Biology · Ecosystems · NEET
NCERT (Class 12, Ch 12) says: an ecosystem can be visualised as a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. This one line is the safest to write in NEET. Note the key words: 'functional unit' and 'interact with the physical environment'.
Both. An ecosystem always contains living (biotic) parts and non-living (abiotic) parts together. If you only have living organisms, that is a community, not an ecosystem. The ecosystem is community PLUS its physical environment, working as one unit.
Because inside it, processes actually happen and are linked: energy flows (through food chains), and nutrients cycle (through decomposition). 'Functional' means it does work, not that it is just a group of organisms. For NEET, remember: input = productivity, transfer = food chain/web and nutrient cycling, output = degradation and energy loss.
The biosphere is the largest ecosystem. Many ecologists regard the entire biosphere as one global ecosystem, made of all local ecosystems on Earth added together. A single ecosystem (like a pond) is one small part of that global whole.
A small pond (or an aquarium) is an example of a small ecosystem. A forest, a sea, or finally the whole biosphere are examples of large ecosystems. NCERT says ecosystems vary greatly in size, from a small pond to a large forest or a sea.
Yes. NCERT clearly states that crop fields and an aquarium may also be considered as man-made ecosystems. So an ecosystem does not have to be fully natural. This point is sometimes turned into a tricky NEET statement, so remember it.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
An ecosystem is a functional unit of nature where living organisms interact among themselves and with their surrounding physical environment.
A.G. Tansley coined the term ecosystem in 1935. This is a common NEET fact, covered fully on the next page.
Terrestrial (like forest, grassland, desert) and aquatic (like pond, lake, wetland, river, estuary). NCERT divides all ecosystems into these two categories.
A forest is one ecosystem. The biosphere is the sum of all ecosystems on Earth, so it is much larger than a single forest.
Yes. NCERT lists an aquarium and crop fields as man-made ecosystems, because they still have living organisms interacting with a physical environment.
