The document discusses the Gaia Hypothesis, which proposes that all living things on Earth function together as a single superorganism to regulate conditions for life. The hypothesis views Earth as a closed system with four interacting spheres - the biosphere, hydrosphere, atmosphere, and lithosphere. These spheres work together to maintain surface temperature, atmospheric composition, and ocean salinity over time in ways that sustain life. The Earth is seen as a self-regulating system driven by energy from the sun, and disruption to its natural cycles could upset the balance required for life.

1. The Gaia Hypothesis & The Earth As A System Global Geography 12, CP Allen High School

2. What is Gaia? Greek mythology – goddess of the earth mother of living things, sustainer of life

3. Hypothesis=? thesis= main idea or argument (like in an essay or debate) hypothesis= a theory or proposal based on scientific or logical reason

4. 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

5. 4 Systems The 4 systems that sustain life are: Biosphere (living things) Hydrosphere (all water on earth’s surface) Atmosphere (air) Lithosphere (soil)

6. 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

7. 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.