Question

Match the items in Column-I with those in Column-II:

	Column - I		Column - II
(a)	Herbivores-Plants	(i)	Commensalism
(b)	Mycorrhiza-Plants	(ii)	Mutualism
(c)	Sheep-Cattle	(iii)	Predation
(d)	Orchid-Tree	(iv)	Competition

Select the correct option from the following:

• A. (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
• B. (a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)
• C. (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
• D. (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)

Answer 1

The correct option is B (a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)

No species lives in isolation in nature and populations of different species live together and interact in several ways.

These interactions can be beneficial, detrimental (harmful) or neutral (neither harm nor benefit) to the species.

The various population interactions observed in nature are mutualism, commensalism, competition and predation.

In mutualism, both the interacting species are benefited.

Mycorrhiza is a very good example of mutualism. The association of fungi with the roots of higher plants is called mycorrhiza. In this association both fungi and plants are benefitted. The plants provide energy-yielding carbohydrates to the fungi and in turn the fungal filaments absorb essential mineral nutrients from the soil and provide it to the plant.

In commensalism, out of the two interacting species, one species is benefitted (commensal) and the other is neither harmed nor benefited (host).

For example, some orchids grow as epiphytes on the branches of a mango tree. In this case, orchids are commensal organisms as they benefit from the mango tree. The tree provides support to the orchids. The mango tree is neither benefited or harmed from this interaction.

Predation is a type of interspecific interaction, in which one organism called the predator eats the entire or part of the body of another organism called the prey. In this interaction, the one that gets benefited is the predator and the one that gets harmed is the prey.

The solar energy fixed by the plants is transferred to various trophic levels by the predators. The herbivores feed on plants and energy from plants is transferred to herbivores. The herbivores can be called as predators of plants.

Competition is a type of population interaction in which the fitness of one species is significantly lower in the presence of another species. It occurs when more than one species competes for the same resources that are limiting and has a negative effect on both the interacting species. Example: Sheep and cattle.