Organisms and Populations - NEET Previous-Year Questions
Organisms and Populations is among the most dependable scoring chapters in NEET Botany - it has yielded questions in every recent paper, usually worth 3 to 5 marks. Looking across NEET 2019-2026, the examiners keep returning to a small number of question families. Treat the list below as a checklist of skills, not as an answer key: each line tells you what you must be able to do before you attempt the set, and deliberately withholds the values, the names and the exact wording, because those are precisely what is being tested.
1. Interspecific interactions. Be able to assign a (+), a (-) or a (0) to each partner in competition, predation, parasitism, mutualism, commensalism and amensalism, and to say which of these leave one partner entirely unaffected, justifying the sign you give in each case. The examiner disguises this in several formats: a match-the-column of harm-and-benefit patterns against interaction names, a multi-statement select, and an item built on a named NCERT exemplar. Keep the exemplar list for every interaction ready, and practise going from exemplar to sign, and from sign back to exemplar. You should also be able to set the standard modes of nutrition, and the classical fungal partnerships the syllabus names, against their correct definitions, since these too are examined in match-the-column form.
2. The growth equations. Know what every symbol in the exponential expression and in the Verhulst-Pearl expression stands for - N0, r, t, e, N and K - and be able to say which model assumes an unlimited habitat and which assumes a finite one. Assertion-Reason items appear in this set.
3. Per capita rate arithmetic. Be able to compute a per capita birth or death rate from raw counts, to state its units, and to predict the fate of a population when b exceeds d, when d exceeds b, and when b and d are equal. You should also be able to rearrange the exponential relation to solve for r, or for the time a population takes to double. These numericals need only the definitions - but they do need the right denominator.
4. Competition. Recall Gause's principle in the wording the chapter gives it, the condition it places on the resources the rivals are contesting included. Know NCERT's own remark about which feeding group competition appears to hit hardest, and the evolved route by which close competitors manage to coexist on one tree.
5. Population attributes and age pyramids. Know the properties the chapter lists as attributes of a population, and be able to read growth status off the relative widths of the pre-reproductive, reproductive and post-reproductive cohorts.
6. Abiotic factors and the responses organisms make to them. Temperature, water, light and soil set the conditions an organism has to meet, and the chapter attaches a settled vocabulary to the various ways organisms answer those conditions. Know that vocabulary, and be able to fasten the right term on to a response that is described to you rather than named. Do not revise this as a growth-equation chapter only.
7. Factual anchors. The named workers the chapter credits - the pioneers of the subject, and the authors of its classical field experiments.
How to use this set. Most questions below are previous-year NEET questions carrying the year they appeared in; the remainder, tagged Exam Pattern, are built on patterns NEET has examined repeatedly. Where a previous-year question is reproduced, its wording follows the paper as printed, apart from the correction of obvious printing errors. Attempt all 18 in a single timed sitting of 35 to 50 minutes with these notes closed, then read every explanation - including for the items you answered correctly.