Describe mutualism in detail.

Interaction conferring benefits on both the interacting species.

- Lichens-mutualistic relationship between fungus and photosynthesising algae or cyanobacteria.

Mycorrhizae- mutualistic relationship between fungus and roots of higher plants. Fungi absorbs essential nutrients from soil and in return plant provides energy yielding carbohydrates to fungi. Most spectacular and evolutionary fascinating example is plant-animal interaction.

Plant needs animals for pollination, dispersal of seeds.

- Animals are rewarded for their services in the form of pollens, nectars, juices, fruits and seeds.

In many species of fig trees, there is a tight one-to-one relationship with pollinator species of wasp.

- Fig species is pollinated by its partner wasp and no other species.

Female wasp uses fruit not only as an oviposition (egg-laying) site but uses the developing seeds within fruit for nourshing its larvae.

The wasp pollinates the fig inflorescence while searching for suitable egg - laying sites.

Mutual relationship between fig tree and wasp : $(a)$ Fig flower is pollinated by wasp $(b)$ Wasp laying eggs in a fig fruit