bio unit 7 vocab

relative fitness

The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population.

basal taxon

In a specified group of organisms, a taxon whose evolutionary lineage diverged early in the history of the group

branch point

The representation on a phylogenetic tree of the divergence of two or more taxa from a common ancestor. Usually shown as a dichotomy in which a branch representing the ancestral lineage splits into two branches, one for each of the two descendant lineages.

adaptive evolution

A process in which traits that enhance survival or reproduction tend to increase in frequency over time, resulting in a better match between organisms and their environment.

evolutionary tree

A branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms.

genetic drift 

A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of genetic drift are most pronounced in small populations

phylogeny

The evolutionary history of a species or group of related species.

adaptation 

Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment

convergent evolution

The evolution of similar features in independent evolutionary lineages.

speciation

An evolutionary process in which one species splits into two or more species.

bottleneck effect 

Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population.