The Life Of Sea Stars Essay Example

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 they cannot survive. The sea floor may be too deep, or there may not be enough food of the right type to keep an adult sea star fed.

If a sea star larva finds itself in any of these problems after it leaves the plankton, it will die. Some sea star larvae, however, both survive the plankton and find themselves in favorable conditions when they settle to the ocean floor.

If this is the case, a larva attaches itself to a rock or a piece of coral with a sucker and begins an amazing transformation. It takes only a few hours for the larva to completely change the shape of its body and turn itself into a small adult. When the change is done, the new sea star leaves its rocky land and leaves off across the ocean floor in look for food.

Its adult life has started. Carrillo 3 It takes most sea stars one or two years to reach maturity after they become adult in form. When maturity is reached, it is time for a sea star to reproduce and create new sea stars. Nearly all sea stars reproduce by spawning.

This means that

females release eggs and males release sperm into the water around the same time. Most sea stars are nowhere each other when they spawn. The eggs and sperm meet up by chance as they float through the ocean. Spawning usually happens in the spring or early summer.

At these times of the year, light and temperature conditions bring about chemical changes in a female sea stars body. The chemical changes cause the female to release eggs. “A single female may produce over 2 million eggs in one spawn” (fact monster. com, sea star-reproduction).

Different species of sea stars release different numbers of eggs, but the numbers are usually large. Once released, the females eggs drift away on the ocean currents. With a little luck they will drift past male sea stars, who sense the eggs and release sperm in response. The sperm then fertilize the eggs, which eventually grow into brand new larvae.

Laboratory observations show that, at spawning, the males become restless and move around while the sperms are being discharged like white strings through the gonopores. In most cases about six to eight testes discharge at the same time.