| A | B |
|---|
| Macroevolution | Evolution above the species level |
| Speciation | Origin of a new species |
| Anagenesis | Accumulation of changes that gradually transform a given species into a species with different characteristics |
| Phyletic Evolution | alternative name for anagenesis |
| Cladogenesis | Splitting of a gene pool into two or more separate pools that gives rise to one or more new species |
| Branching Evolution | alternative name for cladogenesis |
| Species | A group whose members possess similar anatomical characteristics and have the ability to interbreed |
| Prezygotic Barriers | A reproductive barrier that impedes mating between species or hinders fertilization of ova if interspecific mating is attempting |
| Prozygotic Barriers | A reproductive barrier that prevent hybrid zygotes, that overcome prezygotic barriers, from developing into a viable, fertile adult |
| Morphological Species Concept | Characterizes a species by its body shape, size and other structural features |
| Recognition Species Concept | Characterizes a species as a set of organisms that recognizes each other as potential mates. |
| Ecological Species Concept | Characterizes a species by ecological niche |
| Evolutionary Species Concept | Also known as the phylogenetic species concept, it defines a species as a set of organisms as a unique genetic history |
| Cohesion species Concept | Characterizes a species by its a population, or series of populations, that has genetic or demographic cohesion |
| Allopartic 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 |
| Sympatric Speciation | A mode of speciation occuring as a result of a radical change in the genome of a subpopulation, reproductively isolating the subpopulation from the parent population |
| Adaptive Radiation | The emergence of numerous species from a common ancestor introduced into an environment that presents a diversity of new opportunities and challenges |
| Polyploidy | A chromosomal alteration in which the organism possesses more than two complete chromosome sets |
| Autopolyploid | An individual that has more than two chromosome sets, all derived from a single species |
| Allopolyploid | A common type of polyploid species resulting from two different species interbreeding and combining their chromosomes |
| Hybrid Zone | Range where two species both exist and interbreed. |
| Punctuated Equilibrium | In evolutionary theory, long periods of apparent stasis (no change) interrupted by relatively brief periods of sudden change |
| Exaptation | a process in which a feature acquires a function that was not acquired through natural selection. |
| Paedomorphisis | The retention in an adult organism of the juvenile features of its evolutionary ancestors |
| Allometric Growth | The variation in the relative rates of growth of various parts of the body, which helps shape the organism |
| Heterochrony | Evolutionary change in the timing or rate of an organism's development |
| Homeosis | transformation of one body part into another, arising from mutation in or misexpression of specific developmentally critical genes |
