← Ap Bio chapter 24 Export Options Alphabetize Word-Def Delimiter Tab Comma Custom Def-Word Delimiter New Line Semicolon Custom Data Copy and paste the text below. It is read-only. Select All adaptive radiation The emergence of numerous species from a common ancestor introduced into an environment that presents a diversity of new opportunities and problems. allometric growth The variation in the relative rates of growth of various parts of the body, which helps shape the organism. allopatric speciation A mode of speciation induced when an ancestral population becomes segregated by a geographic barrier or is itself divided into two or more geographically isolated subpopulations. allopolyploid A common type of polyploid species resulting from two different species interbreeding and combining their chromosomes. autopolyploid An individual that has more than two chromosome sets, all derived from a single species. biological species concept Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are not able to produce viable, fertile offspring with members of other populations. 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 Any of the genes that control the overall body plan of animals and plants by controlling the developmental fate of groups of cells. macroevolution Evolutionary change above the species level, including the appearance of major evolutionary developments, such as flight, that we use to define higher taxa. microevolution Evolutionary change below the species level; change in the genetic makeup of a population from generation to generation. morphological species concept Defining species by measurable anatomical criteria. paedomorphosis The 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—that is, as one branch on the tree of life. polyploidy A chromosomal alteration in which the organism possesses more than two complete chromosome sets. postzygotic barrier Any of several species-isolating mechanisms that prevent hybrids produced by two different species from developing into viable, fertile adults. prezygotic barrier A reproductive barrier that impedes mating between species or hinders fertilization of ova if interspecific mating is attempted. punctuated equilibrium In evolutionary theory, long periods of apparent stasis (no change) interrupted by relatively brief periods of sudden change. reproductive isolation The existence of biological factors (barriers) that impede members of two species from producing viable, fertile hybrids. speciation The origin of new species in evolution. species A group whose members possess similar anatomical characteristics and have the ability to interbreed. species selection A theory maintaining that species living the longest and generating the greatest number of species determine the direction of major evolutionary trends. sympatric speciation A mode of speciation occurring as a result of a radical change in the genome of a subpopulation, reproductively isolating the subpopulation from the parent population.