Question Bank [2022] — BIOLOGY STD 12 Science — Question

Definition: The interaction between nature, animals, plants and microbes to form a biological community is known as population interaction. These interactions can be intraspecific i.e. existing between organisms of same population, and interspecific i.e. between members of different species.

i. Mutualism: The type of interaction in which both the species are benefitted is called as mutualism.

1. This interaction is obligatory and interdependent.
2. In this type of interaction, both species - alga and lichen are benefited.
3. Lichens represent an intimate, mutualistic relationship between a fungus and photosynthetic algae or cyanobacteria.

ii. Competition: Competition is the type of interaction where both the species are harmed.

1. Totally unrelated species may compete for the same resource e.g. in shallow creeks on the west coast of Mumbai, visiting flamingos and resident fish compete for their common food, the zooplankton.
2. However, resources need not always be limiting for competition to occur. In competition, the feeding efficiency of one species is reduced due to the interference or inhibitory presence of the other species, even if resources (food and space) are abundant, e.g. Leopards do not hunt in close proximity of lion pride.