1. Lesson 8 – Biodiversity
Our World Ontario

2. Biodiversity
Biodiversity is the number of different species living in a given area or ecosystem
Approximately 1.5 million species have been identified and studied
Biologists estimate that there are between 5 and 50 million species on Earth
Greater biodiversity exists in ecosystems near the equator than in those near the poles
Higher temperatures and greater amounts of rainfall contribute to high biodiversity

3. Benefits of Biodiversity
Ecosystems with high rates of biodiversity are better able to remain healthy and stable when disturbed
The more diverse, the better able to withstand diseases, droughts, loss of a species, or arrival of new species
Ecosystems with less diversity are more fragile

4. Protecting Biodiversity
Human actions such as pollution, habitat destruction, and the introduction of new species can harm ecosystems
The best way to protect biodiversity is to limit these disturbances
Protecting biodiversity keeps ecosystems healthy

5. Biodiversity under Attack!
There is greater threat to biodiversity in areas that are heavily populated by humans such as southern Ontario
More natural ecosystems are cleared for farming, housing, or road construction
More pollution is created, which can damage ecosystems and the organisms that live in them

6. Species at Risk
The greatest threat to biodiversity is that a species can become extinct
An extinct species no longer exists on Earth
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) monitors species and separates them into four categories:

7. Species at Risk
Special Concern – may become threatened or endangered because of various factors
E.g. Polar bear, great blue heron, Atlantic cod

8. Species at Risk
Threatened – likely to become endangered if no action is taken
E.g. Humpback whale, wood bison, Kentucky coffee-tree

9. Species at Risk
Endangered – in immediate danger of becoming extirpated or extinct
E.g. Barn owl, swift fox, northern cricket frog

10. Species at Risk
Extirpated – no longer exists in the wild in a specific area
E.g. Paddlefish, grey whale

11. Species at Risk Extinct – no longer exists on Earth
E.g. Great Auk, passenger pigeon, sea mink

12. Extinction
Extinction is a process that may result from natural catastrophes or gradual changes
Asteroid impacts, volcanic eruptions, or natural climate changes can wipe out entire species, but they are rare
The greatest threat to today’s species is human activity
Of 700 known vertebrates to have become extinct in the last 400 years, 12 had lived in Canada

13. Reasons to Protect Biodiversity
Ensure ecosystem stability and sustain all life forms
Provide natural processes to produce oxygen, carbon dioxide, and nitrogen that protect our planet
Help species adapt to changes in their environment
Provide raw materials for food, clothing, medicine
Enhance our quality of life by adding variety to our surroundings
Help shape our culture and inspire poets, painters, and writers