Ecosystems Objective 1.06

Explain and evaluate some ways that humans affect ecosystems.

Habitat reduction due to development, pollutants,And increased nutrients.

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)

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)

Example of Deforestation/Habitat Reduction

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

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.

Air and Water Pollution

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?

Overpopulation of Plants

Questions

An area of land is cleared to build a new neighborhood. What effect (consequence) does building construction have on an ecosystem?

a. Increases habitatb.Decreases habitatc. Has little effectd.Has a positive effect

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 foodc. It would not affect (change) the pondd. Increased nutrients could damage the pond

by creating too much plant growth

What is one way that soil pollution gets into the water?

a. It is washed from the soil during rainb. It melts when sunlight hits itc. It melts during the forest firesd. It is carried there by insects

What is a positive way that humans can impact (make a difference) in the

environment?a. Planting treesb. Increasing nutrientsc. Reducing habitatsd. pollution

Ecosystems Objective 1.07

Determine how materials are recycled in nature

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.

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.

Questions

What is the main purpose of decomposers in an environment?

a. Make food for the animalsb.Convert sunlight into energyc. Take in carbon dioxide and give off oxygend.Dispose of waste matter into the environment

What would happen if the decomposers in the ecosystem were

eliminated?a. Some other organism would take the

decomposer’s placeb. There would be not effect (result or

consequence) on the ecosystemc. Nutrients would become scarce (limited) in

the ecosystemd. The plants in the ecosystem would become

decomposers

End of Ecosystems Review