Newton's Apple Banner SuChin's Photo

SuChin sloshes through wetlands to discover their ecological role.
Segment length: 7:00

Teacher's Guides Index


Show Number 1413

What are wetlands
and why are they so important?

What type of wildlife lives in wetlands?

Why do people drain or fill them in?

[Apple Image] Getting Started

Collect about 1/4 liter (1 cup) each of several different soil types. Try sand, clay soil, forest soil, and any others you can find. Air-dry them. Put each soil sample in its own coffee filter and fit the filter into the neck of a jar. Tape it in place. Pour 1/2 liter (2 cups) of water into each jar, very slowly.

The water that goes into the jar is water that the soil couldn't hold. How do they differ?

Do you live near a wetland? How is it unique from other areas? What kinds of wildlife live in the wetland? How does the wetland change from season to season? Which soil do you think would be best in a wetland? Why?

[Apple Image] Overview
Heated controversy has surrounded attempts to preserve wetlands. For decades, many thought wetlands were mucky, mosquito-infested places and drained them to use as farmland, industrial sites, or residential areas. Fewer than half as many acres of wetlands remain in the continental United States compared with when the first European settlers arrived about 500 years ago. Now, wetlands are recognized as important wildlife refuges and water purification systems.

Wetlands are areas that have standing water for at least part of the year. Marshes, swamps, tidal flats and associated pools, bayous, and bogs are the most common. Marshes are water-saturated, poorly drained areas with both aquatic and grasslike plants. Swamps, unlike marshes, have trees and bushes. Water flows into swamps and marshes from streams, or even an ocean. Bogs are waterlogged, spongy ground in former lakes now filled with living and dead mosses, which eventually become peat.

Wetlands are important for many reasons. They support a large volume of plants, which in turn supply cover and food for animals. Wetlands retain water like a giant sponge - flowing water is slowed as it passes through and is absorbed by plants and soils. By soaking up the water, wetlands not only prevent floods but make water available during a drought. They also help reduce the threat of low salinities in coastal waters.

Wetlands can also clean up contaminated water. Organisms and soils in a wetland act as a filter for fertilizers and other pollutants. Algae and bacteria break down mineral and organic matter, which can then be used as food for plant life. Some municipalities use wetlands as the final stage in treating waste from sewage treatment plants. Other communities are actually constructing wetlands for this purpose. However, wetlands can't perform miracles. They can be ruined by too much waste.

Because the economic and health benefits of wetlands are now well known, Congress has passed several laws protecting them. However, in many areas developers want to build on the land, farmers want to cultivate it, and oil companies want to remove the oil under the ground. As long as our population keeps growing, the struggle over what will become of the wetlands will continue.

[Apple Image] Connections

1. Flooding has always been a problem in many parts of the world, but it appears to be a growing problem. Why? What can we do to prevent it?

2. Imagine that you own property designated as a wetland. Should you be able to do whatever you want with that land?

[Apple Image] Resources

Levantines, L. (1995, July-Aug) Science gets swamped. Audubon, p. 112.

Lewis, W.M., Jr. (1996, July) Wetlands on the line. Geotimes, p. 5.
(This issue includes other articles on wetlands)

Manks, M. (1996, June-July) The beauty of wetlands. National Wildlife, p. 20.

Niering, W.A. (1985) Wetlands: The Audubon Society Guides. New York:
Alfred A. Knopf, Inc.

Rood, R. (1994) Wetlands. New York: Harper Collins.

Rybolt, T.R. & Mebane, R.C. (1993) Environmental experiments about life.
Hillside, NJ: Enslow Publishers, Inc.

U.S. Fish and Wildlife ServiceÐnational wetlands inventory:

Wetnet (includes virtual bird tour):

Ducks Unlimited
1 Waterfowl Way
Memphis, TN 38120
(901) 758-3825

Student Activity:
Dragonfly Image

Insect Inventory

Examine the insects that live in a nearby pond or stream.

[Apple Image] Main Activity

(Note: This activity should be done before the first frost of fall or after spring thaw.)

Wetlands are important habitats for animals. One kind of animal that you might not think to look for there is insects. Yet there are more species of insects than of all the other animal species combined, and they live in almost all known habitats on earth. You can find insects in any body of water, unless it1s very polluted.


1. Go to a nearby body of water. Before you do any collecting, look around. What wildlife do you see? Do you notice any insects?

2. Draw or write about any insects that you see. Look them up in your field guide. Can you identify them?

3. See if you can catch any insects. Put them in a jar to take back to the classroom.

4. Now look in the water. What wildlife do you see? Do you notice any insects?

5. Pull your strainer through the water and look at what animals you catch. If it isn't a fish or polliwog, chances are it's an insect. Put any insects you catch in a jar with some water.

6. Draw or write about the insects you caught. Were there any you could see that you couldn't catch? Look them up in your field guide. Can you identify them?

7. Chances are that many of the insects you see in the water are larval stages of the insects you see on land and in the air. Many insects start their lives in water and then move out of the water as they mature. Can you figure out which of the insects you caught in the water are an earlier stage of the same insects you saw on land?

8. Take the insects you caught back to the classroom and try to identify them more clearly. See what else you can learn about them.


  1. How would the food chain change if many insects didn't have aquatic life-history stages?
  2. What roles do insects have in nature?

[Try This]
Research a wetlands controversy in your county or state. Find a situation where someone wanted to develop a wetland somehow. Were there people who were against that? Who were they? What were the arguments for each side? How was it resolved? What do you think?

[Try This]
Go to a wetland and measure an area 1 meter x 1 meter (3.3' x 3.3'). Count how many different species of plants you find in that area. See if you can identify any of them. Then measure the same area in a field or forest. How many different species of plants do you find there?

[Try This]
Predict puddles. Before a rain, look at your yard or the school grounds. Where do you think puddles will form? Put markers where you think water will gather. Do you think it will stay longer in one place than another? Why? After the rain, go check out your hypotheses. Were you right? Are any animals using the puddles?

Tapes of this episode of Newton's Apple and others are available from GPN for only $24.95.
Please call 1-800-228-4630.
For information on other Newton's Apple resources for home and school,
please call 1-800-588-NEWTON!

3M Innovation We encourage duplication for educational non-commercial use.
Educational materials developed with the National Science Teachers Association.
NEWTON'S APPLE is a production of KTCA Saint Paul/Minneapolis. Made possible by a grant from 3M.
PBS Online - Minnesota Online - Welcome to Newton's Apple - Teacher's Guides Index