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拦截广告5.2 species of its own
Special species and genetic failure, often leading to endangered species and even the underlying caus of extinction. Some kinds of wild animal in the long process of evolution, adapted to a particular habitat and have had a special habits (including diet), making it difficult to adapt to changes in the environment or other environment, resulting in "not to be eliminated". Such as the giant panda, specialization is the main bamboo diet, lo their existing habitat or a large area of bamboo blossom withered, the giant panda is not edible bamboo, a large number of inevitable death, the survival of the crisis. Some wild animal in the long-term evolution of the process, for various reasons have been declining viability receded and the heritability of the threat, leading to its population and tend to be difficult to restore endangered. Such as the crested ibis, few in number, there is a certain degree of inbreeding coefficient, plus in human mi feeding condition, individual adapt to the wild life gene may be gradually lost, and the safety and survival, and even lead to extinction.
5.3 habitat destruction and loss
如何做帐Human deforestation for economic development, the circumference of the lake foreshore reclamation, overgrazing, a direct result of the wild animal habitat loss, indirectly led to the endangered wild animal. Forests and grasslands are wild animal, especially one of the habitat, birds, reptiles and mammals in the inct's main. Deforestation and subquent cultivation and overgrazing, which occupied the wild animal natural homes, and wild animal will be divided into many small island like stocks, making their survival of the race was a great influence. Reclaiming land from the lake and occupied beach is the result of waterfowl, amphibians and reptiles and fish are endangered reasons. Wetlands, lakes and coastal shoals were developed into industrial and agricultural land, which depends on the animal lost habitat, breeding ground to the verge of extinction. Such as the Chine alligator, have lived on the earth for billions of years, due to habitat loss, the wild population is going extinct, the authorities intend to u artificial breeding individuals re introduction of engineering, but it is no more and had to wait for the wild population extinction.
5.4 environmental pollution
Since twentieth Century, due to the widespread u of pesticides, rodenticide, fertilizer, coal, oil, resulting in a large number of industrial "three wastes" and toxic substances, and rious pollution of the atmosphere, soil and water, wild animal damage to health, the growing low fecundity, survival many rivers and lakes are no longer suitable for aquatic wild animal. Some higher niche in the wild animal becau of the food chain is also affected in varying degrees of guilt.
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5.5 luanbulanlie
Luanbulanlie is caud by the direct cau of many endangered species. The turtles, snakes, eagles, Tibetan antelope, ornamental birds and frogs are hunting the animal for veral categories of rious.
Turtle meat, snake and frog legs delicious, bird song and beautiful posture, Saker Falcon in vivo and in shatoosh international market etc., are touting the animal hunting disaster, resulting in its wild resource loss, many are endangered or critically endangered status.
Due to human over grazing and reclamation, the grassland dertification increasingly rious. The number of wild goats, sheep, grassland species also declined.
5.6 natural disasters
Natural disaster is one of the caus of threatened species. For example, in 1998 the Yangtze River flood, many inhabits plains or hilly area of wild animal suffered a crowning calamity.
5.2 物种自身的原因
物种特化和遗传衰竭，往往是导致物种濒危甚至灭绝的内在原因。某些种类的野生动物在长期的进化过程中，适应了某种特定的栖息环境而产生了特别的习性（包括食性），使其难以适应变化了的环境或其他环境，最终落得“不适者被淘汰”的结局。如大熊猫特化为主要以竹为食，一旦失去其现有栖息地或竹子大面积开花枯死，大熊猫无竹可食，必然大批死亡，出现生存危机。一些野生动物在长期的演化过程中，由于种种原因而受到生活力减退和遗传力衰退的威胁，导致其种群数量难以恢复而趋于濒危。如朱鹮，现存数量很少，
存在一定程度的近亲繁殖，再加上处于人类的半饲养状态，个别适应于野外生活的基因可能会逐步丢失，进而危及其生存，甚至导致其绝灭。
5.3 栖息地破坏与丧失
人类为发展经济砍伐森林、围湖围海造田、过度放牧等，直接造成了野生动物栖息地丧失，间接导致了野生动物的濒危。森林和草原是野生动物，特别是兽类、鸟类、爬行类以及昆虫最主要的栖息地之一。森林的砍伐和紧随其后的开荒种地以及草原过度放牧，既占据了野生动物固有的家园，又将野生动物人为地分割成许多孤岛状的小种群，使得它们的生存繁衍遭到极大的影响。围湖造田和占用滩涂是导致水禽、两栖和爬行动物以及鱼类濒危的主要原因。湿地、湖泊以及沿海滩涂被大量开发成工农业用地后，使依赖于此的动物丧失了栖息地、繁殖地而濒于灭绝。如扬子鳄，在地球上已经生活了上亿年，由于栖息地的丧失，野生种群快要绝迹了，有关部门打算利用人工繁殖的个体实施再引进工程，但苦于无地而不得不坐等扬子鳄野生种群灭绝。
5.4 环境污染
数字计算机
20世纪以来，由于农药、鼠药、化肥、煤炭、石油的广泛使用，产生了大量工业“三废”和有毒物质，严重污染了大气、土壤和水体，野生动物健康受到损害，繁殖力日渐低下，许多江河湖泊已不再适于水生野生动物的生存繁衍。某些生态位较高的野生动物因为食物链的关系也受到了程度不同的株连。
5.5 乱捕滥猎
乱捕滥猎是造成许多物种濒危的直接原因。龟鳖类、蛇类、鹰隼类、藏羚羊、观赏鸟类和蛙类是目前猎捕最为严重的几类动物。
龟鳖肉、蛇肉和田鸡腿的美味、野鸟的动听歌声和艳丽身姿、猎隼活体和藏羚羊绒的国际黑市等，均招徕了上述动物的捕杀之祸，致使其野外资源量锐减，不少已处于濒危或极度濒危状态。
因人类过度放牧和开垦，使草原沙化愈加严重。野山羊、黄羊等草原生物的数量也在锐减。
5.6 自然灾害
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自然灾害也是导致物种濒危的原因之一。比如，1998年长江流域罕见的洪灾，使许多栖息于平原地区或丘陵地区的野生动物蒙受了灭顶之灾。
苹果双系统怎么切换
5.7 protection
特色龙The endangered animal is a rare, irreplaceable, renewable natural resources, in the maintenance of ecological balance, promote economic development, to meet the people's growing material and cultural needs, the development of foreign relations, improve the socialist spiritual civilization plays an important role in.
张卫平5.8, the maintenance of ecological balance
Each species is an important part of ecological system, through the food chain, between species to interdependence, mutual restraint effect. Once a part of the food chain problems, the balance will be the whole ecosystem verely affected. For example, becau of the uncontrolled hunting snake, the snake resource depletion, forest, grassland and farmland in rodents in the local area. Also, due to the large number of the
u of pesticides and chemical fertilizers and hunting for the pet trade in vivo, resulting in a sharp reduction in the number of inctivorous birds, resulting in pine caterpillars, grasshoppers, forests and crops dias and inct pests occurrence. Rodent and pest for agriculture and animal husbandry has caud enormous loss, the cost of ecological imbalance is incalculable.
