ECOLOGY

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What is Environment ?

Environment has different meaning for different people. Most definitions include the physical, chemical and biological components that influence the life of an organism. All the external factors, conditions and influences that effect an organism or a biological community i.e. known as environment. The term environment etymologically means surroundings . The place, where an organisms lives - habitat , indeed presents a particular set of environmental conditions - the environmental complex . Thus, environment is a complex of so many things i.e. light, air, soil, water, temperature etc have been variously called as environmental factors , ecological factors or may be living i.e biotic factors (plants, animals, microorganisms etc.) and non-living i.e. abiotic factors . Daubenmire (1959) classified the factors into seven coordinate headings as i. soil, ii. water, iii. temperature, iv. light, v. atmosphere, vi. fire and vii. biotic factor . Most of the ec...

Approaches to Ecology : Its Main Subdivisions and Developmental Facets

A perusal of the developmental history of ecology reveals that ecological studies made from time to time are based upon three principal aspects --- i. Taxonomic affinities, ii. Habitat and iii. Levels of organisation. Accordingly, these approaches could lead to the development of the following main subdivision of ecology. Based On Taxonomic affinities : In early days of ecology, botanists and zoologists engaged themselves separately in the study of ecology of plants and animals respectively. This led to the development of such sub-divisions are as plant ecology and animal ecology . However, modern ecologists feel that the principles in the study of plants and animals are not only much similar, but these two great groups of organisms are very much inseparably interrelated with each other. Thus, modern ecology prefers not to make much distinction between ecology of plans and animals. The term ecology indeed includes the interrelationships and interdependencies of all...

Basic Concept of Ecology (II)

Ecosystem When both, biotic and abiotic components are considered , the basic structural and functional units of nature are ecosystem. Ecosystem was adopted as the unit of ecological studies. Tansley (1935) thus emphasized the role of environment, with its various factors interacting with each other in his comprehensive term ecosystem. Each population occupies a specific niche , a unique functional position with respect to other organisms with which it interacts. Particular population has within a given habitat . Population ecologists study interactions at population as well as community level. They study competition , usually between populations from the same trophic level ( such as herbivores competing for the same grass i.e., population e...

Basic Concept of Ecology

The four basic concept of ecology are i. holism, ii. ecosystem, iii. succession and iv. conservation (R.Mishra , 1991). Holism The term holism (from a Greek word holon , meaning entity) was coined by the South African statesman, Jan Christian Smuts in his book Holism and Evolution in 1926 to explain the process of evolution by the coming together of lesser wholes in order to create the universe. Smuts defined holism as " the tendency in nature to form wholes that are greater than the sum of the parts through creative evolution ." The hierarchical levels at which we discuss interacting units of ecology are, individual < population < community < ecosystem < biome < biosphere . Each unit is a whole built up by the interactio...

ECOLOGY IN INDIA

During the first third of 20th century , there started to develop such specialised areas of ecology as paleo-ecology, zoogeography, oceanography, limnology etc., and then was introduced the population concept on which statistical studied and sampling techniques were employed for solving the community problems. this era is popularly called as era of population and community ecologist . Ecological studies during the first half of the 20th century could make it evident that humans are an integral part of the complex ecosystem ' the ecosphere ' and how anthropogenic activities disrupted the ecological processes leading to degradation of the environment that affected the humans as much as other forms of life, plants, animals and microbes. We are facing the greatest challenge to our intellect and wisdom for saving the humanity from extinction. It has arisen from our activities constricting the environment and depleting the natural resources of biosphere, specially so ...

INTRODUCTION & HISTORICAL BACKGROUND

In 1859, the French Zoologist, Isodore Geoffroy St. Hilaire had proposed the term ethology for " the study of the relations of the organisms within the family and society in the aggregate and in the community." In 1868 , there are, however, references in literature of German biologist, H. Reiter introduced the term oekologie and Ernst Haeckel ( 1869 ) put the first precise definition of this term as "...the knowledge of the sum of the relations of organisms to the surrounding outer world , to organic and inorganic conditions of existence...". The term ecology was coined by combining two Greek words, oikos (meaning 'house' or 'dwelling place') and logos (meaning ' the study of ' ) to denote such relationship between the organisms and their environment. There is some controversy about the author who coined the term ecology and first used it in the literature. Ernst Haeckel in his definition of ecology, refers to the "surrounding ...