1. Chapter 6 Humans in the Biosphere
Unit 2-Ecology
Chapter 6
Humans in the Biosphere

2. Humans influence on the Biosphere

3. Human activities that affect the biosphere
Hunting& Gathering
Agriculture
Industry
Urban development
Austin Smart Growth Initiative

4. Types of resources Nonrenewable resources:
unable to be replenished through natural means
Ex: fossil fuels, natural gas
Renewable resources:
able to be replenished but is not unlimited
Ex: freshwater

5. Sustainable development
A way to use natural resources without causing long term environmental problems
This plan takes into consideration environmental, economic, and community demands

6. Problems land resources face
Desertification
the process of overusing land and drought leading to the formation of arid, desert lands that cannot sustain agriculture

7. Soil erosion
loss of topsoil layer from over farming (plowing) lands

8. Deforestation
The process of cutting down (logging) forests for lumber and land.
Leads to severe erosion during heavy rains.
Which can lead to permanent changes to local soils and microclimates.

9. Overfishing
Harvesting fish faster than they can be replaced by reproduction.
What happens to aquatic food webs if overfishing continues to occur?

10. Aquaculture raising water animals for human use
Pictured to the right are tilapia fish farms in Australia that then export the fish to markets.

11. Air pollution
Combustion of carbon fuels released nitrogen and sulfur that combine with water to form acid rain.
Pollutant:
any harmful substance that enters the biosphere from land, air, or water

12. Acid rain

15. Why should we preserve biodiversity?
sum total of genetically based variety of all organisms in the biosphere
Ecosystem diversity
Species diversity

16. Why should we preserve biodiversity?
Biodiversity is one of Earth’s greatest natural resources.
Species of many kinds have provided us with foods, industrial products, and medicines – including painkillers, antibiotics, heart drugs, antidepressants and anticancer drugs.

17. Threats to species biodiversity
Human activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments.

18. Threats to species biodiversity
Endangered: species that is declining in population size
Extinction: species that disappears from all or part of its range
Endangered status:
Ailuropoda melanoleuca 

20. Habitat fragmentation
When land is developed through or around ecosystems, the species residing within are impacted in what way?
Central Park in New York City is a perfect example of habitat fragmentation.

21. Biomagnification:
Increasing the concentration of harmful materials up the food chain

22. Introduced species
Humans transport animal and plant species from one part of the world to another.
Many of these species can become invasive. They reproduce rapidly and lack parasites and predators that helped control their populations “back home.”
Nutrias are native to South America but have become pests in coastal US cities.

23. Conserving Biodiversity
To conserve biodiversity and multi faceted approach is best:
Protection of species
Protection of habitat
Protection of biodiversity

24. Conserving Biodiversity Challenges
Balancing :
Public need and economics
Public policy
Conservation

25. Charting a Course for the Future
Researchers are gathering data to monitor and evaluate the effects of human activities on important systems in the biosphere.
Issues:
Ozone depletion
CO2 emissions
Global warming
Alternative fuels
Alternative food sources

26. Ozone depletion
Ozone: layer of concentrated gas that protects the Earth from harmful UV rays
1970s, scientists found a gap in the ozone layer near Antarctica.
NASA image

27. Global warming
Compounding the ozone depletion was the buildup of CFCs (chlorofluorocarbons) from aerosols and AC units with Freon.
CFCs trap heat, leading to a rise in the global temperature.

29. Click on image to play video.
Ozone
Click on image to play video.

30. Value of a Healthy Biosphere
More complex and diverse ecosystems are the more stable they are.
Complexity + Diversity = Stability
All ecosystems play a role in the health of the biosphere.