Lesson 1: Plant and Animal Wastes

• There are no garbage cans in nature. Plants and animals do not need them. Can you imagine your world without garbage cans? All the trash in the environment would make it hard to move around. You will see how plants and animals get rid of their waste.

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• Do you remember how plants give off oxygen, and how animals use it? Plants also use many of the wastes that animals make. Do you know that plants use carbon dioxide? Carbon dioxide is a gas that animals exhale as a waste gas. Nature is quite good at finding something to use another’s waste.

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• In the fall, leaves drop from trees. Wild grass that has grown tall over the summer turns brown. The growing season is over. Dead plant material is everywhere. When winter comes, a blanket of snow covers the leaves and the dead plants. When the snow melts, much of the dead plant material is gone. Where did it go?

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• The dead plant material broke down and became part of the soil. This is the fate of leaves,

• grasses, and other plants in the forest. They break down or decay.

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• Organic matter is matter that occurs in nature. Organic matter decays. That means that it breaks down into simpler things. Nature reuses these simpler things over and over again. Matter that humans make, like plastic bags, glass, and tin cans, is not organic.

• When you see decay, you know that a decomposer has been at work. Have you ever seen moldy food? This is another sign that decomposers are at work. The food begins to rot and change. It breaks into smaller pieces.

• Bacteria, earthworms, fungi, snails, and many insects are decomposers. They break down organic matter. This broken-down organic matter enriches the soil.

• Nature is a great recycler. When leaves fall to the ground, they decay and become food for plants and animals.

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• Humans and animals need to get rid of their body wastes. Body wastes would poison people if they did not get rid of them. Humans use a bathroom. House cats use kitty litter. Wild animals do not use a toilet or kitty litter. In nature, animal waste decays. It contains building blocks or simple nutrients that nourish the soil.

• The same thing happens when animals die; they become food for other living things.

• Humans and animals need to get rid of their body wastes. Body wastes would poison people if they did not get rid of them. Humans use a bathroom. House cats use kitty litter. Wild animals do not use a toilet or kitty litter. In nature, animal waste decays. It contains building blocks or simple nutrients that nourish the soil.

Decomposers return these nutrients to the soil. People often refer to animal waste as manure. Gardeners mix well-rotted (decomposed) manure into their soil. It improves the soil and helps plants grow faster, bigger, and healthier.

Run-off is the water that soil doesn’t retain or soak up when rain falls on it. It is excess water.

Run-off can wash things from the land into creeks, rivers, and lakes. This can pollute the water into which it flows.

What kinds of things can find their way into run-off?

If many animals are kept together, animal waste can build up quickly. It is hard for the decomposers to keep up. This lets animal waste become part of the run-off. Cities and towns produce pollutants as well. Fertilizers and pesticides used on gardens, lawns, and farms may be carried by run-off. Oil and gas that spills from cars and other vehicles can also pollute the water.

Activity 1: Decomposing Lunch – see experiment sheet

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When it comes to recycling, nature is a great recycler. Decomposers work to break down plant and animal waste and return nutrients to the soil. These nutrients provide food for new plants. Nature’s recycling program works all the time, and it doesn’t pollute the environment.

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Lesson Glossary

decay - to rot and break down

decomposer - an organism that feeds on the waste and dead tissues of other organisms

environment - all of the surroundings and conditions that affect the growth and development of living things

manure - animal waste

organic matter - material that occurs naturally, such as wood, straw, hair, skin, fur, and bone

pollute - put damaging waste into the land, air, or water

run-off - excess water that drains into creeks, lakes, and rivers

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