Processes of Macroevolution - Key Terms & Concepts

1. Chapter 8, Processes of Macroevolution Key Terms

2. metazoaMulticellular animals; a major division of the animal kingdom. • chordataThe phylum of the animal kingdom that includes vertebrates.

3. vertebratesAnimals with bony backbones; includes fishes, amphibians, reptiles, birds and mammals. • homologiesStructures that are shared through descent from a common ancestor.

4. analogiesStructures in organisms that are used for the same function, but have developed independently and are not the result of common descent. • homoplasyThe process by which similarities can develop in different groups of organisms.

5. evolutionary systematicsA traditional approach to classification in which presumed ancestors and descendents are traced in time by analysis of homologous characters. • Cladistic taxonomyAn approach to taxonomy that groups species according to shared derived characteristics.

6. ancestral (primitive)Referring to characteristics that are inherited by a group of organisms from a remote ancestor. • derived (modified)Referring to characteristics that are modified from the ancestral condition and thus are diagnostic of particular evolutionary lineages.

7. therapodsSmall to medium-sized ground-living dinosaurs, dated to approximately 150 m.y.a. and thought to be related to birds. • phylogenetic treeA chart showing evolutionary relationships as determined by phylogenetic systematics.

8. cladogramA chart showing evolutionary relationships as determined by cladistic analysis. It is based solely on interpretation of shared derived characteristics. • biological species conceptA depiction of species as groups of individuals capable of fertile inbreeding but reproductively isolated from other such groups.

9. speciationThe process where a new species evolves from a prior species. • recognition species conceptA depiction of species where the key aspect is the ability of individuals to identify members of their own species for purposes of mating.

10. ecological species conceptThe concept that a species is a group of organisms exploiting a single niche. • allopatricA model of speciation that emphasizes complete reproductive isolation of divergent populations from their ancestral population.

11. intraspecificWithin species, refers to variation seen within the same species. • interspecificBetween species; refers to variation beyond that seen within the same species to include additional aspects between two different species.

12. PaleospeciesSpecies defined from fossil evidence, often covering a long time span. • genusA group of closely related species.

13. geological time scaleThe organization of earth history into eras, periods, and epochs. • continental driftThe movement of continents on sliding plates of the earth’s surface.

14. ecological nichesThe positions of species within their physical and biological environments, together making up the ecosystem. • epochsCategories of the geological time scale; subdivisions of periods.

15. viviparousGiving birth to live young. • HeterodontHaving different kinds of teeth; characteristic of mammals whose teeth consist of incisors, canines, premolars, and molars.

16. endothermicAble to maintain internal body temperature. • large-bodied hominoidsHominoids including the great apes and hominids as well as all ancestral forms back to the time of divergence from small bodied hominoids.

17. hominidsColloquial term for members of the family Hominidae, which includes all bipedal hominoids back to the divergence of the African great apes. • adaptive radiationThe relatively rapid expansion and diversification of life forms into new ecological niches.

18. punctuated equilibriumThe concept that evolutionary change proceeds through long periods of stasis punctuated by rapid periods of change.