Diferencia entre revisiones de «Extinción masiva»

== Prospectiva ==

 

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Most biologists believe that humans are currently causing another extinction event, the [[Holocene extinction event]]. E.O. Wilson of Harvard University, in his book ''The Future of Life'' ( ISBN 0-679-76811-4 ) estimates that at current rates of human destruction of the biosphere one-half of all species of life will be extinct in 100 years. Other scientists however view this estimate as exagerated. For example it can be noted that only 9 species of [[mammal]]s have been gone extinct in [[North America]] since [[Columbus]]' discovery. Of these, 7 are small rodents [http://web4.si.edu/mna/search_status.cfm]. Compared to a background global extinction rate of roughly 2 mammal species per millenia, this is quite high, but probably not enough by itself to make dire predictions about. The most species rich environment on Earth are the rainforest, and their destruction could lead to major losses. However, though 12,5% of the [[amazon rainforest]] have been cleared, studies suggest that only a far smaller fraction of its diversity has been destroyed. Because animals and plants can frequently be found in many distant locales within the rainforest, it may be possible to preserve most of the rainforest's diversity in an área 1/3 to 1/2 its original size. Hence conservation efforts may be able to save a majority of these species.