Biota by Conservation Status - Extinction, Iucn Red List, Endangered Species, Conservation Status, Conservation Reliant Species (Paperback)

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 23. Chapters: Extinction, IUCN Red List, Endangered species, Conservation status, Conservation reliant species, Regional Red List, NatureServe, NatureServe conservation status, Threatened species, Least Concern, Extinct in the Wild, Critically Endangered, Near Threatened, Rare species, Data Deficient, Vulnerable species, Not Evaluated. Excerpt: In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "re-appears" (typically in the fossil record) after a period of apparent absence. Through evolution, new species arise through the process of speciation-where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche-and species become extinct when they are no longer able to survive in changing conditions or against superior competition. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive virtually unchanged for hundreds of millions of years. Most extinctions have occurred naturally, without human intervention: it is estimated that 99.9% of all species that have ever existed are now extinct. Mass extinctions are relatively rare events; however, isolated extinctions are quite common. Only recently have extinctions been recorded and scientists have become alarmed at the high rates of recent extinctions. Most species that become extinct are neve...