| the ability of a population to maintain or increase its numbers in succeeding generations |
| variation in traits such as body weight or height in which a series of types are distributed on a continuum, not grouped into discrete categories |
vestige ves·tige (věs'tĭj)
n.
A rudimentary or degenerate, usually nonfunctioning, structure that is the remnant of an organ or a part that was fully developed or functioning in a preceding generation or an earlier stage of development.