1. Ecosystems Objective 1.06
Explain and evaluate some ways that humans affect ecosystems.
Habitat reduction due to development, pollutants,
And increased nutrients.

2. Habitat Reduction
Humans affect (change) natural habitats in many ways.
Due to land development (building of homes and businesses) trees and plants are cut down and the land is cleared. This is called deforestation.
When this happens the habitat can no longer support the other organisms.
Which needs are taken away when this happens? (water, food, shelter, sun)

3. Results of habitat reduction
Increased soil erosion because the roots are no longer present to help hold the soil in place.
Organisms are left with out food and shelter
Organisms must now find a smaller habitat to live in. This causes competition between animals for living and nonliving things.
So now we have organisms living in smaller habitats. What are some things they are competing for? (think about the needs of every living thing)

4. Example of Deforestation/Habitat Reduction

5. Pollution
Many of the machines and vehicles that we use produce unwanted changes in the environment
Chemicals are released from cars and factories into the air
Air pollution can hurt animals, plants and other organisms
Air pollution can cause acid rain. Some pollutants in the air react with the water vapor to form acids
Acid rain is just rain containing these acids

6. Pollution continued…
Harmful chemicals are thrown into the water. This harms the animals, making it difficult for them to breathe. The food the animals consume are now affected by the chemicals causing many animals to die.

7. Air and Water Pollution

8. Increased nutrients Too many nutrients in an ecosystem can cause harm
Humans use fertilizers, which are nutrients for the soil, on farms, golf courses, and gardens
These fertilizers often run-off into near-by water sources when it rains
This increase of nutrients can cause too many organisms to grow.
One type of plant may take over an area causing the other producers to die out
How will herbivores be affected by the lost of these plants?

9. Overpopulation of Plants

10. Questions
An area of land is cleared to build a new neighborhood. What effect (consequence) does building construction have on an ecosystem?
Increases habitat
Decreases habitat
Has little effect
Has a positive effect

11. In Alex’s neighborhood everyone uses fertilizer to make their grass grow better. What effect could this have on the pond near the neighborhood?
a. Plants in the pond would decrease (get smaller) b. Animals in the pond would have more food c. It would not affect (change) the pond d. Increased nutrients could damage the pond by creating too much plant growth

12. What is one way that soil pollution gets into the water?
It is washed from the soil during rain
It melts when sunlight hits it
It melts during the forest fires
It is carried there by insects

13. What is a positive way that humans can impact (make a difference) in the environment?
a. Planting trees b. Increasing nutrients c. Reducing habitats d. pollution

14. Determine how materials are recycled in nature
Ecosystems Objective 1.07
Determine how materials are recycled in nature

15. Materials Recycled in Nature
Recycling is used when matter is broken down so new things can be made
Recycling happens in nature and with man-made materials
Perhaps your have seen a dead plant or animal slowly disappear. When this happens nature’s recyclers are at work.
They use dead organisms for food.

16. Materials Recycled in Nature continued…
When an organism dies, all the pieces of matter that make up the organism, must be recycled
Decomposers break down the nutrients in the dead organism and release a form of nitrogen that the plants use
This process is know as decomposition
Animals get these nutrients when they eat plants or when they consume each other.

17. Questions What is the main purpose of decomposers in an environment?
Make food for the animals
Convert sunlight into energy
Take in carbon dioxide and give off oxygen
Dispose of waste matter into the environment

18. What would happen if the decomposers in the ecosystem were eliminated?
Some other organism would take the decomposer’s place
There would be not effect (result or consequence) on the ecosystem
Nutrients would become scarce (limited) in the ecosystem
The plants in the ecosystem would become decomposers

19. End of Ecosystems Review