Native populations in any habitat evolved through a long process of natu- ral selection, creating a complex set Of biological relationships such as food webs. As species are eliminated, food webs begin to collapse. The se- verity of the ecological impact from a loss of species diversity depends on the functional role and the overall contribution each species plays in that unique food web. The richness of living systems, called biodiversity, has several compo. nents, including the diversity of all organisms, the diversity within and among species and populations, and the diversity of ecosystems. Consider that each species is important to its habitat, and the presence of a variety of species helps to increase the capability Of an ecosystem 10 be resilient in the face of a changing environment. The loss of cer tain organisms, such as top-order predators, in a food chain may have more ecological impact than the loss Of one rare species because Of these predators' critical ecological role and their impact on a food web. Preserving broad-scale biodiver- sity is important to maintaining biological bal-