Previous Year Question

Sere refers to the complete sequence of ecological Communities that successively replace one another over time in a particular area. This change occurs through Ecological Succession.

Ecological Succession is the gradual and relatively predictable change in the Species Composition of a particular area. The first community to establish itself at the beginning of succession is called the Pioneer Community. Subsequently, different intermediate communities develop, and under suitable conditions, a relatively stable Climax Community may eventually become established. For example, on bare rock, Lichens may be followed by Mosses, grasses, shrubs, and eventually trees.

The two principal types of succession are Primary Succession and Secondary Succession. Primary Succession begins in areas where no biological community was previously established, such as newly formed volcanic rock. Secondary Succession occurs in areas where a community previously existed but was affected by fire, floods, or human activities. Since soil is already present, Secondary Succession is generally faster. Succession beginning in aquatic environments is called Hydrosere, whereas succession beginning under dry conditions is called Xerosere.

The distinction between Sere and Ecological Succession is important. Ecological Succession is the process of gradual community change, whereas Sere is the complete sequence of communities developing through that process. Community Dynamics is a broader concept involving changes in community structure, populations, and interactions. In contrast, the Pyramid of Biomass represents the total biomass of living organisms present at different Trophic Levels.