1. Topic 2: Human Impacts on Ecosystems
Grade 7 Unit 1
Topic 2: Human Impacts on Ecosystems

2. Objective: I can identify examples of human impacts on ecosystems
I can analyze the relationship between the impact of humans and their needs and desires

3. Introduction:
The habitat is the particular place where an organism lives.
Living things can share a habitat with no problems.
People are animals too, thus we are apart of nature.
To meet our basic needs we rely on the ecosystem around us.

4. An Overview Many human technologies depend on naturals resources
The materials and products found in nature. Ex: trees, oil, water and minerals

5. An Overview cont.
When humans and other living things use the same habitat, human needs are often in conflict with those of other living things.
This result in some impacts or changes to ecosystems.

6. An Overview cont.
Human impact on the environment is not always easy to predict.
Songbirds in Toronto were dying in great numbers as they flew into the windows of high-rise buildings lit at night.

7. Read the « Did You Know » on page 19
? Read the « Did You Know » on page 19. ? What impact do humans have on other living organisms

8. The environment will change depending on the needs of the organisms that live in it. For example: The population of Canada grew and the territory was covered. Give three major changes that took place due to this growth in population.
Cut down trees
Built roads
Transformed the prairies into agricultural land

9. The impact that humans can have can be minor or major and can put a lot of pressure on the environment. What impact do millions of cars have on the environment? (4) 
Roads – parking lots
- urban growth - polluted air

10. People and Nature - A Changing Relationship
The ways people interact with the environment has changed over time.
This change often had a great deal to do with technological advancement
Before modern engines and machines, people had a relatively small impact on the environment.
Modern technology has resulted in an increased impact on the ecosystems in which we live.

11. As the population grows, our needs put pressure on our ecosystem and because we have the same vital needs as other living things, these needs often come in conflict.

12. Activity Explain how the following situations have an impact on our environment.
A student is mountain biking in the scenic parts of the forest.
________________________________________________________________________________
A biologist puts trout in a lake.

13. Needs vs wants
People often mix the idea of ​​needs and wants. Needs refer to one of our four basic needs, so what the body needs to survive. Whereas wants relate to things that make life more comfortable, enjoyable and convenient. Organisms can survive if their wants are not met.

14. Ex : Food is a need because organisms can not live without eating.
Ex : Video games are a want. We can survive without video games, but life would not be as fun.

15. Activity – classify the following things as needs or wants

16. When Is a Need a Want?
Most Canadians do not have an ongoing problem finding food and shelter, so they can spend more time, and attention, on attaining their “wants”.
This has resulted in the line between needs and wants becoming blurred.
I need new shoes. I need to go to the party.

17. When Is a Need a Want? cont.
Since meeting needs and wants often requires natural resources, each time we satisfy a need or a want we are making a choice to impact our environment.
While food is a need, having food imported from distant locations is a luxury.

18. When Is a Need a Want? cont.
Our demand for consumer products often conflicts with the health of the ecosystem.
In our haste to satisfy our wants, we often forget the basic needs of plants and animals.

19. Activity
using your textbook answer the following questions in your notes.  

20. No Simple Answers
Sometimes what appears to be damaging to the environment is actually good.
After years of doing everything to fight forest fires, Park Wardens have discovered that some forest fires are beneficial.
By controlled burning, Park Wardens clear areas of small trees, leaves, and other forest debris. This allows rebirth in the form of new grasses, and other plants that provides nourishment to wildlife.

21. No Simple Answers cont.
Sometimes what appears to be good for the environment is actually damaging.
The use of DDT in the early 1900’s

22. No Simple Answers cont.
Through the continued study of natural areas and natural systems Ecologist continue to learn how humans can reduce their impact on the environment.
Predators such as wolves, coyotes, and cougars were once seen as “bad” and unnecessary animals. Now we have come to realize their role, as natural controls, in the ecosystem and how they help control the deer, mice, rabbit and other small animal populations.

23. Based on what we have just learned what can we do to limit our impact on the environment…

24. Wetlands
Wetlands are areas where the soil is wet for all or most of the year.
These areas drain slowly and are important parts of the ecosystem, for they have more wildlife than either fields or forests.
When wetlands are filled in, the flow of water can change, causing flooding and droughts.
Wetlands are one of the most endangered habitats in Canada.

25. Bill Nye: Wetlands