuals with one version of the trait have greater reproductive success than individuals with a different version of that trait.
natural selection
A group of organisms of the same species living in a particular geographic region.
population
A method of determining both the relative and the absolute ages of objects such as fossils by measuring both the radioactive isotopes they contain, which are known to decay at a constant rate, and their decay products.
radiometric dating
The process by which natural selection favors traits, such as ornaments or fighting behavior, that give an advantage to individuals of one sex in attracting mating partners.
sexual selection
Selection that, for a given trait, produces the greatest fitness at the intermediate point of the phenotypic range.
stabilizing selection
Any characteristic or feature of an organism, such as red petal color in a flower.
trait
A structure that was once useful to the organism but has lost its function over evolutionary time; an example is molars in bats that now consume an exclusively liquid diet.
vestigial structure
