noun
1. Biology.
a. The reappearance in an individual of characteristics of some remote ancestor that have been absent in intervening generations.
b. An individual embodying such a reversion.
2. Reversion to an earlier type; throwback.
EX. Remember, even Pokemon evolution could be subject to atavism and, rather than getting something better, its conceivable that they could play a cruel joke on us with the new games (since they'll be coming out simultaneously worldwide) and have the Pokemon evolve into disgusting blob monsters.
