MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH CHAPTER 1 Environmental Problems, Their Causes, and Sustainability Environmental Science Is a Study of Connections in Nature • Environment: Everything around us • Sustainability: the capacity of the earth’s natural systems and human cultural systems to survive, flourish, and adapt into the very long-term future • Environmental science: interdisciplinary science connecting information and ideas from • Natural sciences: ecology, biology, geology, chemistry… • Social sciences: geography, politics, economics • Humanities: ethics, philosophy Nature’s Survival Strategies Follow Three Principles of Sustainability 1. Reliance on solar energy • The sun provides warmth and fuels photosynthesis 2. Biodiversity • Astounding variety and adaptability of natural systems and species 3. Chemical cycling • • Circulation of chemicals from the environment to organisms and then back to the environment Also called nutrient cycling Solar energy Natural Capital Natural Capital = Natural Resources + Natural Services Air Renewable energy (sun, wind, water flows) Air purification Climate control UV protection (ozone layer) Life (biodiversity) Population control Water Water purification Pest control Waste treatment Soil Nonrenewable minerals (iron, sand) Soil renewal Land Food production Nutrient recycling Nonrenewable energy (fossil fuels) Natural resources Natural services Fig. 1-4, p. 9 We Are Living Unsustainably • Environmental degradation: wasting, depleting, and degrading the earth’s natural capital • Happening at an accelerating rate • Also called natural capital degradation Natural Capital Degradation Degradation of Normally Renewable Natural Resources Climate change Shrinking forests Decreased wildlife habitats Air pollution Soil erosion Species extinction Water pollution Aquifer depletion Declining ocean fisheries Fig. 1-9, p. 13 Some Sources Are Renewable and Some Are Not • Resource • Anything we obtain from the environment to meet our needs • Renewable resource • Several days to several hundred years to renew • E.g., forests, grasslands, fresh air, fertile soil • Nonrenewable resources • does not renew itself at a sufficient rate for sustainable economic extraction • Energy resources • Metallic and nonmetallic mineral resources Some Sources Are Renewable and Some Are Not • Sustainable yield • Highest rate at which we can use a renewable resource without reducing available supply • Perpetual resource • Solar energy • Reuse and Recycle • Possible 80-90% of currently used resources Countries Differ in Levels of Unsustainability • Economic growth: increase in output of a nation’s goods and services • Gross domestic product (GDP): annual market value of all goods and services produced by all businesses, foreign and domestic, operating within a country • Per capita GDP: one measure of economic development Pollution Comes from a Number of Sources • Sources of pollution • Point sources • E.g., smokestack • Nonpoint sources • E.g., pesticides blown into the air • Main type of pollutants • Biodegradable - a pollutant which can be detoxified in some manner in the environment • Nondegradable – not subject to or capable of degradation. Ecological Footprints: A Model of Unsustainable Use of Resources • As our ecological footprints grow, we are depleting and degrading more of the earth’s natural capital. • In 2003, the US per capita ecological footprint was about 4.5 times the average global footprint per person and 6 times larger than China’s per capita footprint • In 2008, the global ecological footprint was at least 30% higher than the earth’s biological capacity and is projected to be twice the planet’s biological capacity by around 2035. Cultural Changes Have Increased Our Ecological Footprints • If per capita usage of renewable resources continues at the current rate, we will need 2 planet Earth’s • If per capita usage equals that of the US, we will need 5 planet Earth’s. • Three major cultural events • Agricultural revolution • Industrial-medical revolution • Information-globalization revolution • Current need for a sustainability revolution Major Causes of Environmental Problems Fig. 1-17, p. 20 Harmful Effects of Poverty Fig. 1-20, p. 22 MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH CHAPTER 2 Science, Matter, Energy, and Systems Core Case Study: A Story About a Forest • 1963 river valley experiment in New Hampshire • Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site) • 3 years of collecting data showed the stripped site had: • 30-40% more runoff • More dissolved nutrients being carried away with the runoff • More soil erosion The Effects of Deforestation on the Loss of Water and Soil Nutrients Fig. 2-1, p. 31 Science Is a Search for Order in Nature • Scientific Method – a series of steps to learn how the physical world works. • Scientific Theory – a widely accepted hypothesis supported by observations and measurements. • Scientific Law – a tested and accepted description of what happens repeatedly in nature. The Scientific Process Fig. 2-2, p. 33 Matter Consists of Elements and Compounds • Matter • Has mass and takes up space • Elements • Unique properties • Cannot be broken down chemically into other substances • Compounds • Two or more different elements bonded together in fixed proportions • Molecule • Two or more atoms of the same or different elements held together by chemical bonds Atoms, Ions, and Molecules Are the Building Blocks of Matter (1) • Atomic theory • All elements are made of atoms • Subatomic particles • Protons with positive charge and neutrons with no charge in nucleus • Negatively charged electrons orbit the nucleus • Atomic number • Number of protons in nucleus • Mass number • Number of protons plus neutrons in nucleus Organic Compounds Are the Chemicals of Life • Organic compounds • Contain at least 2 carbon atoms combined with atoms of one or more other elements • Simple carbohydrates (sugars) • Macromolecules: complex organic molecules • • • • Complex carbohydrates Proteins Nucleic acids Lipids • Inorganic compounds • All other compounds (with the exception of Methane CHâ‚„) Matter Comes to Life through Genes, Chromosomes, and Cells • Cells: fundamental units of life; all organisms are composed of one or more cells • High-quality matter • Highly concentrated • Near earth’s surface • High potential as a resource • Low-quality matter • Not highly concentrated • Deep underground or widely dispersed • Low potential as a resource Matter Undergoes Physical and Chemical • Physical change • No change in chemical composition • Chemical change, chemical reaction • Change in chemical composition • Reactants and products • Law of conservation of matter • Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed Energy Comes in Many Forms (1) • Kinetic energy • Flowing water • Wind • Heat • Transferred by radiation, conduction, or convection • Potential energy • Stored energy • Can be changed into kinetic energy • Sun provides 99% of earth’s energy • Warms earth to comfortable temperature • Plant photosynthesis • Winds Energy Changes Are Governed by Two Scientific Laws • First Law of Thermodynamics • Law of conservation of energy • Energy is neither created nor destroyed in physical and chemical changes • Second Law of Thermodynamics • Energy always goes from a more useful to a less useful form when it changes from one form to another Time Delays Can Allow a System to Reach a Tipping Point • Time delays vary • Between the input of a feedback stimulus and the response to it • Tipping point, threshold level • Causes a shift in the behavior of a system • Melting of polar ice • Population growth MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH CHAPTER 3 Ecosystems: What Are They and How Do They Work? Core Case Study: Tropical Rain Forests Are Disappearing • Cover about 2% of the earth’s land surface • Contain about 50% of the world’s known plant and animal species • Disruption will have three major harmful effects • Reduce biodiversity • Accelerate global warming • Change regional weather patterns The Earth’s Life-Support System Has Four Major Components • Atmosphere • Troposphere: where weather happens • Stratosphere: contains ozone layer which filters 95% of UV radiation • Hydrosphere • Contains all water on and near Earth • Biosphere • Where all life is found Ecologists Study Interactions in Nature • Ecology: how organisms interact with each other and their nonliving environment • Organisms: different species interacting with one another • Biotic – living like plants, animals, microbes; Abiotic – nonliving like water, air , rocks • Populations: Groups of the same species living in a particular place • Communities: Populations living in a particular place, potentially interacting with one another Producers and Consumers Are the Living Components of Ecosystems (1) • Producers, autotrophs – self-feeders • Photosynthesis: • CO2 + H2O + sunlight → glucose + oxygen • Consumers, heterotrophs • Primary consumers = herbivores • Secondary consumers = carnivores that eat herbivores • Tertiary consumers = carnivores that eat carnivores • Omnivores = eat plants and animals Producers and Consumers Are the Living Components of Ecosystems (2) • Decomposers • Consumers that release nutrients • Bacteria • Fungi • Detritivores • Feed on waste and dead bodies of other organisms • Earthworms • Vultures Producers and Consumers Are the Living Components of Ecosystems (3) • Aerobic respiration • Using oxygen to turn glucose back to carbon dioxide and water • Anaerobic respiration = fermentation • End products are carbon compounds such as methane or acetic acid Science Focus: Many of the World’s Most Important Species Are Invisible to Us Microorganisms • Bacteria – helps purify water • Protozoa – helps provide planet’s oxygen • Fungi – decomposer Energy Flows Through Ecosystems in Food Chains and Food Webs • Food chain • Movement of energy and nutrients from one trophic level to the next • Food web • Network of interconnected food chains Usable Energy Decreases with Each Link in a Food Chain or Web • Biomass • Organic matter in a food chain or food web • Decreases at each higher trophic level due to heat loss • Pyramid of energy flow • 90% of energy lost with each transfer • Less chemical energy for higher trophic levels Some Ecosystems Produce Plant Matter Faster Than Others Do • Gross primary productivity (GPP) • Rate at which an ecosystem’s producers convert solar energy to chemical energy and biomass • Kcal/m2/year • Net primary productivity (NPP) • Rate at which an ecosystem’s producers convert solar energy to chemical energy, minus the rate at which producers use energy for aerobic respiration • Ecosystems and life zones differ in their NPP Estimated Annual Average NPP in Major Life Zones and Ecosystems Fig. 3-15, p. 66 Nutrients Cycle in the Biosphere • Biogeochemical cycles, nutrient cycles • • • • • Hydrologic Carbon Nitrogen Phosphorus Sulfur • Nutrients may remain in a reservoir for a period of time Water Cycles through the Biosphere • Natural renewal of water quality: major processes • • • • Evaporation Precipitation Transpiration Condensation • Alteration of the hydrologic cycle by humans • Withdrawal of large amounts of freshwater at rates faster than nature can replace it • Clearing vegetation causing increased runoff • Increased flooding when wetlands are drained • Special properties of water • Solvent, stays liquid, filters UV rays, expands as it freezes, holds lots of heat Carbon Cycle Depends on Photosynthesis and Respiration • Link between photosynthesis in producers and respiration in producers, consumers, and decomposers • Additional CO2 added to the atmosphere • Tree clearing • Burning of fossil fuels • Warms the atmosphere Carbon dioxide in atmosphere Respiration Photosynthesis Animals (consumers) Diffusion Burning fossil fuels Forest fires Plants (producers) Deforestation Transportation Respiration Carbon in plants (producers) Carbon dioxide dissolved in ocean Carbon in animals (consumers) Decomposition Marine food webs Producers, consumers, decomposers Carbon in limestone or dolomite sediments Carbon in fossil fuels Compaction Process Reservoir Pathway affected by humans Natural pathway Fig. 3-19, p. 70 Nitrogen Cycles through the Biosphere: Bacteria in Action (1) • Nitrogen fixed by lightning • Nitrogen fixed by bacteria and cyanobacteria • Combine gaseous nitrogen with hydrogen to make ammonia (NH3) and ammonium ions (NH4+) • Nitrification • Soil bacteria change ammonia and ammonium ions to nitrate ions (NO3-) • Denitrification • Nitrate ions back to nitrogen gas Nitrogen Cycles through the Biosphere: Bacteria in Action (2) • Human intervention in the nitrogen cycle 1. Additional NO and N2O in atmosphere from burning fossil fuels; also causes acid rain 2. N2O to atmosphere from bacteria acting on fertilizers and manure 3. Destruction of forest, grasslands, and wetlands 4. Add excess nitrates to bodies of water 5. Remove nitrogen from topsoil Nitrogen Cycle in a Terrestrial Ecosystem with Major Harmful Human Impacts Fig. 3-20, p. 71 Phosphorus Cycles through the Biosphere • Cycles through water, the earth’s crust, and living organisms • Limiting factor for plant growth • Impact of human activities 1. Clearing forests 2. Removing large amounts of phosphate from the earth to make fertilizers 3. Erosion leaches phosphates into streams Impacts Fig. 3-21, p. 73 Sulfur Cycles through the Biosphere • Sulfur found in organisms, ocean sediments, soil, rocks, and fossil fuels • SO2 in the atmosphere • H2SO4 and SO4• Human activities affect the sulfur cycle • Burn sulfur-containing coal and oil • Refine sulfur-containing petroleum • Convert sulfur-containing metallic mineral ores Natural Capital: Sulfur Cycle with Major Harmful Impacts of Human Activities Fig. 3-22, p. 74 Unit 1 Test Review • Terms: Natural capital (examples), renewable and nonrenewable resources (examples), GDP, sustainable yield, ecological footprint, matter, element, energy types, first law of thermodynamics • Scientists estimate we can recycle and reuse what % of resources we use now? • More-developed countries have what% of the population and use what% of all resources? • Human activities have degraded what% of natural resources? • How many earth’s would we need if everyone in the world consumed like the US? Unit 1 test review • Ecological footprint of a US citizen vs. China. • 3 major cultural revolutions. • Examples of pollution and effects. Point vs. nonpoint pollution. • % needed to bring about social change. • Scientific method and steps. Law vs. theory. • Policy life 4 stages, environmental lawsuits, SLAPP • Public lands in the US • Diane Wilson story • Sustainibility and lobbyists (essays)