What are the Earth’s 4 subsystems and their definitions?
Hint: A subsystem refers to a self-contained or a self-sufficient system within a larger system. A system refers to a group of elements that interact with each other and work a complete unified form for a larger purpose. For e.g. a water cycle is a system in which liquid water, steam, temperature, clouds etc. interact with each other to maintain the natural cycle of water.
Complete answer: The four subsystems of the Earth are; A) Lithosphere – It is the rigid, outermost shell of the Earth and is made up entirely of rocks. All rocks, minerals, ores, etc. are found in this layer of the Earth. The lithosphere is of two types, oceanic and continental. Oceanic lithosphere forms the crust of the earth that is under the oceans and the continental lithosphere forms the continents. B) Hydrosphere – This is the total combined mass of all the water that is present on our planet. Around 71% of the earth’s surface makes up the hydrosphere. 97% of the total hydrosphere is accounted for by the saltwater in seas and oceans. Only 2.5% is freshwater. C) Atmosphere – It is the layer of gases that envelope the earth and is commonly called as air. It exerts pressure on the earth and allows water to exist in liquid form is the hydrosphere so as to support life on earth. Air itself contains gases that are essential for life forms, for e.g. carbon dioxide, oxygen, ozone etc. D) Biosphere – It is that subsystem of the earth, which includes the existence and interaction of living organism with each other and the earth itself. It is a self-regulating system in which plants alone generate around 130 terawatts of energy every year. They form this energy by converting solar energy into chemical energy.
Note: Out of all the four system, only the Biosphere has not been detected anywhere outside of our planet. All planets are composed of lithosphere and an atmosphere. In some planets the lithosphere is very small as compared to their atmosphere. Such planets are called gas giants. The hydrosphere requires very specific temperature and pressure conditions and hence it is also not found on any other planet yet.