2.  Environmental scientists study how the natural world works, and how humans and the environment affect each other.

3.  The environment includes all the living and nonliving things with which organisms interact.

4.  Environment is often used to mean the nonhuman or “natural” world. But humans are a part of nature.

5.  Biotic factors: refer to the living organisms. Example: fish, bacteria, tree  Abiotic factors: refers to the non-living things. Example: water, soil, air

6.  Environmental science is the study of how the natural world works, how the environment affects us, and how we affect our environment.

7.  Understanding interactions between humans and the environment is the first step toward solving environmental problems.

8.  Environmental science is interdisciplinary which means it will involve more than one study of science including ecology, earth science, chemistry, biology economics, political science and others.

9.  Environmental science is the pursuit of knowledge about the world whereas environmentalism is a social movement dedicated to protecting the natural world.

10.  In the last several hundred years, both human population and resource consumption have increased dramatically. There are limits to our resources.

11.  Renewable resources can be replaced in a short period of time.  Nonrenewable resources cannot be replaced or it takes millions of years to replace.

12.  When they are used up, they are gone forever. Resources are considered sustainable if it can continue at the same rate into the foreseeable future.

13.  Renewable resources: fruits, grains, sunlight, wind energy, etc.  Nonrenewable resources: crude oil, natural gas, coal, copper, etc.  Sustainable resources: timber, water, soil, agricultural crops

14.  Recently our population has grown to about 7 billion people. We add about 78 million people to Earth every year, that’s more than 200,000 people a day. Population growth leads to many environmental problems. It’s not just the number of people but the amount of resources we consume.

15.  Ecological footprint expresses the environmental effects of an individual or population in terms of the total amount of land and water required:

16.  To provide the raw materials the individual/population consumes  To dispose of or recycle the waste the individual/population produces

17.  The ecological footprint is usually applied to humans but every organism, natural or synthetic object has a footprint.