EARTH AS A SYSTEM

ESSENTIAL QUESTION: HOW DOES THE EARTH WORK TO BE A SYSTEM?

SYSTEM

• Definition: A group of interdependent parts enclosed within a certain boundary.

• The objective of Earth System Science is to understand how the Earth is changing and the effects for life on Earth, with a focus on enabling prediction and alleviation of undesirable effects.

• Within the boundary of the earth is a group of four interdependent parts called subsystems.

BIOSPHERE

• Definition: The part of the earth's crust, waters, and atmosphere that supports life.

• Within the biosphere, living things form ecological communities based on the physical surroundings of an area. These communities are referred to as biomes.

• The term "biosphere" was coined by geologist Eduard Suess in 1875, which he defined as; "The place on Earth's surface where life dwells.“ He like many other scientists engaged in the study of the biosphere, or ecology.

GEOSPHERE

• Definition: The solid portion of the earth (distinguished from atmosphere, hydrosphere).

• The word "lithosphere" will be used in reference to all land in Earth's system.

• The solid, semi-solid, and liquid land of the lithosphere form layers that are physically and chemically different.

• The word "lithosphere" can take on different meanings depending on the speaker and the audience.

HYDROSPHERE

• Definition: The watery part of the earth's surface, including oceans, lakes, water vapor in the atmosphere, etc.

• Ninety-seven percent of Earth's water is salty. These large collections of salty water are referred to as oceans.

• Some scientists place frozen water--glaciers, icecaps, and icebergs--in its own sphere called the "cryosphere."

ATMOSPHERE

• Definition: The gaseous envelope surrounding the earth; the air.

• It extends from less than 1 m below the planet's surface to more than 10,000 km above the planet's surface.

• The upper portion of the atmosphere protects the organisms of the biosphere from the sun's ultraviolet radiation.

• It also absorbs and emits heat. When air temperature in the lower portion of this sphere changes, weather occurs.

CRYOSPHERE

• Definition: Some places on Earth are so cold that water is a solid—ice or snow. Scientists call these frozen places of our planet the "cryosphere."

• The word "cryosphere" comes from the Greek word for cold, "kryos.“

• Snow, ice, or both are key ingredients in every aspect of the cryosphere, including sea ice, glaciers, ice shelves, icebergs, and frozen ground.

CITATIONS

• http://www.cotf.edu/ete/ESS/ESSmain.html

• http://education.gsfc.nasa.gov/esssproject/ess_definition.htm

• http://nsidc.org/cryosphere/allaboutcryosphere.html

• http://www.cotf.edu/ete/ESS/ESSspheres.html