STRUCTURE OF ENVIRONMENT

INTRODUCTION:

          The structure of the environment is composed of various elements such as Ecosystem, Natural Resources, etc. The human activities had caused a lot of damages to the environment and the elements of the environment have suffered a lot of changes. The main reason for the damage of the environment is due to the increase in population which lead to the destruction of the lot of trees and forest areas.

ECOSYSTEM:

          The ecosystem is combination of living beings and physical environment that interacts and exchange things among them. The ecosystem may be temporary such as a pond that is made of rain water or permanent (pond water), etc. A very small ecosystem is called as micro-ecosystem. An ecosystem is made up of two types of components. They are biotic and abiotic components. They are described as follows:

BIOTIC COMPONENTS:

          They constitute all the living members of an ecosystem. The different biotic components are connected through food and a number of other relations. Food is a group of materials that contain energy and all the essential ingredients required for body building, growth and body functions. Both matter and energy are transferred in the living world through food. The biotic components are of two types. They are producers and consumers. They are described as follows:

PRODUCERS:

          They are photosynthetic plants that are able to synthesise organic food from inorganic raw materials with the help of solar radiations. The process is called photosynthesis. Producers are also called transducers because they are able to change radiant or light energy into chemical form. All other organisms depend upon the producers for their supply of organic compounds or food. They pick up carbon dioxide from the atmosphere and release oxygen during the process of photosynthesis.

CONSUMERS:

          They are the animals which feed on other organisms or their parts. They are divided into two categories: herbivores and carnivores. Herbivores obtain their food and energy directly from plants. They are called as first order consumers. Some common herbivores are deer, rabbit, mouse, grass-hopper, goat, cattle, etc. Carnivores ingest or prey on other animals. The carnivores which feed on herbivores are named as primary carnivores or second order consumers. Some examples are frog, birds, fishes, wild cat, jackal, fox, snakes, etc. The animals which feed on primary carnivores are called secondary carnivores or third order consumers.  

DECOMPOSERS:

          They are microorganisms which feed on dead bodies of organisms and organic wastes of living organisms. The decomposers organisms decompose the organic matter by a process called mineralisation. Decomposers are also called as reducers because they are able to remove or degrade the dead bodies of organisms. Because of their small size they are known as micro-consumers.  

ABIOTIC COMPONENTS:

          Abiotic component of an ecosystem consists of non-living substances and factors. They are broadly divided into climatic and edaphic factors. Climate is a complex formed by interaction of solar radiations with various constituents of lithosphere, hydrosphere, latitude and altitude, rocks, etc. to produce variables like temperature, humidity, precipitation, air currents, lights, etc. Abiotic factors limit the distribution, behaviour and relationships with other organisms.

BIOMES:

          Biomes are defined as a large natural ecosystem which is distinct in its climatic conditions and has its specific type of plant and animal life. Thus biomes are the major ecosystems of the world which are the largest ecological units. Characteristics of a biome are determined by a number of factors such as Temperature range, Latitude and altitude, Intensity and duration of summer and winter, etc.

          These ecosystems are disturbed by a number of human activities. Because of the human activities, the basic natural resources such as water and air get affected. This causes changes in the ecosystem. The natural resources in the ecosystem are discussed below:

NATURAL RESOURCES:

          The word resource means a source of supply or support that is usually held in reserve. It includes wealth, supplies of goods, raw materials, etc., which can be used by organisms. The natural resources are the components of the atmosphere, hydrosphere and lithosphere essential for life. These include energy, air, water, soil, minerals, plants and animals. The nature of resources varies from society to society. Depending on the abundance and availability of the natural resources they are classified into two categories. They are inexhaustible and exhaustible.

ATMOSPHERE:

          It’s defined as transparent gaseous envelope surrounding the earth. It consists of four layers. They are Troposphere, Stratosphere, Mesosphere and Thermosphere. Troposphere is the surface of the earth to an altitude of 10 kilometres. Stratosphere extends between altitudes of 10 and 60 kilometres. Mesosphere extends between altitude of 60 and 100 kilometres. Temperature decreases with height in this layer. Thermosphere lies from an altitude of 100 kilometres upward. In this layer the temperature increases with height.

COMPOSITION OF ATMOSPHERE:

          The atmosphere is a mixture of several gases. Near the earth’s surface it consists of 78% nitrogen, 21% oxygen and the remaining 1% includes 0.93% argon, 0.03%carbon dioxide and small quantities of hydrogen , helium, neon, krypton and traces of many other gases. Besides gases it also contain water vapour, dust particles, smoke and salts. A layer of ozone called ozonosphere or ozone layer is present in the stratosphere.

ROLE OF ATMOSPHERE:

          The ozone layer protects the living organisms from the harmful radiations from the sun. Air acts as a medium for locomotion of flying animals such as insects, birds and bats. Atmosphere supplies oxygen, carbon dioxide and nitrogen to those living organisms which utilize them. Manmade satellites used for communication, weather monitoring and research move around or are stationed in the thermosphere at particular altitudes. The ionosphere has a large number of ions and free electrons. It reflects the radiowaves back to earth, thus helping in long distance communication. Circulation of air is responsible for specific climatic conditions and water cycle.

BIOSPHERE:

          All of the ecosystems of the earth, together, form the biosphere. The biosphere is that portion of the earth within which life exists. It includes all oceans and freshwater, the lower layer of the atmosphere and the outer skin of the earth’s crush- the rocks and soil of the earth’s surface.

          Within the biosphere all the functions and structure described for anyone ecosystem exist. Green plants capture sun energy and combine it with chemical raw materials from soil, water and air. The food they produce supports all animal life, including the decay organisms which return it to the soil for plant use once more.

          Man is a part of the biosphere and depend on its continued functioning for this own existence. He can modify or even destroy any one ecosystem. He cannot, however, risk major modifications of the biosphere except at the risk of his own extermination.

Thus the continued production of plant materials, whether wild or cultivated, is the basis for the nutritional support of man as wells as all other animals. The continued functioning of green plants is the source of atmospheric oxygen on which man and other animals depend. The continued functioning of the reducer organisms is the means by which the chemicals in human wastes or in the bodies of plants and animals are made available for further use by living things. A breakdown in any of these biosphere systems would imperil human survival. Man has been able to take major risks in modifying local ecosystems. He cannot afford major risks in dealing with the functioning of the biosphere.

LAND ENVIRONMENT:

          Land forms about one fifth of the earth’s surface, covering about 13,393 million hectares. About 36.6% of the land area is occupied by houses, factories, roads, railways, deserts, mountains, rocks, glaciers and polar ice marshes. About 30% of the land is covered by forests. About 22% of the land is occupied by meadows and pastures. Only 11% of the land is suitable for ploughing. The surface layer of land is called soil. About four-fifth of the land consists of soil. Soil is a dynamic natural body, on the surface of the earth in which plants grow, composed of mineral and organic materials and living forms. The components of the soil are described below:

1.     Mineral Matter 4.5%

2.     Organic Matter 5%

3.     Soil water 35%

4.     Soil air 25%

There are fine spaces between the soil particles which are called interstices. The latter are filled with air arid water containing dissolved substances. If the volume of water decreases due to evaporation, the volume of air in the soil increases. If the volume of water increases after irrigation or rain, the volume of air decreases. Soil also contains flora (plants) and fauna (animals).

TYPE OF SOIL PARTICLES:

          The type of soil is determined by the mineral composition of the parent rock and the size of particles present in the soil. Four types of soil particles are found.

• Gravel Particles: They consist of small stones with coarse sand particles as used for roads and paths.
• Sand Particles: They are porous and, therefore well aerated. However, they have little water holding capacity.
• Silt Particles: They are carried by moving water and left at the mouth of a river. They also consist largely of quartz and are chemically inert.
• Clay Particles: They are rich in nutritive salts and can hold or retain water very firmly. Thus clay particles are chemically more active. However pure clay particles are not suitable for plant growth because they form a solid impenetrable mass. When clay soil is mixed with other constituents of the soil, the granular soil is formed, which becomes ideal soil for cultivation, because it combines the properties of porosity and water holding. It is also rich in nutritive salts.

      Lammy Soil contains about 1 part clay, 2 parts silt and 2 parts sand. It is ideally suited for plant growth because it possesses good aeration, sufficient nutritive salts and good water retaining capacity. The changes made by the human beings have caused many species to die and caused to the endangerment of the species. They are described as follows:

ENDANGERED SPECIES:

          These species are in danger of extinction and they are not likely to survive if the factors threatening their extinction continue. Their numbers have been reduced to a critical level or their habitats have been so drastically reduces that they are in immediate danger of extinction. Lion, Tiger, Musk Deer, Kashmir Stag, Panda, etc. are facing extinction in India.

VULNERABLE SPECIES:

          These species are likely to be in danger of extinction in the near future if the factors threatening their extinction continue. Their population have been greatly reduced and their survival is not assured. This category of species also includes those species whose populations are still abundant but are somehow threatened throughout their range. Some species that are small in population in the world and that are confined to limited areas are called as Rare Species. The major cause for the extinction of these species is Pollution.

POLLUTION:

          It is defined as an undesirable change in physical, chemical or biological characteristics of the air, water and land that may or will harmfully affect human life. There are different types of pollutions. They are Air Pollution, Water Pollution, Soil Pollution, Radioactive Pollution and Noise Pollution. WHO defines air pollution as the presence of materials in the air in such concentration which are harmful to man and his environment. It is the occurrence of addition of foreign particles, gases and other pollutants into the air which have an adverse effect on human beings, animals, vegetation, buildings, etc. Water Pollution is defined as the contamination of water and makes it unusable. The major sources of water pollution are the sewages from the industries that are let into the ponds and river and make them contaminated. There are many dangerous effects of water pollution which causes many diseases. Radioactive pollution is a special form of physical pollution of air, water and soil with radioactive materials. This form of pollution is one of the major issues since if there are some radioactive materials getting leaked; it can cause destruction to the human genetic system.

CONCLUSION:

          The major causes for the changes in the structure of the environment have been discussed and safety measures needs to be taken so that the biodiversity should be maintained.