BIO 182 FINAL EXAM ASU QUESTIONS AND ANSWERS

What is mass extinction? - ans --A decline in biodiversity greater than the background extinction rate What What is extinction? - ans --The loss or death of a species is background extinction? - ans --Background extinction occurs when certain populations are reduced to zero because of normal environment change, emerging disease, predation pressure, or competition with another species How are mass extinctions detected and how many have been detected? - ans --They're detected geologically, and there have been 5 detected What organisms became extinct during the Pleistocene and Cretaceous and what are possible causes for these extinctions? - ans --Pleistocene: Wooly Mammoth, Giant Short-Faced Bear, Dire Wolf, Giant Beaver, Shasta Ground Sloth, American Lion -Could be extinct because of climate change (warmer temps), human overkill (predation), pathogens Cretaceous: Dinosaurs -Could be extinct because of asteroid (impact hypothesis) What is the evidence to support that there will be a 6th mass extinction? - ans --Modern rates of extinction are 100 to 1000 time greater than the background rate What is overexploitation? - ans ---Any unsustainable removal of wildlife from the natural environment by use of humans -Harvesting of organisms at rates exceeding the species ability to replace itself -The dominant threat to marine species -Overhunting What is habitat destruction? - ans --Terrestrial Ecosystems: Conversion agriculture, logging, development and urbanization Aquatic Ecosystems: Draining and developing wetlands, damming rivers Species area curve - As the land area decreases, the number of species decreases What is habitat fragmentation? - ans ---The breakup of large pieces of natural habitat into small, isolated pieces -Can reduce a habitat to where it's too small to support a species -Reduces the ability of individuals to disperse from one habitat to another (could be more vulnerable to catastrophes) -Creates a large amount of "edge" habitat (Edge effects light levels, pollution, poachers, and competition) -The species most impacted by this are those that require large territories to find food