Question

A universal process of directional change in community composition on an ecological time scale is called :

• A. Displacement
• B. Evolution
• C. Succession
• D. Extinction

Hint:

Ecological succession is the step-by-step directional development of a community over time, progressing from simple pioneer species to a complex climax community.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Ecological communities are dynamic systems that undergo structured, non-random changes in species composition, vertical structure, and community function over time, especially following disturbances.

Step 2: Detailed Explanation:
The universal process characterized by a directional, predictable, and sequential change in the species composition of an ecological community over time is called Succession (specifically, ecological succession).
Succession begins with a pioneer community colonizing a bare habitat (primary succession) or a disturbed habitat (secondary succession), transitioning through intermediate seral stages, and ultimately culminating in a stable, self-perpetuating, and highly complex climax community.
Let us review the other choices:
1. Displacement: A physical or competitive process where one species is forced out of its habitat by another, but it does not represent a whole-community directional developmental pathway.
2. Evolution: Occurs over evolutionary time scales (generation to generation genetic changes), whereas succession occurs over ecological time scales (years to centuries).
3. Extinction: The complete elimination of a species globally, which is a different evolutionary process.

Step 4: Final Answer:
Thus, the directional change in community composition on an ecological time scale is called Succession.