Interactions Within Ecosystems

By: Ms. Moya

What is Competition?

• An ecosystem depends on a balance, sometimes called the balance of nature, which only provides for a certain number of organisms to survive within it.

• So organisms need to compete for survival, but what is competition?

Scenario

Plants in a forest are growing close together. The tallest plants receive the most sunlight, while the smallest plants receive less, because the taller plants shade them from the Sun’s rays.

Are these plants in competition with each other? Explain your thinking.

Plants Compete For Resources

• Ecologists say that all of the plants within an ecosystem are in competition with each other; they are competing for the sunlight.

• Plants also compete for water. In desert ecosystems, where water is scarce, the roots of the cactus plant spread out under the surface of the soil to search for water. The plant with the longest roots will survive.

A Little More About Competition!

Animals Also Compete

• How are the animals within these ecosystems in competition?

• Directions: Each group must observe their pictures and explain how the organisms are in competition. You must use evidence from the picture to support your answer.

Picture 1

The Wildebeest and the zebra are in competition for grass?

Picture 2

The Antlers and the Zebra are in competition for water.

Picture 3

These seals are in competition with each other for mating/reproduction rights.

Picture 4

These King penguins are in competition with each other for space.

FINAL THOUGHTS

• Did you notice a pattern in the pictures?• What makes one species better than others at

competition?

HomeworkIdentify how organisms in your ecosystem are in

competition for resources.• Identify and explain how one species of plant is in

competition with other plants for resources within your ecosystem.

• Identify one animal species and explain how it is in competition with another species for resources within the ecosystem.

• Identify one animal species and explain how it is in competition with members of its own species for resources within the ecosystem.