Starfishes

Interesting Facts about Starfishes!

There are about 1,800 living species of starfishes, which are also known as sea stars, and they can be found in all of the Earth's oceans. The greatest variety of sea stars are found in the tropical Indo-Pacific. Areas known for their great diversity include the tropical-temperate regions around Australia, the tropical East Pacific, and the cold-temperate water North Pacific.

Sea stars do not have movable skeletons, but instead possess a hydraulic water vascular system. The water vascular system has many projections called tube feet, located on the face of the sea star's arms, which function in locomotion and aid with feeding.

The mouth is located underneath the sea star on the oral or ventral surface, while the anus is located on the top of the animal.

Most starfish have five arms, however some have more or less. In fact some starfish can have different numbers of arms even within one species. Some species of sea star have the ability to regenerate lost arms and can regrow an entire new arm!

Sea stars have a simple photoreceptor eyespot at the end of each arm. The eye is able to "see" only differences of light and dark, which is useful in detecting movement.

Sea stars are capable of both sexual and asexual reproduction. Individual sea stars are either male or female. Fertilization takes place externally, with both male and female releasing their gametes into the environment. Some species of sea star also reproduce asexually by fragmentation, often with part of an arm becoming detached and eventually developing into an independent individual sea star.

A sea star arm can only regenerate into a whole new organism if some of the central ring of the sea star is part of the chopped off arm. The regeneration of these stars is possible due to the vital organs kept in their arms.

How interesting! :D i love starfishes!