1. Chapter 7
Threats to Survival
Lesson 2

2. Science Essential Question
How does a system of living and non-living things operate to meet the needs of the organisms in an ecosystem?
Science
Essential
Question

3. MAIN IDEA
Different species of plants and animals face a number of threats to their survival.

4. Vocabulary For Today Page B68
Extinct – When the last member of a species has died
Migrate – To move to another region when seasons change and food is scarce
Species – A group of living things that produces living things of the same kind

5. How Organisms Change Environments Pages B68 – B69
Every living thing causes changes to its environment.
These changes affect other living things.
An environmental change caused by humans or other organisms can have positive and negative effects.
Nature and humans can threaten the survival of living things.

6. Natural and Human Threats Page B70
Humans can be one of the biggest threats to the survival of a species.
A species is a group of living things that produces living things of the same kind.
Some animals migrate, or move to another region when seasons change and food becomes scarce.
Can you think of an animal that migrates?

7. Natural and Human Barriers
Migrating animals face natural and human barriers.
Natural barriers include mountain ranges.
Some migrating birds will not cross mountains.
Human barriers include highways.
Migrating caribou usually will not cross highways.

8. Lesson Wrap Up All living things cause changes in their environment.
Changes in a habitat, including changes made by humans, can have both good and bad effects.
There are human and natural threats to the survival of living things.

9. Threats to Biodiversity – Discovery Education
Movie Time
Threats to Biodiversity – Discovery Education