CK-12 Biology I - Honors

by CK-12 Foundation

  Wetlands, greatly reduced because of earlier views that they were wasted land, provide many ecosystem services, including flood control, water purification, aquifer recharge, plant and wildlife habitat, and recreation.

  Liquid fresh water, the primary water resource for human use, comprises less than 1% of all water on Earth; most of this is groundwater.

  As industry, agriculture, development, and a growing world population use more water, fresh water supplies are shrinking due to over-drafting of groundwater and pollution of surface and groundwater.

  According to the United Nations, the current Water Crisis involves 1.1 billion people without adequate water supplies and 2.6 billion people who lack adequate water for sanitation.

  Agricultural fertilizer runoff and waste water add excess nutrients to surface waters, leading to algal blooms and eutrophication.

  Dead zones in coastal areas such as the Gulf of Mexico result from agricultural runoff from large areas of land. The dead zone at the mouth of the Mississippi River was the size of New Jersey in the summer of 2007.

  Virtual water is the water used in the production of a good or service.

  The more water we use, the more likely we are to overdraft aquifers and pollute water supplies.

  Concepts similar to virtual water highlight the importance of REDUCING USE as a first principle in conservation or sustainable use.

  A second principle is to REUSE resources. For water conservation, this can mean re-using gray water from laundry or showers for gardens or flush toilets.

  Legislation can set standards for water quality and limits on pollution.

  Local, national, and international organizations can work to promote awareness and encourage action.

  Review Questions

  Distinguish between renewable and nonrenewable resources, and relate these concepts to the Laws of Energy.

  Classify the following resources as renewable or nonrenewable: coal, copper, iron, natural gas, nuclear power, oxygen, sunlight, water, wood, wool. Briefly explain your reasoning for each resource.

  Describe the formation of soil, and classify it as a renewable or nonrenewable resource.

  Compare and contrast land which has undergone desertification to ecosystems which harbor natural deserts. How can the apparently life-promoting act of irrigation eventually have the opposite effect?

  We no longer experience the obvious tragedies associated with the Dust Bowl of the 1930s. Does this mean that soil erosion is no longer a significant problem?

  Connect land use changes (e.g. forest to agriculture) to global warming. How important is this relationship?

  List the ecosystem services of wetlands, and describe the extent of their loss.

  Earth is the “water planet.” Why are we threatened with a Water Crisis?

  Explain why eutrophication – “too much a good thing” results in problems for aquatic life.

  Analyze the disappearance of the Black Sea “dead zone” for its potential to help solve water pollution problems.

  Further Reading / Supplemental Links

  Schumacher, E. F., "Small Is Beautiful: Economics As If People Mattered : 25 Years Later...With Commentaries," 1999. Hartley & Marks Publishers.

  Hari Eswaran, Paul Reich, and Fred Beinroth, “Global Desertification Tension Zones.” US Department of Agriculture Natural Resources Conservation Services, 1998. Available online at:

  http://soils.usda.gov/use/worldsoils/papers/tensionzone-paper.html.Jeff

  Dukes, “Burning Buried Sunshine,” CBC Radio One Quirks and Quarks Online, 1 November 2003.

  Available online at:

  http://www.cbc.ca/quirks/archives/03-04/nov01.html

  Bob Hartwell, “Natural Resource Definition.” US Department of Energy NEWTON Ask A Scientist, 4 February 2005. Available online at:

  http://www.newton.dep.anl.gov/askasci/gen01/gen01773.htm

  United States Geological Survey, “Earth’s Water Distribution.” USGS Water Science for Schools, US Department of the Interior, last modified August 2006. Available online at:

  http://ga.water.usgs.gov/edu/waterdistribution.html

  World Water Council, “World Water Council: An International Multi-Stakeholder Platform for a Water Secure World.” Last updated 21 November 2007. Available online at:

  http://www.worldwatercouncil.org/

  Krishna Ramanujan and Brad Bohlander, “Landcover changes may rival greenhouse gases as cause of climate change.” NASA Goddard Space Flight Center, 1 October 2002. Available online at:

  http://www.gsfc.nasa.gov/topstory/20020926landcover.html

  “Is the dust bowl returning?” US Government Information Oklahoma Department of Libraries, 2004. Available online at:

  http://www.odl.state.ok.us/usinfo/maps/dustbowl/index.htm

  http://www.usgs.gov/themes/resource.html

  http://www.wri.org/

  http://www.energy.gov/energysources/index.htm

  http://www.greeningschools.org/resources/view_cat_teacher.cfm?id=192

  http://www.eia.doe.gov/kids/

  http://www.priweb.org/ed/pgws/systems/systems_home.html

  http://www.nrcs.usda.gov/FEATURE/education/squirm/skQ13.html

  http://www.biodiversity911.org/soil/soil_main.html

  http://forces.si.edu/soils/

  http://www.nrcs.usda.gov/feature/backyard/watercon.html

  http://water.usgs.gov/education.html

  http://www.epa.gov/water/

  http://www.lifewater.org/

  http://www.amnh.org/exhibitions/water/

  http://www.smm.org/deadzone/

  http://www.sevengenerationsahead.org/about_us.html

  http://www.iisd.org/natres/

  http://en.wikipedia.org

  Vocabulary

  acid rain

  Precipitation in any form which has an unusually low pH.

  algal bloom

  A rapid increase in the growth of algae, often due to a similar increase in nutrients.

  anthropogenic sources

  Sources of pollution related to human activities.

  biodiversity

  Variation in life – at all levels of organization: genes, species, and ecosystems.

  biological magnification (food chain concentration)

  The process in which synthetic chemicals concentrate as they move through the food chain, so that toxic effects are multiplied.

  dead zone

  Region of the ocean in which nutrient runoff and consequent eutrophication lower oxygen levels to the point at which life can no longer survive; less often applies to similar conditions in freshwater lakes.

  desertification

  Degradation of formerly productive land (usually at least semi-arid).

  ecosystem

  A functional unit comprised of living things interacting with their nonliving environment.

  eutrophication

  An increase in nutrient levels in a body of water, often followed by an increase in plant or algae production.

  global warming

  The recent increase in the Earth’s average near-surface and ocean temperatures.

  greenhouse effect

  The trapping by the atmosphere of heat energy radiated from the Earth’s surface.

  natural resource

  Something supplied by nature which supports life, including sources of energy and materials, ecosystems, and ecosystem services.

  nonpoint source pollution

  Runoff of nutrients, toxins, or wastes from agricultural, mining, construction, or developed lands.

  nonrenewable resource

  A resource which is not regenerated or restored on a time scale comparative to its consumption.

  ozone depletion

  Reduction in the stratospheric concentration of ozone molecules, which shield life from damaging ultraviolet radiation.

  point source pollution

  Single site sources of nutrients, toxins, or waste, such as industrial or municipal effluent or sewer overflow.

  p
ollution

  Release into the environment of chemicals, noise, heat or even light beyond the capacity of the environment to absorb them without harmful effects on life.

  primary pollutants

  Substances released directly into the air by processes such as fire or combustion of fossil fuel.

  renewable energy sources

  Sources of energy which are regenerated by natural sources within relatively short time periods, e.g. solar, wind, and geothermal, as opposed to fossil fuels.

  renewable resource

  A resource which is replenished by natural processes at a rate roughly equal to the rate at which humans consume it.

  salination

  Addition of salts to soils, often by irrigation.

  secondary pollutants

  Substances formed when primary pollutants interact with sunlight, air, or each other.

  soil erosion

  Removal of soil by wind and water in excess of normal processes.

  sustainable use

  Use of resources at a rate which meets the needs of the present without impairing the ability of future generations to meet their needs.

  virtual water

  The water used in the production of a good or service.

  wetland

  Swamps, marshes and bogs whose soil is saturated.

  Points to Consider

  What is your own concept of natural resources? What relationship between humans and the Earth does it contain?

  Aldo Leopold wrote:“There are two spiritual dangers in not owning a farm. One is the danger of supposing that breakfast comes from the grocery, and the other that heat comes from the furnace.” ( http://en.wikiquote.org/wiki/Aldo_Leopold) Is your life close enough to “the farm” to recognize and fully appreciate the values of soil and of energy resources?

  Were you surprised by the virtual water data for beef or jeans? What other “virtual resources” are part of the products we consume?

  What kinds of legislation help to incorporate this level of water use in prices? What types of legislation prevent water use from being included in costs?

  Compare this statement from The Great Law of the Iroquois Confederacy to the contemporary concept of sustainable use: "In every deliberation we must consider the impact on the seventh generation... even if it requires having skin as thick as the bark of a pine." ( http://en.wikipedia.org/wiki/Seven_generation_sustainability)

  Lesson 18.3: Natural Resources II: The Atmosphere

  Lesson Objectives

  Recognize that the Earth’s atmosphere provides conditions and raw materials essential for life.

  Review the changes in the atmosphere over the history of the Earth.

  Describe the dynamic equilibrium which characterizes the natural atmosphere.

  Analyze the ways in which population growth, fossil fuel use, industrialization, technology, and consumption result in atmospheric changes.

  Explain the effects of these changes on ecosystems.

  Relate these effects to current global stability.

  Describe how human activities including technology affect ecosystem services such as:

  nutrient cycling

  hydrologic cycle

  waste disposal

  Evaluate the effects of changes in these services for humans.

  Identify the ways in which humans have altered the air for other species.

  Relate air pollution to ecosystem loss.

  Interpret the effects of air pollution on biodiversity.

  Define acid rain.

  List the natural and anthropogenic causes of acid rain.

  Identify the effects of acid rain.

  Discuss solutions specific to the problem of acid rain.

  Locate and describe the origin of the ozone layer.

  Distinguish between ozone depletion and the ozone hole.

  Explain the role of ozone in absorbing ultraviolet radiation.

  Indicate the ways in which the ozone layer varies naturally.

  Discuss the relationship between recent changes in the ozone layer and human activities.

  Describe the measures taken to restore the ozone layer and evaluate their effectiveness.

  Introduction

  Air: so easy to take for granted. In its pristine state, we cannot see it, smell it, taste it, feel it, or hear it, except when the wind blows or clouds form. Yet its complex and dynamic mix of gases is essential for life. Nitrogen (78%) provides atoms which build proteins and nucleic acids via the nitrogen cycle. Oxygen (21%) permits the production of the ATP through cellular respiration, to power life. Carbon dioxide (.04%) provides the carbon for carbohydrate fuels and carbon skeletons to build life’s bodies. Water (1-4% near the Earth’s surface) has so many unique properties (adhesion, surface tension, cohesion, capillary action, high heat capacity, high heat of vaporization…and more) that it is difficult for us to imagine any form of life on any planet which does not depend on it. As a major component of the hydrologic cycle, the atmosphere cleans and replenishes Earth’s fresh water supply, and refills the lakes, rivers, and oceans habitats for life (Figure below). The Earth’s atmosphere thins but reaches away from its surface for 100 kilometers toward space; between about 15 and 35 km lies the Ozone Layer – just a few parts per million which shields life from the sun’s damaging Ultra-Violet radiation. Earth’s atmosphere appears ideal for life, and indeed, as far as we know it is the only planetary atmosphere which supports life.

  Figure 18.35

  A composite photo of satellite images shows Earth and its life-supporting waters and atmosphere.

  As we noted in the History of Life chapter, the Earth’s atmosphere has not always been this hospitable for life. Life itself is probably responsible for many dramatic changes, including the addition of oxygen by photosynthesis, and the subsequent production of ozone from accumulated oxygen. Changes in CO2 levels, climate, and sea level have significantly altered conditions for life, even since the addition of oxygen some 2 billion years ago. On a daily time scale, dramatic changes take place:

  most organisms remove O2 and add CO2 through cellular respiration

  most autotrophs remove CO2 and add O2 through photosynthesis

  plants transpire vast quantities of water into the air

  precipitation returns it, through gentle rains or violent storms, to the Earth’s surface

  On a human time scale, the daily dynamics balance, and the atmosphere remains at equilibrium – an equilibrium upon which most life depends.

  Upsetting the Equilibrium of the Atmosphere: Air Pollution

  Despite the atmosphere’s apparent vastness, human activities have significantly altered its equilibrium in ways which threaten its services for life. Chemical substances, particulate matter, and even biological materials cause air pollution if they modify the natural characteristics of the atmosphere. Primary pollutants are directly added to the atmosphere by processes such as fires or combustion of fossil fuels (Figure below). Secondary pollutants, formed when primary pollutants interact with sunlight, air, or each other, can be equally damaging. The chlorine and bromine which threaten the Ozone Layer are secondary pollutants, formed when refrigerants and aerosols (primary pollutants) decompose in the stratosphere (Figure below).

  Figure 18.36

  Burning fossil fuels by factories, power plants, home furnaces, and motor vehicles is a major source of air pollution.

  Figure 18.37

  Levels of sun-blocking aerosols declined from 1990 to the present. A corresponding return to pre-1960 levels of radiation suggests that pollution control measures in developed countries have counteracted Global Dimming. However, particulates are still a problem in developing countries, and could affect the entire global community again in the future. Aerosol increases in 1982 and 1991 are the result of eruptions of two volcanoes, El Chichon and Pinatubo.

  The majority of air pollutants can be traced to the burning of fossil fuels. We burn fuels in power plants to generate electricity, in factories to power machi
nery, in stoves and furnaces for heat, in airplanes, ships, trains, and motor vehicles for transportation, and in waste facilities to incinerate waste. Since long before fossil fuels powered the Industrial Revolution, we have burned wood for heat, fireplaces, and campfires and vegetation for agriculture and land management. The resulting primary and secondary pollutants and the problems to which they contribute are included in Table below.

  Pollutant Example/Major Source Problem

  Sulfur oxides (SOx) Coal-fired power plants Acid Rain

  Nitrogen oxides (NOx) Motor vehicle exhaust Acid Rain

  Carbon monoxide (CO) Motor vehicle exhaust Poisoning

  Carbon dioxide (CO2) All fossil fuel burning Global Warming

  Particulate matter (smoke, dust) Wood and coal burning Respiratory disease, Global Dimming

  Mercury Coal-fired power plants, medical waste Neurotoxicity

  Smog Coal burning Respiratory problems; eye irritation

  Ground-level ozone Motor vehicle exhaust Respiratory problems; eye irritation

  Beyond the burning of fossil fuels, other anthropogenic (human-caused) sources of air pollution are shown in Table below.

  Activity Pollutant Problem

  Erosion

  Herbicides and Pesticides

  Fertilizers

  Agriculture: Cattle Ranching

  Dust

  Persistent Organic Pollutants(POP): DDT, PCBs, PAHs*

  Ammonia (NH3), Volatile Organic Chemicals(VOCs)

  Methane (CH4)

  Global Dimming

  Cancer

  Toxicity, Global Warming