4 biosphere
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The biosphere is the global sum of all ecosystems and can be defined as the narrow layer around Earth's surface in which life exists. It extends approximately 11 km into the oceans and 9 km into the atmosphere. The biosphere receives energy from the sun which is used by plants through photosynthesis and transferred through food chains, though some energy is lost as heat at each transfer between organisms. It forms a thin living crust on the planet within which the complex interactions between different environmental components sustain life.
4 biosphere
- 1. Scientists define the biosphere as the narrow layer around Earth's surface in which life can exist..
- 2. In a broader sense; biospheres are any closed, self-regulating systems containing ecosystems;
- 3. The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed (apart from solar and cosmic radiation), and self-regulating system.
- 4. The biosphere is located near Earth's surface because most of the sunlight is available near the surface. Plants need sunlight to produce their food, and almost every other organism gets its food from plants and algae. Most of these algae float at the surface of the ocean.
- 5. The biosphere extends about 11 km into the ocean and about 9 km into the atmosphere, where insects, bacteria, and pollen grains have been discovered. Both the biosphere and environment influence each other a lot.
- 6. Life exists on Earth because of several important factors. Life requires liquid water, temperatures between 10°C and 40°C, and a source of energy. The materials that organisms require must continually be cycled. Suitable combinations of the things that organisms need to survive are found only in the biosphere.
- 7. The actual thickness of the biosphere on earth is difficult to measure. Birds typically fly at altitudes of 650 to 1,800 meters, and fish that live deep underwater can be found down to -8,372 meters
- 8. Energy Flow in the Biosphere The energy used by organisms must be obtained in the biosphere and must be constantly cycled for life to continue. When an organism dies, its body is broken down and the nutrients in it become available for use by other organisms. This cycling of energy allows life on Earth to continue to exist.
- 9. Energy enters the biosphere in the form of sunlight, which plants use to make their food. When an animal eats a plant, the energy stored in the plant is transferred to the animal. Animals in turn eat other animals. At each stage in the food chain, some of the energy is lost to the environment as heat, which is eventually lost to space.
- 10. The biosphere forms a thin crust of living beings over the surface of our planet and consists of an immense variety of organisms out of which only about 1.5 million species have been identified and described.
- 11. The existence and well being of living organisms depend on a system of complex interactions within and in between the components of environment - the lithosphere, hydrosphere, atmos-phere and the biosphere itself. It is these interactions which satisfy all needs of all living organisms, such as shelter, water, oxygen to respire, mates to reproduce etc.