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What are resources? Objectives • Distinguish between renewable and nonrenewable resources. • Identify renewable and nonrenewable resources. Vocabulary – natural resource – renewable resource – sustainable yield – nonrenewable resource What are resources? What are resources? • You and every other living thing on Earth must have certain resources to grow, develop, maintain life processes, and reproduce. • In addition to food and water, most animals also need shelter. What are resources? Natural Resources • Natural resources are the resources that Earth provides, including air, water, and land; all living things; and nutrients, rocks, and minerals in the soil and deep in Earth’s crust. • Neither matter nor energy can be created or destroyed, but both can be changed from one form to another. • Natural resources are changed through cycling, as in the carbon, nitrogen, and water cycles. What are resources? Renewable Resources • Renewable resources are natural resources that can be used indefinitely without causing a reduction in the available supply. • Resources that exist in an inexhaustible supply, such as solar energy, also are renewable resources. • Renewable resources are replaced through natural processes at a rate that is equal to, or greater than, the rate at which they are being used. What are resources? Renewable Resources Living Things – Plants and animals reproduce, and therefore, as long as some mature individuals of a species survive, they can be replaced. – Humans who use natural resources responsibly are practicing management techniques to replace resources as they are used. – A sustainable yield results when renewable resources are replaced at the same rate at which they are consumed. What are resources? Renewable Resources Sunlight – The Sun provides an inexhaustible source of energy for all processes on Earth. – Sunlight is considered to be a renewable resource because it will continue to be available for at least the next 5 billion years. What are resources? Nonrenewable Resources • A nonrenewable resource is a resource that exists in a fixed amount in various places in Earth’s crust and can be replaced only by geological, physical, and chemical processes that take hundreds of millions of years. • Nonrenewable resources are exhaustible because they are being extracted and used at a much faster rate than the rate at which they were formed. What are resources? Distribution of Resources • Natural resources are not distributed evenly on Earth. • The availability of natural resources helps determine the wealth and the power of countries around the world. • The United States has a high standard of living and it consumes approximately 30 percent of Earth’s mineral and energy resources each year, even though it has only 6 percent of the world’s population. What are resources? Distribution of Resources This graph shows the percentage of crude oil that is consumed by the United States and worldwide. Note that the United States consumes 27 percent of the total crude oil used each day. Land Resources Objectives • Describe why land is considered to be a natural resource. • Recognize the need to protect Earth’s land as a resource. • Explain how humans adjust to the uneven distribution of land resources. Vocabulary – desertification – ore – bedrock – gangue – aggregate Land Resources Land Resources • Land is a valuable natural resource. – Land provides places for humans and other organisms to live and interact. – Land also provides spaces for the growth of crops, forests, grasslands, and for wilderness areas. Land Resources Protected Land • Of all the land in the United States, 42 percent is certified as public land, which consists of forests, parks, and wildlife refuges. • These land areas are federally administered to protect timber, grazing areas, minerals, energy resources, and recreational interests. • National forests are managed for sustainable yield and include multiple-use areas where resources are used for many purposes, including recreation. Land Resources Protected Land • Wilderness areas are places that are maintained in their natural states and protected from development. • The national park system preserves scenic and unique natural landscapes, preserves and interprets the country’s historic and cultural heritage, and provides areas for various types of recreation. • National wildlife refuges provide protection of habitats and breeding areas for wildlife, and some provide protection for endangered species. Land Resources Soil • It can take up to 1000 years to form just a few centimeters of topsoil, yet it can be lost in a matter of minutes as a result of erosion by wind or water. • The loss of topsoil makes soil less fertile and less able to hold water, which results in poorer crops. • Topsoil is currently eroding faster than it forms on about one-third of Earth’s croplands. Land Resources Soil • Desertification, which can occur in arid and semiarid areas of the world, is the process whereby productive land becomes desert. • Desertification can be prevented by reducing overgrazing and by planting trees and shrubs to anchor soils and retain water. Land Resources Bedrock • Underneath the topsoil is a layer of soil consisting of inorganic matter, including broken-down rock, sand, silt, clay, and gravel. • Bedrock is a base of unweathered parent rock underlying the soil that may consist of limestone, granite, marble, or other rocks that can be mined in quarries. Land Resources Aggregates • An aggregate is a mixture of gravel, sand, and crushed stone that naturally accumulates on or close to Earth’s surface. • Aggregates are found in river valleys, in alluvial fans, and in glacial moraines, eskers, kames, and outwash plains. • Aggregates used in construction are mixed with cement, lime, gypsum, or other materials to form concrete or mortar. • The most commonly used natural aggregates are sand, crushed or broken rocks, and gravel. Land Resources Ores • An ore is a useful, natural resource that can be mined at a profit. • Ores can be classified by the manner in which they formed. • Some ores are associated with igneous rocks, whereas others are formed by processes at Earth’s surface. Land Resources Ores Settling of Crystals – Ores associated with igneous rocks may contain iron, chromium, and platinum. – Chromium and platinum ores can form when minerals crystallize and settle to the bottom of a cooling body of magma. Land Resources Ores Hydrothermal Fluids – Hydrothermal fluids are the most important sources of metallic ore deposits. – Atoms of metals such as copper and gold do not fit into the crystals that form during the cooling process and become concentrated in the remaining magma. – Eventually, a solution rich in metals and silica moves into the surrounding rocks to create ore deposits, known as hydrothermal veins, along faults and joints. Land Resources Ores Chemical Precipitation – Ores of manganese and iron most commonly originate from chemical precipitation in layers. – Iron ores in sedimentary rocks are often found in bands made up of alternating layers of iron-bearing minerals and chert called banded iron formations. Land Resources Ores Placer Deposits – Heavy sediments, such as grains of gold and silver, may be deposited in bars of sand and gravel when stream velocity decreases. – Placer deposits are sand and gravel bars that contain heavier sediments such as gold nuggets, gold dust, diamonds, platinum, and gemstones, as well as rounded pebbles of tin and titanium oxides. Land Resources Ores Concentration by Weathering – Some ores form when the minerals in rocks are concentrated by weathering. – Aluminum forms in bauxite through weathering in tropical climates. – Other metals that become more concentrated as rocks weather include nickel, copper, silver, lead, tin, mercury, uranium, and manganese. Land Resources Other Land Resources • Clay is used to make bricks, china, ceramics, tiles, and pottery. • Salt, or sodium chloride, occurs in deposits both on Earth’s surface and underground. • Deposits of both salt and gypsum, which is used to make plaster, can form when seawater evaporates. Land Resources Using Land Resources • The extraction of some resources can have negative impacts on the surrounding environment. – Mines can destroy the original ground contours and leave behind waste rock that can release pollutants. – Gangue, which is the material left after ore is extracted through grinding the parent rock, may release harmful chemicals into groundwater or surface water. – Mercury is used to extract gold from alluvial deposits. – Materials that form acids as they weather, such as pyrite, can be exposed through mining. – Mining has been identified as the most dangerous occupation in the United States. Air Resources Objectives • Recognize that the atmosphere is an Earth resource. • Describe the importance of clean air. Vocabulary – pollutant – air pollution Air Resources Air Resources • Air contains substances that all organisms need to survive, including nitrogen, carbon dioxide, hydrogen, helium, methane, ozone, neon, and argon. • Water vapor can make up as much as five percent of air by volume. • For animals, the most important component of air is oxygen. Air Resources Origin of Oxygen • Most organisms on Earth require oxygen or carbon dioxide to maintain their life processes. – Scientists hypothesize that 4.6 to 4.5 billion years ago, Earth’s atmosphere included primarily carbon dioxide, nitrogen, and water vapor. – Early life-forms in the seas used carbon dioxide during photosynthesis and released oxygen and water vapor. – Over time, oxygen in the atmosphere built up to levels that allowed the evolution of organisms that required oxygen for life processes. Air Resources Disrupting Earth’s Cycles • The geochemical cycles of Earth’s atmosphere are in a delicate balance. – Volcanic eruptions release various gases and dust particles into the atmosphere. – Photosynthetic organisms in the oceans and on land take in and use carbon dioxide and release oxygen. – Other organisms take in this oxygen and release carbon dioxide. Air Resources Disrupting Earth’s Cycles • Human activities that release carbon dioxide into the atmosphere, such as burning fossil fuels, can disrupt the geochemical cycles. • Global warming, which is the gradual rising of Earth’s average surface temperature, may be one result of the human alteration of the carbon cycle. • Deforestation has changed precipitation patterns in the tropical rain forests of the Amazon River Basin. Air Resources Disrupting Earth’s Cycles In the Amazon River Basin, scientists estimate that 1 hectare (ha, about 2.47 acres) of rain forest is cut down each hour. Nearly 20 million ha of rain forest is destroyed each year worldwide. This graph indicates the fate of the world’s tropical rain forests if the current rate of deforestation continues. Air Resources Disrupting Earth’s Cycles • Nitrogen oxides released by human activities are converted to nitric acid, which returns to Earth in acid precipitation. • Sulfur released into the atmosphere is converted to sulfuric acid, which also forms acid precipitation. • Pollutants are substances that can adversely affect the survival, health, or activities of organisms. • Air pollution results when pollutants in air occur in quantities that become harmful to human health and the health of the environment. Air Resources Sources of Air Pollution • Air pollution has both natural and human origins. – Natural sources of air pollution include volcanic eruptions and forest fires. – Human sources of air pollution include gases, smoke, and dust. – The largest human source of air pollution is the burning of fossil fuels in power plants and motor vehicles. – In some large cities, motor vehicles are responsible for 80 to 88 percent of the air pollution. Air Resources Sources of Air Pollution • When humans inhale harmful gases, the gases can be absorbed by the bloodstream and interfere with various body systems. • Pollution can also cause burning eyes, irritated throats, and breathing difficulties. • As clean air in the troposphere moves across Earth’s surface, it collects both naturally occurring and human-made pollutants. Air Resources Sources of Air Pollution Transport and Dilution – Transport of pollutants downwind from their origin depends upon wind direction and speed, topographical features, and the altitude of the pollutants. – If air movement in the troposphere is turbulent, some pollutants are diluted and spread out, which reduces their concentration. Air Resources Sources of Air Pollution Transformation and Removal – Some pollutants undergo chemical changes, called photochemical changes, that are triggered by reactions with ultraviolet (UV) radiation. – Some air pollutants can undergo physical changes and become heavy enough to fall back to Earth’s surface. – Air pollutants are removed from the atmosphere in precipitation, which includes snow, mist, and fog, as well as rain. Air Resources Indoor Air Pollution • About 90 percent of the furniture sold in the United States also contains formaldehyde, which is just one of the many air pollutants that occurs indoors. Air Resources Indoor Air Pollution Air Resources Indoor Air Pollution “Sick” Buildings – Indoor air pollutants have been linked to headaches, coughing, sneezing, burning eyes, nausea, chronic fatigue, and flulike symptoms. – A building is said to be “sick” when these symptoms are experienced by 20 percent of its occupants. – Often, these symptoms disappear when the affected people go outside. – New buildings are more likely to be “sick” than older buildings. Air Resources Indoor Air Pollution Radon Gas – Radon-222 is a colorless, odorless, and tasteless naturally occurring gas produced by the radioactive decay of uranium-238. – Outdoors, radon gas seeps from the ground into the atmosphere, where it is diluted to harmless levels. – Radon gas can enter through cracks in a foundation and build up to high levels indoors. – Once indoors, radon gas decays into radioactive elements that can be inhaled, causing an increased risk of lung cancer. Water Resources Objectives • Explain the importance of clean freshwater. • Analyze how water is distributed and used on Earth. • Identify ways in which humans can reduce the need for increasing production of freshwater resources. Vocabulary • desalination Water Resources Water Resources • The oceans contain 97 percent of the planet’s water, which means that only 3 percent of Earth’s water is freshwater. • Of this freshwater, about 2.997 percent is either locked up in ice caps and glaciers or stored as groundwater that is too deep to extract. • Only 0.003 percent of Earth’s total volume of water is available to humans for domestic, agricultural, and industrial purposes. Water Resources The Importance of Water • About 71 percent of Earth’s surface is covered by water. • The oceans help regulate climate, provide habitats for marine organisms, dilute and degrade many pollutants, and help shape Earth’s surface. • Freshwater is an important resource for agriculture, transportation, recreation, and numerous other human activities. • Most animals are about 50 to 65 percent water by weight, and even trees may be composed of up to 60 percent water. Water Resources The Importance of Water Liquid Water – Water can exist as a liquid over a wide range of temperatures because of the hydrogen bonds between water molecules. – The hydrogen bonds cause water’s surface to contract and allow water to adhere to and coat a solid. – Water also has a high boiling point, 100°C, and a low freezing point, 0°C. Water Resources The Importance of Water Heat Storage Capacity – Liquid water can store a large amount of heat without a correspondingly high increase in temperature. – This property protects organisms that live in water from abrupt temperature changes, and it is also responsible for water’s ability to regulate Earth’s climate. – Water absorbs large quantities of heat as it changes into water vapor. Water Resources The Importance of Water Water as a Solvent – Liquid water can dissolve a wide variety of compounds. – This ability enables water to carry nutrients into, and waste products out of, the tissues of living things. – Water also dilutes water-soluble waste products of humans and thus serves as an all-purpose cleanser. Water Resources The Importance of Water Solid Water Expands – Water expands when it freezes. – Because ice has a lower density than liquid water, it floats on top of water causing bodies of water to freeze from the top down. – Ice forming in existing cracks can fracture rocks, thus becoming part of the weathering process. Water Resources Location of Freshwater Resources • Freshwater resources are not distributed evenly across Earth’s landmasses. – Although the United States has plenty of freshwater, much of it is concentrated in the eastern states or has been contaminated by agricultural or industrial processes. – Worldwide, water distribution is a continuing problem, even though most continents have plenty of water. – About 25 countries, primarily in Africa, experience chronic water shortages. Water Resources Location of Freshwater Resources Countries experience severe water stress when there is less than 1000 m3 of freshwater per person. Extreme water stress occurs when there is less than 500 m3 of freshwater per person. Water Resources Use of Freshwater Resources • The current rate of withdrawal of freshwater from both surface and groundwater sources worldwide is five times greater than it was just 50 years ago. – About 70 percent of the water withdrawn each year is used to irrigate 18 percent of the world’s croplands. – About 23 percent of freshwater is used for cooling purposes in power plants, for oil and gas production, and in industrial processing. – About 7 percent goes to domestic and municipal uses. Water Resources Use of Freshwater Resources Water Resources Managing Freshwater Resources • Most countries manage their supplies of freshwater by building dams, transporting surface water, or tapping groundwater. • Some countries also have had success removing the salts from seawater to provide needed freshwater supplies. Water Resources Managing Freshwater Resources Dams and Reservoirs – Building dams is one of the primary ways that countries try to manage their freshwater resources. • Large dams are built across river valleys, usually to control flooding downstream. • Reservoirs behind dams capture the rivers’ flow, as well as rain and melting snow. • Dams and reservoirs currently control between 25 and 50 percent of the total runoff on every continent. Water Resources Managing Freshwater Resources Transporting Surface Water – Many countries use aqueducts, tunnels, and underground pipes to bring water from areas where it is plentiful to areas in need of freshwater supplies. • The California Water Project transports water from northern California to southern California. • There is a demand for even more water to be diverted to the south to which the residents of northern California object. • Conflicts over the transport of surface water will probably increase as human populations create higher demands for water. Water Resources Managing Freshwater Resources Tapping Groundwater – In the United States, about 23 percent of all consumer freshwater consists of groundwater pumped from aquifers. – Groundwater normally moves from points of high elevation and pressure to points of lower elevation and pressure at a rate of only about 1 m/year. – Drawdown occurs when the withdrawal rate of an aquifer exceeds its natural recharge rate, and the water table is lowered. – Groundwater depletion can affect stream flow and can result in the intrusion of salt water into shallow aquifers in coastal areas. Water Resources Managing Freshwater Resources Desalination – Desalination is the process of removing salt from ocean water to provide freshwater. – Desalination occurs when salt water is distilled. • The water is first heated until it evaporates, then it is condensed and collected. • The evaporation process leaves the salts behind. • Most countries that use desalination to produce freshwater use solar energy to evaporate sea water. Water Resources Managing Freshwater Resources Reducing Freshwater Use – The best way to meet the need for freshwater is to use available supplies more efficiently. • Farmers can prevent evaporation of irrigation water by using irrigation methods such as trickle irrigation. • Industries can use recycled water instead of clean freshwater for manufacturing processes. • Many domestic uses can be reduced by installing low-flow toilets, using plants that are droughtresistant for landscaping, and fixing leaky pipes and faucets.