A relatively small area with an exceptional concentration of species. bioenergetics The study of how organisms manage their energy resources. biogeochemical cycles[Gk. bios, life + geo, earth + chemeia, alchemy; kyklos, circle, wheel] The various nutrient circuits, which involve both biotic and abiotic components of ecosystems.

a biogeographic region that is both aFind thousands of free online definitions and reference guides at TheFreeDictionary

an area that contains a large or uniquely different collection of species that require preservation

an area of rich biodiversity that faces serious threats to its existence