Q.59
Match the types of ecological interactions in Group 1 with their respective definitions in Group 2.
| Group 1 | Group 2 |
|---|---|
| (P) Protocooperation | (i) One species is harmed but the other is neither harmed nor benefitted |
| (Q) Commensalism | (ii) A type of mutualism where one species is benefitted more than the other |
| (R) Amensalism | (iii) Both the species are benefitted but the interaction between them is not obligatory |
| (S) Helotism | (iv) One species is benefitted without harming the other |
The correct matching is: P–iii, Q–iv, R–i, S–ii, so the right option is (A).
Introduction
Ecological interactions such as protocooperation, commensalism, amensalism and helotism describe how different species coexist and influence each other in an ecosystem. These interspecific relationships range from mutually beneficial to one‑sided and are frequently asked in CSIR NET, NEET and other competitive exams.
Understanding each term (Group 1)
Protocooperation (P)
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Protocooperation is a type of mutualism in which both species benefit but the association is not obligatory for survival.
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Each partner can live independently; hence protocooperation is also called facultative mutualism.
Therefore, P matches with (iii): “Both the species are benefitted but the interaction between them is not obligatory.”
Commensalism (Q)
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Commensalism is a symbiotic association where one species is benefited while the other is neither harmed nor benefited.
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The benefiting organism is called the commensal and the unaffected one is the host; common examples include barnacles on whales and epiphytic plants on trees.
So, Q matches with (iv): “One species is benefitted without harming the other.”
Amensalism (R)
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Amensalism is an interaction in which one species is harmed or inhibited, whereas the other species remains unaffected (−/0 interaction).
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A classic example is Penicillium secreting penicillin that kills nearby bacteria, while the fungus itself is unaffected.
Thus, R matches with (i): “One species is harmed but the other is neither harmed nor benefitted.”
Helotism (S)
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Helotism is a master–slave type symbiotic association where one partner (master) is dominant and benefits more, while the other (slave, the helot) benefits less but is not harmed.
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It is considered an unequal form of mutualism, typically described in some lichen associations between fungi (master) and algae (slave).
Hence, S matches with (ii): “A type of mutualism where one species is benefitted more than the other.”
Option‑wise analysis
| Option | Matching pattern | Evaluation |
|---|---|---|
| (A) P–iii, Q–iv, R–i, S–ii | Uses correct definitions of protocooperation, commensalism, amensalism and helotism, so all four pairs are correct. | Correct |
| (B) P–ii, Q–i, R–iii, S–iv | Assigns “one benefits more” to protocooperation and “harmed but other unaffected” to commensalism, both contradict standard definitions. | Incorrect |
| (C) P–i, Q–iv, R–iii, S–ii | Treats protocooperation as harmful and amensalism as mutualistic, which is conceptually wrong. | Incorrect |
| (D) P–iii, Q–i, R–iv, S–ii | Correct for protocooperation and helotism but mislabels commensalism and amensalism by swapping their definitions. | Incorrect |
Therefore, Option (A) is the only option where every ecological interaction is correctly matched with its definition.
1 Comment
Sonal Nagar
January 10, 2026Option A