Lesson 7 & 8: How Do Ecosystems Change? and How do Humans Them?

A natural change to an ecosystem occurs when

• a severe drought causes plants to die.

• trees are cut down to make paper.

• roads are built through a forest.

• a dam is constructed to hold water back.

What kind of changes take place during succession?

• Animals move from one ecosystem to another.

• One or more species die out and no longer exist on Earth.

• Species slowly replace each other as the landscape changes.

• Plants stop growing and making food when days get shorter and colder.

After a forest fire, new plants and those that were not burned will __________ because the fire released nutrients into the soil.

• slowly die

• grow faster

• stop growing

• become extinct

Some animals hibernate during the winter because they

• lay eggs that need to be kept warm.

• need to avoid predators.

• change from one form to another.

• cannot find enough food.

Climate change can cause changes to ecosystems. What can happen to organisms that do not change with their ecosystems?

• They can disappear from Earth.

• They can stop the ecosystem from changing.

• They can form new ecosystems.

• They can be unaffected by the change.

Clearing prairies to plant crops is a negative change to an ecosystem because

• people plant trees to replace the ones they cut down.

• the way organisms interact in food webs is disrupted.

• humans are using the land to build farms instead of homes.

• organisms interact in the same ways before and after the change.

Anything that people add to the environment that harms living things is called

• pollution.

• chemical waste.

• damage.

• human development.

All the goods and services people need or want are either made of __________ or produced using them.

• plants

• animals

• chemicals

• natural resources

After an ecosystem has been destroyed, it

• sometimes can be restored.

• always slowly recovers on its own.

• can never recover from the damage.

• usually returns back to how it was before.

A(n) __________ species is a non-native organism that causes harm to the environment.

• native

• natural

• extinct

• invasive