1 Ch11: Biodiversity and Conservation Biology •Earth’s biodiversity is enormous •We are facing the 6th major extinction event on Earth •Primary causes of biodiversity loss: HIPPO •Biodiversity is beneficial •Conservation biology is a science that seeks to protect biodiversity I. Multiple levels of biodiversity A. Humans are reducing Earth’s biodiversity B. Biodiversity – sum total of all organisms in an area: •species diversity •genetic diversity •ecosystem diversity C. Species diversity = number or variety of species in the world or in a particular region 1. richness = number of spp. 2. evenness or relative abundance = extent to which numbers of individ. of diff. spp. are equal or skewed –speciation generates new spp. –extinction reduces spp. richness. D. Taxonomy of species 1. taxonomists = scientists who classify spp. (discover, _______________________) a. physical appearance & genetics determines a sp. b. spp. are classified (grouped) into several categories genera = related species are grouped together 2. every sp. has a 2-part scientific name: genus + specific epithet = 3. subspecies = popns of spp. in diff. areas that differ slightly from each other –Siberian tiger = Panthera tigris altaica . E. Genetic diversity 1. = differences in DNA among individ. within spp. & among popns ; raw material for adaptation to local conditions 2. popns with greater genetic diversity can survive --- cope with environ. change 3. popns with low genetic diversity are vulnerable --- to environ. change •disease •inbreeding depression = genetically similar parents mate & produce inferior offspring. ENV 2100 Environmental Science, Dr. L. Kelly2 II. Some taxa (groups) have more spp. than others A. Insects predominate over all other life-forms B. Groups accumulate spp. via 1. speciation 2. low rates of extinction. III. Only a small proportion of Earth’s biodiversity is known: 2 million of 10-100 million spp. A. Difficult to identify spp. 1. remote spots on Earth remain unexplored 2. small organisms are easily overlooked 3. many spp. look identical until thoroughly examined B. Entomologist Terry Erwin found IV. Biodiversity is unevenly distributed on Earth A. Latitudinal gradient = spp. richness for many taxa increases towards ___________ Climate stability, high plant productivity, & no glaciation B. More heterogeneous environments support more spp. C. Islands & mountaintops support many endemic spp. V. Extinction is forever A. Background rate of extinction = natural extinctions for a variety of reasons 1. 1 sp. out of 1,000 mammal & marine spp. would go extinct every 1,000 to 10,000 years 2. 1 extinction per 1 to 10 million spp. for _________________________ spp. annually B. 5 major extinction spasms in the past. C. We are in the midst of a 6th extinction spasm -- _________________________________ spp. are being lost, popns are being lost, & ecosytems are being destroyed. D. IUCN Red List 1. an updated list of spp. facing high risks of extinctions •23% of mammal species •12% of bird species •31 - 86% of all other species 2. since 1970, 58 fish spp., 9 bird spp., & 1 mammal sp. have gone extinct in the world 3. in the U.S., in the last 500 years, 236 animal & 17 plant spp. are confirmed extinct. VI. Humans are causing the 6th extinction spasm A. Reasons are multifaceted; factors may interact synergistically 1. HIPPO 2. Global climate change is now the fifth cause. B. Habitat loss/alteration3 1. fragmentation occurs when habitats are 2. agriculture, grazing, construction, urbanization, boating, dam building C. Invasive exotic spp. 1. invaders have no natural predators, competitors, or parasites in new home accidental: deliberate: 2. island spp. are especially vulnerable 3. cost billions of dollars in economic damage D. Pollution = most subtle, universal form of degradation 1. examples: pesticides, herbicides, fertilizers, sewage, oil, fossil fuel emissions, sediment!!! 2. the damage can be severe E. Overharvesting 1. most vulnerable spp. are large, few in number, long-lived, have few young --- since 1989, Siberian tiger --- poaching increased in 1990s because of 2. many other spp. affected: Atlantic gray whale, sharks, gorillas, Atlantic bluefin tuna F. Global climate change 1. greenhouse gas emissions warms temps. --modifies global weather patterns, increases the frequency of extreme weather events --increases stress on popns, forces organisms to shift their geographic ranges 2. most animals & plants will not be able to cope. VII. Value of biodiversity •Provides food, shelter, fuel, fiber, medicine •Purifies air & water; detoxifies •Stabilizes climate, moderates •Generates soil fertility; cycles •Pollinates plants, controls •Maintains genetic resources & •Provides cultural, aesthetic, •Allows us to adapt to change. VIII. Conservation biology A. Science that seeks to conserve world’s biodiversity B. 3 major goals: 1. inventory world’s biodiversity 2. identify the causes of biodiversity loss 3. develop practical solutions C. Solutions?4 1. captive breeding 2. protecting hotspots of biodiversity 3. reintroducing popns into the wild 4. laws (ESA of 1973). 5. Convention on International Trade in Endangered Species of Wild Fauna & Flora (CITES) bans transport of body parts of endangered spp. 6. community based conservation 7. debt-for-nature swaps pays off some portion of a country’s international debt 8.