The Four Spheres of the Earth

Diagram of the Earth’s Spheres

1) Lithosphere The lithosphere is the solid, outer layer of the earth. Since the lithosphere includes the soil, it provides a home for many different organisms.

How do human actions affect the lithosphere? Negative mining- strips the earth of nutrients - littering/using non-recyclables- ends up in landfills and contaminates the earth - construction- destroys natural environments, decreases drainage - pesticides- add unnatural chemicals to soils - deforestation- increases soil erosion because tree roots no longer help hold soil in place Positive composting- can decrease the amount of garbage in landfills - aeration- allows for air to enter soils - conservation areas and provincial parks- preserve/protect the land - planting trees- prevent soil erosion - gardening/green rooftops- regreens the landscape in urban areas

2) Hydrosphere The hydrosphere consists of all of the water on Earth. Of this water: 97% is salt water in the earth’s oceans 3% is freshwater such as in lakes and streams Since all living organisms need water, all organisms depend on the hydrosphere.

How do human actions affect the hydrosphere? Negative dumping garbage into the ocean- contaminates the water - driving boats- adds gasoline to the water which contaminates it - oil spills- contaminates water and can kill organisms in the water - building on shorelines- can contaminate water or kill vegetation in the water - overfishing- can decrease the amount of organisms in the water therby decreasing nutrient content overall - building dams- changes water levels which can destroy habitat and reduce the amount of wildlife Positive sewage treatment plants- water returning to the lakes and oceans contains less contaminants - fish sanctuaries- allow a safe habitat for fish which helps them survive and contribute to the nutrients in the lake

3) Atmosphere The atmosphere is the layer of gases that surrounds the earth. It is composed of: 78% nitrogen, 21 % oxygen, 1% trace gases (eg. carbon dioxide, water vapour) Greenhouse gases in atmosphere trap the sun’s energy to warm the earth so organisms can survive.

How do human actions affect the atmosphere? Negative - aerosols- deplete the ozone layer - driving cars- adds excess greenhouse gases to the atmosphere - factories- (same as cars) - burning tires/garbage- adds harmful gases to the atmosphere Positive hybrid vehicles- decreases the amount of greenhouse gas emissions - alternative power (wind/solar)- (same as hybrid vehicles) - planting trees- absorbs CO2 from the atmosphere and adds O2

4) Biosphere The biosphere is the part of the earth where life exists including water, land and air. The lithosphere, hydrosphere and atmosphere interact to create the physical environment of the biosphere.

Venn Diagram: atmosphere Clouds hydrosphere biosphere Water Table Top Soil lithosphere

Homework