Class 12 · Organisms and Populations

Interspecific Interactions & Notation — NEET Biology

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📖 NCERT Source

Interspecific interactions arise from the interaction of populations of two different species. They could be beneficial, detrimental or neutral (neither harm nor benefit) to one of the species or both. 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 (Table11.1).

NCERT Biology · Class 12 · Chapter 11 · Paragraph 39
How NTA Uses This Concept

The NTA tests your understanding of how to classify interspecific interactions (between two different species) using the +/−/0 notation system. The '+' sign indicates the interaction is beneficial to a species, '−' indicates it's harmful/detrimental, and '0' means neutral (no effect). Students often confuse this notation with the actual interaction type (predation vs competition vs symbiosis) and forget that the same interaction can have different signs for each species involved. For example, in predation, the sign is + for predator but − for prey. Always remember: the sign represents the outcome (benefit/harm/neutral) for each species individually, not the category of interaction itself.

Solve This NEET Question
QuestionNEET 2023

Match List-I with List-II: (NEET 2023) List-I (Interaction) A. Mutualism B. Commensalism C. Amensalism D. Parasitism List-II (Effect) I. + (A), O (B) II. – (A), O (B) III. + (A), – (B) IV. + (A), + (B) Choose the correct option:

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