Définition : An oceanic island, often having a characteristic ring-like shape surrounding a lagoon. Atolls are formed when coral reef grows around a volcanic island that later subsides into the ocean.
Définition : Capable of creating a new organism by combining the genetic material of two gametes, which may come from two parent organisms or from a single organism, in the case of self-fertilizing hermaphrodites.
Définition : A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
