In part, these variations have been caused by the evolution of new types of organisms and the elimination of others due to environmental changes. Now, however, humans are effecting environmental changes at an accelerated pace, significantly impacting Earth's biodiversity. In fact, changes are occurring rapidly enough that the impact is a net loss of species rather than a proliferation of new life forms. Direct exploitation and deliberate extermination also pose a serious threat to biological diversity, particularly in East Africa and the North Sea where species such as the Black Rhino and whales are being hunted to extinction. Deliberate or accidental introduction of non-native species can also trigger serious ecological imbalances and species elimination, particularly in isolated environments, such as islands, where fixed boundaries tend to put native species at greater risk.
Loss of species is significant in several respects.
First, breaking of critical links in the biological chain can disrupt the functioning of an entire ecosystem and its biogeochemical cycles. This disruption may have significant effects on larger scale processes. Second, loss of species can have impacts on the organism pool from which medicines and pharmaceuticals can be derived. Third, loss of species can result in loss of genetic material, which is needed to replenish the genetic diversity of domesticated plants that are the basis of world agriculture. In recent years, the international scientific community has made considerable progress toward fostering global awareness of the importance of biodiversity.