Looking At Endangered Species Biology Essay
Over 19,000 plant species and 5,000 animal species on the globe are classified as endangered. Thousands of speciii reach the brink of extinction in each year before biologists can identify them.
The main causes of extinction of plant and animal species are habitat destruction, commercial exploitation (collection of plants, hunting and poaching irrational), the damage produced by acclimatized species and pollution. Of these cases, habitat destruction is the greatest threat to these species.
Over geological ages, different species of plants and animals have evolved slowly and disappeared because of climate change and radical inability to adapt to competition for survival. However, in the 1600s, the rate of extinction has increased progressively with increasing human population and consumption of natural resources.
Many scientists consider that the extinction of the dinosaurs, the latter by 65 million years, today we are among the largest critical period, irreversible destruction of many species of plants and animals.
Maintain current ecosystems such as forests, coral reefs and wetlands, depends largely on their biodiversity. The disappearance of one species that make up such a trophic chain that may lead to ecosystem decline.
Irreversible decline of biodiversity has a serious impact on living standards of people.
Healthy ecosystems provide food, clean air, water and fertile soil for agriculture. Also, 40% of modern medicines come from plants and animals.
â€¢ Destruction of habitats by human activities is the primary cause of extinction of plant and animal species. As the creatures evolve, they adapt to specific habitats, which provides optimal living conditions they need. Pollution, drainage of wetlands, deforestation, urbanization and road construction (Transamazonianul, Transsiberian) lead to the destruction or fragmentation of their living environments. Thus, species lose contact with other populations, thus reducing genetic diversity and adapting to changing climate conditions more difficult. In some cases, fragmented habitat is an area too narrow to support a large population.
â€¢ In the last 400 years, global commercial exploitation of animals for food and other products increased significantly. Many species of whales have reached the brink of extinction after being simply slaughter for oil and meat. Another example of African black rhino is killed on a large scale for its horn, which is valued as a medicine and aphrodisiac. Also, whole families of cacti and orchids are endangered because of their indiscriminate collection.
â€¢ acclimatized species introduced a new ecosystem caused, often native species decline. In 1959, British settlers introduced Nile perch in Lake Victoria in East Africa. This predatory fish drastically reduced native fish populations and caused the loss of no more than 200 endemic species, which feed the algae. Thus, aquatic vegetation of Lake Victoria has increased enormously and the natural balance has been disturbed, irreversible until today.
â€¢ Another major issue that led and lead to drastic reduction of the fauna and flora is environmental pollution. Various toxic chemicals have spread all over the circuit feeding the ecosystem. Water pollution and high water temperatures have wiped out many species of fish endemic. Acid rain destroyed by the end sec.XX, 118 million m3 of timber in Europe. Also, chemical spills affecting long and ocean floor.
List of plant and animal species recognized as endangered is too long to be remembered each species separately. More conclusive examples are:
â€¢ passenger pigeon once held absolute rule that the number of copies between birds and mammals. In 1813, included more than 1 billion of pigeons in the U.S. state of Kentucky, more than a century, in the same state, died last specimen of this species.
â€¢ bird "dodo", like the dove, but nezburÄƒtoare was first spotted in 1598 in the Indian Ocean island of Mauritius, the last copy disappeared sometime around 1681.
â€¢ California condor, considered the most endangered bird, came to the attention of specialists who took the last copies of their natural environment and have passed the special reserves, where their breeding attempts.
â€¢ bald eagle, white head and covered with feathers, despite its name, was declared in 1782 as a symbol of U.S. poultry Existence has been in great difficulty because of excessive pollution, but after vigorous measures taken by specialists, his number has recovered significantly.
â€¢ Many parrots are seriously threatened by the ruthless destruction of their forests in tropical and subtropical habitats, and strong demand for cage birds. Among the threatened species is the country's Spix, in northeastern Brazil, from which it is believed that only one male still alive in the wild. Kakapo parrot of New Zealand is another threatened, pushed nearly to extinction by predators as hermeline, cats, rats introduced by European colonists in their habitat.
Of the 4600 known mammal species, is considered more than 1,000 species are affected, many are endangered, including:
â€¢ Tasmanian wolf, whose last specimen died in captivity in 1936.
â€¢ Giant Panda Bear in China became the world symbol of endangered animals and is being done to preserve it.
â€¢ Irbis (Snow Leopard), with habitat in the Himalayas and surrounding areas, its existence is endangered because of excessive hunting for its valuable fur.
â€¢ Yakul Tibetan, once the very large number was greatly reduced in number of copies because of extensive hunting.
â€¢ Being ruthlessly hunted for their skin sensitivity, species of the American crocodile and the Nile crocodile today see their existence threatened.
â€¢ Elephants are themselves endangered because of ivory traders who bring great price on this product. Afica in 1979 to 1.3 million live in the wild because of poaching of elephants but this number dropped to 600,000 in 1989. Indian elephant-like species-is in a much more difficult. Because reducing habitat in the wild are alive 35000-54000 copies, mostly in India. Other 16,000 copies are kept as domestic animals in several countries in Asia.
â€¢ rhino and it was long Holders hunters, leading to a sharp decrease in the number of species of exeplare. White rhino, rhino of Sumatera and Borneo, Java and the African rhinoceros are now only several hundred copies
â€¢ Seals are also threatened because of hunters who were only interested in skin and fur animals. Ringed seal population came from a few thousand asute just 10,000 copies in the Arctic-Canadian. Monk seal, which lives in warm waters, is the rarest of seals in some regions it is already gone.
â€¢ Primates are also making a long list of endangered animals, which due to the lower areas occupied by tropical forests. The species is endangered orangutan. Number of mountain gorillas and he fell to only 350 individuals left in the wild.
Other animals in danger of extinction are sea otters and the huge lizard of Komodo, killer whales and the humpback, Siberian tiger, some species of hyenas, jaguars and some species of reptiles and amphibians such as the Galapagos giant tortoise, golden frog, tuatara or iguana.
The situation does not lie nor our country better. Once the very large number, auroch and remaining eagle emblem only as symbols of Moldavia and Wallachia. Buffalo not only in legends appear related Dragos-Voda. Bearded Vulture Falnicul remained only in the mountain Zaganu toponymy.
IV. Preservation efforts:
The situation became downright dramatic. Experts consider that today the day disappear from the Earth's surface many species of plants and animals, many of them even before known to man.
To curb this intolerable state of facts, both globally and nationally, have been developed a lot of laws that lead to prevent environmental degradation, ecosystems, and thus to save from destruction many plant species and animals, including:
â€¢ In 1973, 125 nations signed the International Convention on Protection of fauna and flora that are endangered (CITES);
â€¢ Under the aegis of the United Nations, was established many nature reserves;
â€¢ have been established organizations (Greenpeace) and political parties (Green Parties) that militate against environmental pollution and to save the fauna and flora, practically our planet from destruction.
â€¢ There is growing pressure to impose a total ban on imports of wild parrots, and whoever wants to buy a parrot should ensure that he was raised in captivity.
â€¢ Because of concerns regarding the fate fate of elephants in the world in 1989 were placed restrictions on international trade in ivory. Following this measure, the number living in the wild African elephant was 600,000 in 1995.
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