Ecology is the easiest unit to read and one of the easiest to lose marks in, because students leave it for the last week. Its three chapters are packed with examples, numbers and names that NTA asks directly. This ecology NEET PYQ analysis shows what repeats, so you can turn the unit into sure marks.
For concept building, pair this with our ecology preparation strategy guide, and see where the unit fits in the plan to score 360 in Biology. This article focuses on what past papers actually ask.
Want to test yourself first? Solve the Organisms and Populations PYQs, the Ecosystem PYQs and the Biodiversity and Conservation PYQs for free, then use this guide to fix the gaps.
Table of Contents
Why Ecology Deserves Early Attention
The NEET syllabus now has three Ecology chapters: Organisms and Populations, Ecosystem, and Biodiversity and Conservation. Environmental Issues is no longer included. Together they usually give six to eight questions.
Keep the class notes open as you revise: Organisms and Populations notes, Ecosystem class 12 notes and Biodiversity and Conservation notes.
Ecology NEET PYQ Analysis: The Repeated Question Types
When you sort a decade of NEET biology PYQs from this unit, six question types cover almost everything.
| Question type | Frequency | What it tests |
|---|---|---|
| Population interactions | Most frequent | Type of interaction and its NCERT example |
| Population growth | Very frequent | Exponential and logistic equations, age pyramids |
| Ecological pyramids and energy flow | Very frequent | Upright or inverted, 10% law |
| Productivity and decomposition | Regular | GPP, NPP, steps of decomposition |
| Biodiversity patterns | Very frequent | Species–area relationship, global and Indian numbers |
| Conservation | Regular | Hotspots, in situ and ex situ methods |
For a quick warm-up before the full set, try these five quick ecology practice questions.
Population Interactions
| Interaction | Species A | Species B | NCERT example |
|---|---|---|---|
| Mutualism | + | + | Lichens, mycorrhizae, fig and wasp |
| Competition | − | − | Flamingoes and fish for zooplankton |
| Predation | + | − | Tiger and deer; Pisaster starfish |
| Parasitism | + | − | Cuscuta on hedge plants; cuckoo (brood parasitism) |
| Commensalism | + | 0 | Orchid on mango; cattle egret and cattle; clownfish and sea anemone |
| Amensalism | − | 0 | One species harmed, the other unaffected |
Names to remember with population interactions:
- Gause’s competitive exclusion principle: two closely related species competing for the same resource cannot coexist indefinitely.
- MacArthur’s warblers avoided competition by resource partitioning.
- Connell’s experiment: Balanus excluded Chthamalus from the intertidal zone.
- The orchid Ophrys uses sexual deceit for pollination.
- Calotropis produces cardiac glycosides as a defence against grazing.
Population Growth
- Exponential growth: dN/dt = rN. It gives a J-shaped curve when resources are unlimited.
- Logistic growth: dN/dt = rN (K − N)/K. It gives a sigmoid curve and is also called Verhulst–Pearl logistic growth.
- K is the carrying capacity and r is the intrinsic rate of natural increase.
Age pyramids come in three shapes: expanding (triangular), stable (bell-shaped) and declining (urn-shaped).
Ecosystem: Productivity, Energy and Pyramids
- NPP = GPP − R, where R is respiration loss.
- The annual net primary productivity of the biosphere is about 170 billion tons (dry weight). Oceans contribute only about 55 billion tons.
- Decomposition has five steps: fragmentation, leaching, catabolism, humification and mineralisation.
- Decomposition is faster when detritus is rich in nitrogen and sugars, and slower when it is rich in lignin and chitin.
- Lindeman’s 10% law: only about 10% of energy passes to the next trophic level.
| Pyramid | Shape |
|---|---|
| Number | Upright in grassland; inverted for a single large tree |
| Biomass | Upright on land; inverted in the sea |
| Energy | Always upright |
Ecological pyramids questions nearly always ask which one can never be inverted. The answer is the pyramid of energy.
Biodiversity and Conservation
- India has only 2.4% of the world’s land area but 8.1% of its species diversity, and is one of 12 mega-diversity countries.
- Robert May estimated global species diversity at about 7 million.
- More than 70% of recorded species are animals, and insects make up more than 70% of those.
- Species–area relationship (Alexander von Humboldt): log S = log C + Z log A. The value of Z is 0.1 to 0.2 for small areas and 0.6 to 1.2 for whole continents.
- The rivet popper hypothesis was proposed by Paul Ehrlich.
- The Evil Quartet: habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinctions.
- Alien species examples: Nile perch in Lake Victoria, Parthenium, Lantana, water hyacinth and the African catfish Clarias gariepinus.
- There are 34 biodiversity hotspots worldwide. Three cover India: Western Ghats and Sri Lanka, Indo-Burma, and the Himalaya.
- In situ conservation includes national parks, sanctuaries, biosphere reserves and sacred groves. Ex situ includes zoos, botanical gardens, seed banks and cryopreservation.
- The Earth Summit was held in Rio de Janeiro in 1992.
Worked PYQ-Pattern Questions
Q1. Which ecological pyramid is always upright?
Answer: The pyramid of energy, because energy is lost at each trophic level.
Q2. An orchid growing on a mango branch is an example of: (a) Mutualism (b) Commensalism (c) Parasitism (d) Amensalism
Answer: (b) Commensalism. The orchid benefits; the mango tree is unaffected.
Q3. In the logistic growth equation, what does K stand for?
Answer: Carrying capacity.
Q4. If GPP is 1000 units and respiration loss is 400 units, what is the NPP?
Answer: 600 units. NPP = GPP − R.
Q5. Which of these is not part of the Evil Quartet? (a) Habitat loss (b) Over-exploitation (c) Co-extinction (d) Genetic drift
Answer: (d) Genetic drift.
Common Traps in This Unit
- Mixing up commensalism and mutualism examples
- Writing K as the growth rate
- Saying the pyramid of biomass is always upright
- Confusing the Z values for small areas and continents
- Listing sacred groves under ex situ conservation
Practise Every Ecology PYQ
This ecology NEET PYQ analysis gives you the tables and numbers. Practice makes them automatic. All three chapters are available chapter-wise, free:
👉 Solve Organisms and Populations NEET PYQs
👉 Solve Biodiversity and Conservation NEET PYQs
Solve one chapter a day and keep a single page of examples and numbers. That page is all you need in the final week.
Conclusion
Ecology is a unit of examples and figures. Use this ecology NEET PYQ analysis to master the interaction table, the growth equations, the pyramids and the biodiversity numbers. Then practise until each example brings its interaction to mind at once.
❓ FAQ
Q: How many questions come from Ecology in NEET? A: Usually six to eight questions from the three chapters together, which is around 30 marks.
Q: Which Ecology chapter is most important for NEET? A: Organisms and Populations and Biodiversity and Conservation usually give the most questions, followed by Ecosystem.
Q: Is Environmental Issues in the NEET syllabus? A: No. The current syllabus lists Organisms and Populations, Ecosystem, and Biodiversity and Conservation.
Q: Which ecological pyramid can be inverted? A: The pyramid of biomass in the sea and the pyramid of number for a tree can be inverted. The pyramid of energy is always upright.
Q: How should I revise Ecology for NEET? A: Use an ecology NEET PYQ analysis to list the repeated examples and numbers, make one summary page, and solve past questions chapter-wise.
Q: Where can I practise Ecology NEET PYQs for free? A: You can solve every previous year question from all three chapters for free using the practice links in this article.