HUMANS IN THE BIOSPHERE Chapter 6

A Changing Landscape  Growing populations depend on the limited natural resources of earth for survival.  Humans rely on ecological life support systems to provide us with; clean air, water, and fertile soil.  Humans must be aware that our activities on earth have an impact on and can change our environment.

Human Activities  Hunting & Gathering:  Human hunting and gathering causes mass extinction of animals  Agriculture:  Farming destroyed many forests to make farm land. (decrease in oxygen, increase in carbon dioxide).  Fertilizers & pesticides contaminate water supplies  Irrigation strains water supply  Food supply demand puts strain on environment( soil nutrients).  Industrial Growth & Urban Development:  Makes life easier and more productive  Causes pollution (Acid rain).

Renewable & Nonrenewable Resources  Renewable Resource: Resource that can regenerate or be replenished quickly by the earth.  Not unlimited  Example; Water  Nonrenewable Resource: Cannot be replenished by the earth.  Example; Fossil fuels  Sustainable Development: Using natural resources without depleting them and still providing for human need as well as, without causing environmental harm.  Example: Using lady bugs to eat insects that eat crops instead of using insecticides/pesticides.

Human Impact on Renewable Resources  Land Resources: Space for construction, over farming/over grazing.  Soil Erosion- wearing away of surface soil by air & water.  Desertification-turning farmlands into deserts.  Forest Resources: Wood supplies for building and heat, oxygen, habitats, food.  Deforestation-loss of forest that can’t re-grow.  Fishery Resources: Food supply, over fishing.  Aquaculture- Raise aquatic animals for human consumption.  Air Resources: Air quality, pollution, burning of fossil fuels, smog, acid rain.  Freshwater Resources: Only 3 % of water on earth is freshwater, very limited resources.

Charting a Course for the Future  Ozone Depletion:  Ozone Layer: high concentration of ozone gas in the earths atmosphere. Absorbs UV radiation (sunscreen for the earth).  Ozone Depletion: the breakdown of the ozone layer. Caused by CFC’s (chloroflurocarbons). CFC’s mostly banned today. Scientists predict that damage done to the ozone by CFC’s should be repaired within 50yrs.  Global Warming: Increase in the average temperature of the biosphere.  Caused by humans; Burning of fossil fuels, deforestation, landfills, fertilizers.