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 kinds of organisms with their environment. 

Based on Habitat :

Some ecologists thought of the study of habitats and their effects upon the organisms,  such as freshwater, marine, estuarine, grassland, forest etc. habitat are then studied in detail for their possible relationship with there present kinds of organisms. Such a habitat approach led to the development of another subdivison of ecology i.e. habitat ecology.

Based on Levels of organisation :

In this approach area of ecology, study either individual organisms or groups of organisms. Accordingly the other subdivisions are arise i.e a) Autecology and b) Synecology. 

           a) Autecology :  With an autecological approach, individual species are the units of study.                                                  These are studied for details of their geographic distribution, morphology,                                              taxonomic position and life-cycle etc., along with the various ecological                                                 factors which might influence different stages of their life cycles.   

           b) Synecology :  An approach where units of study are groups of organisms --- plants,                                                      animals, microbes etc., live together as a natural group and affecting each                                          other's  life in several ways, is called synecology.    

                              Depending upon the conditions as these exist, synecology may deal with                                         population, community, biome or an ecosystem.

           Population ecology :

The units of study are pure stands of individuals of a single species i.e. population and their size, growth rates etc., which are chiefly governed by interactions of the members of population. The main job of population ecologist is , " Why is this population of a particular density?" To answer this he studies competition between population from the same trophic level (herbivores competing for the same grass). Population ecology is also concerned with communities.

Fig. Diagrammatic sketch showing the population of species 'A' where its individuals interact with each other -- Population ecology.  

       Community ecology :    

Here the units of study are groups of individuals belonging to different species-plants as well as animals. Major concerns of community ecologist are, " Why is this community of a particular diversity? Why does a particular community occur at a given location? How communities interact and how these change through time?"  

Fig. Diagrammatic sketch showing a community of four different species A, B, C, D interacting with each other --- Community ecology.

       

             Biome ecology :  

In this units studied interactions between different communities of area. Here exist a complex of more than one communities, some in their climax stages and others in different stages of succession and these all communities grow under more or less similar climatic conditions in an area.   

Fig. Diagrammatic sketch showing a biome of three communities under different stages of development and interacting with each other ---- Biome ecology. 

              Ecosystem ecology : 

This has been the most recent development in ecology. This interacting biotic and abiotic components, then interact with each other to form an integrated system --- eosystem or ecological complex or ecological system. 

Fig. Diagrammatic sketch showing the living (biotic) and non-living (abiotic) components of nature interacting with each other to form integrated ecosystem --- Ecoystem ecology.

Here we mainly emphasize the similarities and differences in food relationships among living organisms and various forms of energy supporting their life. In ecosystem ecology the movements of energy and nutrients among the biotic and abiotic components, referred as bioenergetic approach in modern ecology. A major concern is, "How much and what rates are energy and nutrients being stored and transferred between components of an ecosystem?"