Planet Earth is made up of four overlapping systems that contain all of world’s land masses, water sources, living organisms, and gases. These four systems are known as spheres. Three of these spheres are abiotic and one sphere is biotic.
Geographers break down the Earth’s systems into four spheres that make up the world’s air (atmosphere), water (hydrosphere), land (geosphere), and living organisms (biosphere). In this breakdown, all of the Earth’s water is included in the hydrosphere. This includes surface water (such as rivers, lakes, and oceans), water in the ground, ice and snow, and water in the atmosphere in the form of water vapor.
The Earth’s atmosphere is the gaseous layer that envelopes the world. This layer mostly contains a mixture of mostly nitrogen (78%), Oxygen (21%), and argon (0.9%). In addition, trace gases (carbon dioxide, nitrous oxides, methane, and ozone) account for another tenth of a percent. Water vapor, dust particles, pollutants, and pollen also can be found in mixed into the atmosphere.
All of the water on Earth is known collectively as the Earth’s hydrosphere. Water is found in all three states on Earth. As water vapor in the atmosphere, as liquid in such as in streams, rivers, lakes, ponds, and oceans, and as ice and snow.
The lithosphere contains the elements of the Earth crust and part of the upper mantle. This is the hard and rigid outer layer of the Earth. The term is taken from the Greek word lithos meaning “rocky”. This part of the Earth includes soil.
The biosphere covers all living organisms on Earth. There is an estimated 20 million to 100 millions different species in the world organized into 100 phyla that make up the five kingdoms of life forms. These organisms can be found in almost all parts of the geosphere. There are organisms in the air, soil, and water on Earth.
Earth Divided into Two Major Systems
Some scientists organized of the parts of the Earth can be divided into two main systems. These two systems include all the organic and inorganic matter of the world. Every living and non-living thing on Earth falls under one of these two main spheres which are the Earth’s geosphere and biosphere. As with the four system organization, the biosphere represents all of the Earth’s living organisms. The geosphere is the collective name for the earth’s atmosphere, lithosphere, hydrosphere, and cryosphere. The atmosphere is the space above the Earth’s surface. This includes the air that we all breath. The lithosphere is the solid part of the Earth such as rocks and mountains. The hydrosphere is the liquid water such as the rivers, lakes, and oceans. The cryosphere is the frozen water of the earth and is further broken into four types: glaciers, snow cover, floating ice, and permafrost.
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