Four Realms Of Earth By Sheefa 5s6d66

Introduction: The earth is unique because it is only known planet that s life. The earth’s surface consists of only both land and water. A blanket of air is surrounding the earth. It is inhabited of living organism, both plants and animals. The environment on the earth consists of only three realms, namely land or lithosphere, water or hydrosphere, and air or atmosphere. All these three domains combine to form the life-giving domain of the earth, called the biosphere. The biosphere is the narrow zone of between land, water, and air where life exists.

Lithosphere: The surface of the earth is made up of solid rock and soil is called the crust or lithosphere. The lithosphere, sometimes called the geosphere, refers to all of the rocks of the earth. It includes the planet's mantle and crust, the two outermost layers. It comprises the seven continents and the rocky ocean beds. The actual thickness of the lithosphere varies considerably and can range from roughly 40 km to 280 km. The lithosphere ends at the point when the minerals in the earth's crust begin to demonstrate viscous and fluid behaviors. The exact depth at which this happens depends on the chemical composition of the earth, and the heat and pressure acting upon the material. Continents are large land masses on the surface of the earth. They are usually separated from each other by water called oceans. Together the continents and the ocean floor form the lithosphere. The boulders of Mount Everest, the sand of Miami Beach and the lava erupting from Hawaii's Mount Kilauea are all components of the lithosphere.

Hydrosphere: The hydrosphere is the combined mass of water found on, under, and above the surface of a planet, minor planet or natural satellite. It occupies about 71 per cent of the earth’s surface, which is why the earth is also called the watery planet. The hydrosphere It has been estimated that there are 1386 million cubic kilometers of water on Earth. This includes water in liquid and frozen forms in groundwater, oceans, lakes and streams. Saltwater s for 97.5% of this amount. Fresh water s for only 2.5%. Of this fresh water, 68.9% is in the form of ice and permanent snow cover in the Arctic, the Antarctic, and mountain glaciers. 30.8% is in the form of fresh groundwater. The hydrological cycle transfers water from one state or reservoir to another. Reservoirs include atmospheric moisture (snow, rain and clouds), streams, oceans, rivers, lakes, groundwater, subterranean aquifers, polar ice caps and saturated soil. Solar energy, in the form of heat and light (insulation), and gravity cause the transfer from one state to another over periods from hours to thousands of years. Most evaporation comes from the oceans and is returned to the earth as snow or rain. Sublimation refers to evaporation from snow and ice. Transpiration refers to the

expiration of water through the minute pores or stomata of trees. Transpiration is the term used by hydrologists in reference to the three processes together, transpiration, sublimation and evaporation.

Atmosphere: An atmosphere is a layer of gases surrounding a planet or other material body, is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low. The atmosphere of Earth is mostly composed of nitrogen about 78%, oxygen about 21%, argon about 0.9% with carbon dioxide and other gases in trace amounts. Oxygen is used by most organisms for respiration, nitrogen is fixed by bacteria and lightning to produce ammonia used in the construction of nucleotides and amino acids and dioxide is used by plants, algae and cyan bacteria for photosynthesis. The atmosphere helps protect living organisms from genetic damage by solar ultraviolet

radiation, solar wind and cosmic rays. Its current composition is the product of billions of years of biochemical modification of the pale atmosphere by living organisms. Troposphere: The troposphere is the lowest portion of Earth's atmosphere, and is also where nearly all weather takes place. It contains approximately 75% of the atmosphere's mass and 99% of the total mass of water vapor and aerosols. The lowest part of the troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to 2 km (1.2 mi) deep depending on the landform and time of day. The tropopause is an inversion layer, where the air temperature ceases to decrease with height and remains constant through its thickness.

Stratosphere: The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. About 20% of the atmosphere's mass is contained in the stratosphere. The stratosphere is stratified in temperature, with warmer layers higher and cooler layers closer to the Earth. The increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet radiation by the ozone layer.

Temperature vary within the stratosphere with the polar night winter

Mesosphere: The mesosphere is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the mesopause. In the mesosphere, temperature decreases as the altitude increases. The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally occurring place on Earth with temperatures below −143 °C. The exact upper and lower boundaries of the mesosphere vary with latitude and with season, but the lower boundary of the mesosphere is usually located at heights of about 50 kilometers above the Earth's surface and the mesopause is usually at heights near 100

kilometers except at middle and high latitudes in summer where it descends to heights of about 85 kilometers.

Thermosphere: The thermosphere is the layer of the Earth's atmosphere directly above the mesosphere. The exosphere is above that but is a minor layer of the atmosphere. Within this layer of the atmosphere, ultraviolet radiation causes photo ionization of molecules, creating ions in the ionosphere. The radiative properties of UV rays cause an imbalance of positive and negative energy, creating ions. The thermosphere begins about 85 kilometers above the Earth. Temperatures are highly dependent on solar activity, and can rise to 2,000 °C. Radiation causes the atmosphere particles in this layer to become electrically charged enabling radio waves to be refracted and thus be received beyond the horizon.

Exosphere: The exosphere is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitational bound to that body, but where the density is too low for them to behave as a gas by colliding with each other. In the case of bodies with substantial atmospheres, such as Earth's atmosphere, the exosphere is the uppermost layer, where the

atmosphere thins out and merges with interplanetary space. It is located directly above the thermosphere.

Biosphere: The biosphere also known as the ecosphere is the worldwide sum of all ecosystems. The two ed words are "bio" and "sphere". It can also be termed as the zone of life on Earth, a closed system and largely selfregulating. By the most general biophysiological definition, 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.