A global movement toward the generation of alternative energy sources, which are renewable, is therefore under way to help meet increased energy needs. Some of these, like solar radiation, wind energy, and hydropower, were mentioned briefly in the section on renewable resources. Let’s discuss these and others now in more detail.
Solar power (Figure below) involves using solar cells to convert sunlight into electricity. When sunlight hits solar thermal panels, it is converted to heat water or air. It can also be used to heat water (producing steam) via a parabolic mirror, or it can be used for passive solar heating of a building simply by passing through windows.
Figure 25.18
An example of solar power, using solar cells to convert sunlight into electricity.
Wind power, the conversion of wind energy into forms such as electricity via wind turbines, is only used for less than 1% of the world’s energy needs. However, growth in harvesting wind energy is rapid, with recent annual increases of more than 30%.
Hydropower (Figure below) uses the energy of moving water to turn turbines or water wheels, which drive a mechanical mill or an electric generator. Today, the largest use of hydropower is for electric power generation, which allows low cost energy to be used at long distances from the water source. Electricity can also be generated constantly, as long as sufficient water is available, it produces no primary waste or pollution, and it is a renewable resource.
Figure 25.19
Small hydropower plant, Buchholz, Switzerland.
Other alternative energy sources to the burning of fossil fuels include geothermal power; biomass, biofuels; tidal power; nuclear energy; and fusion power. Let’s examine these briefly to see how they compare with the sources of energy we’ve already discussed. Keep in mind as we do so what you think the best alternatives might be.
Geothermal power uses the natural flow of heat from the earth’s core to produce steam, which is used to drive turbines, which, in turn, power electric generators.
Biomass production involves using garbage or other renewable resources such as corn or other vegetation to generate electricity. When garbage decomposes, the methane produced is captured in pipes and burned to produce electricity. Advantages of these types of energy include using organic waste products from agriculture; biomass is abundant and is generally renewable.
Power can be extracted from Moon-gravity-powered tides by locating a water turbine in a tidal current. The turbine can turn an electrical generator, or a gas compressor, which can then store energy until needed (Figure below).
Nuclear power plants use nuclear fission to generate energy inside a nuclear reactor. The released heat, heats water to create steam, which spins a turbine generator, producing electricity (Figure below).
Figure 25.20
Dam of the tidal power plant on the estuary of the Rance River, Bretagne, France
Figure 25.21
Aerial photo of the Bruce Nuclear Generating Station near Kincardine, Ontario
Now that we have reviewed the pros and cons of fossil fuels and alternative energy sources, what type or types do you think makes the best use of the natural resources available to us? As we move into our last section, also think about how reducing waste and reusing and recycling resources can help us reach our goals for energy production as well.
Reduce, Reuse, and Recycle
When we think of reducing, we’re talking about reducing our output of waste. That could also mean cutting down on use of natural resources. Reusing and recycling are other ways we can cut down on use of resources.
Minimizing of waste may be difficult to achieve for individuals and households, but here are some starting points that you can include in your daily routine:
When you go shopping for items, buy quantities you know you will use without waste; sometimes buying larger may be a better deal, cost-wise, but make sure you will really finish what you buy
To minimize usage of electricity, turn lights off when not using and replace burned out bulbs with ones that are more ecologically efficient
Reduce water use by turning off faucets when not using water; use low-flow shower heads, which save on water and use less energy, since less water is being heated; use low-flush and composting toilets
Purchase water-efficient crops, which require little or no irrigation
Put kitchen and garden waste into a compost pile
In the summer, change filters on your air conditioner and keep your thermostat at a temperature as warm as you can tolerate; in winter, make sure your furnace is working properly, keep the temperature as cold as you can tolerate, and make sure there is enough insulation on windows and doors
Mend broken or worn items, when feasible
Walk or bicycle to destinations, when possible, rather than using an automobile, in order to save on fuel costs and to cut down on emissions
When buying a new vehicle, check into hybrid and semi-hybrid brands (many new ones are coming rapidly onto the market) to cut down on gas mileage
Consider which makes more sense – to spend valuable gas to go further to recycle, for example, or to sometimes use the trash instead of recycling
Let’s now look at what we can reuse. Reusing includes using the same item again for the same function and also using an item again for a new function. Reuse can have both economic and environmental benefits. New packaging regulations are helping society to move towards these goals.
Some ways of reusing resources (think about ways these might be incorporated into your home) include:
Use of gray water – water which has been used for laundry or washing, for example, can be used to water the garden or flush toilets * At the town level, sewage water can be used for fountains, watering public parks or golf courses, fire fighting, and irrigating crops that will be peeled or boiled before use
Catching of runoff, which will also slow nonpoint source pollution and erosion – rain barrels next to buildings, recharge pits to re-fill aquifers
Perhaps you can think of some other ways to reuse resources!
Now we move on to recycling. Sometimes it may be difficult to understand the differences between reuse and recycling. Recycling differs in that it breaks down the item into raw materials, which are then used to make new items, whereas reusing uses the same item again. Even though recycling requires extra energy, it does often make use of items which are broken, worn out, or otherwise unsuitable for reuse.
The things that are commonly recycled include aggregates and concrete, batteries, biodegradable waste, electronics, iron and steel, aluminum, glass, paper, plastic, textiles, timber, industrial breaking of ships, and tires. Each type of recyclable requires a different technique. Perhaps you or your school could arrange for a trip to a recycling plant!
Here are some things you can do to recycle in your home, school, or community:
If you have recycling in your community, make sure you separate out your plastics, glass, and paper, according to your local guidelines; have containers set up for easy placement
See if your school recycles; if not perhaps you and some friends could start a recycling, or ecology, club, or organize efforts to better recycling goals
In order to judge the environmental and economic benefits of recycling, the cost of this process must be compared to the costs of extracting the original resource. In order for recycling to make economical sense, there usually must be a steady supply of recyclables and constant demand for the reprocessed products. Government legislation can stimulate both of these. As with all environmental issues, individuals can communicate with their representatives to make sure their wishes are heard.
The amount that an individual wastes is small in proportion to all waste produced by society. Yet all small contributions, when added up, can make a difference. In addition, influence on policy can be exerted in other areas. Awareness by you and your family, for example, of the impact and power of certain purchasing and recycling decisions can influence manufacturers and distributors to avoid buying
products that do not have eco-labeling, are currently not mandatory, or that minimize the use of packaging.
Lesson Summary
A natural resource is a naturally occurring substance which is necessary for the support of life.
Resources are either renewable or nonrenewable.
Examples of renewable resources include sunlight, wind tides, and hydropower.
Some resources may seem to be renewable, but may have some limits, as to how accessible a nonpolluted resource is and what effect overexploitation of the resource has.
Some renewable materials include the sustainable harvesting of certain products.
Nonrenewable resources include fossil fuels and nuclear power.
Burning of fossil fuels causes harmful effects in the environment and can lead to regional and global conflicts.
There are a number of renewable energy sources which offer alternatives to the burning of fossil fuels; they include solar radiation; wind energy; hydropower; geothermal power; biomass, biofuels, and vegetable oil; tidal power; nuclear energy; and fusion power.
There are pros and cons to all alternative energy sources.
Reducing waste and the reusing and recycling of resources can help save natural resources as well as help us reach our goals for energy production.
There are many things you can do in your household and community towards the goals of reducing, reusing, and recycling; individual efforts can also add up to make a difference nationally, and even internationally.
Awareness of wise resource use at the consumer level can influence decisions at the manufacturing and distributing levels.
Government legislation is also important to enforce these changes; it is up to individuals to communicate to their representatives the carrying out of wise use of natural resources, and to vote for those leaders who stand for sound ecological practices.
Review Questions
Under what conditions is a resource renewable?
Why must some natural renewable resources, such as geothermal power, fresh water, timber, and biomass be carefully managed?
Why is nuclear power considered a nonrenewable resource?
With resources that have limited supplies, what human factors put increasing pressure on how fast we consume such resources?
What are the main disadvantages to the burning of fossil fuels as an energy source?
What two advantages do solar power, wind power, and hydropower all have in common?
Further Reading / Supplemental Links
Unabridged Dictionary, Second Edition, Random House, New York, 1998.
Natural Resources
http://dnr.state.il.us/lands/education/index.htm
http://www.nrcs.usda.gov/feature/education/squirm/skworm.html
http://fossil.energy.gov/education/energylessons/index.html
http://www1.eere.energy.gov/education/report_resources.html
http://www.epa.gov/region5/students/waste.htm
http://en.wikipedia.org/wiki/Water_conservation
Vocabulary
biofuels
The production of fuels, such as wood or ethanol, from biomass.
biomass
Use of garbage or other renewable resources such as corn or other vegetation to generate electricity.
erosion
Process by which the surface of the Earth is worn away by the action of winds, water, waves, glaciers, etc.
fossil fuels
Formed from plant or animal remains over periods from 50 to 350 million years ago and used to produce sources of energy, such as petroleum and coal.
fusion power
The production of atomic energy by the process of nuclear fusion.
geothermal power
The use of the natural flow of heat from the Earth’s core to produce steam.
hydropower
Use of power from falling water or other water movement to generate and distribute electricity; also known as hydroelectric power.
natural resources
Naturally occurring substances necessary for the support of life.
nonrenewable resource
A natural resource that exists in fixed amounts and can be consumed or used up faster than it can be made by nature.
nuclear power
A nonrenewable resource, where nuclear fission is used to generate energy.
recycling
The breaking down of an item into raw materials to make new items.
reducing
Minimizing the use of resources.
renewable resources
Resources that are replenished by natural processes at about the same rate at which they are used.
solar power
The use of solar cells to convert sunlight into electricity.
sustainable
A rate which meets the needs of the present without impairing future generations from meeting their needs.
tidal power
Power generated from tidal currents.
wind power
The conversion of wind energy into electricity via wind turbines.
Points to Consider
Minimizing use of some resources helps to preserve habitats; for example, conservation of human water use helps to preserve freshwater habitats for local wildlife and migrating waterfowl.
Habitats are another resource for both humans and other organisms. Now that we have considered conservation of natural resources, we will move on in the next lesson to examining the effects of habitat destruction and how to protect habitats. Why do you think this is an important topic?
Discuss how the protection of natural resources may be important for biodiversity.
Protection of natural resources, including habitats, is also important to avoid dire consequences, such as extinction of species. Discuss why.
Lesson 25.4: Habitat Destruction and Extinction
Lesson Objectives
Discuss what causes destruction of habitats.
Explain why habitat destruction threatens species.
Describe causes of extinction other than habitat destruction.
Explain why biodiversity is important.
Explain why habitat protection is important, including for maintaining biodiversity.
Check your Understanding
What is a habitat?
What is habitat destruction?
What is the effect of habitat destruction?
What is biodiversity? (Figures below, below and below.)
Figure 25.22
A sampling of some of the wide diversity of animal species on earth.
Figure 25.23
Coral reefs are one of the biomes with the highest biodiversity on earth.
Figure 25.24
This tropical rain forest demonstrates another biome having one of the greatest biodiversities on earth.
Introduction
From a human point of view, a habitat is the environment where you live, go to school, places where you go to have fun, and other places you regularly visit. Maybe if we think of habitat in this way we will have a better sense of other species’ habitats and a better appreciation for how valuable a habitat is to its occupants.
When we likewise consider habitat destruction, we might evaluate more carefully human influences such as land clearing (Figure below) and introduction of non-native species of plants and animals and how this can have even catastrophic effects, like extinction of species (Figure below), some of which give us great beauty and some of which have medicinal or other useful qualities! In human terms, how would we feel if someone came in and radically changed our habitat, and either drove us out or worse yet, caused us to eventually die?
Figure 25.25
Slash-and-burn agriculture, shown here in southern Mexico, clears land for agriculture.
Figure 25.26
An exotic species, the brown tree snake, hitch-hiked on an aircraft to the Pacific Islands, causing the extinctions of many bird and mammal species which had evolved in the absence of predators.
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In this lesson, we will also examine other causes of extinction besides habitat destruction and the importance of biodiversity. Finally, we will see, that as our planet becomes more threatened and as we see how this also impacts the human species, human awareness of these issues has led to measures, such as habitat protection, that can help all of the earth’s inhabitants.
Causes of Habitat Destruction
Clearing some habitats of vegetation for purposes of agriculture and development is a major cause of habitat destruction or loss. Within the past 100 years, the area of cultivated land worldwide has increased 74%. Land for the grazing of cattle has increased 113%! Agriculture, alone, has cost the United States 50% of its wetlands (Figure below) and 99% of its tallgrass prairies (Figure below). Native prairie ecosystems, with their thick fertile soils, deep-rooted grasses, diversity of colorful flowers, burrowing prairie dogs and burrowing owls, herds of bison and pronghorn antelope, and other animals, are virtually extinct (Figure below).
Figure 25.27
Wetlands such as this one in Cape May, New Jersey, filter water and protect coastal lands from storms and floods.
Figure 25.28
Big bluestem grasses as tall as a human were one of the species of the tallgrass prairie, largely eliminated by agricultural use.
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