Why is the starfish given that name?
Named for its star-like shape, this starfish belongs to the class (Asteroidea) derived from the Greek words (Aster) meaning star, and (eidos) meaning shape or likeness.
There are about 1,600 species of sea stars in all the oceans.
The most numerous of them are found in the North Pacific Ocean. Some of their limbs average between 20 and 30 cm in length, others may reach 65 cm in length, and they usually have five hollow arms. covered with short spines.
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Why is a starfish in the shape of a star?
Scientists believe that the starfish acquired its star shape more than 400 million years ago, and for this reason, they postulate some hypotheses, among which are the following:
- It is believed that it helps him move in all directions to get food.
- It is believed that the shape of the starfish enables it to touch the sea floor due to its broad and flat shape, which increases its chances of obtaining food.
- It is believed that the sea star's arm length enables it to cling tightly to the sea floor, thus keeping it away from predators.
starfish properties
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The starfish has many characteristics, including the following:
- Regeneration of limbs.
He can replace his arm if he loses it, and this process is called regeneration.
- Genitals
Each arm of the starfish contains reproductive organs called gonads.
These glands store gametes, or reproductive cells that are released during the process of fertilization, which in most species is external.
- Reproduction
Starfish can reproduce in one of two ways.
The first is through sexual intercourse between males and females. The male's sperm fertilises the female's eggs, resulting in larvae that settle to the ocean floor and grow into adult sea stars.
The second is called asexual reproduction, and it occurs with the loss of an arm, as the arm grows and becomes a starfish.
- The hunt
The starfish wraps the mollusks with its sticky ends, then pushes its stomach forward to digest the prey, and then sucks it to feed on it.
- The food
Some species of starfish feed on many small marine invertebrates, such as clams, clams, and snails, while some other species feed on corals and small plankton.
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- The danger of extinction
Fish and dried starfish are sold in tourist shops, and this process has put some species at risk.
- Defending himself
The spines of starfish are used to protect them from predators such as birds, fish, and sea otters.
- It has no blood in its composition.
The sea star's body doesn't have any blood inside, but it does have a circulatory system that relies on seawater instead of blood.
- Vision
The starfish has a small eye at the end of each arm, which enables it to sense both light and darkness.