List of top Behavioural Ecology Questions on Effect of Competition asked in GATE EY

Ecologists have studied the distributions of birds on archipelagos. Some studies found an interesting "checkerboard" pattern within island groups. Sister species were never present on the same island, even when the islands were very close to each other. Which one of the following processes best explains this checkerboard pattern?

Living in groups gives benefits but also brings costs. The graph below plots per capita benefits (solid line) and per capita costs (dashed line), both measured in the same units, against group size. Four group sizes are marked on the x axis: P, Q, R, and S.

Given these patterns in benefits and costs, which one of the group sizes P, Q, R, S best represents the optimal group size?

Species 1 and 2 belong to the same genus and co-occur at the same site. Which one or more of the following strategies would facilitate their coexistence at the site?