Биология Extinction просмотров - 268
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Extinction, the death of species, occurs when the last individual member of a species dies. A natural biological process, extinction has been greatly accelerated by human activities. The increasing human population has forced us to spread into almost all areas of Earth. Wherever humans invade an area, the habitats of many plants and animals are disrupted or destroyed, which can contribute to their extinction.
Biodiversity is the variety of living organisms and of the ecosystems in which they live. Biodiversity includes the number of different species, the genetic variety within a species, and the variety of interactions within and among ecosystems.
Biodiversity is currently decreasing at an alarming rate. It is likely that thousands of species will be eliminated within the next few decades. As many as one –fourth of Earth`s plant families may be extinct by the end of the 21st century. And countless animal species, that depend on those plants for food and habitat will probably also become extinct.
There have been periods of mass extinction, such as that which wiped out the dinosaurs during the Cretaceous era, 65 million years ago. But the current situation differs from the previous periods in several respects. First, its case is directly attributable to human activities. Second, it is occuring in a tremendously compressed period of time.
As we all know, our resourcefulness has enabled us to construct massive industrial and educational centers, explore the depths of Earth’s oceans and the mysteries of outer space, and manufacture weapons powerful enough to make all species including ourselves on the planet extinct. Unfortunately, we have been so busy with our own interests that we have lost sight of the fact that we might consider sharing some of Earth’s resources with other species.
The key question is whether or not we have taken this problem seriously yet. And if so, do we simply think it’s a matter that can be easily solved? We are
fairly well aware of how we have polluted our environment, but at least that’s a trend that can be reversed if we are willing to make the sacrifices needed to clean up the air and waterways we have dirtied. Extinction of a species, however, is permanent. When a species disappears from the face of the Earth, it’s gone forever; and no sacrifices can bring it back.
Interestingly, man has shown an inclination toward preserving some of
Earth’s more charismatic creatures such as whales, polar bears, chimpanzees and bald eagles in recent years, and he deserves credit for the exceptional efforts involved. The problem, however, is that while the attention was focused on such worth-while projects, it’s probable that several thousand other species disappeared during that time.
It’s not really fair to say that species are driven to the brink of extinction through sheer ignorance or stupidity on the part of mankind, but modern man’s insatiable appetite for expansion into the wild has deprived many species of the habitat
they require. In other words, relatively few creatures are facing dangers because of the activities of persons with direct or deliberate intent to kill them. Instead, species are being eliminated through the activity of many millions of people who are unaware of the “spill-over” consequences of their complex lifestyles. Thus, we can say that while we are not deliberately destroying our world, it’s also a fact that we have made it virtually impossible for some species to co-exist with us.
Every form of life on our Earth should have an opportunity to exist,
and at the same time! Humanity has no right to exterminate a species. Some people may think that some forms of life are unimportant, but we may actually be influencing the course of evolution.
Species become endangered and extinct for a variety of reasons, including the destruction or modification of habitats and the production of pollution. Humans also upset the natural balance by introducing new, exotic species or by controlling native pests or predators. Illegal hunting and uncontrolled commercial harvesting are also factors.
Organisms are important natural resources that are not fully appreciated. The current reduction in biodiversity caused by extinction of many species results in the increased instability of ecosystems and in lost opportunities and lost solutions to future problems.
The world`s forests provide many environmental services as well as commercially important timber and numerous recreational opportunities. The greatest problem facing forests today is deforestation, the temporary or permanent removal of forests.
Production of atmospheric pollutants that trap solar heat in the atmosphere will probably heavily affect Earth`s climate in the nearest future. Global warming and the accompanying changes in precipitation patterns could alter food production, destroy forests, reduce biological diversity, and submerge coastal areas
Text 1 Read and translate the text. Working with textsA Extinction, the death of species, occurs when the last individual member of a species dies. A natural biological process, extinction has been greatly accelerated by human activities. The increasing human population has forced us to spread into almost all areas of Earth. Wherever humans invade an area, the habitats of many plants and animals are disrupted or destroyed, which can contribute to their extinction. B ... [читать подробенее]