CHAPTER 5: The Universe, Earth, Natural Spheres, and GAIA


Summary of the Chapter

The nature of the Universe and the Earth are examined in this chapter. The Big Bang theory is presented as a model to explain the origin, history, and future of the Universe. Most cosmologists and physicists believe matter, energy, space, and time in our Universe were created from a huge explosion about 15 billion years ago. Ever since this explosion the Universe has been expanding at the speed of light. About 5 billion years ago our solar system formed. Verification of the Big Bang theory is based on four pieces of evidence.

The formation and evolution of the Earth is then explored next. The Earth began forming about 4.6 billion years ago. The timing and development of the Earth's continents and the atmosphere is discussed. It is then suggested that the Earth can be seen to be composed of four principal components: lithosphere, biosphere, atmosphere, and hydrosphere. It is also suggested that linkages exist between the components through biogeochemical cycling.

The topic concludes with an examination of the Gaia hypothesis. This theory suggests that life has the ability to control and modify certain aspects of the Earth’s lithosphere, atmosphere and hydrosphere. This modification is done when one of these components is change in a way that is detrimental to living organisms. Life can respond and reverse the changes to the environment through growth to attain the optimum conditions for their survival.


List of Key Terms

Abiotic, Angiosperm, Atmosphere, Average Global Temperature,

Big Bang, Big Crunch, Biogeochemical Cycling, Biosphere, Biotic,

Carbon Dioxide, Condensation,

Deduction, Deposition,

Element, Evaporation,

Falsification, Fossil,

Gaia Hypothesis, Glacier, Greenhouse Effect, Groundwater, Groundwater Flow,

Hydrologic Cycle, Hydrosphere,

Igneous, Infiltration, Inorganic,

Lithosphere, Lake, J.E. Lovelock,

Magma, Metamorphic, Methane, Mineral,


Ocean, Organic, Organic Matter, Ozone,

Photo-Dissociation, Photosynthesis, Precipitation,

River, Rock, Runoff,

Sedimentary, Snowfield, Sublimation,


Ultraviolet Radiation, Universe


Study Questions, Problems, and Exercises

Essay Questions

(1). Give a brief account of the formation of the Earth since its beginnings 4.6 billion years ago, noting important stages in its formation.

(2). Explain the origin, history and future of the Universe.

(3). What is the Gaia hypothesis? Is there any evidence for this theory?

(4). Define the following: lithosphere, hydrosphere, biosphere and atmosphere. How are they related to each other?

(5). Using the hydrological cycle as an example, show how the four spheres of the Earth are connected and interrelated.







Created by Dr. Michael Pidwirny & Scott Jones University of British Columbia Okanagan

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Copyright © 1999-2009 Michael Pidwirny

05/25/2009 9:51