Question

Read the following statements:

A. They act as conduits for the transfer of energy across various trophic levels.
B. They are prudent in nature.
C. They maintain the species diversity.

The statements (A, B and C) given above describe the role of ___________in an ecosystem.

• A. commensal
• B. predator
• C. prey
• D. Both a and c

Answer 1

The correct option is B predator

Populations of different species live together and interact in several ways. These interactions can be beneficial, harmful or neutral to the species.

Predation is a type of interspecific interaction, in which one organism called the predator eats the entire or part of the body of another organism called the prey.

In this interaction, the one that gets benefited is the predator and the one that gets harmed is the prey and this interaction can be represented as (+, -)

Predator-prey relationships are of great importance to maintain the ecological balance.

The various roles of predators in nature are:

• The predators act as conduits for the transfer of energy across various trophic levels. The solar energy fixed by the plants is transferred to various trophic levels by the predators. The herbivores feed on plants and energy from plants is transferred to herbivores. The herbivores can be called as predators of plants. The herbivores become prey to other organisms called carnivores. These primary carnivores are eaten by other top carnivores. Hence, the predators act as channels (conduits) for the transfer of energy from plants (producers) to various other organisms.
• The predators maintain species diversity in a community. This can be understood by considering the following example. The starfish Pisaster is an important predator in the rocky intertidal communities of the American Pacific Coast. This predatory starfish feeds on the mussels (molluscs) and keeps its population under control and creates space for several other invertebrate species to coexist along with the mussels. This is how Pisaster maintains the species diversity of that community. In a field experiment, when Pisaster was removed, the mussel population increased rapidly due to the absence of its predator. These mussels covered the entire intertidal shore and there was severe interspecific competition for space and hence other invertebrate species could not establish themselves. This severe interspecific competition for space led to the extinction of more than 10 invertebrate species.
• If the predator over-exploits the prey, then the prey species will go extinct and eventually the predator too gets extinct due to the lack of food. Therefore, predators never over exploit the prey. Hence, predators are prudent in nature.

Commensalism is a type of interaction between two species, in which one species is benefitted and the other one is neither benefited or harmed. The organism that gets benefited is called commensal.