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Chapter 5 Biodiversity and Conservation Section 1: Biodiversity Section 2: Threats to Biodiversity Click on a lesson name to select. Chapter 5 Biodiversity and Conservation 5.1 Biodiversity What is biodiversity? Biodiversity is the variety of life in an area that is determined by the number of different species in that area. Chapter 5 Biodiversity and Conservation 5.1 Biodiversity The variety of genes or inheritable characteristics that are present in a population comprises its genetic diversity. Genetic diversity increases the chances that some species will survive during changing environmental conditions or during the outbreak of disease. Chapter 5 Biodiversity and Conservation 5.1 Biodiversity The number of different species and the relative abundance of each species in a biological community is called species diversity. Chapter 5 Biodiversity and Conservation 5.1 Biodiversity The variety of ecosystems that are present in the biosphere is called ecosystem diversity. Chapter 5 Biodiversity and Conservation 5.1 Biodiversity The Importance of Biodiversity Most of the world’s food crops come from just a few species. Teosinte plant Domestic corn plant Chapter 5 Biodiversity and Conservation 5.1 Biodiversity A healthy biosphere provides many services to humans and other organisms that live on Earth. Green plants provide oxygen to the atmosphere and remove carbon dioxide (via photosynthesis). Natural processes provide drinking water that is safe for human use. Chapter 5 Biodiversity and Conservation Vocabulary Section 1 extinction biodiversity genetic diversity species diversity ecosystem diversity Chapter 5 Biodiversity and Conservation 5.1 Formative Questions Which has indirect economic value? A. ecosystems that decompose wastes B. organisms that provide food and shelter C. plants that contain medicinal substances D. species that have desirable genetic traits 1. 2. 3. 4. A B C D Chapter 5 Biodiversity and Conservation 5.1 Formative Questions It is likely that some of the world’s unidentified species will have economic value. A. true B. false 1. 2. 0% A 0% B A B Chapter 5 Biodiversity and Conservation 5.1 Formative Questions When does the aesthetic value of an ecosystem become most apparent? A. when scientists begin to study the ecosystem B. when the ecosystem has been destroyed C. when the ecosystem is given economic value 0% A 0% B 1. 2. 3. 0% C A B C Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Extinction Rates The gradual process of species becoming extinct is known as background extinction. Mass extinction is an event in which a large percentage of all living species become extinct in a relatively short period of time. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Factors that Threaten Biodiversity The current high rate of extinction is due to the activities of a single species—Homo sapiens. Humans are changing conditions on Earth faster than new traits can evolve to cope with the new conditions. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Overexploitation Overexploitation, or excessive use, of species that have economic value is a factor increasing the current rate of extinction. Bison Passenger pigeons Ocelot Rhinoceros Rhinoceros Ocelot Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Habitat Loss If a habitat is destroyed or disrupted, the native species might have to relocate or they will die. Destruction of Habitat The destruction of habitat, such as the clearing of tropical rain forests, has a direct impact on global biodiversity. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Disruption of Habitat The declining population of one species can affect an entire ecosystem. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Fragmentation of Habitat The separation of an ecosystem into small pieces of land is called habitat fragmentation. The smaller the parcel of land, the fewer species it can support. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Pollution Pollution and atmospheric changes threaten biodiversity and global stability. Biological magnification is the increasing concentration of toxic substances in organisms as trophic levels increase in a food chain or food web. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Acid Precipitation Sulfur and nitrogen compounds react with water and other substances in the air to form sulfuric acid and nitric acid. Acid precipitation removes calcium, potassium, and other nutrients from the soil, depriving plants of these nutrients. Assessing Water Quality Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Eutrophication Eutrophication occurs when substances rich in nitrogen and phosphorus flow into waterways, causing extensive algae growth. The algae use up the oxygen supply during their rapid growth and after their deaths during the decaying process. Other organisms in the water suffocate. Chapter 5 Biodiversity and Conservation 5.2 Threats to Biodiversity Introduced Species Nonnative species that are either intentionally or unintentionally transported to a new habitat are known as introduced species. Introduced species often reproduce in large numbers because of a lack of predators, and become invasive species in their new habitat. Chapter 5 Biodiversity and Conservation Vocabulary Section 2 background extinction mass extinction edge effect biological magnification natural resource eutrophication overexploitation introduced species habitat fragmentation Chapter 5 Biodiversity and Conservation 5.2 Formative Questions Which describes the current rate of species disappearance? A. background extinction B. mass extinction C. natural extinction D. progressive extinction 1. 2. 3. 4. 0% A 0% 0% B C A B C D 0% D Chapter 5 Biodiversity and Conservation 5.2 Formative Questions Where are most extinctions likely to occur in the near future? A. deserts B. grasslands C. tropical forests D. temperate forests 1. 2. 3. 4. 0% A 0% 0% B C A B C D 0% D Chapter 5 Biodiversity and Conservation 5.2 Formative Questions What is the primary factor that has endangered the North American bison and the white rhinoceros? A. habitat loss B. eutrophication C. overexploitation D. nonnative predators 1. 2. 3. 4. 0% A 0% 0% B C A B C D 0% D Chapter 5 Biodiversity and Conservation 5.2 Formative Questions What is the number one cause of species extinction today? A. habitat loss B. human predators C. transported diseases D. background extermination 0% A 1. 2. 3. 4. 0% 0% B C A B C D 0% D