Species diversity provides the foundation for individual ecosystems and thus is the prerequisite for the functioning of the biosphere. It is an immeasurable source of food and medicinal products, and an irreplaceable resource as a gene pool. Due to the increasing destruction and pollution of natural habitats, over-fishing and hunting, humans are destroying the biological multitude of life, and with that, the basis of their own well-being. The public is concerned when a well-known species like the tiger, whale, or mountain gorilla becomes endangered; however, the majority of other cases are hardly ever noticed by the public. Apart from the decline of species diversity within habitats, loss of genetic diversity within individual species has also been observed. The destruction of individual populations leads to a reduction in genetic regeneration capacity within a species. For instance, selective deforestation reduces the quality of the genetic material of affected tree species, since only strong, healthy trees are logged and the weaker ones are left behind. Humankind’s intentional or unintentional introduction of exotic animal and plant species to new habitats plays an important role as well. These so-called “neozic species” can become a threat to local species and lead to their complete extinction. For instance, the flightless Kiwi bird in New Zealand is threatened with extinction by introduced rats and feral cats.