1. Humans in the Biosphere

2. A Changing Landscape
* Human activities change the flow of energy in an ecosystem and can reduce the ability of ecosystems to recycle nutrients. Some activities that have transformed the biosphere:
Hunting and gathering
Agriculture – domestication of animals, modernization of practices – Green Revolution (farming practices that increased yields of rice, wheat, and other crops)
Industry – machines and factories during 1800s – cities grow rapidly
Urban development – spread of suburban communities to new lands
All of this activity by humans has affected ecosystems

3. Renewable and Non-renewable Resources
Renewable – can regenerate and are replaceable, but not necessarily unlimited
Non-renewable – cannot be replenished by natural means (fossil fuels – coal, oil, gas, uranium)
Sustainable Use – using natural resources at a rate that does not deplete them
* Human activities affect the supply and quality of renewable resources, including resources such as land, forests, ocean resources, air, and water.

4. Renewable Resources There are several renewable resources available:
Land
Forest
Ocean
Air
Water

5. Renewable Resources (continued)
Land Resources – soil – should be renewable if managed properly – plowing leads to increased rate of soil erosion – leads to desertification

6. Renewable Resources (continued)
Forest Resources – lumber – should be renewable – selective cutting vs. clear cutting – deforestation = erosion

7. Renewable Resources (continued)
Ocean Resources – commercial fishing – should be renewable – overfishing leads to stock collapse – Aquaculture (farming of aquatic ecosystems) an option or limiting fishing amounts

8. Renewable Resources (continued)
Air Resources – air pollution – smog – asthma – acid rain, ozone depletion, global warming – all affect air as a renewable resource

9. Renewable Resources (continued)
Water Resources – industrial pollution, domestic pollution, groundwater contamination
Need to protect water supply to keep it as a renewable resource

10. Biodiversity
* Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere
Three divisions of biodiversity
Ecosystem diversity
Species diversity
Genetic diversity

11. Ecosystem Diversity
Ecosystem Diversity – variety of habitats, communities, ecological processes

12. Species Diversity
Species Diversity – number of different species in biosphere
Insects
54.4%
Protists
Other Animals
4.2%
19.7%
Plants
18%
Bacteria
Fungi
0.3%
3.4%

13. Genetic Diversity
Genetic Diversity – sum total of all the different forms of genetic information carried by all organisms

14. Biodiversity (continued)
*****Biodiversity is one of Earth’s greatest natural resources. Biodiversity provides us with foods, industrial products, and medicines.*****
* 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.
Extinction and endangered species (possibly due to over-hunting) – can destroy food webs/ecosystems
Development of land = habitat fragmentation (split ecosystem into pieces) – less species can live here
Pollution - DDT – biological magnification – concentrations of a harmful substance increases in organisms at higher trophic levels – can destroy food webs/ecosystems
Introduced species – invasive species – transported/not native – crowd out native species, often killing native species

15. Pollution 10,000,000 1,000,000 100,000 10,000 1000 1 Magnification of
DDT Concentration
Fish-Eating Birds
10,000,000
Large
Fish
1,000,000
100,000
Small Fish
10,000
Zooplankton
1000
Producers
Water 1

16. Biodiversity (continued)
Conservation efforts focus on protection of entire ecosystems as well as single species. This will ensure that the natural habitats and the interactions are preserved.

17. Charting a Course for the Future
2 major concerns: Thinning/Depletion of Ozone and Global Warming
Ozone Depletion – Ozone absorbs UV radiation – “hole” in ozone layer = damaging UV radiation. Must limit CFCs which destroy ozone
Global Warming – human activities vs. natural variations in climate (not sure which is the cause…must study more with models)
Value of a Healthy Biosphere
- recycle, energy conservation – will help maintain a healthy biosphere