The starfishbelonging to the Order of Asteroids and Phylum Echinodermi, They evoke images of the sea and holidays, but beyond the appearance these are organisms with these and many really surprising properties and characteristics and still not entirely known today, to the point that it is difficult to describe them all. Distant relatives of curls and sea cucumbers, they are present in all the oceans in the world with beyond 1900 Living species And they are voracious predatory with the ecological role of numerical regulators of other bodies in marine ecosystems. I am able to regenerate their arms If they are accidentally amputated or voluntarily lost to escape predators: in addition, they can have them up to 50not just five! They move thanks to a particular hydraulic system that deflates and swells the small peduncles located on the ventral side. They also have one “expandable” stomach which allows some species to eat even much bigger than them! They even hold a pharmaceutical interest since they produce metabolites with properties antiviral, antifungal and antimicrobial. Although they are particularly attractive it is absolutely reckless manipulating them or pull them out of the water because this action will condemn them to death.
How many species of starfish exist, where they live and what they eat
Stars represent an entire order of marine invertebrates: the Asteroidso called for the shape similar to stars, of the stars precisely. They belong to the phylum Echinodermi And there are over 1900 living species, distributed in all the oceans in the world by tropics to polar waters. In addition, they adapt to different depths from areas closest to the coasts up to the abysses, almost 6000 meters deep. Fossil finds show that current asteroids are morphologically very different from those of Paleozoic: the starfish of the Paleozoic were also very diversified, but they suffered a mass extinction during the permian like many other organisms. The species we see today are therefore the result of a new diversification.
They are predators, particularly gluttonous of molluscs So much to be considered a problem for mussel farms. However, some species are also satisfied with organic material in decomposition. The most advanced species manage to eat even more organisms than them thanks to one pocket -shaped stomach that can be Estroflex from the animal’s body. In the presence of a large prey, the stomach is pushed outside, rests on the prey and secretes enzymes that prediger the food before ingestion. The intestine is also wide, occupies the central record and extends to the arms of the starfish.
An animal all head
It would not be said by appearance, but recent research shows that the starfish is an animal with a great head! In fact, the head as we commonly understand it is not seen, but a complex genetic analysis has shown the opposite. The starfish is an animal a radiated symmetrythis means that ideally It is possible to divide its body into five equal partsa bit like the rays of a wheel. This symmetry is different from that of most animals that are a bilateral symmetry and have a body that can be divided into Two half of them mirror: Think of the right and left sides of the human body. In these bilateral symmetry organisms the genes that in the embryonic phase express the differentiation of the tissues of the head are concentrated In a part of the body corresponding to what will be the head in the developed organism. Instead, in the starfish that have radiated symmetry these genes are distributed a bit in the whole body of the animal And they reach the end of the arms: in short, their “head” is scattered everywhere.
Structure of the Marine Star: a hydraulic system to move
These animals manage to move and exchange gas with the environment thanks to a sophisticated hydraulic system. On the dorsal part, there is a sort of porous oxicino, called mother -of -the -praise, which ends in the shape of a sieve and allows the entry of the water into the body of the starfish. The water once entered is distributed in a canalization system (radial channels) that starting from the animal’s central body radiate along the arms. Along the radial canals there are thousands of small protuberances that protrude from the body of the sea star on the ventral side and that come into contact with the marine substrate: they are the ambulatory pedicels, So said because they are used to walk. Each pedicel is connected a sort of orientation of muscle tissue in the shape of a ampoule, capable of pumping water towards the pedicels making them swell and deflate. This micro-pumping mechanism allows the animal to adhere to the substrate and make movements.
The arms can regenerate themselves
The arms I’m not necessarily 5 As they represent in many drawings, but there are species that come to have even 50 very long and thin 50. Stars can voluntarily detach One or more arms in case of danger, stress or to escape a predator, but they subsequently regenerate them. This ability, known as a truck, is present in some animal species and is a valid survival strategy. In the marine star the scientists identified a neurramone released in conditions of dangercholecystochinin, which induces a muscle contraction at the base of the arm and regulates its detachment.
Why can’t star stars can be touched?
The worst condemnation that can be inflicted on these extraordinary animals is to manipulate them and keep them out of the watercondemning them to certain death. They should not be considered trophies or decorations e they should not be touched. They are extremely sensitive to touchat the lightthe temperature and quality of the water, as well as having a delicate hydrosaline balance, maintained constant only in sea water. Extracting them from the water or putting them in fresh water involves in a few minutes a osmotic stress and the formation of air bubbles that obstruct the respiratory canals. Manipulate them involves injury to the ambulacial pedicels, removal of the protective mucus of which the animal is covered and bacterial contamination that causes lethal infections for the starfish.
