A "genetic resource" or "Biological Resource" is defined by the Convention on Biological Diversity (CBD) as the "plant, animal or microbial material or material of other origin containing functional units of heredity". A genetic resource is also defined by the CBD as "genetic material of current or potential value." This includes genetic resources conserved in situ and ex situ (i.e. in the field or in a collection.) In situ conservation is the "conservation of ecosystems and natural habitats and the maintenance and renewal of viable populations of species in their natural surroundings and, in the case of domesticated or cultivated species, in the surroundings where they have developed their distinctive characteristics". (Article 2 of the CBD). Ex situ conservation is "the conservation of components of biological diversity outside their natural environment."