Extinctions contemporary

At the present time, extremely intensive extinction of organisms is occurring around the world as a consequence of human activity and the increase in the abundance of human populations. It has been estimated that the contemporary extinction rate is approximately 1000 times greater than the usual rate of background extinction (Novacek & Cleland 2001). This extinction is not, at first glance, obvious, because only a small percentage of known endangered fauna have so far become extinct. However, the vast majority of species of organisms on the Earth consist of arthropods and helminths living in the tropics, the greater majority of which have not yet even been named. Because of the destruction of natural habitats, especially tropical rain forests, 30% of these species will become extinct to the middle of this century, i.e. only slightly less than 30% of all species. The extent and rate of contemporary extinctions are thus approaching those of mass extinction. It is encouraging that the 30% reduction in diversity will apparently not be accompanied by a 30% reduction in disparity, as the number of basic types of body structure will apparently be preserved, although quite probably as a result of the efforts of zoological gardens and reservations. On the other hand, it is discouraging that, in contrast to all the former periods of mass extinctions, following which the original biodiversity was renewed with a certain delay, something similar will apparently not occur in this case. Humans not only exterminate species but primarily irreversibly take over their environment. This means that nature will have to wait until the period following the next successful mass extinction for renewal of the original biodiversity. Unfortunately, if the mass extinction is to be “successful”, members of our species will not be able to enjoy the renewed biodiversity.

Was this information useful for you?
You voted 'not at all'.
The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more