| Term | Definition |
|---|
| speciation | formation of new species, occurs when population diverge from one another |
| prezygotic barrier | a pre-mating reproductive barrier |
| habitat isolation | organism occupies a specific niche and because they occupy a different niche they may not come into contact with one another. |
| temporal isolation | "calander of events". controlled by temperature/day length. breed at different times of day or season |
| behavioral isolation | visual, auditory, chemical signals that differ between species |
| mechanical isolation | post-mating, sizen and shape of reproductive organs don't fit, transfer of gametes cannot occur |
| genetic isolation | gametes are incompatible and fusion of gametes cannot occur or egg cannot divide |
| postzygotic barriers | post-mating reproductive barriers |
| hybrid inviability | development of fertilized egg does not take place. |
| hybrid sterility | hybrid produced unable to reproduce |
| geographic barriers | gene pool of population separated. allows changes in gene pool to occur |
| allopatric speciation | "other country" a geographic barrier blocks gene flow, then genetic drift may occur, and new species may form |
| adaptive radiation | diversifications of a group of organisms from a common ancestor. numberous species originate from one parent species |
| sympatric speciation | "same country" physical separation of population not requried. occurs within population and establishes a reproductive barrier |
| polyploidy | increase in chromosome number |
| autopolyploid | 2n to 4n, one species with 2x the normal chromosome number as original parent species |
| allopolyploid | 2n + 4n=6n two different, but related species produce a polyploid hybrid. usually sterile and common in plant evolution |
| macroevolution | evolution of new taxonomic group |
| gradualism | evolution proceeds slowly and at a constant rate over time and populations slowly diverge from one another |
| punctuated equilibrium | species diverge in spurts of rapid speciation separated by long periods without change. unique features originate "rapidly" as time of split. most species spend time in stasis, which is period without change |
| cladogenesis | branching evolution, occurs when a population is separated or removed from a main population and undergoes changes causing it to be reproductively isolated from main population and therefore a separate species |
Combine with other sets
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