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16.1 Human Population Growth And Natural Resources KEY CONCEPT As the human population grows, the demand for Earth’s resources increases. 16.1 Human Population Growth And Natural Resources Objectives • Summarize the current state and effects of human population growth • Explain the importance of effective resource management 16.1 Human Population Growth And Natural Resources Earth’s human population continues to grow. • Earth’s human carrying capacity is unknown. 16.1 Human Population Growth And Natural Resources • Technology has helped to increase Earth’s carrying capacity. – gas-powered farm equipment – medical advancements 16.1 Human Population Growth And Natural Resources The growing human population exerts pressure on Earth’s natural resources. • Nonrenewable resources are used faster than they form. – coal – oil 16.1 Human Population Growth And Natural Resources • Renewable resources cannot be used up or can replenish themselves over time. – wind – water – sunlight • Growing use of nonrenewable resources may lead to a crisis. • Resources must be properly managed. 16.1 Human Population Growth And Natural Resources • An ecological footprint is the amount of land needed to support a person. • The land must produce and maintain enough – food and water – shelter – energy – waste 16.1 Human Population Growth And Natural Resources • Several factors affect the size of the ecological footprint. – amount and efficiency of resource use – amount and toxicity of waste produced 16.1 Human Population Growth And Natural Resources Give 3 examples of how technology has influenced human population growth • Advances in medicine have reduced infant mortality and prolonged life spans • Industrial technologies have made transportation and agriculture more productive and easier, allowing for easier food production and distribution • Plumbing and sewage treatment have improved sanitation, reducing incidence of water born illness 16.1 Human Population Growth And Natural Resources What is the difference between renewable and nonrenewable resources Renewable Resources Nonrenewable Resources • Are difficult to replenish in • Can be replenished by a time span meaningful to Earths natural processes humans 16.1 Human Population Growth And Natural Resources What factors can limit the growth of the human population? • • • • • Disease Drought Overexploitation of limited resources Crop pests War 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources KEY CONCEPT Fossil fuel emissions affect the biosphere. 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Objective • Describe the sources, types, and effects of pollution • Explain how air pollution contributes to acid rain 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Pollutants accumulate in the air. • Pollution is any undesirable factor added to the air, water, or soil. • Smog is one type of air pollution. – sunlight interacts with pollutants in the air – pollutants produced by fossil fuel emissions – made of particulates and ground-level ozone 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources • Smog can be harmful to human health. • Acid rain is caused by fossil fuel emissions. – produced when pollutants in the water cycle cause rain pH to drop – can lower the pH of a lake or stream – can harm trees 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Air pollution is changing Earth’s biosphere. • The levels of atmospheric carbon dioxide rise and fall over time. • High levels of carbon dioxide are typical of Earth’s warmer periods. 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources • The greenhouse effect slows the release of energy from Earth’s atmosphere. – sunlight penetrates Earth’s atmosphere – energy is absorbed and reradiated as heat – greenhouse gases absorb longer wavelengths – Greenhouse carbon dioxide (CO ) gas molecules methane (CH ) water (H O) rerelease infrared radiation 2 4 2 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources • Global warming refers to the trend of increasing global temperatures. North Pole 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Name and describe 2 ways in which pollution affects ecosystems • Pollution can result in smog and acid rain • Smog is caused by the interaction of sunlight with pollutants produced by fossil fuel emissions • Acid rain results from the mixture of these emissions with water 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources How does the greenhouse effect keep Earth warm? • Infrared energy Radiating from Earths surface is absorbed by greenhouse molecules such as water, carbon dioxide, and methane. • This energy, also called heat, is then released and absorbed by other molecules of Earths surface or the atmosphere. 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Explain how a build-up of CO2 in the atmosphere could increase Earths global temperature. • With more greenhouse molecules in the atmosphere, less heat would be allowed to escape, causing Earth to become warmer. 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Greenhouse gasses are found close to earths surface and high above in the atmosphere. Name 2 important functions of greenhouse gasses at Earths surface. • At Earths surface water vapor condenses to form precipitation which is part of the hydrologic cycle • Carbon dioxide is a necessary reactant for photosynthesis 16.2 AirGrowth Quality And Natural 16.1 Human Population Resources Ocean producers such as phytoplankton are an important part of food webs, but they require a specific temperature range to survive. How might increased water temperature affect these ocean food webs? • If increased water temperatures kill the phytoplankton, the lowest trophic levels will be gone and the food webs will probably collapse 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources KEY CONCEPT Pollution of Earth’s freshwater supply threatens habitat and health. 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources Objectives • Describe how water pollution affects ecosystems • Explain how biomagnification causes accumulation of toxins in food chains 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources Biomagnification causes accumulation of toxins in the food chain. • Pollutants can move up the food chain. – predators eat contaminated prey – pollution accumulates at each stage of the food chain • Top consumers, including humans, are most affected. 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources How do PCBs affect bird populations through biomagnification? • PCBs travel up through trophic structure of an ecosystem and accumulate in large amounts in the eggs of large birds. • PCBs can negatively impact growth and development within the egg, causing – Genetic mutations – Deformities – Death • The population of birds may crash as a result 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources Would a buffalo or a mountain lion be more affected by biomagnification? Why? • A mountain lion would be more affected because it is higher on the food chain and would ingest more contaminants from its food supply 16.3 Water QualityAnd Natural 16.1 Human Population Growth Resources How does the biomagnification pyramid compare with the energy pyramid? • They are opposite • Energy decreases as you move up the food chain, but pollution increases 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources KEY CONCEPT The impact of a growing human population threatens biodiversity. 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources Objectives • Assess the consequences of loss of biodiversity • Explain how loss of habitat and introduced species affect ecosystems and biodiversity 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources Preserving biodiversity is important to the future of the biosphere. • The loss of biodiversity has long-term effects. – loss of medical and technological advances – extinction of species – loss of ecosystem stability 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources Loss of habitat eliminates species. • Habitat fragmentation prevents an organism from accessing its entire home range. – occurs when a barrier forms within the habitat – often caused by human development 16.1 Human Population Growth And Natural Resources • Habitat corridors are a solution to the problem. – corridors can be road overpasses or underpasses – allow species to move between different areas of habitat 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources Introduced species can disrupt stable relationships in an ecosystem. • An introduced species is one that is brought to an ecosystem by humans. – accidental – purposeful • Invasive species can have an environmental and economic impact. 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources Invasive species often push out native species. Burmese python (Florida Everglades) & mice (Australia) kudzu (southeastern United States) 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources List reasons that biodiversity is important to humans • A loss of diversity could mean a loss of food, medicine, and economic activity 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources How does habitat fragmentation affect migrating bird populations? • Birds need large areas of land or water on which to rest and feed during long migrations. • If these habitats aren’t available they may not be able to complete a migration 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources What types of damage can introduced species cause? • Introduced species can disrupt ecosystems, threaten human health, and physically dominate or overtake waterways and human-made structures 16.4 Threats to Growth biodiversityAnd Natural 16.1 Human Population Resources How could continued fragmentation reduce biodiversity? • If species are cut off from habitats they need for survival or reproduction, they could become extinct, thereby reducing biodiversity 16.1 Human Population Growth And Natural Resources Due Wednesday: In your Study guide Workbook Chapters 13 & 14 Chapters 15 & 16 Pages Numbers Pages Numbers 133 1-5 155-156 All 134 10 157 1-4 135 All 158 All 137-144 All 161 5-6 145-146 1-6 162 all 147 1-5 148 7-10 150 6-13 151 1-4 152 6-9 153-154 1&4