It shows that many species are extinct or on the verge of extinction due to the destruction of plant living environment, climate change, invasion of exotic species, overuse and pollution of natural resources. By the end of 2 1 century, it is estimated that12 plants will be threatened by global warming, and more than 2/3 vascular plants may disappear completely. Experts warn that human beings should be aware of this situation as soon as possible, and take protective measures to protect species diversity, reduce the discharge of harmful substances and avoid natural disasters when facing the possible sixth extinction. 20 10 is the international year of biodiversity designated by the United Nations. On July 18, the Capital Science Lecture Hall invited Mark Ping, director of the Institute of Botany, Chinese Academy of Sciences, and secretary-general of the China Committee of the International Biodiversity Program, to think that the earth may be entering the sixth extinction period due to the influence of human activities. Even some foreign scholars think that the extinction rate of contemporary biological species is faster than that of natural extinction 1000 times. IUCN) In the Red List of Species IUCN)2004, 65,438+05,589 species were threatened with extinction, of which 65,438+02% were birds, 23% were mammals, 32% were amphibians, 25% were gymnosperms, 52% were cycads and 42% were turtles.