BIOL 101 Lecture 26: The 6th Mass Extinction: Animals in Peril
Document Summary
26: the 6th mass extinction: animals in peril. Total number is not known with any certainty. Tropical rainforests: 7% of earth"s surface, 50% of all species. Coral reefs: 0. 2% of ocean"s surface, 30% of ocean fish species. Extinction: a natural process: some extinctions are natural, part of evolution, five mass extinctions, extinctions rates: past and present. In the past 600 my (from the fossil record) Wildlife populations have declined 58% since 1970. Prediction: 50% of all species will be extinct by 2100. Present extinction rate: 1 species per hour. The 6th mass extinction is driven by human activities: extinction is forever: The product of millions of years of evolution. Species are going extinct before they are discovered, named and studied: causes of modern extinction: The single most important cause of extinction. Organisms are adapted to their habitats by evolution. Natural habitats are being destroyed around the globe. Most future extinctions will occur in tropical rainforests.
