التعريف: directly or indirectly modulating the availability of resources to other species, by causing physical state changes in biotic or abiotic materials; modifying, maintaining and/or creating habitats
التعريف: Gravel is an environmental material which is composed of pieces of rock that are at least two millimeters (2mm) in its largest dimension and no more than 75 millimeters.
التعريف: 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.
التعريف: Hard framework, internal or external, which supports and protects softer parts of plant, animal or unicellular organism, and to which muscles usually attach in animals, includes skeletons (derived from Lawrence, 2005).
التعريف: 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)
