BILD 3 Lecture Notes - Lecture 18: Bild, Ernst Haeckel, Developmental Biology
30 May 2016
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Document Summary
Background extinction: extinctions that occur at a normal rate. Mass extinction: high percentage of species go extinct within a short period of time due to some large event. Extinction rates are currently 100 - 1000x above background levels. That is higher than the rates that caused the big five previous mass extinctions. Current extinction rates are sever enough to carry extinction magnitudes to the. Big five benchmark in as little as 300 years. The 6th mass extinction is going on now, caused by a single species. 2,000 pacfic bird species extinct in past 2,000 ears. >15% of all bird species have been lost so far. Galapagos islands had almost no people until 1800. Within the past 6,000 years there were 3 extinctions, but since the past. Extinctions are now mostly due to habitat loss (expanding human populations) Habitat loss is caused by more people, consuming more things.
