Chapter 7, Processes of Macroevolution: Mammalian/Primate Evolutionary History

1. Chapter 7, Processes of Macroevolution: Mammalian/Primate Evolutionary History Key Terms

2. ClassificationIn biology, the ordering of organisms into categories, such as orders, families, and genera, to show evolutionary relationships. • MetazoaMulticellular animals; a major division of the animal kingdom.

3. ChordataThe phylum of the animal kingdom that includes vertebrates. VertebratesAnimals with bony backbones; includes fishes, amphibians, reptiles, birds, and mammals.

4. HomologiesSimilarities between organisms based on descent from a common ancestor. AnalogiesSimilarities between organisms based strictly on common function,with no assumed common evolutionary descent.

5. HomoplasyThe separate evolutionary development of similar characteristics in different groups of organisms. Evolutionary systematicsA traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traced in time by analysis of homologous characters.

6. CladisticsAn approach to classification that seeks to make rigorous evolutionary interpretations based solely on analysis of certain types of homologous characters (those considered derived characters). DerivedReferring to characters that are modified from the ancestral condition and thus are diagnostic of particular evolutionary lineages.

7. AncestralReferring to characters inherited by a group of organisms from a remote ancestor and thus not diagnostic of groups (lineages) branching subsequent to the time the character first appeared. Shared derivedRelating to specific character states shared in common between two forms and considered the most useful for making evolutionary interpretations.

8. Phylogenetic treeA chart showing evolutionary relationships as determined by phylogenetic systematics. It contains a time component and implies ancestor-descendant relationships. CladogramA chart showing evolutionary relationships as determined by cladistic analysis. It is based solely on interpretation of shared derived characters. No time component is indicated, and ancestor descendant relationships are not implied.

9. Biological species conceptA depiction of species as groups of individuals capable of fertile interbreeding but reproductively isolated from other such groups. SpeciationThe process where a new species evolves from a prior species. Speciation is the most basic process in macroevolution.

10. 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 seen between two different species.

11. PaleospeciesSpecies defined from fossil evidence, often covering a long time span. GenusA group of closely related species.

12. Geological time scaleThe organization of earth history into eras, periods, and epochs; commonly used by geologists and paleoanthropologists. Continental driftThe movement of continents on sliding plates of the earth’s surface. As a result, the positions of large landmasses have shifted dramatically during the earth’s history.

13. Ecological nichesThe positions of species within their physical and biological environments, together making up the ecosystem. A species’ ecological niche is defined by such components as diet, terrain, vegetation, type of predators, relationships with other species, and activity patterns, and each niche is unique to a given species.

14. EpochsCategories of the geological time scale; subdivisions of periods. In the Cenozoic, epochs include the Paleocene, Eocene, Oligocene, Miocene, and Pliocene (from the Tertiary) and the Pleistocene and Holocene (from the Quaternary). Adaptive radiationThe relatively rapid expansion and diversification of life forms into new ecological niches.

15. HeterodontHaving different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars. EndothermicAble to maintain internal body temperature through the production of energy by means of metabolic processes within cells; characteristic of mammals, birds, and perhaps some dinosaurs.

16. Large-bodied hominoidsThose hominoids including the great apes (orangutans, chimpanzees, gorillas) and hominids, as well as all ancestral forms back to the time of divergence from small-bodied hominoids (i.e., the gibbon lineage). Hominids Colloquial term for members of the family Hominidae, which includes all bipedal hominoids back to the divergence from African great apes.

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