1. Biodiversity
The variety of plants and animals that live in a habitat at a particular time.
Biodiversity provide us with medicines, food, clean water and air, and important services our healthy planet depends on.

2. When a habitat is no longer fit for its organisms.
Habitat Destruction
When a habitat is no longer fit for its organisms.
Examples of Habitat Destruction include:
Cutting down trees in a tropical rain forests
A fire that burns up a prairie
A river that is polluted and can no longer support life

3. Non-native species that have a harmful effect on a habitat.
Invasive Species
Non-native species that have a harmful effect on a habitat.
Illinois has been working hard to keep Asian carp out of Lake Michigan. Officials are afraid that Asian carp would change the existing food webs in the lake and kill the native organisms.

4. Examples of pollution: Chemicals dumped into water by factories
Something introduced into the environment that is dirty, unclean or has a harmful effect.
Examples of pollution:
Chemicals dumped into water by factories
Car exhausts that make the air dirty.
Factories that burn coal, oil or gas

5. Human Population Growth When the number of people increase
Sometimes humans take the space that animals or plants used to live in.

6. Killing too many of a species.
Overexploitation
Killing too many of a species.
When too many members of a species dies, that species becomes in danger of extinction.

7. Ecological Footprint
The amount of the environment necessary to produce the goods and services necessary to support a particular lifestyle.
Your ecological footprint includes:
Your transportation choices
The amount you recycle
The kind of food you eat
Where and how you live