5.9C Changes to the Environment

5.9C Changes in an Ecosystem

5.9C: Predict the effects of changes in ecosystems caused by living organisms, including humans, such as the overpopulation of grazers or the building of highways

Objective:

​Many living things live on Earth and have the ability to cause changes to Earth whether big or small.

Most ecosystems have a near perfect balance of living and non-living things and if they become unbalanced, entire ecosystems can be destroyed

​Changes to the Earth

​Things that Can Cause Changes

• Overgrazing

• Overpopulation

• Building roads and buildings

• Deforestation

• Invasive species

• Overhunting and overfishing

​Overgrazing

​It can be caused by farm animals that aren't managed well

It can also be caused by animals that do not leave an area

Land becomes useless by overgrazing and can eventually become a desert

​Overgrazing

​Grazing is when animals such as cows or rabbits eat up plants (producers)

Overgrazing happens when plants are exposed for long periods of time, or don't have enough time to recover.

Multiple Choice

problem that occurs when grazing animals like cattle and sheep eat too much vegetation (grass)

• habitat

• overgraze

• thrive

• global warming

​Building Roads & Buildings

​By building on land, animals lose their habitats.

Animals that lose their habitats have two choices, die or migrate to a new location which will affect another ecosystem.

Multiple Choice

Which of the following would have a negative impact on an ecosystem

• constructing highways

• planting trees

• recycling paper

Multiple Choice

How will the construction shown above most likely effect (change) the environment?

• Animals of the ecosystem will thrive (increase in population)

• Plants will stop growing in the cleared ground

• Populations of predators will increase in this region.

​Deforestation

The clearing of a wide area of trees
​
By cutting down trees:
- Animals lose their habitats
- Oxygen production reduces

Companies cut down trees for things like:
- furniture
- paper
- any wooden materials

Multiple Choice

A park is home to a large number of robins, squirrels and rabbits. The robins and squirrels live in the park’s trees. The robins feed on earthworms and insects that live on the ground. The squirrels eat the acorns produced by the park’s oak trees. The rabbits hide in the bushes and feed on the grass. Which factor would negatively impact the number of rabbits living in the park?

• Collecting acorns off the ground.

• Planting more trees.

• Removing park bushes.

Multiple Choice

Which of the following would most likely result in a decrease in the population of insect-eating birds that build their nest on trees?

• Overhunting of animals that prey on birds

• Observation of birds by scientist

• Clearing of forests to build a highway

​Pollution

​The air and the environment around us gets affected by pollution.

Pollution is caused by fossil fuels burned and by humans and their trash.

Pollution leads to habitat destruction, animal death, plant death and illness.

It is also one of the causes of global warming

Multiple Choice

Most incidents of pollution are deliberately caused by______.

• humans

• animals

​Introducing New Animals to an Ecosystem

​New animals can destroy an ecosystem

For example:
- Lake trout are native to the Great lakes, but are considered to be an Invasive Species in Yellowstone Lake in Wyoming

- This is because Lake trout are NOT native to Yellowstone Lake, they compete with native cutthroat trout for resources.

Multiple Choice

Scientists are concerned about overfishing of shark populations. Sharks feed on rays and rays feed on scallops. Without sharks, rays consume all the scallop beds. This situation demonstrates that:

• humans can improve an ecosystem by removing predators.

• humans can upset an ecosystem by removing species through overfishing.

• reducing the shark population increases the quantity of scallops that can be taken.

​How do Prairie Dogs Change their Environment?

Watch the video and answer the questions on
page 5 of your booklet

​

Multiple Choice

Prairie dogs change their environment by

• Running away from predators

• digging burrows in the soil for shelter

• Sharing food with other organisms

• Help other organisms reproduce

​How do Beavers Change their Ecosystem?

Watch the video and answer the questions on page 6 of your booklet

​

Multiple Choice

How do beavers change the land to meet their needs?

• Leaving trees to grow taller

• Planting new trees to cut down later

• Cutting down trees to build a dam

The Vine that Ate the South

Watch the video and answer the questions on page 7 of your booklet

Multiple Choice

Kudzu is a nonnative plant that:

• competes with native plants for resources

• is not an invasive species

• shares resources with native plants