Biological Species as a special case of Evolutionary Species

An Evolutionary Species is an ancestor-descendant lineage that changes through time (vertical axis). At any given point in time, such a lineage is a Biological Species with a certain range of variation (bell curves). The morphological differences between two contemporary, related Biological Species (red & blue curves) are the result of change within an evolutionary lineage over time.

Text material © 2005 by Steven M. Carr