The first activity of human induced extinction means the annihilation of large mammals IN EUROPEAN Australia, North and South America thousands of years ago at the start of colonialism in the continent. In a very short time, after the human exploration of this land has from 74% to 86% of large animals (body weight of 44 kg) became extinct here that one of the reasons directly as a result of hunting and indirectly by burning, deforestation. The extinction of birds, mammals studied much and recognizable. 99% of the extinction of other species in the world today are only preliminary forecast. However even with the animals and birds, the data on the extinction did not have the exact figures, some species were considered to be extinct has been rediscovered, and some species remain almost exist, it is likely extinct. According to statistics about 85 species of mammals and 113 bird species have become extinct since 1600, respectively 2.1% and 1.3% of mammals and birds. Extinction rate for mammals and birds are approximately 1 species in 10 years at the time from 1600 to 1700, but this rate increased to one species / year in the period from 1850 to 1950. Many species in principle has yet to be extinct but continues to be the object of human hunting and surviving only with a very small amount as rhinos, tigers ... in Vietnam. These species may be deemed to have become extinct in terms of ecology because their numbers are so few, do not play a role in community structure. The risk to freshwater fish and molluscs are also worrying. The plants are also threatened, group gymnosperms and palm are particularly vulnerable group extinction. Extinction worth just a natural process, but 99% of all species became extinct primarily caused by humans. In the history of previously geographically period of biodiversity is relatively stable thanks to balanced off between the evolution of new species and species extinction old. However, human activity has made the extinction rate far exceeds many times the speed of species formation. The loss of species occur as in the current period did not follow any rules and any future consequences are incalculable and can not save well.
đang được dịch, vui lòng đợi..