Talking about what animals are going extinct.

Three species go extinct every hour. The research team led by Jeremy Thomas of the British Center for Ecology and Hydrology published a report on the wildlife survey in Britain in the recently published Science magazine. In the past 40 years, the number of native birds in Britain has decreased by 54%, the number of native wild plants has decreased by 28%, and the number of native butterflies has decreased by an astonishing 765,438+0%. Insects, which have always been considered to have a large number of species and strong adaptability, are also facing extinction. Scientists infer that the earth is facing the sixth mass extinction. Dr. Jiang Zhigang, chief researcher of Institute of Zoology, Chinese Academy of Sciences and executive deputy director of China Endangered Species Science Committee, also believes that from the perspective of nature conservation biology, since the industrial revolution, the earth has entered the sixth extinction period. According to statistics, 75 species are extinct every day and 3 species are extinct every hour in the world. If we extend the butterfly survey to other insects in Britain and invertebrates on the whole earth, we are obviously facing a serious biodiversity crisis. A species refers to a natural group of individuals who can mate with each other and produce fertile offspring. Extinct species are those that have not been clearly found in the wild in the past 50 years. "Mass extinction is not only the extinction of one species, but the extinction of many species in a relatively short geological history, that is, hundreds of thousands or millions of years." Dr Jiang Zhigang said. Thomas said: "Insect species account for more than 50% of the global species, so their mass extinction is bad news for the biodiversity of the earth." Since the industrial revolution, many species have appeared on the earth, such as great auk, North American passenger pigeon, South African spotted donkey, Bali Lake in Indonesia, Australian marsupial, Zhili macaque, Alpine antelope, Platts wild horse, Taiwan clouded leopard and so on. According to the Red List of Endangered Species published by IUCN, there are still 1/4 species of mammals, 1.200 species of birds and 30,000 species of plants in the world at present. The first five extinctions are natural. Since multicellular organisms were born on the earth 600 million years ago, there have been five mass extinctions. The first mass extinction on the earth occurred at the end of Ordovician 440 million years ago, and about 85% of the species became extinct. About 365 million years ago, in the late Devonian, the second extinction occurred, and marine life suffered heavy losses. The third extinction occurred at the end of Permian about 250 million years ago, which was the largest and most serious in the history of the earth. It is estimated that 96% of species on the earth are extinct, including 90% of marine life and 70% of terrestrial vertebrates. The fourth time happened 65438+85 million years ago, and 80% of reptiles became extinct. The fifth time happened in the Cretaceous period 65 million years ago, which is also a well-known one. The dinosaurs that ruled the earth for 65.438+600 million years became extinct. The first five mass extinctions were mainly caused by geological disasters and climate change. For example, the first mass extinction was caused by global climate cooling, and the one that happened at the end of Cretaceous was that an asteroid hit the earth and caused the global ecosystem to collapse. The sixth extinction of mankind is the culprit. Now the sixth mass extinction is in progress, and human beings have become the culprit. Experts believe that it is difficult to say whether humans will be included. Dr Jiang Zhigang does not deny that species extinction is a natural law from an evolutionary point of view. For example, the giant panda population is currently in decline. However, since the emergence of mankind, especially since the industrial revolution, the population of the earth has been increasing and more and more means of subsistence are needed. The scope of human activities is getting bigger and bigger, and there are more and more disturbances to nature. In this way, a large number of forests, grasslands and rivers disappeared and were replaced by roads, farmland and reservoirs ... The natural habitat of living things was fragmented by traces of human activities. "Every road is an insurmountable obstacle for animals. Even the butterfly populations distributed on both sides of the road are isolated and no longer fly around for gene exchange as before. " Dr. Jiang Zhigang said sadly, "Not to mention the large animals such as Tibetan antelope, lion and tiger." Some scientists estimate that in the past 200 million years, 90 species of vertebrates have become extinct every 100 years, and one higher plant has become extinct every 27 years. However, due to human interference, the extinction rate of birds and mammals increased by 1000 times, reaching1000 times. Stuart Pim, a famous biologist at Duke University in the United States, believes that if species decrease at this rate, by 2050, a quarter to half of the existing species will be extinct or endangered. It is difficult to produce new species. The existing species are decreasing, but it is difficult to produce new species. According to the fossil record, after each extinction, some new advanced groups were replaced. The rapid reproduction of mammals after the extinction of dinosaurs is a typical example. But Dr. Jiang Zhigang believes that creatures are always evolving, and all the creatures we see now have evolved over a long period of time. So it takes a long time and a lot of space to produce new species. But now, under the management of people everywhere, the natural environment is getting worse and worse, and organisms have lost the environment and conditions for natural evolution. Species are constantly dying out naturally, but it is difficult to produce new species. Just like a tiger, if it is given enough living space to hunt freely, it may evolve and produce a new species similar to a tiger, but now it is difficult for it to survive, let alone evolve. The surface of the earth is a huge biosphere composed of all biological species such as animals, plants and microorganisms and their living environment, and human beings are one of them. A large number of creatures disappeared in the sixth extinction, but it is difficult to produce new species like the first five. The earth's ecosystem is far more fragile than we thought. When it is damaged to a certain extent, it will lead to the collapse of the system on which we live. If the last moment doomed by human actions comes, will human beings become survivors? One Million Species Extinction in 2050 Scientists from Europe, Australia, Central and South America and Africa conducted a two-year study on the six regions with the richest biological species in the world, accounting for 20% of the earth's surface area, and reached an amazing preliminary conclusion: due to global warming, in the next 50 years,14 of the animals and plants on the earth will be destroyed. They predict that there will be 1 10,000 species extinct on the earth in 2050. According to scientists' research, because climate warming is a fait accompli, one tenth of the species that will be extinct are irreversible. But from now on, countries' efforts to control global harmful gas emissions will be able to save more species from the same fate. According to the research results of scientists, biological species living in high mountains are more likely to survive than those living in other areas, because in the case of global warming, species in this area can migrate to higher and cooler areas. Those who live in flat areas, such as those in Brazil, Mexico and Australia, will have a very fragile living environment in the future. It is almost impossible for creatures in these areas to adapt to the changed climate and environment and have to move to areas thousands of miles away. Birds are the most promising species to survive, and birds are one of the most promising species in theory with their strong migration ability. In order to find a more suitable area, birds can fly long distances, but due to the deterioration of natural conditions such as forests, they may not be able to find a truly suitable natural environment for survival. As a result, you can only face death. Professor Thomas, a conservationist from the University of Leeds, one of the members of the above-mentioned research team, said: "Scientists all hope to reach a clear conclusion when conducting scientific research. However, I really hope that we haven't reached the conclusion we have reached. The facts are far more serious than we thought, and our conclusions are likely to underestimate the cruel living environment faced by biological species. " 12 species of butterflies in Australia will disappear. Another amazing discovery of scientists is that half of the 24 species of butterflies in Australia will disappear forever in the next few years. In South Africa's major biological reserves, 60% of the protected biological species are in danger of extinction. In the savanna area of central and western Brazil, which accounts for one fifth of Brazil's total area, research shows that more than 70% of the 163 trees in this area will be extinct. Many of these plants are rare species endemic to this area. Europe is the least affected. Europe is the region where the natural environment is least affected by global climate change. The survival probability of animals and plants in this area is greater than that in other parts of the world. Even so, under the influence of climate warming, a quarter of the birds and 1 1% to 17% plants in Europe will gradually become extinct in the future. Studies in Mexico show that plants and animals in plain and arid areas are most affected by climate warming. Once the climate changes slightly, these animals and plants need to migrate far away to find a new environment suitable for survival. Of the 65,438+0,870 species of animals and plants studied in this area, one third will face survival crisis in the future. Xinhua News Agency, Washington, April 2 1 According to the popular view in the scientific community, the extinction of dinosaurs was caused by the impact of alien objects on the earth. However, there are different opinions about the consequences of the impact of alien celestial bodies directly accelerating the extinction of dinosaurs. For example, British and American researchers put forward a new view that the climate cooling caused by the impact of alien celestial bodies may cause more males and fewer females in dinosaur offspring, and dinosaurs will eventually go to a dead end because of "gender imbalance." Professor david miller of Leeds University and his colleagues pointed out in the new issue of American magazine Fertility and Sterility that the sex of offspring of mammals, birds, snakes, most lizards and some fish is determined by chromosomes or genes. In mammals, for example, the offspring who inherit two X chromosomes are females, and the offspring who inherit one X chromosome and one Y chromosome will be males. However, some reptiles living on the earth at present, such as crocodiles, turtles, etc., the environmental temperature of their eggs will affect the sex of their offspring. Researchers say that the sex of some extinct species, such as dinosaurs, is probably determined by the temperature at which they hatch. Miller and others believe that the impact of foreign celestial bodies on the earth about 65 million years ago is likely to lead to a large number of dust entering the earth's atmosphere and the global climate becoming cold. As a result, males dominated the descendants of dinosaurs. This sex ratio imbalance may be an important factor causing the extinction of dinosaurs. The researchers speculate that the Y chromosome of male mammals may have evolved mainly to prevent the extinction of species related to climate change. This mechanism of determining sex through heredity can ensure the balance of sex ratio in future generations. They believe that the current global warming trend may pose a threat to the survival of some existing species, which rely on environmental temperature to determine the sex of their offspring. Endangered animals (class I) include: animals 1, primate hummingmonkeys (all species); Bear monkey; Taiwan Province monkey; Dolphin-tailed monkey; Langur (all species); Golden monkey (all species); Gibbon (all species). 2. Carnivora Malay bear; Giant panda; Sable; Mink bear; Bear raccoon; Clouded leopard; Leopard print; Tiger; Snow leopard. 3. Manatee dugong 4. Cetaceans are white and cut; China Bai Haizhuo. 5. Long-nosed elephant 6. Chiroptera Mongolian wild donkey; Tibetan wild donkey; Mustang 7. Artiodactyla wild camel; Elk; Black muntjac; White-lipped deer; Polu sika deer; Dolphin deer; Milu; Bison; Wild yak; Przewalski's gazelle; Antelope with a long nose; Pronghorn; Rat antelope in Taiwan Province province; Red impala; Tal sheep; Goat. 8. Beaver Birds of the Beaver Family 9. Short-tailed albatross 10, white-bellied frigate bird 1 1, stork; Black stork; Zhu Si. 12, China mergansers 13, golden eagles; White shoulder carving; Jade belt sea sculpture; White-tailed sea eagle; Tiger-headed sea eagle; Vultures; Vultures. 14, chicken-shaped grouse; Spotted-tailed hazel chicken 15, pheasant quail of pheasant family; Sichuan mountain partridge; Hainan mountain partridge; Blackhead pheasant; Red breasted pheasant; Gray-bellied pheasant; Yellow-bellied pheasant Rainbow pheasant (all species); Brown eared pheasant; Blue thrush; Black-necked long-tailed pheasant; White-necked long-tailed pheasant; Black-tailed pheasant; Peacock pheasant; Green peacock; 16, crane-shaped black-necked crane; White-headed crane; Red-crowned crane; White crane; Red-necked crane; Great bustard (all species) 17, gully reptile 18, tortoise with four claws; Catfish 19, lizard crocodile lizard; Monitor lizard 20. Snake python 2 1, alligator alligator 22, cypriniforme bighead carp 23, Chinese sturgeon; Sturgeon; 24, 25, 26, 27, 28, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 28, 28, 28, 28, 28, 28, 28, 28, 28, 29, 28, 28, 28, 28, 28, 28, 29, 29