Everything Life Sciences Grade 10

• Biosphere: is the sphere that includes all living organisms, from plants to bacteria to
  multicellular organisms.


• Hydrosphere: is the combined mass of water found on, under and above the surface
  of the earth. The hydrosphere is made up of lakes, rivers and springs and can be called
  freshwater and salt water. The hydrosphere is home to a wide diversity of aquatic plant
  and animal life.


• Lithosphere: refers to the outermost surface of the Earth, the Earth’s crust. Theoceanic
  lithosphereis associated with the oceanic crust and exists in oceanic basins.Continen-
  tal lithosphereis associated with continental crust which covers the Earth’s landmass.
  The lithosphere shields living organisms from the heat of the Earth’s core and contains
  ionic compounds which allow plant and animal life to exist.


• Atmosphere: is the layer of gases surrounding the earth. The atmosphere’s ability to
  absorb the ultraviolet rays of the sun is what allows life on earth to survive.

Spheres on Earth

Biosphere Hydrosphere

Lithosphere Atmosphere

The connections between spheres imply that disturbances in one sphere affect the other
spheres. For example, excessive deforestation (biosphere) results in increased erosion of soil
(the upper layer of the lithosphere-pedosphere) into rivers (hydrosphere). Deforestation also
results in an increase in atmospheric carbon dioxide (atmosphere). Deforestation therefore is
an example of how disturbances in one sphere produces effects in the hydrosphere, upper-
lithosphere and atmosphere.

Chapter 9. Biospheres to ecosystems 257