Realms of Earth:The Four Great Realms: The natural systems encountered in physical geography operate within the four great realms, or spheres, of the Earth. These are the atmosphere; the lithosphere, the hydrosphere, and the biosphere.

Lithosphere - All processes associated with the solid earth

Hydrosphere - All processes associated with water

Atmosphere - All processes associated with the gases that envelope the earth

Biosphere - All processes that involve living organisms

Four great Realms

The biosphere is the global sum of all ecosystems. The biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere.

The biosphere is postulated to have evolved, beginning with a process of biopoiesis (life created naturally from non-living matter such as simple organic compounds) or biogenesis (life created from living matter), at least some 3.5 billion years ago.

On land, the life layer is the zone of interactions among the biosphere, lithosphere, and atmosphere

Biosphere

BioSphere and Four Realms of Earth.

The hydrosphere describes the combined mass of water found on, under, and over the surface of a planet.

Hydrosphere

Lithosphere

A lithosphere is the rigid outermost shell of a rocky planet, and can be identified on the basis of its mechanical properties.

It comprises the crust and the portion of the

upper mantle that behaves elastically on time scales of thousands of years or greater

This outermost solid layer of the Earth provides a platform for most life-forms.

The solid bedrock bears a shallow layer of soil in which nutrient elements become available to organisms. The surface of the lithosphere is sculpted into landforms which provide varied habitats for plants, animals, and humans.

Lithosphere• Different Layers

Inside the Earth

Rock Formation

Thin Gaseous envelope

The gaseous layer that surrounds the Earth. It receives heat and moisture from the surface and redistributes them, returning some heat and all of the moisture to the surface. It supplies vital elements needed to sustain life forms.

Atmosphere

ATMOSPHERIC TEMPERATURE � This diagram shows the

average global temperature of air at altitude.

� Temperature tends to decrease with altitude

� Temperature inversions (when it increases with altitude) occur where various gases cause varying rates absorption of radiation

Greenhouse gases

ENVIRONMENTAL LAPSE RATE

Atmospheric Layers

Figure 1.7

Troposphere – Temp decrease w/ heightMost of our weather occurs in this layerVaries in height around the globe, but Averages about 11 km in height.

Atmospheric Layers

Figure 1.7

StratosphereTemperature inversion in stratosphereOzone plays a major part in heating the air at this altitude

Atmospheric Layers

Figure 1.7

MesosphereMiddle atmosphere – Air thin, pressure low,Need oxygen to live in this region. Air quite Cold -90°C (-130°F) near the top of mesosphere

Atmospheric Layers

Figure 1.7

Thermosphere“Hot layer” – oxygen molecules absorb energy from solar Rays warming the air. Very few atoms and molecules in this region.