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AP Biology
AP Biology - Chapter 19 - Speciation and Macroevolution
Term | Definition |
---|---|
adaptive radiation | The evolution of a large number of related species from an unspecialized ancestral organism. |
adaptive zone | A new ecological opportunity that was not exploited by an ancestral organism; used by evolutionary biologists to explain the ecological paths along which different taxa evolve. |
allopatric speciation | Speciation that occurs when one population becomes geographically separated from the rest of the species and subsequently evolves. |
allopolyploid | A polyploid whose chromosomes are derived from two species. |
anagenesis | Progressive evolutionary changes in a single lineage over long periods. |
autopolyploid | A polyploid whose chromosomes are derived from a single species. |
background extinction | The continuous, low-level extinction of species that has occurred throughout much of the history of life. |
behavioral isolation | A prezygotic reproductive isolating mechanism in which similar species don't mate because of differences in courtship behavior. |
clade | A taxon containing a common ancestor and all the taxa descended from it; a monophyletic group. |
cladogenesis | A branching type of evolution in which two or more populations of an ancestral species split and diverge. |
development | All the progressive changes that take place throughout the life of an organism. |
extinction | The elimination of a species; occurs when the last individual member of a species dies. |
gradualism | The idea that evolution occurs by a slow, steady accumulation of genetic changes over time. |
habitat isolation | reproduction between similar species is prevented because they live and breed in different habitats |
hybrid breakdown | A postzygotic reproductive isolating mechanism in which, although an interspecific hybrid is fertile and produces a second (F2) generation, the F2 has defects that prevent it from successfully reproducing. |
hybrid inviability | A postzygotic reproductive isolating mechanism in which the embryonic development of an interspecific hybrid is aborted. |
hybrid sterility | A postzygotic reproductive isolating mechanism in which an interspecific hybrid cannot reproduce successfully. |
hybrid zone | An area of overlap between two closely related populations, subspecies, or species, in which interbreeding occurs. |
macroevolution | Large-scale evolutionary change over long time spans. |
mass extinction | The extinction of numerous species during a relatively short period of geological time. |
mechanical isolation | A prezygotic reproductive isolating mechanism in which fusion of the gametes of two species is prevented by morphological or anatomical differences. |
microevolution | The small genetic changes a population undergoes. |
paedomorphosis | Retention of juvenile or larval features in a sexually mature animal. |
preadaptation | A novel evolutionary change in a preexisting biological structure that enables it to have a different function; feathers, which evolved from reptilian scales, represent a preadaptation for flight |
prezygotic barrier | One of several reproductive isolating mechanisms that interfere with fertilization between male and female gametes of different species |
punctuated equilibrium | The idea that evolution proceeds with periods of little or no genetic change, followed by very active phases, so that major adaptations or clusters of adaptations appear suddenly in the fossil record. |
reproductive isolating mechanisms | The reproductive barriers that prevent a species from interbreeding with another species; as a result, each speciesĀ“ gene pool is isolated from other species. |
sexual reproduction | A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from the gametes of the two parents. |
sexual selection | A type of natural selection that occurs when individuals of a species vary in their ability to compete for mates; individuals with reproductive advantages are selected over others of the same sex. |
speciation | Evolution of a new species. |
stasis | Long periods in the fossil record in which there is little or no evolutionary change. |
sympatric speciation | The evolution of a new species within the same geographical region as the parental species. |
synthetic theory of evolution | The synthesis of previous theories, especially of Mendelian genetics, with Darwin's theory of evolution by natural selection to formulate a comprehensive explanation of evolution; also called neo-Darwinism. |
temporal isolation | A prezygotic reproductive isolating mechanism in which genetic exchange is prevented between similar species because they reproduce at different times of the day, season, or year. |