Read the following passage and answer the items that follow. Your answers to these items should be based on the passage only.
A species that exerts an influence out of proportion to its abundance in an ecosystem is called a keystone species. The keystone species may influence both the species richness of communities and the flow of energy and materials through ecosystems. The sea star Pisaster the flow of energy and materials through ecosystems. The sea star Pisaster ochraceus, which lives in rocky intertidal ecosystems on the Pacific coast of North America, is also an example of a keystone species. Its preferred prey is the mussel Mytilus Californians. In the absence of sea-stars, these mussels crowd out other competitors in a broad belt of the intertidal zone. By consuming mussels, sea star creates bare spaces that are taken over by a variety of other species. A study at the University of Washington demonstrated the influence of Pisaster on species richness by removing sea stars from selected parts of the intertidal zone repeatedly over a period of five years. Two major changes occurred in the areas from which sea stars were removed. First, the lower edge of the mussel bed extended farther down into the intertidal zone, showing that sea stars are able to eliminate mussels completely where they are covered with water most of the time. Second, and more dramatically, 28 species of animals and algae disappeared from the sea star removal zone. Eventually only Mytilus, the dominant competitor, occupied the entire substratum. Through its effect on competitive relationships, predation by Pisaster largely determines which species live in these rocky intertidal ecosystems.
With reference to the passage, consider the following statements:
Which of the statements given above is/are correct?
Both Statement 1 and Statement 2 are incorrect.
Statement 1: The passage indicates that mussels (Mytilus californianus) become the dominant competitor and crowd out other species specifically in the absence of keystone species like the sea star Pisaster ochraceus. The study cited demonstrates that when sea stars were removed, Mytilus eventually occupied the entire substratum. This suggests that their dominance is conditional upon the absence of their predator, rather than being a general characteristic across all intertidal ecosystems.
Statement 2: The passage primarily describes the ecological role of sea stars as a keystone species, highlighting their influence on mussel populations and overall species richness within intertidal ecosystems. It details how sea stars consume mussels, thereby creating space for other species and preventing mussels from monopolizing the substratum. The passage does not provide any information regarding the factors that determine the survival of sea stars or suggest that their survival is dependent on the abundance of mussels. The focus is on the impact of sea stars on the ecosystem, not the reverse.