La Starfish It is one of the most popular marine animals, and it should be noted that these are only from the sea, so they are not found in fresh water. These have a very curious structure, they have different shapes and colors, they are also appreciated as one of the most defenseless and striking animals in the sea.
What is the Starfish?
The sea star is a type of Asteroidea, an invertebrate that corresponds to the edge of the echinoderms, its body is flattened, made up of five arms and on rare occasions even more, these are joined by a kind of central disc, a form by which resembles a star.
The Asteroidea class is made up of approximately 1.900 species, which can be found in the different oceans of the planet, including the Atlantic, Indian, Pacific, Arctic and Antarctic oceans, the sea stars They usually live in very deep waters, even below 6.000 meters.
It is unfortunate to say it, but currently many species of starfish are in serious danger of extinction, as a result of many of the activities that human beings carry out, without considering the serious consequences that can affect the living beings that surround them.
Characteristics of the Starfish
This species, in addition to being among the Animals with E, has many characteristics that most human beings know, and others that are not so famous:
- They can regenerate themselves, have a wide variety of body shapes and feeding procedures.
- It has calcareous skin, aspects that protect them from the vast majority of predators. They also use their colors to camouflage themselves or more striking shades to scare away potential predators.
- sea stars they are radially symmetrical and usually have pentaradial symmetry in their adult stage.
- There are species of starfish that has six or more arms, others can have up to 10 and 15 arms, however, the species of starfish that more arms can have is the Labidiaster Annulatus Antarctica, which can have up to a maximum of 50.
- The body of the starfish It has very curious peculiarities, such as the fact that it has no brain, no head and no blood.
- Starfish have very sharp spines, which in the case of being consumed by a predator, can cause terrible pain and it is for this reason that many avoid them, although in other cases they simply manage to resist in some way, such as in the case of king crabs, sea otters and gulls
- This is one of the species that present the asexual reproduction in animals.
- Although starfish do not have a brain, they can perceive what is happening in their environment, this is because the cells they have in their skin collect all the information about the environment that surrounds them, they communicate through the nerve endings within your body.
- Starfish are also very useful for humans, since they have medicinal and healing properties, with which inflammatory diseases such as arthritis and hay fever are treated. It is a non-stick material, which allows its healing properties to reject bacteria and viruses that cause diseases in man.
What does the starfish eat?
sea stars They have a great ability to eat their food, since they have suction discs that they use to hold and open the shells of mollusks, where after doing so, the star stretches the stomach membranes through the mouth, inserting it into the shell entrance and distills its gastric juices, which break down the body of the mollusk and then suck it up with the stomach membranes.
In the case of the type of starfish that does not have suction discs, they eat their food without processing it whole, however the parts of it that are not digested are later returned. The sea stars They are predators of not very specific customs, they can feed on mollusks, clams, oysters, snails or any animal that is not capable of avoiding their leisurely assault.
In another case, there are starfish that eat detritus or putrefying substances, such as sponges, plankton, dead animals or organic sheets attached to substrates. Another species such as Acanthaster Planci, eat coral coelenterate, which means a potential threat to the increase of species in coral reefs.
Origin of the Starfish
The truth is that identifying the sea stars in the fossil record it has not been an easy task, just like that of other similar invertebrates, because its soft parts do not fossilize well and its more rigid parts separate from the rest when the animal decomposes.
Despite this, it is believed that its origin corresponds to the Ordovician period, just in the Paleozoic Era almost 485 million years ago. While the stage of pluralization as a species was during the Early Jurassic and Middle Jurassic times, after the mass extinction events during the Late Devonian and Late Permian.
Types of Starfish
There are approximately 2.000 species of starfish, which inhabit all the oceans of the planet, from tropical to marine and very cold oceans, however, starfish that have five arms are the most common, but also remembering that there are others of these species that have between 10 and 50.
Reproduction of the Starfish
Sea stars have two ways of reproducing, these are the following:
- Sexual: A large part of the starfish show an evident differentiation between those that are male and female, although this difference is not noticeable with the naked eye. There are others that are hermaphrodite animals, that is, they possess both sexes at the same time. Similarly, the reproduction of starfish In this case, it is carried out through the release of the gametes from the ducts located between the arms, in the center of the organism.
What is meant is that in most cases this means external fertilization, in which the spermatozoa and the ovules are found in the water to what is called free spawning, developing eggs stuck to stones and other surfaces.
- Asexual: The sea stars They also reproduce autonomously asexually, that is, by dividing their central discs or by amputating their arms, from where they can reproduce completely. That is, asexual reproduction usually occurs when a new starfish appears with its arms ripped off.
The eggs of the starfish they are large, the larvae can obtain sustenance from the yolk of the eggs and may occasionally eat other starfish eggs for food.
Parts of the Starfish
the body of the sea stars It is made up of two parts, first of all by a central disc, which preserves the proportion between its parts, it is also just the place where the organs and its mouth are located. Second is the set of hollow arms, which can be between 5 and 40.
The two parts are covered by a rigid and very strong crust of calcium carbonate sheets, which are called ossicles and can be found on the outside of spines or granules. In the lower part are the tube feet, which are small appendages that perform locomotion and transportation functions.
The body of the starfish itself is made up of distinct layers of tissue, with a thin epidermis and a thicker dermis, between which is the circulatory system. In each arm a simple eye, which helps to detect the alterations and the variability of when there is light and/or its absence. They do not have a brain, however they are very sensitive to touch, light, orientation, temperature, orientation and nearby waters.
Where is the starfish found?
Starfish live in the depths of the oceans throughout the planet, these little animals cannot survive in almost any region and are unable to subsist in most of the seas, they are mostly located in the tropical region of the Indo-Indian Ocean. Pacific, and the five-armed are the most predominant species of all.
How long do starfish live?
The life span of starfish can be up to 24 years, although this is related more than anything to the species, that is, the largest ones usually live longer than the smaller ones, which can only live up to 10 years, reaching sexual maturity at 2 years
How do starfish breathe?
sea stars They are animals that breathe through their tube feet, where from these the oxygen of the water reaches them through the internal fluids of the body cavities, that is to say that the oxygen enters the animal's body through a layer of tissue and the other. It should be noted that the starfish can't breathe out of water.
Starfish Movement
Starfish move slowly due to their appendages or feet, which cover the lower part of their body. This is done by means of an internal system of water circulation and the segregation of chemicals, which transform the end of the foot into a kind of suction cup, which is why starfish can stick tightly to any rock or surface.
Tissue Regeneration
These have the quality of regenerating, that is to say that if they lose any tissue from their body naturally, it grows back, as in the case of their extremities. It will depend on the amount of central disc that they lose if the regeneration of this is total or not, although it is likely that the regeneration includes larger fragments of the entire organism.
State of conservation
Starfish are very numerous marine animals, at the same time that they are very sensitive to the existence of toxic entities or chemicals in the water, substances by which they can be affected because the water is pumped in and out of their bodies. .
For this reason, oil or chemical spills are unfortunate for them, as is the damage they can do to tourists by taking them out of the water to photograph them and observe them closely, preventing them from exchanging gases and thus drowning.
Behavior
sea stars they move with their feet, which can stick to any surface and to the sea floor where they live, despite not having a brain, they can perceive everything that happens around them, since the sensory cells of their skin allow them to feel different aspects .