Starfish They are echinoderms that do not have mobility and yet are living beings. They are quite peculiar and live in the oceans. Accustomed to talking about various species de peces, this article is quite special and curious. These animals are similar and related to sea urchins and sponges. The scientific name is Asteroidea and we can find various species that we will see throughout the post.
Do you want to learn everything about the starfish? Keep reading because this article is packed with valuable information
Key features
The starfish differs from many other species such as the fish that we are used to talking to in many ways. The first thing is that they do not need gills to breathe. They have a hole through which they exchange gases to introduce dissolved oxygen in the water into your body.
Unlike many other animals, they are quite long-lived, being able to last up to 35 years if conditions are favorable. Depending on the conditions and the species, they are animals that can weigh up to 5 kg. Its skin is prickly and is made up of a fairly resistant coating of calcium carbonate composition. Thanks to this coating they go unnoticed and can be protected against predators.
The starfish has 5 limbs around a central body that is shaped like a disk. It is these animals that have five-point radial symmetry. Some species that increase the number of limbs are capable of having up to 40 arms.
Although they cannot be moved since the calcium carbonate coating does not allow it, they can move from one place to another. There are species that, although they do not have a very pronounced movement, they are capable of moving some limbs. To move they crawl on the ground since they cannot swim. The arms are covered with some organs similar to clamps and suction cups that they use to expel air by propulsion and to be able to move slowly across the ocean floor.
On the tips of the arms they have sensors that help them to locate, perceiving the amount of light there is and this is how they find the food they need to live.
Types of starfish
Starfish comprise thousands of species with different characteristics each of them. They are distributed throughout the world. The best known for their abundance and for their spread in the media are those classic 5-armed starfish. As we have mentioned before, this is not always the case. It has been possible to find specimens of other species of echinoderms with up to 40 arms.
We are now going to see some of the best known species.
Brisingide
It is starfish that They are made up of between 6 and 16 arms. This type of starfish comprises six families and 16 genera of sea stars, the same ones that are composed of arms.
Forcipulatide
This type is composed of 400 species that are distributed in 6 families of 70 genera. Its main characteristic is that of having pediculate pedicels visible on the surface of its body.
Notomyotide
This type of star has about 70 species that are contained in about 12 genera. These arms are more flexible than those of most starfish. This movement is due to the fact that they have bands of muscles along their internal surface that allow them to move and help in their movement along with the aforementioned wind speeds.
veiled
This starfish has a fairly robust body that has a large disc in the center of the body and small depressions. There are more than 300 species of velatida in 25 genera and 5 families.
Valvatide
They are the best known in the world. There are 700 species with a total of 170 genera and 14 families. They are the most famous for having 5 arms.
Habitat and food
Starfish live in almost all marine habitats. They are vulnerable to contamination as they put water directly into your body to filter dissolved oxygen. Thus, if the water is contaminated they die intoxicated and drowned.
In the seas and oceans, these animals make up a large part of the biomass present. They also play an important role in the ocean floor and the communities that inhabit it. The habitats where we can find them are oceans, rockier coasts, beds of seaweed, coral reefs, sea grasses, tidal pools and sandy bottoms up to 9.000 meters of darkness where some abyssal fish live.
As for food, starfish feed mostly on mollusks such as some oysters, snails and clams. To feed they have some forms that are the result of their evolution and adaptation. Once the starfish has attached its body to the prey that it wants to ingest, it extends its stomach outwards by taking it out through its mouth. The stomach generates enzymes capable of degrading its prey until it is completely ingested. This helps the food go directly to the stomach and it can digest easily and completely. Smaller organisms are easy prey for starfish.
Contrary to them, the main predators of these echinoderms are sharks like the White shark o the bull shark, manta rays, other larger starfish and some species de peces.
Lifestyle
To defend themselves from predators they use some defense mechanisms such as tough skin and thorns, others have bright colors to appear poisonous and are able to camouflage themselves among plants and corals or lose an arm to stay alive.
These animals they are not social at allInstead, they live lonely for most of their lives. In some moments they can be seen together with others in times when there is more food.
I hope that with this information you can learn more about the starfish.