Previous Year Question
Which of the following statements is not true about “ecological niche”?
Dominant species occupy extensive and broader ecological niche.
Number of species becomes large in ecological niche of natural ecosystem, if resources are sufficient
Number of species becomes small in ecological niche, if resources are sufficient.
Dominance of single species becomes minimum if the resource distribution is equitable in a habitat.
Correct Answer: C
Detailed Solution
An Ecological Niche represents the Functional Role, Resource Utilization, environmental requirements, and ecological interactions of a species within an Ecosystem. It may include an organism's food, habitat, activity patterns, reproductive conditions, and competitive relationships. An ecological niche is not merely the physical location where an organism lives; Habitat describes where an organism lives, whereas its niche explains how it survives in its environment and utilizes available resources.
Sufficient Resource Availability can support greater Species Coexistence in natural ecosystems. When resources such as food, water, light, nutrients, and space become more available, conditions for the survival and reproduction of multiple species may improve. This can increase Species Richness. However, resource abundance alone does not guarantee higher biodiversity; competition, climate, habitat diversity, and other ecological factors are also important. The claim that sufficient resources necessarily reduce the number of species is not scientifically justified.
Dominant Species may occupy a prominent position within a biological community based on their abundance, Biomass, or resource utilization. Some dominant species utilize a Broad Ecological Niche, enabling them to exploit different resources and environmental conditions. However, a broad niche is not an essential characteristic of every dominant species. If resources are distributed relatively evenly and different species have opportunities to utilize them, excessive dominance by a single species may decrease. Thus, resource availability and its distribution influence Community Structure and species diversity.
Gause's Competitive Exclusion Principle states that two species competing for the same limiting resources cannot coexist indefinitely within an identical ecological niche. However, through Resource Partitioning, species may reduce competition by adopting different feeding times, locations, or foraging methods. Ecologist Robert MacArthur demonstrated that five closely related species of Warblers could coexist on the same tree by searching for food in different parts of it. This example illustrates how differentiated resource utilization enables multiple species to survive within the same habitat.