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23 Cards in this Set

  • Front
  • Back
adaptive radiation
Macroevolutionary pattern; burst of genetic divergences from a lineage that give rise to many species, each using a novel resource or a new habitat.
adaptive zone
Any way of life available for organisms that are physically, ecologically, and evolutionarily equipped to live it.
allopatric speciation
[Gk. allos, different, + L. patria, native land]. Speciation model. A physical barrier arises, separates populations or subpopulations of a species, ends gene flow, and favors divergences that end in speciation.
Speciation pattern; changes in allele frequencies and morphology accumulate within an unbranched line of descent.
Island chain some distance away from a continent.
biological species concept
Defines a species as one or more populations of individuals that are interbreeding under natural conditions, producing fertile offspring, and are isolated reproductively from other such populations. Applies to sexually reproducing species only.
[Gk. clad-, branch] Speciation pattern in which a lineage splits and isolated populations undergo genetic divergence.
dosage compensation
Any mechanism that balances gene expression between the sexes during critical early stages of development.
evolutionary tree
Treelike diagram; a branch point means divergence from a shared ancestor and branches signify separate lines of descent.
Irrevocable loss of a species.
gene flow
Microevolutionary process; alleles enter and leave a population as an outcome of immigration and emigration, respectively.
genetic divergence
Gradual accumulation of differences in gene pools of populations or subpopulations of a species after a geographic barrier arises and separates them; thereafter, microevolution occurs independently in each.
gradual model, speciation
Idea that species arise by many small morphological changes that accumulate over great spans of time.
hybrid zone
Where adjoining populations are interbreeding and producing hybrid offspring.
key innovation
A structural or functional modification to the body that by chance, gives a lineage opportunity to exploit aspects of the environment in more efficient or novel ways.
mass extinction
Catastrophic event or phase in geologic time when entire families or other major groups are irrevocably lost.
parapatric speciation
Idea that neighboring populations can become distinct species while maintaining contact along a common border.
Having three or more of each type of chromosome in the nucleus of cells at interphase (3n, 4n, etc.).
punctuation model, speciation
Idea that most morphological changes occur in a brief span when populations start to diverge; speciation is rapid, and the daughter species change little for the next 2-6 million years or so.
reproductive isolating mechanism
Heritable feature of body form, functioning, or behavior that prevents interbreeding between two or more genetically divergent populations.
The formation of a daughter species from a population or subpopulation of a parent species by way of microevolutionary processes. Routes vary in their details and duration.
[L. species, a kind] One kind of organism. Of sexually reproducing organisms, one or more natural populations in which individuals are interbreeding and are reproductively isolated from other such groups.
sympatric speciation
[Gk. sym, together, + patria, native land] A speciation event within the home range of an existing species, in the absence of a physical barrier. Such species may form instantaneously, as by polyploidy.