BILD Conservation Biology

BILD Conservation Biology - BILD 3 21 May 2008 MID-TERM...

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21 May 2008 Woodruff: conservation biology 1 MID-TERM EXAM in MANDEVILLE AUDITORIUM : A – L in YORK 2722 [HERE]: M – Z EXAM IS CLOSED BOOK. NO CALCULATORS, CELL PHOTO ID Expect many short answer questions. No scantrons. There are ~50 questions and most can be answered with 3-10 words. Help Session: Thursday 2:00 - 4:00 pm in MUIR Biology 1103 No Sections this Friday or next Monday (Memorial Day) No Office Hours this Friday No Lecture Monday STATE OF THE WORLD Forests, wetlands, mangroves all half gone, Grasslands 70% degraded, losing 25B tons topsoil/yr. Productive land desertified Lakes acidified, water contaminated Oceans: polluted, overharvested, rising 1–2 m, Coral reefs 40% degraded Atmosphere warming 2–3 o C Ozone shield depleted Wildlife: sixth great mass extinction 100–1000x background 40 hectares of habitat lost every minute [Half a football field every second] S = CA z NO. OF SPECIES DOUBLES WITH 10X INCREASE IN AREA NOW FUTURE Log HABITAT AREA LOG SP. NO. A 10-FOLD DECREASE IN AREA CUTS SPECIES NUMBER IN HALF. HALF THE LARGER VERTEBRATES THREATENED WITH EXTINCTION. CAUSES OF EXTINCTION/THREAT 2. OVER-EXPLOITATION 3. SPECIES INTRODUCTIONS PREDATORS/PATHOGENS COMPETITORS 4. SECONDARY EFFECTS COMMENSALS POLLINATORS/DISPERSERS PESTICIDES 5. CATASTROPHES 6. CLIMATE CHANGE WHY DO WE SAY THERE IS A BIODIVERSITY CRISIS? 10 million species of which 2/3 live in tropics 40% of tropical forest degraded by 2020 So >700,000 sp. will go extinct in tropical forests and >1 million species worldwide Over 20 years = 15,000 sp./year (guesstimate) Current mammalian rate: 1 every 4 years K-T (dinosaurs) extinction rate of 1 every 10,000 years. Today’s overall extinction rate 1,000x background
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BILD Conservation Biology - BILD 3 21 May 2008 MID-TERM...

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