| A | B |
|---|
| adaptive radiation | emergence of numerous species from a common ancestor introduced into an environment |
| allometric growth | variation in the relative rates of growth of various parts of the body |
| allopatric speciation | ancestral population becomes segregated by a geographic barrier or is itself divided into two or more geographically isolated subpopulations |
| allopolyploid | type of polyploid species resulting from two different species interbreeding and combining their chromosomes |
| autopolyploid | individual that has more than two chromosome sets |
| biological species concept | population whose members have the potential to interbreed in nature and produce viable |
| ecological species concept | defining species in terms of ecological roles (niches) |
| heterochrony | evolutionary change in the timing or rate of an organism’s development |
| homeotic gene | genes that control the overall body plan of animals and plants |
| macroevolution | evolutionary change above the species level |
| microevolution | evolutionary change below the species level |
| morphological species concept | Defining species by measurable anatomical criteria |
| paedomorphosis | retention in an adult organism of the juvenile features of its evolutionary ancestors |
| paleontological species concept | definition of species based on morphological differences known only from the fossil record |
| phylogenetic species concept | definition of a species as a set of organisms with a unique genetic history |
| postzygotic barrier | chromosomal alteration in which the organism possesses more than two complete chromosome sets |
| prezygotic barrier | barrier that impedes mating between species or hinders fertilization of ova if interspecific mating is attempted |
| punctuated equilibrium | long periods of apparent stasis (no change) interrupted by relatively brief periods of sudden change |
| reproductive isolation | existence of biological factors (barriers) that impede members of two species from producing viable |
| speciation | origin of new species in evolution |
| species | group whose members possess similar anatomical characteristics and have the ability to interbreed |
| species selection | species living the longest and generating the greatest number of species determine the direction of major evolutionary trends |
| sympatric speciation | speciation occurring as a result of a radical change in the genome of a subpopulation |
| polyploidy | polyploidy, chromosomal alteration in which the organism possesses more than two complete chromosome sets |
