Wildlife needs protection to maintain both genetic diversity within individual species and ecological diversity within various environmental zones. Biodiversity in both areas is important to sustain the well-being of human populations and to maintain healthy natural systems in the face of natural and man-made disturbances.
Although there about 1.7 million identified species of living things, estimates of the actual number of species range from 3 million to 300 million, and each wildlife species interacts with its environment and with other wildlife in ways that people cannot always predict. The loss of just one species from an ecosystem potentially impacts many others and makes the ecosystem less able to adapt to further changes. Some species are particularly important to ecosystems because they serve as indicators warning of declines in environmental quality.
People depend on the ecosystems around them for food, medicines and clothing, as well as for natural regulation of flooding, air and water purification, soil generation, and other functions. Thus, preserving wildlife helps preserve human life as well and may contribute to future discoveries benefiting humankind. Wildlife preservation also benefits ecotourism, which provides a sustainable source of income for people living in developing nations, and preserves living things for future generations.