Select correct statement:

Question

Accepted Answer

The correct option is 1:
Predators maintain the diversity in a community. This statement is ecologically correct and highlights the crucial role of what are known as "keystone predators." A keystone predator is a species that has a disproportionately large effect on its natural environment relative to its abundance. The classic way they maintain diversity is by selectively consuming the competitively dominant prey species in an ecosystem. By preventing one species from becoming too numerous and monopolizing essential resources, such as space or light, the keystone predator effectively reduces interspecific competition. This allows a greater number of less competitive species to coexist in the community, thereby preventing a decline in species richness and maintaining a high level of biodiversity.

The incorrect option is 2:
Limited resource supply leads to unlimited growth of population. This statement is fundamentally incorrect in the context of population ecology. Limited resources are, by definition, **limiting factors** that prevent a population from growing indefinitely. As a population increases in size under conditions of limited resources, competition for those resources intensifies, leading to increased mortality, reduced birth rates, or both. This pattern of growth is described by the **logistic growth model**, where population expansion slows down and eventually stabilizes. The stable maximum population size that the environment can sustain is known as the **carrying capacity (K)**; thus, limited resources lead to *limited* and stable growth, not unlimited growth.

The incorrect option is 3:
All plants show seed dormancy. This is an overgeneralization that makes the statement false. Seed dormancy—a temporary suspension of growth and metabolism—is an important adaptive mechanism for many wild plants, allowing them to delay germination until conditions like temperature, light, or moisture are favorable for seedling survival. However, many plant species, particularly those that have been domesticated and cultivated by humans (like many common vegetables and cereals), have been selectively bred to exhibit minimal or no seed dormancy at all. This lack of dormancy allows for quick and uniform germination when sown, which is highly desirable for agriculture. Therefore, not all plants possess the trait of seed dormancy.

The incorrect option is 4:
The species that invade a bare area is called climax. This statement confuses the initial and final stages of **ecological succession**. Ecological succession is the process of change in the species structure of an ecological community over time. The first species to colonize a bare or disturbed area (a pioneer stage) are called the **pioneer species** (e.g., lichens and mosses on bare rock). These species are responsible for starting the process of soil formation. The **climax community** refers to the stable, mature, self-sustaining community that develops at the end of the succession process and remains relatively unchanged unless a major disturbance occurs.