In the rocky intertidal communities of the American Pacific Coast, which one of the following organisms is an important predator?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Starfish Pisaster
Predation is an interaction in which one species (the predator) kills and eats another (the prey). Predators also keep the species diversity of a community high, because they reduce the strong competition among the prey species. The starfish Pisaster is the example.
(1) Starfish Pisaster — Correct. It is the important predator of the rocky intertidal communities of the American Pacific Coast.
(2) Oysters — Incorrect. Oysters are filter feeders. They sieve tiny food particles from the water and do not hunt other animals.
(3) Pacific salmon fish — Incorrect. The Pacific salmon is a fish of the open sea and rivers. It is not a predator of the rocky intertidal community.
(4) Barnacle — Incorrect. Barnacles are fixed, filter-feeding animals of rocky shores. They compete for space and are prey, not predators.
NCERT Extract:
Population Interactions – “… Predators also help in maintaining species diversity in a community, by reducing the intensity of competition among competing prey species. In the rocky intertidal communities of the American Pacific Coast the starfish Pisaster is an important predator. In a field experiment, when all the starfish were removed from an enclosed intertidal area, more than 10 species of invertebrates became extinct within a year, because of inter-specific competition.”