Using Natural Resources Organisms and Their Environment Energy and Resources Pollution and Recycling

Objectives  Explain the structure of an ecosystem  Describe the effects one species can have on an ecosystem  Discuss two ways natural forces can change ecosystems  Discuss two ways humans can change ecosystems

Key Terms  Ecosystem  Community  Succession  Hydroelectric power

Organisms and Their Environment  What is an Ecosystem?  A mix of living and nonliving pieces of the environment  All ecosystems are not the same size  The Earth is a very complex ecosystem  A rain puddle is smaller and less complex  Living things are adapted to their ecosystem  Ecosystems are divided into communities, populations, and organisms

Organization: from large to small

Organisms and Their Environment  Changes in Ecosystems  Factors can change an ecosystem  Balanced ecosystems remain stable  A change in one factor can affect the whole ecosystem  Sunlight, air, soil, water, animals, plants, etc.  Ecosystems will gradually return to their original conditions  Succession: repopulation over time

Succession

Organisms and Their Environment  Evaluating changes in ecosystems  Short term changes, (the seasons)  Long term changes, (volcanic eruptions)  Climatic changes affect ecosystems, (ice age)  Changes can be caused by human activity  Building dams interrupt water supplies  Changes can be caused by introduction of nonnative species  Birds, insects, amphibians are examples

Objectives  Identify different sources of energy used by living things and trace each source back to the sun  Describe the advantages and disadvantages of particular energy sources  Describe the types of conversion processes needed to produce electricity  Identify the efficiency of energy conversions

Key Terms  Fossil fuels  Nonrenewable resources  Renewable resources  Geothermal energy

Energy and Resources  The search for resources  The sun is a source of energy  Plants change energy from the sun into chemical energy – converting solar to chemical  Fossil fuels form deep underground from once living matter, (dinosaurs, plants)  Fossil fuels can be solids, liquids, or gases  The supply of fossil fuels is limited  Nonrenewable resources

Some see the supply of fossil fuels as a joke!

Energy and Resources  Alternative sources of energy – renewable  Solar cells and solar power plants make electricity directly from sunlight  The energy of wind can be used by windmills  The energy of water may be sued by turbines in dams  Geothermal energy may be collected from “hot spots” in the Earth’s crust  Nuclear energy is produced from atomic fission

Renewable Energy Sources

Energy and Resources  The efficiency of energy conversion  Energy is wasted when input is greater than output  Wasted energy is generally found as heat  Wasted energy may be collected for further use  Heat may be used to warm homes during cold spells

Objectives  Compare the economic and environmental impacts of different energy sources  Identify pollutants created by use of fossil fuels  Describe types of pollution in air, water, and on land  Identify ways to reduce, recycle, and reuse.

Key Terms  Pollution  Global warming  Eutrophication  Recycling

Pollution and Recycling  What causes pollution?  Natural causes – dust and ash  Manmade pollution is more common – (combustion)  Air pollution Combustion of fossil fuels carbon dioxide – one of the main pollutants other pollutants are sulfur dioxide and nitrogen dioxide

Pollution and Recycling  Water pollution  Pesticides and fertilizers  May be found in quantities that make the water “unfit”  May cause eutrophication and kill water organisms  Pollution on the Land  Contaminants in the soil are hard to remove  Some poisons stay in soil for long periods of time  Landfill space is running out  Trash is the greatest pollutant on land

Pollution and Recycling  Reducing pollution  Choosing alternatives often involves trade-offs  Reusable grocery bags rather than paper or plastic  Reducing the use of energy and products can cut down on pollution  Turning off light switches when not in a room  Recycling is another way to prevent pollution  Reusing materials to create new products