Q.What is commensalism? Give an example.

These three interaction types differ in whether each partner is helped, harmed, or unaffected. In mutualism, both species benefit — the classic example is the fig–wasp relationship, in which a specific fig-wasp species is the exclusive pollinator of its fig species: the female wasp enters the fig's enclosed inflorescence to lay eggs, pollinating the flowers inside in the process, while her larvae develop within some of the fig's own developing fruit tissue. Neither fig nor wasp can complete its life cycle without the other, making this an obligate, tightly coupled mutualism.

In commensalism, one partner benefits while the other is unaffected. An orchid growing epiphytically on a mango tree's branches illustrates this well: the orchid gains physical support and better light access from its position on the branch, while the mango tree derives neither benefit nor harm, since the orchid draws no nutrients from the mango's own tissues. …