Bio 3400 1nd Edition Lecture 33 Outline of Last Lecture I Human impacts on ecology II Exam 6 review Outline of Current Lecture I Species extinction II Problems with small population size III Biodiversity IV Types of human impacts on species V Conservation Current Lecture I Human Impacts on Ecology II Have any species actually gone extinct because of humans a Yes b Large mammal populations declined after humans came i Thylacine Tasmanian wolf 1 Northern white rhino 2 Poaching threatens all rhino species 7 left ii Zestos skipper butterfly 1 Range southern Florida 2 6 years of surveys found none in the wild 3 Habitat loss and fragmentation c We don t know how many species there are i Estimates range from 2 30 million 1 9 have been named d We often don t know when extinction happens i One criteria not observed in the wild for 50 years ii Only 2 7 of the 1 9 species have been assessed for extinction by the IUCN iii Sampling biases many species are not sampled e Is the modern rate of extinction greater than the natural background extinction rate f Will a 6th mass extinction occur III Small population size problems a If most species haven t gone extinct and instead have just decreased in size what is the problem i Small populations are more affected by random events These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute IV V VI VII ii What happened to genetic variance in small populations 1 It decreases iii What happens to evolutionary potential in small population Biodiversity a Economic value i Medical applications 40 of all drugs ii Wetlands and wastewater treatment iii Pollination of ag crops iv Ecotourism b Ethical value i All species have inherent value c Where should conservation efforts be directed i The species at highest risk rhinos ii Entire ecosystems iii At root causes pollution habitat fragmentation climate change iv Always try to restore previous state Or develop new solution v Could conservation efforts backfire Types of Human Impacts on Species a Overexploitation i Hunting fishing harvesting bycatches collectors b Habitat destruction i Habitat loss habitat fragmentation interstates ii Pollution c Introduced species i Species interactions ii Case study Zebra Mussels 1 Positive effects a Filter feeders increased water clarity b Increased some populations of smallmouth bass and yellow perch 2 Negative effects a Outcompete many native species b Physically attach to other species c Linked to avian botulism d Economic impacts block pipes water intakes other infrastructure d Climate change How much needs to be conserved a Large fragments are needed to conserve entire communities b Edge effects can have large impacts on species c Should we focus on all species or just functional groups The Role of Captive Populations a Basic research b Genetic reservoirs c Final refuge
View Full Document
Unlocking...