Van Valen 1973: species must continuously evolve just to maintain fitness against co-evolving antagonists (parasites, predators). Explains ubiquity of sexual reproduction (Hamilton-Axelrod-Tanese).
Van Valen 1973: species must continuously evolve just to maintain fitness against co-evolving antagonists (parasites, predators). Explains ubiquity of sexual reproduction (Hamilton-Axelrod-Tanese).