Read the following passage and answer the next five questions:
In nature, populations of different species in a habitat do not live in isolation but interact in many ways. Depending on the outcome, these interactions between two species are classified as competition, predation and parasitism, commensalism, amensalism and mutualism. Through these interactions trophic energy transfer is facilitated. Some predators help in controlling their prey populations, whereas plants have evolved diverse morphological and chemical defences against herbivores.
Identify the incorrect matching from the following population interaction:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Species A −, Species B −: Predation
Each species in an interaction gets a sign: + if it benefits, − if it is harmed, 0 if it is not affected.
Option (1) Species A +, Species B +: Mutualism — A correct matching. In mutualism both species benefit, as the fig and its pollinating wasp do.
Option (2) Species A +, Species B −: Parasitism — A correct matching. The parasite benefits by living on the host, and the host is harmed.
Option (3) Species A −, Species B −: Predation — An incorrect matching. The predator gains food, so predation is (+, −), not (−, −). The (−, −) signs belong to competition, where both species lose.
Option (4) Species A −, Species B 0: Amensalism — A correct matching. In amensalism one species is harmed and the other is not affected.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Population Interactions – “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 (Table 11.1).”
| Table 11.1 : Population Interactions | ||
|---|---|---|
| Species A | Species B | Name of Interaction |
| + | + | Mutualism |
| − | − | Competition |
| + | − | Predation |
| + | − | Parasitism |
| + | 0 | Commensalism |
| − | 0 | Amensalism |