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What is Ecology

Original Article -

Ecology describes the relations of organisms to one another and to their corresponding environment. Three major components studied in ecology are:

  • living organisms,

  • the relationship and interactions with other organisms,

  • and the relationships and interactions with the surrounding environment.

Symbiotic relationships like rhizobium and legume in plant roots as well as the competition among herbivorous animals for food are organism-organism interactions. All animals and plants rely on various aspects of their environment in order to obtain food, nutrients, and water. The response of organisms to climate, soil, topography, atmosphere and water availability are the other types of relationships of organisms to their living environment. For example, animals in cold environments have small ears but, animals in deserts have long ears since long ears help to cool the body by increasing heat loss. Ecology maintains a close relationship with the disciplines of physiology, behaviour, genetics, and evolution. The broader details studied during ecology include:

  • Life processes, interactions, and adaptations of a specific species.

  • The influence of environmental factors on the organisms in a population.

  • The progress changes in the ecosystems.

  • The distribution and abundance of organisms in the environment.

  • Biodiversity within an ecosystem.

Figure 1: Biodiversity of a Coral Reef

What is an Ecosystem

The ecosystem comprises of all living organisms in an area or the community of organisms and non-living abiotic factors dealing with the community. An ecosystem is categorized into biotic and abiotic factors. All living organisms in the environment are identified as the biotic factor. Other non-living physical things which interact with the biotic factor are identified as the abiotic factor. Abiotic factors are climate, sunlight, soil, water, minerals, and other non-living matters. The biotic and abiotic factors are linked by two factors: the flow of energy through the ecosystem and the cycling of nutrients within the ecosystem.

Sunlight is the fundamental energy of the majority of ecosystems. It is used by autotrophs in the ecosystem to produce simple carbohydrates from carbon dioxide and water. Autotrophs are considered as primary producers in an ecosystem. Complex organic compounds like proteins, starch, and lipids are produced inside autotrophs. The heterotrophs in the ecosystem depend on the organic matter produced by the autotrophs. Heterotrophs are the consumers of the ecosystem. The movement of organic matter from the primary producer level to the consumer level makes up a food chain. The final link of the food chain is a decomposer, comprised of microorganisms. The overlapping and interconnecting food chains form the food web. A complete cycle of a food chain is shown in Figure 2.

Figure 2: A complete Cycle of a Food Chain

Similarities Between Ecology and Ecosystem

  • Both ecology and ecosystem describe the relationship and interactions of the living organisms with each other and their surrounding environment.

  • These relationships and interactions with each other fulfil their basic requirements of life like food, nutrients, water, and residence. 

Difference Between Ecology and Ecosystem


Ecology: Ecology is a branch of biology that deals with the relationships of organisms to one another and to their physical environment.

Ecosystem: An ecosystem is a community of interacting organisms and their physical environment.


Ecology: Ecology is the study of ecosystems.

Ecosystem: An ecosystem is a subset of ecology.


Ecology: Ecology includes the study of the relationship between living organisms and their environment.

Ecosystem: An ecosystem is a place like a forest, taiga, grassland, desert, still water, river or a stream, coral reefs, etc.


Ecology and ecosystem describe the relationship between biotic and abiotic factors in an environmental system. Ecology is the study of ecosystems. An ecosystem describes the relationship of the mass of living organisms, which belong to the same or different communities. This is the main difference between ecology and ecosystem. Organisms maintain relationships and interactions between each other as well as the external environment for the purpose of obtaining basic life requirements like food, nutrients, water, and residence.


  1. “What is ecology?” Khan Academy. N.p., n.d. Web. Available here. 06 June 2017. 

  2. Gaia. “Environment and Ecology.” What is Ecology. N.p., n.d. Web. Available here. 06 June 2017. 

  3. “Ecosystem.” Encyclopædia Britannica. Encyclopædia Britannica, inc., 12 Dec. 2016. Web. Available here. 06 June 2017. 

  4. “ECOLOGY AND ECOSYSTEM.” Bihar Envis Centre – Environment Information System. N.p., n.d. Web. Available here. 06 June 2017.

Image Courtesy:

  1. “Blue Linckia Starfish” By Copyright (c) 2004 Richard Ling (CC BY-SA 3.0) via Commons Wikimedia

  2. “Complete-circle-foodchain”By Junjira saetae – Own work (CC BY-SA 4.0) via Commons Wikimedia

About the Author:

Lakna, a graduate in Molecular Biology & Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things.

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