Interactions between two species could be beneficial (+), detrimental (−) or neutral (0) to one of the species or both.
Match List-I with List-II.
| List-I (Interaction) | List-II (Species A, Species B) |
| A. Amensalism | I. −, − |
| B. Mutualism | II. +, 0 |
| C. Competition | III. +, + |
| D. Commensalism | IV. −, 0 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-IV, B-III, C-I, D-II
(A) Amensalism — this matches (IV) −, 0. One species is harmed while the other is unaffected.
(B) Mutualism — this matches (III) +, +. Both species benefit, as in lichens and mycorrhizae.
(C) Competition — this matches (I) −, −. Both species lose, because they use the same limited resources.
(D) Commensalism — this matches (II) +, 0. One species benefits and the other is neither benefited nor harmed, as with the orchid growing on a mango branch.
Note: This whole match was lifted from Table 11.1, a table many students skip on the way to the next heading. Tables are short to read and generous with marks, so give them a minute.
NCERT Extract:
Population Interactions – “… Assigning a ‘+’ sign for beneficial interaction, ‘-’ sign for detrimental and 0 for neutral interaction, let us look at all the possible outcomes of interspecific interactions …. … Both the species benefit in mutualism and both lose in competition in their interactions with each other. … The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism. In amensalism on the other hand one species is harmed whereas the other is unaffected.”
| … : Population Interactions | ||
| Species A | Species B | Name of Interaction |
| + | + | Mutualism |
| − | − | Competition |
| + | − | Predation |
| + | − | Parasitism |
| + | 0 | Commensalism |
| − | 0 | Amensalism |