What is the Biosphere?

The geologist Eduard Sues coined the term biosphere. The biosphere is characterized as a part of the earth, which includes ground and air. Moreover, the organisms on earth live in the biosphere. The biosphere is a confined area on the earth's surface where water, soil, and air combine to promote life. Several different types of life exist here.

Role of the Biosphere

The interaction between organisms plays an important role in maintaining the ecosystem. Therefore, the regulation of the climate biosphere is important. The artificially constructed biosphere is a self-contained area. The composition of nitrogen and oxygen in the earth's atmosphere is 78% and 21%, respectively. The phenomenon by which carbon atoms travel continuously from the atmosphere to earth and earth to the atmosphere is known as the carbon cycle. The parts of the biosphere are the atmosphere, lithosphere, and hydrosphere.

The United Nations Educational, Scientific, and Cultural Organization (UNESCO) biosphere reserve facilitates solutions for conserving biodiversity. The large-scale chemicals, biological, geological, and physical disturbance of the earth's surface are addressed by the global environmental change.

Many environmental issues exist in today's environment, such as air pollution, water pollution, deforestation, ozone layer depletion.

Biosphere Resources

Some important resources are provided from the biosphere. For example, people rely on the biosphere for food, medicines, and many more. The biosphere is a very thin layer present on the surface of the earth where life is supported. It is made up of living and non-living components from which nutrients and energy are obtained.

All living organisms are expected to adapt to the biosphere. Biosphere reserves are the areas where plants and animals on the verge of extinction are kept in protection. Biosphere assists in the control of atmospheric composition, soil quality, and water cycle and hence functions as the planet's life support system.

The scientific study of the relationship between organisms and the environment is referred to as ecology. A complex relationship exists between organisms and the environment; thus, both organisms and the environment are interdependent. The term environment means surrounding. Therefore, the biotic and abiotic components are included within the environment.

Physical Environment

Soil

The uppermost weathered layer of the earth's crust is soil. It comprises minerals, rock particles, and organic matter. It is a biologically active matrix. The various diverse group of organisms resides in the soil. The study of soil is referred to as pedology.

Composition of soil

The soil includes particles of minerals, organic matter, air, and water. The mineral particle present in soil includes sand, silt, and clay. Organic matter is also present in the soil, which includes living biomass, humus, and detritus. It comprises humic as well as non-humic substances. The carbohydrate, proteins, lignin, lipid, and organic acid comprise non-humic substances, whereas humic substances are formed from the decomposition of organic substances. Soil's 80-90% organic matter is humus. Humus is a dark-colored amorphous substance. The composition of humic substances is carbon, hydrogen, nitrogen, and sulfur.

Based on the interaction between soil particles and water molecules, soil water is divided into the following types.

• Hygroscopic water: The hygroscopic water surrounds the soil particle as a thin film and remains firmly attached to the soil. Hygroscopic water is not available to plants.
• Capillary water: Between the soil particles, capillaries are present in which water is present and is referred to as capillary water. Capillary water is available to plants. 
• Gravitational water: The earth's gravitational force pulls the water deep into the soil, forming gravitational water. It is not available to plants.
• Chemically bound water: The water present in hydrated oxides of iron, aluminum, silicon is known as chemically bound water. The chemically bound water is not available to plants.

Air and atmosphere

A mixture of gases, called air, makes the atmosphere. The celestial body is surrounded by a gaseous mass or envelope known as the atmosphere. At the earth's surface, the atmosphere is dense due to gravity that tends to pull the gases at the earth's center.

The atmosphere is divided into four layers

1. Troposphere: Of the earth's atmosphere, more than 80% is the troposphere. The precipitation, water vapor, and clouds appear in the troposphere, extending from the earth's surface to an altitude of up to 8-18 km. The tropopause is the top of the troposphere, and it forms the boundary between the troposphere and stratosphere.
2. Stratosphere: After tropopause, the stratosphere starts, and it extends up to 50 km. At the height of 15 to 30 km, a thin layer of ozone is present in the stratosphere. Finally, the top of the stratosphere is stratopause, and it forms the boundary between the stratosphere and mesosphere.
3. Mesosphere: This layer starts from 50 km and extends up to 85 km. Mesopause lies between the mesosphere and the thermosphere. Therefore, the coldest part of the earth's atmosphere is the mesosphere.
4. Thermosphere: Thermosphere extends from 85 km to 600 km in the atmosphere. Thermopause exists between the thermosphere and exosphere.

Adaptation to the Physical Environment

Organisms require specific environmental conditions for their normal growth and development. The product of natural selection is adaptation. Organisms acquire new genetic traits through natural selection. An adaptation is a genetically determined heritable trait of an organism that gets evolved over some time through natural selection.

The earth's environment is heterogeneous and dynamic. The condition of the environment varies in both space and time. Acclimatization is different from adaptation. There is physiological, anatomical, and morphological adjustment within a single organism in acclimatization, thereby improving performance and survival in response to environmental change.

Ecosystem

The functional unit of organisms in a particular place interacting with one another and environment is defined as the ecosystem. The botanist Tansley has first proposed the concept of the ecosystem.

Components of the Ecosystem

The components of the ecosystem include abiotic as well as biotic factors. Physical and chemical factors come under abiotic factors. The chemical factors include light, temperature, and moisture.

Organisms that make up the biotic components are divided into autotrophs and heterotrophs. Autotrophs are organisms that can synthesize organic compounds. Two kinds of autotrophs occur, photoautotrophs and chemoautotrophs.

The autotrophs which can make food by the process of photosynthesis are known as photoautotrophs. The chemoautotrophs are those which synthesize their food by the chemicals. The heterotrophs are those which are not able to synthesize their food. Instead, they obtain their food by feeding on the tissues of producers. Consumers are those that feed on producers and other consumers. There are several classes of consumers based on food sources: herbivores, carnivores, and omnivores. Herbivores are those who feed directly on plants; carnivores are those that feed on animals; omnivores are those that feed on animals and plants. Decomposers such as fungi are heterotrophs that feed on dead organic matter. They do so by the process of decomposition.

Biodiversity, also known as biological diversity, is defined as the total variety and variability of life in a defined area. The term biodiversity was coined for complex kinds of variations within and among organisms at various levels of the organization. It is defined as a totality of genes, species, and ecosystem of a particular region.

Sustainable development refers to people living so that current needs are made without compromising with future resources.

Context and Applications

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for 

• Bachelors of Science in Biological Science 
• Bachelors of Science in Zoology
• Master of Science in Environmental Science