Earth Systems

Concept of a “system”

• provides framework for understanding how each part of the Earth works and why it is changing

Concept of a “system”

• provides framework for understanding how each part of the Earth works and why it is changing

System

a group of interdependent materials that interact to form a united whole and are influenced by related forces.

Materials in a System

change in an effort to reach and maintain equilibrium.

move to a lower level of energy to attain balance and peace

Earth Systems: Closed

Type of system that exchanges only energy (no matter) with its surroundings

Eg. Earth and the Sun

Earth Systems: Open

Type of system that exchanges both heat and matter with surroundings; applies to most earth systems

Eg. river systems, volcanic systems, etc.

State of equilibrium

(Direction of Change in Earth Systems)

There is a universal tendency for systems to move toward a/an _________

Equilibrium

A condition in which the net result of the forces acting on a system is zero

Fundamental law

Any system tends to run down: to lose energy to the surroundings.

Direction of Change in Earth Systems

For spontaneous change to occur, the total energy of a system must decrease. The most stable state is the one with the lowest energy.

James Lovelock and Lynn Margulis

Proponents of Gaia Hypothesis

Gaia Hypothesis

The biosphere is a self-regulating system that controls its physical and chemical environments

We don’t have to do much to maintain the system

The Daisyworld Model of Earth Systems

Daisies represent the materials on the surface of earth (oceans, lands, clouds) where white daisies reflect light and black daisies absorb heat

The Earth can only survive because the Sun exists.

Mechanisms for Manipulating the Environment (Natural Manipulation)

Negative and Positive Feedback

Negative feeback

attainment of equilibrium involves a response that opposes the change; “mitigates” the impact(s) of the process. ( more solar radiation = global warming then more white daisies = reflect radiation, lower surface temperature)

Positive feedback

the reaction invokes a response that amplifies the change; “enhances” the impact(s) of the process.

Major Earth Systems

Hydrologic System
Tectonic System

Hydrologic System

A complex cycle through which water moves from the oceans, to the atmosphere, over the land, and back to the oceans again.

Water moving as surface runoff, groundwater, glaciers,ocean waves and current- erodes, transports, and deposits surface rock materials

Hydrologic Cycle

Precipitation = Runoff + Evapotranspiration + Infiltration

Precipitation = _______________

If water did not return to the oceans, sea level will drop by 1 m/year; all ocean basins will dry out in 4,000 years!

Tectonic System

Involves the movement of the lithosphere which broken into a mosaic of separate plates which move independently, separating, colliding, and sliding past one another.

The margins of the plates are sites of considerable geologic activity such as seafloor spreading, continental rifting, mountain building, volcanism, and earthquakes.

Major Tectonic Plates

Plate Motions and Boundaries

Earth Systems

biosphere

atmosphere

hydrosphere

geosphere

Earth Systems

The Earth is an interacting system of matter and energy, that as part of its functioning produces phenomena like volcanoes, glaciers, mountain ranges, oceans, and continents.

Earth Systems

The Earth is an interacting system of matter and energy, that as part of its functioning produces phenomena like volcanoes, glaciers, mountain ranges, oceans, and continents.

Internal heat (from radioactive decay)

The reason why there is still energy in Earth’s system, keeping it moving. Drives plate tectonics.

Solar energy

External source of energy for Earth’s Systems. Maintains ocean and atmosphere circulation and helps to drive erosion.