GEOG 1220 Chapter Notes - Chapter 2: Upper Paleolithic, Open-Pit Mining, International Union For Conservation Of Nature
16 Jan 2017
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Document Summary
Biodiversity at all levels is currently being lost as a result of human impacts. We could see the extinction of more than half of all species. Today"s mass extinction is different from past ones in 3 ways : humans are causing it, humans will suffer as a result of it, it may be happening more rapidly than the past (cid:498)big 5(cid:499) extinctions. A wave of extinctions usually follows human arrival on an island or continent: when polynesians reached hawaii half the birds went extinct, north america lost 33 genera of large mammals when people arrived on the continent. Current global extinction rate is 100-1000 times greater. 75: actual numbers of threatened species are likely greater than the known numbers. In 2011 barnosky concluded that the extinctions in the last 500 years do not yet constitute a mass extinction: but rates today are much higher than in similar periods of the last big.
