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.