OBJECTIVE FORESTRY

Detailed explanation-1: -The movement of organisms out of a range is called emigration. It is the migration or movement of individuals out of a population and leads to a decrease in the size of a given population. Immigration is the arrival of new individuals into a population.

Detailed explanation-2: -For instance, a flock of birds would move from an old habitat to a new habitat when the season is unfavourable. In physiology, migration occurs at the cellular level. For instance, leukocytes may move towards the region where they are essential for their immunologic function.

Detailed explanation-3: -In animal population, dispersal can be divided into following different forms: 3.1 Emigration: It is the outward movement of organisms in one direction from a given population. Emigration of individuals excessive production of young ones, shortage of various resources, unfavourable environmental conditions.