At a Glance
Four facts to hold on to.
Definition
Organisms plus their environment.
Coined
Arthur Tansley, 1935.
Two parts
Biotic and abiotic.
Size
From a pond to a biome.
In this lesson
The Precise Definition
Organisms and environment together
- An ecosystem is a community of organisms together with the environment in which they live.
- Both are studied as one linked system.
- It can be a forest, grassland, desert, lake, river, ocean or small pond.
Two wrong answers
- “Organisms interacting” alone describes a biological community. It leaves out the environment.
- “The part of Earth inhabited by living things” alone ignores the two-way link between life and surroundings.
- “The flora and fauna of an area” leaves out the non-living environment.
Who coined it?
- Botanist Arthur Tansley coined “ecosystem” in 1935.
- He wanted a word for organisms and their physical environment as one system.
- Sources: Tansley, Ecology, 1935 (JSTOR); Wikipedia, Arthur Tansley.
True or False: A group of organisms interacting, with no mention of their environment, is a complete ecosystem.
Biotic, Abiotic and Scale
Two kinds of parts
| Part | Meaning | Examples |
|---|---|---|
| Biotic | Living organisms | Producers and consumers |
| Abiotic | Non-living factors | Water, air, temperature |
- Producers make their own food.
- Consumers depend on other organisms for energy.
Size does not matter
- An ecosystem can be a single pond or a whole forest biome.
- The defining feature is the organism-environment link, not size.
- Listing flora and fauna alone misses the physical environment.
True or False: An ecosystem’s size does not decide whether it counts as an ecosystem.
True or False: Listing an area’s flora and fauna fully describes its ecosystem.
Tansley’s Idea
A shift in ecology
- Tansley described the ecosystem as the whole system, including the organism-complex and the complex of physical factors that form the environment.
- His point: organisms cannot be understood apart from their physical surroundings.
- Earlier ecology often studied plant and animal communities on their own.
Energy flow
- Energy flows through an ecosystem from producers to consumers.
- That flow ties every organism to others and to the shared environment.
- Wrong exam options often isolate one piece: organisms alone, or habitat alone.
Think it through: why did Tansley treat organisms and surroundings as one system?
Behaviour, survival and interaction cannot be explained without physical factors. Energy and matter flow between organisms and surroundings. One system lets ecologists trace energy flow and nutrient cycling.
True or False: Arthur Tansley argued that organisms cannot be meaningfully studied apart from their physical surroundings.
True or False: Arthur Tansley coined the word “ecosystem” in the 19th century.
Previous Year Questions
UPSC 2015 asked for the best description of an ecosystem.
- UPSC 2015, Q84The options were: (a) organisms interacting, (b) the inhabited part of Earth, (c) organisms together with their environment, (d) flora and fauna of an area. The answer is (c). View the question.
True or False: UPSC 2015 chose “a community of organisms together with the environment in which they live” as the best description of an ecosystem.
Quick Q&A
Definition?
Organisms plus environment.
Coined by?
Arthur Tansley.
Year?
1935.
Non-living parts?
Abiotic.
UPSC 2015 Q84?
(c).
🎲 Practice: What Is an Ecosystem? The Precise Definition
4 verified questions from this topic.
Question 1 of 1
Question 1 of 1
Question 1 of 1
Question 1 of 1
Leave a Reply