1. Natural Events and Human Activities Cause Changes in Ecosystems
Grade 7 Science Unit 1
Natural Events and Human Activities Cause Changes in Ecosystems
Chapter 3

2. The Changing Ecosystem
Have you ever noticed changes in the ecosystems around you?
When? What were the changes like? Do you know what caused the changes?

3. The Changing Ecosystem

4. What do you think is happening here?

5. Succession Succession: A natural change of the ecosystem.
The process where a biological community changes over time. These changes may be slow and hard to see over short time periods.

8. Pioneer species: the first species to live an ecosystem during succession. Example: lichens.
Climax community: the final community of succession in an area. It doesn’t change for many years. Example: Balsam fir forests

9. 2 Types of Succession
1. Primary Succession: Takes place in an area with no soil
Examples: bare rocks, sand dunes, and cooled lava

10. Primary Succession

11. Flow Chart Create your own flow chart of Primary succession
Start with bare Rock!
Have small plants first
Finally have a climax community!

12. 2 Types of Succession
2. Secondary Succession: The process where an ecosystem changes after it has been disturbed.
Example: A forest changing after a fire.
**The re-growth of a community.

14. Flow Chart 2 Create your own flow chart of Secondary succession
Start with a full ecosystem
Have a natural or human change
Have growth of small organisms
Finally have your climax community!

15. Succession Video!

16. Discussion... Read p. 70-1
Succession can have environmental changes such as...
1.Soil composition
2.Plant types
3.Animal types
4.Amount of light
Explain

17. Review Questions: Page 73 Q’s: 1, 2, 6 & 8.

18. “The Two Centimeter Forest”
Core STSE
“The Two Centimeter Forest”

19. The Human Impact... How do you think we have impacted our environment?
1.Harvesting resources
2.Habitat loss/ destruction
3.Introduced species
4.Pollution

20. Harvesting Resources We are Removing resources from ecosystems
These resources may not return and may be needed by other animals

21. Habitat Loss/ Destruction
Removing vegetation and soil removes shelter and food for animals.
Changes on land alter drainage of water which affects rivers and lakes.
See table 3.1 on
p. 77

23. Introduced Species
Species that have spread beyond their natural range into new locations as a result of human activities.
They can take the niche of natural populations and out-compete them.
Also called alien, exotic or non-native species

24. Ex. Of Introduced Species in NL
Moose 1904 (competes with caribou)
Eastern chipmunk 1962
Coyote
Snowshoe hare 1860
American mink 1934
Deer mouse
Norway rat
Masked shrew
American res squirrel 1963
Bank vole
Purple loosestrife
English ivy
Scotch broom

25. Endangered Species of Newfoundland & Labrador
Pine marten
Wolverine
Piping plover
Eskimo curlew
Long’s braya
Barrens willow

26. Pollution
Substances that cause harm to the air, soil, water, or living things are called pollutants.
Can have direct and indirect impacts on the environment.
P. 82

27. Review Questions: Page 85 Q’s: 2, 5, 9 & 13.

28. Humans can harm the environment
Are we doing anything to help?
Conserving habitats!
But – it’s not good for everyone…

29. Habitat Conservation Pros Cons Sustainability of resources
Preservation of biodiversity
Eco-tourism
Artificial habitats
Economic loss (job loss, etc.)
Limited human use

30. Journal Entry – Take a Stand!
A Conservation group wants to protect a pond forest area.
What are two reasons people would want this conservation area?
What are two reasons people may Not want this conservation area?
Do you think they should protect the area?

31. Groups Interested in Protecting the Environment...
Local Examples:
Protected Areas Association
Conservation Corps Newfoundland & Labrador

32. Groups Interested in Protecting the Environment...
National Examples:
Parks Canada
Canadian Native Federation
Nature Conservancy of Canada
David Suzuki

33. Groups Interested in Protecting the Environment...
International Examples:
Friends of the Earth
World Wildlife Fund
Ducks Unlimited

34. Website Activity

35. Chapter 3 Review Questions: Page 94-95 Q’s: 1, 6, 8, 10, 13 & 14.