Question

The attached organism, elkhorn coral, looks like a plant, but is actually a large colony of tiny, interconnected animal coral animals. Other than during the larval stage, coral cannot move from place to place. Like most corals, it lives only in shallow water and lacks most of the sense organs common in other animals. What is the best explanation for how and why coral animals evolved a form that is more like a plant than an animal?

• A. People don't realize that this coral is an animal so they leave it alone.
• B. The plant-like appearance protects the coral from predators.
• C. The coral has a partnership with a type of algae that lives in its cells. As long as there is sufficient sunlight, the algae provide the majority of the food the animal needs. There is no need for locomotory organs or sense organs since the coral does not need to hunt. The flattened shape allows the maximum number of cells to receive sunlight, increasing the sugar output of the algae in the coral.
• D. Fossils of jellyfish have been found in rocks more than 500 million years old. Jellyfish are in the same phylum as sea anemones, hydras, and corals. It is likely that sense organs and ability to move around did not exist when corals first evolved and they have remained the same ever since.

Answer 1

Correct option is'C'.

The corals and the algae called Zooxanthellae form symbiotic relationship ship. It means the algae provides corals with photosynthesis food for it's growth, whereas corals give algae the products of coral metabolism to photosynthesize. So because of this dependency on algae, corals have evolved without locomotive and sensory organs. So practically corals don't need these organs and hence do not grow with them.

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