Adaptive radiation


 * "The first explorer fish would have found it just about impossible to explain to the other fish the full implications of its experience. On the basis of just a few hours or days on land, how could it envision the vast sweep of evolutionary change awaiting life on Earth? . ..
 * "Are our astronauts in much the same situation as that mythical fish?"
 * - Frank White, The Overview Effect: Space Exploration and Human Evolution, p. 8



An adaptive radiation is an event in Earth history when an unusually large number of new species arise in a short time, due to new ecological niches becoming available. The rough opposite of an adaptive radiation is a mass extinction, in which an unusually large number of species go extinct in a short period of time.

Examples in Earth history

 * Diversification of oxygen-breathing microbes after the oxygen crisis.
 * The Ediacaran Explosion and Cambrian Explosion, the first known large radiations of multicellular life.
 * Radiations of plants, arthropods, and vertebrates into new land-based niches after emerging from the oceans.
 * Radiations commonly followed mass extinctions, which leave many empty niches. The best known is the radiation of mammals following the Fifth Great Extinction.

Speculative future possibilities

 * Radiation into niches on a newly habitable world as part of a human-initiated process of ecopoeisis.
 * Radiation of beings adapted to living in space, such as Dyson trees. A diverse space-based ecosystem is described in Gregory Benford's far-future novel, Beyond Infinity.