1. Unit 1: Planetary Systems: Quest for Balance What is a system? - interdependency - impact of change on a system - our needs within a system - dynamics of energy flow

2. What is a system? Group of independent but interrelated elements comprising a _______________; Mutuality: a reciprocal relation between interdependent entities (objects or individuals or groups) The Earth system is a complex interaction between its subsystems the _____________________________________

3. Impact of change on a system The Sacred Balance? Most systems tend toward a state of _______________ where system inputs are balanced by system outputs. Though natural systems change over long periods of time, on the scale of a human lifetime they appear to be static.

4. Impact of change on a system A steady-state equilibrium is reached when the rates of system inputs and outputs are equal, and the amount of material stored in the system is constant over time.

5. Feedback Outputs generated by the functioning of a system component either encourages change in the system (positive feedbacks) or discourage changes (negative feedbacks). Negative feedbacks act to regulate the system to keep it in a state of equilibrium. In order for a system to maintain a _____________ or average condition the system must possess the capacity for ____________________. Self-regulation in many systems is controlled by negative feedback and positive feedback mechanisms

6. Feedback A negative feedback discourages system change. An example of a negative feedback is used to support the notion of biospheric regulation of the atmosphere called the “_______________________" Some feel that the relatively stable conditions on Earth (atmospheric gas composition, temperature, etc) is due to the regulatory influence of the biosphere over the atmosphere

7. GAIA Hypothesis http://www.veoh.com/collection/gaiasel ene/watch/v3044782PYtPad9 http://www.youtube.com/watch?v=44yi Tg7cOVI What is the Gaia Hypothesis?

8. Gaia Hypothesis In 1965, __________________ published the first scientific paper suggesting the Gaia hypothesis… A theory that the living organisms of the biosphere form a single, complex interacting system that creates and maintains a habitable Earth; named after Gaia, the Greek Earth mother goddess. The idea that Earth is a living system. Life helps create the environment it needs in order to live. In simpler terms, biological responses tend to regulate the state of the Earth's environment in their favor

9. This theory is important to Physical Geography and other Earth Sciences for the following reasons: The Gaia theory suggests that the abiotic and biotic environment is made up of many complex interrelationships; Many of these complex interrelationships are quite delicate and may be altered by human activity to a breaking point; and The theory suggests that humans must learn to respect Gaia by reducing their intentional modification of the Earth's abiotic and biotic components.

10. Positive Feedback – Encourages Cange

11. Negative Feedback

12. System changes due to an imposed stress

13. Types of systems Systems can be classified as open, closed, or isolated. __________________ allow energy and mass to pass across the system boundary. A _________________allows energy but not mass across its system boundary. An _________________ allows neither mass or energy to pass across the system boundary.

14. Open Systems

15. Closed System Closed System - is a system that transfers energy, but not matter, across its boundary to the surrounding environment. Our planet is often viewed as a closed system.

16. Earth as a System!

17. Most systems share the same common characteristics: Systems have a ____________that is defined by its parts and processes. Systems tend to function in the same way. This involves the _______ and ________ of material (energy and/or matter) that is then processed causing it to change in some way. The various parts of a system have functional as well as structural relationships between each other. The fact that functional relationships exist between the parts suggests the _________and __________of some type of energy and/or matter. Functional relationships can only occur because of the presence of a driving force. The parts that make up a system show some degree of ______________ - in other words the parts work well together.

18. Our needs within a system? Brainstorm with a partner! Example: System Element System elements are the kinds of things or substances composing the system. They may be atoms or molecules, or larger bodies of matter-sand grains, rain drops, plants, or cows.

19. Dynamics of energy flow Forces that shape the Earth derive their energy from a number of different sources. _________________ are those driven by exogenic forces that primarily derive their energy from solar radiation.

20. Energy Sources For instance, soil erosion is caused by the force of wind acting on bare ground. We can trace the energy that causes wind erosion to the receipt of solar radiation Texas dust storm during the Dust Bowl (1935)

21. Energy Sources _____________ are those that get their energy from endogenic forces originating deep within the Earth. Such as:

22. Energy Sources Many of the great mountain systems like the Himalayas are a product of the collision of lithospheric plates Mt. Paricutin, a cinder cone volcano

23. Self-Sustaining Systems A spacesuit, out of necessity, is a self- sustaining system.

24. Self-Sustaining Systems Biosphere 2 is a structure built in an attempt to build an “Earth-like” system to sustain life and constructed in a size small enough to be put into space. Located in the Arizona desert outside of Tucson, is was built to replicate the Earth’s environment (“Biosphere 1”) www.bio2.com

25. Self-Sustaining Systems