Science ReviewFood Webs and Natural Resources

Unit 4

Pages 196 – 199

Pages 207 - 217

What are Food Chains and Food Webs?

A food chain shows how energy moves from one living thing to another.

A food web shows the relationships among different food chains.

Which animal does not belong in the following food chain? Why?

phytoplankton -> small fish -> seal -> great horned owl -> killer whale

Answer:

The great horned owl belongs in a DESERT food chain!

Movement of Energy in Food Chains

What is the movement of energy in the following food chain?

The movement of energy is from producer (grass) to consumer (rabbit, fox)!

Changes in Food Webs

Suppose the weather in spring is VERY cold. Only a few plants have survived. The mice eat the plants, and the snakes eat the mice. What will happen to the mice and snake population? Why?

What are Natural Resources?

Look at the picture below. What are some natural resources found in this setting?

Natural resources are materials found in nature that are used by living things.

Youtube - How Paper is Made

Renewable Resources

Some natural resources, such as air and water, are used again and again. Other resources form quickly in nature and are easy to replace. Natural resources that can be replaced quickly are called renewable resources.

Which of the following are renewable resources?

Nonrenewable Resources

Natural Resources that aren’t replaced easily are called nonrenewable resources. It can take thousands or millions of years to replace a nonrenewable resource.

Below are some examples of nonrenewable resources.

Coal

Oil

Natural Gas

Nonrenewable Resources (cont.)

Soil, minerals, and rocks are also examples of nonrenewable resources.

What makes soil a nonrenewable resource?

Soil can be washed away if it is left

uncovered or used improperly. As a

result, it is important for us to

conserve soil.

Using Natural ResourcesSometimes land is used for food production. Can

you name 3 ways that people use land for food production?

1. Ranchers use cattle that graze on the land.

2. Dairy farmers use land to raise cows that provide milk to make cream and cheese.

3. Soil is also used to grow crops, such as corn, avacados, and oranges.

Green Energy

Green energy is energy generated using renewable resources.

Explain which natural resource is used by the following pictures to produce green energy.

Hydroelectric dams use water, solar cells use sunlight, and wind farms use wind to produce electrical energy.

Water

Water from 31 states drains into the Mississippi River. All of this water makes the Mississippi River system one of the world’s largest watersheds.

A watershed is all of the land and water that drains into a river system. Why are watersheds important natural resources? What are some ways people use water?

What is a watershed?

How Can You Help?

A huge problem today is pollution. Pollution is harmful to natural resources.

How can you help to conserve natural resources and prevent pollution?

BrainPOP on Humans and the Environment

The End!

Remember to use your book, the virtual lesson, and this powerpoint to study for your test!