The Four Interconnected Spheres of Earth

1. Atmosphere

2. Lithosphere

3. Hydrosphere

4. Biosphere

Atmosphere

• Surrounds Earth as a thin layer of mixed gasses that makes up the air you breath.

• The atmosphere protects you from the intense energy of the sun’s intense energy and distributes heat on Earth.

• Consists primarily of nitrogen and oxygen

Lithosphere

• It consists of rocks, minerals and soil

• Includes the Earth’s crust and the uppermost part of the mantle.

• Broken into a number of pieces called crustal plates.

• These pieces move around very slowly on the underlying

• mantle in the process of plate tectonics

• The thickness of the lithosphere depends on the location.

Hydrosphere

• Includes all of the water on the Earth’s crust –salty, fresh, and frozen.

• Includes oceans, lakes, rivers, glaciers, swamps, and water vapour.

• 70% of the Earth is ocean.

Biosphere

• Means “sphere of life”

• Is the layer of Earth in which life evolves.

• Supports all living things: millions of species, including those in the atmosphere and hydrosphere.

• Often times, all of the spheres together are referred to as the biosphere

The Decay Cycle

• There is no waste in natural systems!

• Creatures such as fungi and bacteria act as decomposers to eat and cycle natures waste materials.

• Ex. As leaves fall and decay, the remaining nutrients enrich the soil and help seeds various plants grow!

• This results in more trees, which in turn, produce more leaves which will fall, decay, and continue the cycle.

How dependent are we on natural systems?

Rule of Four!• We can survive for about four minutes without oxygen.

• Four days without water (Often less!)

• Four weeks without food.

• If our current economic system collapsed tomorrow, what might happen?

– How would people meet their needs and wants? How might people’s priorities change?