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CHAPTER 5 BIODIVERSITY AND CONSERVATION • BIODIVERSITY • MAIN IDEA: Biodiversity maintains a healthy biosphere and provides direct and indirect value to humans. • WHAT IS BIODIVERSITY? • Biodiversity is the variety of life in an area that is determined by the number of different species in that area. – Biodiversity increases the stability of an ecosystem and contributes to the health of the biosphere. • There are 3 types of biodiversity: – Genetic diversity – Species diversity – Ecosystem diversity • Extinction is when the last member of the species dies. • GENETIC DIVERSITY • Genetic diversity is the variety of genes or inheritable characteristics that are present in a population. • Genetic diversity within interbreeding populations increases the chances that some individuals will survive during changing environmental conditions or during an outbreak of disease. • QUESTION: In the picture below, what are some of the different heritable characteristics that you see and how could some of those differences be helpful? • SPECIES DIVERSITY: • Species diversity is the number of different species and the relative abundance of each species in the a biological community. • Species diversity is not evenly distributed over the biosphere. –Species diversity increases as you move further away from the poles & closer to the equator. • QUESTION: In the picture below how many different species are present? • ECOSYSTEM DIVERSITY • Ecosystem diversity is the variety of ecosystems that are present in the biosphere. –Ecosystems are made up of interacting populations and the abiotic factors that support them. • THE IMPORTANCE OF BIODIVERSITY • DIRECT ECONOMIC VALUE • Direct economic value for maintaining biodiversity include: – Food • Need diverse genetic pools to help keep the food source safe from the effects of devastating diseases or insects. – Done through genetic engineering when scientists transfer genes from one organism to another – Clothing – Energy – Medicine • Mostly produced from plants or other organisms. – EX: Madagascar periwinkle flower yields an extract to treat some forms of leukemia increasing survival rate from 20% to more than 95%. – Shelter • INDIRECT ECONOMIC VALUE • Healthy biosphere provides many services to humans and other organisms. – Plants provide oxygen & remove carbon dioxide – Safe water for drinking – Cycling nutrients – Provide protection against floods and droughts – Preserve fertile soils – Detoxify and decompose wastes and regulate local climates • SECTION 2 – THREATS TO BIODIVERSITY • MAIN IDEA: Some human activities reduce biodiversity in ecosystems, and current evidence suggests that reduced biodiversity might have serious long term effects on the biosphere. • QUESTION: What happens when a new building project starts in an area that was previously undeveloped? • EXTINCTION RATES • Background extinction is the gradual process of species becoming extinct. – Occurs when stable ecosystems are changed by: other organisms, climate changes, or natural disasters – Predicted that 1/3 to 2/3 of all plant & animal species, mostly near the equator, will become extinct during 2nd half of this century. • Mass extinction is events where a large percentage of all living species become extinct in a relatively short period of time. – Last one was 65 million years ago for dinosaurs – Large percentage of extinctions take place on islands • Small populations – Affected by newly introduced predators, can’t escape island, nonnative species, and disease • FACTORS THAT THREATEN BIODIVERSITY • Natural resources are all materials and organisms found in the biosphere, including minerals, fossil fuels, nuclear fuels, plants, animals, soil, clean water, clear air, and solar energy. • OVEREXPLOITATION • Overexploitation is the over use of species that have economic value, which increases their current rate of extinction –EX: N. American bison • Previously overexploitation was the primary cause of species extinction, NOW it is the destruction of habitat. • HABITAT LOSS • Habitat loss is the result of: – Destruction of habitat • Tropical rain forest contains more than half of all species on Earth • Clearing the tropical rain forest for agricultural crops or grazing land reduces habitat & species – Disruption of habitat • Fig. 11, Pg. 125 shows how the # of harbor seals & sea lions declined, setting off the chain reaction of what the whales ate (now more sea otters), which normally ate the sea urchins, now their population is up & the kelp is way down. • FRAGMENTATION OF HABITAT • Habitat fragmentation is the separation of an ecosystem into small pieces of land – Populations will stay in the small parcels because they are either unable or unwilling to cross the human-made barriers. • Problems: – Smaller the land means fewer species that are supported – Reduces opportunities for individuals in one area to reproduce with individuals from another area • Genetic diversity decreases over time causing populations to become less resistant to disease, or able to respond to changing environmental conditions. • Creates edge effects, which is when boundaries of the ecosystem have different abiotic factors like temperature, wind & humidity than the rest of ecosystem. • POLLUTION • Pollution changes the composition of air, soil and water. – Pesticides • DDT – enters food chain & remains in tissues of organisms – Industrial chemical • PCB – enters food chain & remains in tissues of organisms • Biological magnification is the increasing concentration of toxic substances in organisms as trophic levels increase in a food chain or web. – Higher level carnivores are most affected • EX: Bald eagle – caused the thinning of the egg shells so no new eagles were being born • POLLUTION – CONTINUED • Acid precipitation is created when fossil fuels are burned releasing sulfur dioxide and nitrogen oxides into the atmosphere. • Reaction with water & other substances in the air create sulfuric acid & nitric acid – Will remove calcium, potassium and other nutrients from soil – Will damage plant tissues & slows their growth or kills • Eutrophication occurs when fertilizers, animal waste, sewage, or other substances rich in nitrogen and phosphorus flow into water, crease extensive algae growth – Algae will use up the oxygen supply causing other organisms to suffocate • INTRODUCED SPECIES • Introduced species are nonnative species that are either intentionally or unintentionally transported to a new habitat. – Reproduce rapidly because there are no predators, parasites and competition to keep them controlled in the new environment. • Now considered an invasive species –EX: Fire ants – Invasive species believe to be responsible for 40% of the extinctions since 1750 • SECTION 3 – CONSERVING BIODIVERSITY • MAIN IDEA – People are using many approaches to slow the rate of extinctions and to preserve biodiversity. • NATURAL RESOURCES • Natural resources are used to meet our basic needs – Industrialized countries use more natural resources per person than developing countries • 2 types of natural resources: – Renewable – Nonrenewable • RENEWABLE RESOURCES • Renewable resources are any resources that is replaced by natural processes faster than they are consumed – EX: solar energy, agriculture, plants, animals, clean water and air • These resources are NOT unlimited. • Any resource can be depleted. If depleted, natural resource would change from renewable to nonrenewable. – EX: Removing a few trees = renewable resource Removing a whole forest = nonrenewable resource • NONRENEWABLE RESOURCE • Nonrenewable resources are found on Earth in limited amounts or that are replaced by natural processes over extremely long period of time. – EX: fossil fuels and minerals deposits – Species are considered nonrenewable when extinction occurs because now it is lost forever • SUSTAINABLE USE • Sustainable use happens when we use the resources at a rate where they can be replaced or recycled them while preserving the long-term environmental health of the biosphere. • Conservation of resources happens when we reduce the amount of resources that are consumed, recycled resources (aluminum cans) occurs, and we preserve and use ecosystems in a responsible manner. • PROTECTING BIODIVERSITY • US helps protect biodiversity by establishing national parks & nature reserves – EX: 1st national park – Yellowstone in 1872 • Currently 7% of the world’s land is set aside as a natural reserve, some of them megareserves • To be classified as a biodiversity hot spot the region must have lost at least 70% of the original habitat and there must be at least 1500 species of plants that are endemic (species found only in specific geographic areas with critical levels of habitat loss) – Hot spots shown on pg. 132 • To improve the survival of biodiversity conservationists are developing corridors or passageways to connect small parcels of land allowing the organisms to move from one area to another safely. • RESTORING ECOSYSTEMS • Biodiversity is destroyed in an area when it no longer provides the abiotic and biotic factors needed for a healthy ecosystem. –EX: clearing tropical rain forest for farming & then is unproductive after a few years. • Recovery from human or natural disasters can happen, but depends on size of the area affected and the type of disturbance. –Larger the area = longer time