1. Human Use of Ecosystems
Lesson 9
September 7th, 2010

2. Human Impacts and Biodiversity
All Ecosystems provide 4 essential services to humans. There are 4 main groups.
1. Provisioning (e.g., providing food, water, and fuel)
2. Regulating (e.g., oxygen and carbon dioxide levels, decomposing wastes)

3. Human Impacts and Biodiversity
3. Cultural (e.g., recreation, scientific discovery, intellectual and spiritual inspiration)
4. Support for these services (e.g., photosynthesis, crop pollination, and seed dispersal in support of food production).

4. Human Impacts and Biodiversity
To maintain biodiversity, we have to use ecosystems in a sustainable way.
Sustainable use - using an ecosystem’s resources in a way that meets our current needs without compromising the ability of future generations to meet their needs

5. Human Impacts and Biodiversity
Diversity applies not only to the number of species, but as well as the diversity in species and number of different ecosystems.

6. In every species there are differences between individuals
In every species there are differences between individuals. This is called genetic diversity.
Genetic diversity is necessary for a species to stay healthy, and decreasing the population size with decrease its diversity.

7. Different ecosystems provide different services.

8. Human Activity decreases all levels of biodiversity
Human Activity decreases all levels of biodiversity. 5 Major causes are listed below
Habitat change
Overexploitation
Pollution
Invasive species
Climate Change

9. 1. Habitat Change
The process by which humans alter a habitat enough so that the native species can no longer live their

10. 1. Habitat Change The most common cause of declines in population
Native Species – species that normally live in a specific habitat.
The most common cause of declines in population
Habitats change for various reasons
Forestry, agriculture, urban development

11. 1. Habitat Change
Altering habitat may also lead to habitat fragmentation.
Small areas within a large region are altered a bit at a time. This creates a patchwork of altered and original habitats.

12. 2. Overexploitation using a resource faster than it can be replaced.
Overexploitation can often lead to extinction.
Example: overfishing – estimated 90% of fish have been removed from the sea since 1950

14. 3. Pollution
Any substance added to the environment that produces a condition that is harmful to organisms.
Example: solid waste that cannot be recycled.
Another form of pollution is air pollution.

15. 3. Pollution Pollution can enter water sources in different ways
Point source pollution enters a body of water at a specific place from an identifiable source. Oil spills from tankers, waste water from pulp and paper mills, and partly treated waste water released from a sewage treatment plant

16. 3. Pollution
Non-point source pollution enters bodies of water indirectly when water from rain or snow travels over land and picks up pollutants from many different sources before entering a stream or a lake. Fertilizer and pesticide run-off from farms and salt runoff from roads are both examples of non-point source pollution.

17. 3. Pollution

18. 4. Invasive Species
Increases in international travel and trade have introduced non-native species to all parts of the globe.
Invasive species - a non-native species that causes harm to the ecosystem into which it has been introduced.

19. 4. Invasive Species
Invasive species tend to out-compete native species, often because they have no natural predators in the new ecosystem or they reproduce faster than native species.

20. 5. Climate Change
Climate change is a cause of loss of biodiversity around the world.
Climate is the average weather conditions that occur in a region over a span of 30 years or more.

21. 5. Climate Change
When climate change occurs in a region, average temperatures may rise or fall, the amount of rainfall may increase or decrease, and even general wind directions may change.

22. 5. Climate Change
Global warming - is an increase in Earth’s average temperature, caused partly by an increase in carbon dioxide in the atmosphere. Over the past two centuries, the amount of carbon dioxide in the atmosphere has increased, largely due to human activities that burn fossil fuels. Global warming has caused relatively rapid climate change.

23. MSIP
The Farmed Fish Vs Wild Fish Assignment Will be worked on for the next 2 days in MSIP