Outline of Last LectureOutline of Current LectureBiodiversity and ConservationMajor Extinction EventsReasons for the Loss of SpeciesOverhuntingExotic SpeciesHabitat DestructionEdge EffectsWhy Preserve Biodiversity?ReviewGradeBuddy Bio 150 1st EditionLecture 23 Outline of Last Lecture 1. Ecosystemsa. Net Primary Productivityb. Biogeochemical Cyclei. Global Carbon Cycleii. The Greenhouse Effectiii. Global Warming1. Effects on Animals2. Main Current ProblemsOutline of Current Lecture 1. Biodiversity and Conservationa. Major Extinction Eventsb. Reasons for Loss of Speciesi. Overhuntingii. Exotic Speciesiii. Habitat Destruction1. Edge Effectc. Why Preserve Biodiversity?Key TermsRestoration Ecology – restoring damaged ecosystemsEdge Effect - the changes in population or community structures that occur at the boundary of two habitatsBiodiversity and ConservationMajor Extinction EventsCurrent Extinction rates are now between 10 and 1000 times the normal rate found in nature.Most recently – the Po’ouli of Hawaii- Discovered in 1973 on Maui- 90% decline over next 10 years- 1997- only three known individuals- 26 Nov 2004- last known individual died in captivityReasons for the Loss of SpeciesCauses of animal extinctions since 1600- Habitat Destruction 36%- Species Introductions 29%- Hunting 23%- Other 2%OverhuntingJohn James Audubon (1813): “the air was literally filled with pigeons; the light of noon-day was obscured as by an eclipse…” the birds were still passing overhead when he reached Louisville 55 miles away, and “continued to do so for three days in succession.”Passenger Pigeon- Largest recorded nesting flock in Wisconsin in 1871 - 136 million pigeons.- 75 miles long and 10 miles wideo 1876 – 50,000 birds killed/day for 5 months (>5 million)o 1896- Last flock of 250,000 killed in Petosky, MIo 1899 – last one shot in WI (Babcock)Exotic SpeciesExamples- Nile percho Introduced to Lake Victoria in 1960’so 200 of 300 species of native cichlids went extinct- Hawaiian Tree Snailso 600 of 1,061 species of snails went extinctExtinctions have occurred primarily on islands- 20% of all birds went extinct during 500 - 1600Habitat DestructionMajor cause of extinction- Tropical Deforestation: 16-20 million ha/year (size of Missouri)o Contributes 20% of greenhouse gases/year- Brazil reducing deforestation by 70%: 7300 to 1900 sq. miles/yr o but more deforestation in other countriesEdge Effects1. Reduced quality of habitata. Increased penetration of sunlightb. More exposure to wind => drierc. Greater temperature fluctuationsd. Greater access to interior by predators and parasites2. Reduced productivityWhy Preserve Biodiversity?- Food & medicineo 57% of most common prescription drugs in US have an active ingredient from natural compounds- Ecotourism, genetic variation for agriculture, and aesthetics.- Increased species diversity improves community functiono Increased productivity which… used more N prevented other species from invading reduced severity of fungal diseaseThe 25 hotspots contain 44% of all plant species and 35% of all terrestrial vertebrates in only 1.4% of the planet's land areaConcentrations of imperiled species occur in California, Hawaii, the Southern Appalachians, and Florida.Restoration Ecology – restoring damaged ecosystemsReview- Main cause of extinction is habitat destruction, followed by overhunting and exotic species- Extinctions have occurred primarily on islands- Habitat fragmentation creates more edge habitat, which have reduced habitat quality (temperature fluctuations, more wind and sunlight, parasitism) and productivity (e.g., increased edge in midwest causing decline in bird populations)- Reasons to preserve biodiversity: Food, medicine, ecotourism, genetic variation for agriculture, aesthetics, and ecosystem