Term
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Definition
| the formation of new species |
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Term
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Definition
| the formation of new species in populations that are geographically isolated from one another |
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Term
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Definition
| the formation of new species in populations that live in the same geographic area |
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Term
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Definition
| an organism that has more than two complete sets of chromosomes as a result of an accident of cell division |
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Term
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Definition
| occurrs when two distinctly different forms of a species mate and reproduce progeny along a geographic boundary called a hybrid zone |
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Term
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Definition
| period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill new or vacant ecological roles in their communities |
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Term
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Definition
| the branch of biology that identifies, names, and classifies species |
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Term
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Definition
| the existence of biological factors that impede members of two species from producing viable, fertile hybrids |
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Term
| morphological species concept |
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Definition
| a defintion of species in terms of measurable anatomical criteria |
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Term
| ecological species concept |
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Definition
| a defintion of species in terms of ecological roles (niches) |
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Term
| phylogenetic species concept |
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Definition
| a definition of species as the smallest group of individuals that share a common ancestor and form one branch on the tree of life |
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Term
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Definition
| A reproductive barrier that impedes mating between species or hinders fertilization if mating between two species is attempted. Includes temporal, habitat, behavioral, mechanical, and gametic isolation. |
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Term
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Definition
| A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults. Includes reduced hybrid viability, reduced hybrid viability, and hybrid breakdown. |
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Term
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Definition
| a geographic region in which members of different species meet and mate, producing at least some hybrid offspring |
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Term
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Definition
| a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates |
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Term
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Definition
| marked differences between the secondary sex characteristics of males and females |
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Term
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Definition
| adaptive changes resulting in nonhomologous similarities among organisms |
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Term
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Definition
| the similarity between two species that is due to convergent evolution rather than descent from a common ancestor with the same trait |
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Term
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Definition
| the evolutionary history of a species or group of related species |
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Term
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Definition
| a scientific discipline focused on classifying organisms and determining their evolutionary relationships |
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