The word ‘ecology’s first proposed by a zoologist named Reiter in 1885, is derived from Greek words, Oikos meaning the dwelling place or home and logos meaning the discourse or study.

The things of the world are classified into two major groups i.e. biotic component and abiotic component. The biotic component includes all types of living organisms, both plants and animals and the abiotic component includes the non-living materials (soil, water, air etc) and the forces of nature (light, gravity and molecular energy).

Sub-divisions of Ecology

Ecology may be divided into two subdivisions, autecology and synecology.

Autecology: The word autecology derived from Greek word “autos’ meaning self i.e. the study of single species or individual organism in relation to the environment or the habitat in which it grows at all stages of its life span.

Synecology: The word synecology is derived from the Greek prefix Syn meaning together, so as to study the groups of organism in relation to their habitat and environment in which they grow.

The different branches of ecology are

(i)   Habitat Ecology: Concerned with the nature of habitat.

(ii)  Ecosystem ecology: - involves the analysis of ecosystem from structural and functional point of view.

(iii) Population ecology-concerned with the study of inter relationship of different groups of organisms.

(iv) Paleoecology-concerned with the organisms and geological environments of the past.

(v)  Production ecology-involves the study of gross and net production of different ecosystems.

(vi) Gene ecology-concerned with the genetic constitution of species or population with respect to its environment.

(vii)      Conservation ecology-includes the proper management of natural resources.

(viii)Radiation ecology-involves the study of radioactive substances, radiation and the environment.

(ix) Human ecology-concerned with man in relation to his environment

(x)  Integrated ecology-concerned with the energy conservation and flow in the organisms within the ecosystem.

The environment is the aggregate of all those things and set of conditions, which directly or indirectly influence not only the life of organisms but also the communities at a particular place. The life-supporting environment of planet earth is called Biosphere. The biosphere is composed of three chief media-air, soil and water and on this basis biosphere has been divided into three-divisions: Atmosphere, Lithosphere and Hydrosphere respectively. Thus environment is a complex of factors acting, reaching and interacting with the organism complex.

Environmental & Ecological Factors

Any external force, substance or condition affecting the organisms in any way is referred to as environmental factor e.g. soil moisture, wind & temperature etc.

The natural place where organisms or communities of organisms live is called habitat. It implies a particular set of environmental factors. Any feature of organisms or its parts, which enables the organisms to exist under conditions of its habitat, is called an adaptation.

The ecological factors and environmental factors are divided into four types:

(A) Climatic factors (related to aerial environment)

(B) Edaphic factors (related to soil conditions)

(C) Physiographic (topographic) factors.

(D) Biotic factors.

Natural Resources

Various natural resources fulfill never-ending needs of human society. With the manifold increase in human population decrease in natural resources has caused severe problems. Among natural resources energy is the most important for man. The energy is generally obtained from fossil fuels, such as oil, coal, natural gases, wood, dry dungs etc. Organic and inorganic are the two types of natural resources of earth. Inorganic are air, water, mineral, fuels, metallic ores, stones, etc. organic are plants, animals, microbes and their products food plants and animal, wood, coal, oil, natural gases forests etc. The natural resources can be grouped into.

Non-renewable sources

They are the sources, which once used cannot be recycled. Minerals are the non-renewable sources. They are distributed unevenly. About 200 metals are widely and extensively used in various industries. Fossil fuels also are a non-renewable fossil energy source. For rapid industrialization of a country, low cost energy resources are necessary. But such resources are very limited and at the present rate of consumption, their resource stocks may reduce drastically and if the rate of consumption far exceeds the rate of formation of energy sources it is bound to lead us to their acute shortage.

Renewable Resources

Renewable resources of energy are that energy which can be regenerated naturally or artificially. Organic waste products either discharged as municipal wastes or from any other sources conserve very high quantity of fossil fuel. This can be utilized in producing chemicals and energy. Vegetation biomass has negligible sulphur contents, hence is better than the fuel. Coal has high contents of sulphur but its ash can be used as fertilizer.

Degradation of Environment and ecology

Humans depend on environment for survival as it gives us oxygen to breathe, food to eat and water to drink. We also get fibre, medicines, fuel etc. from environment. As growth of human population, spread of became agrarian culture and industrialization lead to the environmental degradation in two ways

(i)   depletion of natural resources

(ii) pollution of the environment (air, water and soil)

Natural resources have been depleted through deforestation, excessive use of fossil fuels; mining etc. air has been polluted by toxic gases emitting from motor vehicles, toxic wastes discharged into water bodies.?Better medical facilities and food for all has increased longevity and cut down infant mortality and death due to epidemics. This has resulted in increase in population. Demands of increased population like land for housing and cultivation of food crops, industrialization, and fossil fuels as source of energy resource for industries and homes, ground water have been depleted and air, water and soil polluted.

Humans have cut down trees and cleared forests to obtain firewood and timber and to get land for agriculture and human settlements. Deforestation has resulted in serious loss of biodiversity. Modernized agricultural practices have provided food for teeming millions but created problems of land erosion, environmental pollution from fertilizers and pesticides. Humans have moved from villages to cities in search of better employment opportunities, education and health facilities, resulted in formation of slums which suffer from unhygienic conditions.

Degradation of Environment and ecology

Humans depend on environment for survival as it gives us oxygen to breathe, food to eat and water to drink. We also get fibre, medicines, fuel etc. from environment. As growth of human population, spread of became agrarian culture and industrialization lead to the environmental degradation in two ways

(i)   depletion of natural resources

(ii) pollution of the environment (air, water and soil)

Natural resources have been depleted through deforestation, excessive use of fossil fuels; mining etc. air has been polluted by toxic gases emitting from motor vehicles, toxic wastes discharged into water bodies.?Better medical facilities and food for all has increased longevity and cut down infant mortality and death due to epidemics. This has resulted in increase in population. Demands of increased population like land for housing and cultivation of food crops, industrialization, and fossil fuels as source of energy resource for industries and homes, ground water have been depleted and air, water and soil polluted.

Humans have cut down trees and cleared forests to obtain firewood and timber and to get land for agriculture and human settlements. Deforestation has resulted in serious loss of biodiversity. Modernized agricultural practices have provided food for teeming millions but created problems of land erosion, environmental pollution from fertilizers and pesticides. Humans have moved from villages to cities in search of better employment opportunities, education and health facilities, resulted in formation of slums which suffer from unhygienic conditions.