The Gaia Hypothesis & The Earth As A System Global Geography 12, CP Allen High School
What is Gaia? Greek mythology – goddess of the earth mother of living things, sustainer of life
Hypothesis=? thesis= main idea or argument (like in an essay or debate) hypothesis= a theory or proposal based on scientific or logical reason
Gaia Hypothesis An idea proposed by James Lovelock (published in 1979) All living things on earth (biosphere) function as one SUPERorganism that changes its environment to create conditions that best meet its needs, with the ability to self-regulate critical systems needed to sustain life
4 Systems The 4 systems that sustain life are: Biosphere (living things) Hydrosphere (all water on earth’s surface) Atmosphere (air) Lithosphere (soil)
Self-Regulation Surface Temperature maintenance of a consistent temperature that supports life Atmospheric Composition the composition of the air remains the same, even though it should change a lot over time Ocean Salinity the ocean never gets more/less salty, even though minerals are forever being added from rivers
What is a System? System? A group of parts that function together Open v. Closed all systems require an energy source to drive them parts can be either lost from or added to the system all parts exist in precise amounts, and nothing can be lost or added.
System Earth <ul><li>Earth=closed system. </li></ul><ul><li>All ingredients (water, gases, and chemical nutrients) exist on Earth in limited amounts. </li></ul><ul><li>For life on Earth to continue to function, these ingredients have to be recycled over and over again. </li></ul><ul><li> < linear closed loop> </li></ul><ul><li>Energy source: the sun </li></ul>
SYSTEM WARNING <ul><li>If we use up or seriously deplete any of Earth’s essential ingredients, or if we disrupt its natural cycles, we risk upsetting the balance of the entire system. </li></ul>
To sum up… <ul><li>Earth = single living organism. </li></ul><ul><li>Over 4.6 billion years the Earth has become: </li></ul><ul><li>self- evolving self- regulating self- sustaining </li></ul><ul><li>Evolve: change and become more effective Regulate: able to monitor/control/adjust itself </li></ul><ul><li>Sustain: to maintain current life indefinitely </li></ul>
Furthermore… <ul><li>All living things work act to create environmental changes that benefit all life forms </li></ul><ul><li>The Earth is always changing and adapting in response to its lifeforms </li></ul>
Gaia in action <ul><li>Planetary simulation: Daisyworld </li></ul><ul><li>http://library.thinkquest.org/C003763/flash/gaia1.htm </li></ul>
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