The Life Cycle of a Sea Star
Between birth and death, a sea stars life follows a cycle of development, adulthood, and eventually parenthood. It is the cycle that produces new sea stars and keeps populations balance. Sea stars begin their lives as tiny larvae that look nothing like the adult sea stars. The larvae have different shaped bodies with many projecting arms. “It looks more like a blob of jelly” (Perry 46).
Sea star larvae develop in open water and immediately become part of the plankton, a population of very small plants and animals that floats near the ocean surface. As soon as it enters this population, a sea star larva begins to search. It eats as many of its tiny neighbors as it can catch. As it eats, it becomes bigger and stronger.
Although the plankton stage is a time of great growth and opportunity for a sea star larva, it is also a time of great danger. Sea stars are not the only hunters roaming the plankton. There are many other small but hungry animals searching for food in the same area. Most of these animals do not hesitate to eat a sea star larva. Plankton is also the main food source of some large animals, including some whales and sharks. These animals can swallow huge amounts of plankton in a single gulp. Between predators both small and large, most sea star larva are eaten within days of their birth. If a sea star larva survives the dangers of the plankton life, it eventually gets big and heavy enough to start its
journey toward the ocean floor. In warm waters, it takes about three weeks for a larva to reach this stage. Cold water larvae do not grow fast, so it may take as much as three months for sea star larvae in cooler climates to become large enough to sink to the ocean floor.
Surviving the plankton stage is an important first step for a sea star, but it is no guarantee of success. Because the plankton drifts freely with the ocean currents, many sea star larvae end up in areas where...