When things happen over and over again, we call it a cycle. For example, we need food, air and water to live. The ways we get food, air and water are part of our life cycle.

All living things depend on each other. Animals need oxygen. They breathe in oxygen. They breathe out carbon dioxide as a waste product. Plants need carbon dioxide to perform photosynthesis…Read More

Photosynthesis is the way plants make their food, which is called carbohydrates. Plants use sunlight for energy and make carbohydrates out of carbon dioxide and water. Oxygen, which animals need to live, is a waste product of photosynthesis, along with tiny drops of water. When the plant releases the waste product, we call this transpiration. So, animals depend on plants for oxygen, and plants depend on animals for carbon dioxide. Animals and plants both have to have water. This exchange is a natural cycle.

When natural cycles are changed, the plants and animals have to change, too. Making a change like this is called adapting.

Sometimes a change in a natural cycle is so big, that the animals and plants don’t have the time to change. Or, they cannot make the changes they need to make. That’s often what happens when our environment becomes polluted. The plants and animals are unable to make changes and either die or are driven off before they can change.

Our earth’s five greatest environmental problems are causing changes that make it hard for animals and plants to adapt: air pollution, acid rain, water pollution, waste disposal and the loss of trees.

Scientists and international leaders agree that the year 2012 is a very important year for the environment. We have to begin cleaning up the earth now! If we don’t, by the year 2012 it may be too late. Our earth may never be clean and healthy again.