- Natural evolutionary process that results in the survival of organisms best suited to changing living conditions through the perpetuation of desirable genetic qualities and the elimination of undesirable ones.
Definition from: Psychological Index Terms via Unified Medical Language System at the National Library of Medicine
- A natural process that results in the survival and reproductive success of individuals or groups best adjusted to their environment and that leads to the perpetuation of genetic qualities best suited to that particular environment.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.