Adaptive potential

Adaptive potential is the capacity of a population to respond to environmental change through natural selection — not merely the variation that currently exists, but the variation that can be generated, recruited, and expressed under novel conditions. It is a broader concept than standing variation or evolvability, encompassing not only the genetic substrate but the developmental, ecological, and demographic conditions that determine whether that substrate can be mobilized when selection demands it. A population with abundant genetic variation but low effective population size may have high theoretical adaptive potential and zero realized potential, because genetic drift overwhelms the selective signal before it can produce a response.

The concept matters because it reframes the question of whether a population can adapt to rapid environmental change — climate shifts, invasive species, novel pathogens — from a question about present variation to a question about dynamical possibility. Evolutionary rescue is the successful realization of adaptive potential; extinction is its failure. The gap between the two is not always determined by genetics.