An ecosystem is a community of living organisms interacting with each other and their environment, which includes both biotic factors (like plants, Animals, and microorganisms) and abiotic factors (such as air, water, soil, and climate). This interaction encompasses various processes, including energy flow and nutrient cycling, essential for sustaining life within a specific geographical area.
word ecosystem was first proposed by the British ecologist Sir Arthur G. Tansley (1935).
Natural ecosystems
Contents / Index
Natural Ecosystem : These are the ecosystem established and maintained by the natural forces. Based on habitat, this can be further subdivided into –
Terrestrial ecosystem : Ecosystem present in the terrestrial habitats fall under this category. These includes – Forest ecosystem, Grassland ecosystem, Desert ecosystem, Tundra ecosystem, etc.
Aquatic ecosystem : Ecosystem present in the aquatic habitats are considered under this category. They can be further grouped into –
Freshwater ecosystem : Ecosystems found in the freshwater habitat come under this group. A freshwater ecosystem can be Lotic (running water such as river, stream, springs, etc.) or Lentic (standing water such as a pond, lake, etc.).
Marine ecosystem : Ecosystems of deep water bodies, such as Oceans, Seas, and Estuaries, are categorized as marine ecosystems.
Artificial or man-made ecosystems
Artificial or Man-made ecosystem : These are the ecosystem where one or more factors are controlled or managed by humans. Cropland, aquarium, etc.
The diagram includes agriculture and fishery ecosystems under the artificial or man-made category.
Structure of ecosystems
The ecosystem consists of two main components
Abiotic components
Abiotic (Non-living) component : All the non-living environmental conditions that influence the life of organisms. In Terrestrial Ecosystems, these factors include water, air, soil, nutrients, minerals, sunlight, temperature, wind, and rainfall. In Aquatic Ecosystems, abiotic factors include water depth, turbidity, currents, suspended solids, and other physical and chemical properties of the water.
Biotic components
Biotic (Living) component : All the living organisms together formed the biotic component of an ecosystem. Based on their nutritional requirement living organisms of an ecosystem are grouped into two categories, viz.
Autotrophs : Organism which fixes the atmospheric CO2 with the help of energy either obtained from sunlight (photoautotrophs) or breakdown of chemical (Chemoautotrophs) and water and convert them into a form usable as food (carbohydrate) is known as autotrophs. Organism of this group is also known as producers. Example : Green plants.
Heterotrophs : Organisms dependent on the other for their food requirement are known as heterotrophs. These organisms are also known as consumers. All the animals are under this category
Question from the chapter
What is ecology? What are the major ecosystems on earth? [Arunachal PSC ACF (Main) 2018, Environmental Science Optional | 5 M].
Quick revision
- Natural ecosystems include terrestrial and aquatic ecosystems.
- Freshwater systems include lotic running water and lentic standing water.
- Ecosystem structure includes abiotic and biotic components.
Related concepts
Chapter 4 reading order
- Ecology: Meaning, History and Branches
- Ecological Organization: Population and Community
- Ecosystems: Meaning, Types and Structure
- Food Chains and Food Webs: Types and Examples
- Biomes: Types and Differences from Ecosystems
- Scope of Ecology: Scales, Data and Applications