10BIO5: Unit 2 (Evolution and Biotechnology) Definitions

evolution

change in the genetic composition of a population during successive generations, which may result in the development of new species.

macroevolution

the variation of allele frequencies at or above the level of species over geological time, resulting in the divergence of taxonomic groups, in which the descendant is in a different taxonomic group to the ancestor.

microevolution

small-scale variation of allele frequencies within a species or population, in which the descendant is of the same taxonomic group as the ancestor.

fossil

the preserved remains, impressions or traces of organisms found in rocks, amber, ice or soil.

index fossil

a widespread but short-lived fossil.

half-life

the time it takes for half the quantity of an isotope to decay.

selection pressure

an environmental factor that acts on a population.

species

a group of organisms that can potentially interbreed in nature to produce viable, fertile offspring and are reproductively isolated from other groups.

reproductive isolation

when two or more sections of a population are unable to breed together.

adaptation

any features that enhance an organism’s chances of survival in its environment.