Echinoderms, any of an assortment of invertebrate aquatic creatures having a place with the phylum Echinodermata, portrayed by a hard, spiky skin or covering. Starting with the beginning of the Cambrian Period (542 million to 488 million years back).

Echinoderm has a rich fossil history and is very much spoken to by numerous strange gatherings, the vast majority of which are currently wiped out.

Living agents incorporate the classes, Echinoidea (ocean urchins), Asteroidea (starfishes, or ocean stars), Holothuroidea (ocean cucumbers), Ophiuroidea (serpent stars and basket stars, or fragile stars), Crinoidea (ocean lilies and quill stars), and the as of late found Concentricycloidea (ocean daisies).


Echinoderms have been perceived since antiquated occasions; echinoids, for instance, were utilized widely by Romans and Greeks for medical purposes and as a food source. Amid the Middle Ages, parts of fossil crinoids were objects of fantasy or superstition.

In the early piece of the nineteenth century, Echinodermata was perceived as a distinguished gathering of creatures. Echinodermata was every so often connected with the cnidarians.


NameStarfish, Crinoid
Scientific NameEchinoderm
Synonymsbrittle-star,sea urchin, sand dollars

Vernacular names

  • English: echinoderms, sea stars, sea urchins, sea cucumbers,
  • Brazilian Portuguese: Equinodermas
  • Catalan: Equinoderms
  • Dutch: echinodermaten
  • French: Echinodermata
  • German: Stachelhäuter
  • Japanese: 棘皮動物門
  • Spanish: Echinodermata
  • Swedish: tagghudingar


History about the echinoderms is given below:

Origin of Echinoderms

All oceans of the world

Fossil records

The firstborn echinoderm found in southern Australia might be the Vendian fossil Arkarua. It was delicate bodied yet may have had a type of unmineralized plates on its body. The Vendian fossilTribrachidium may have been identified with the echinoderms, yet this is still discussed.

Echinoderms in the advanced sense, with mineralized bones, entered the fossil record in the initial Cambrian. Eocrinoids and homalozoans were noticeable in the Cambrian. Besides this other Cambrian echinoderm incorporated the bizarre helicoplacoids.

 Brittle stars and starfish showed up in the Ordovician, as did the most initial echinozoans. The most seasoned asterozoans (the Somasteroidea) demonstrate qualities of both brittle stars and starfish. Moreover, starfish and brittle stars are probably separated from a typical somasteroid precursor.

The later Paleozoic was controlled by blastoids and crinoids; appeared here is Agriocrinus, a crinoid from the Devonian Hunsruck Slate located in western Germany. Holothurians (ocean cucumbers) are basic echinoderms today, however, have a scanty fossil record

Distinctive Features of Echinoderms

In the first place, they all have five-section circular symmetry around a central plate. Second, they all have an extremely unique water vascular system. These special attributes recognize echinoderms from different creatures in the set of all animals.

Geo-distribution of Echinoderms

Echinoderms are internationally dispersed in all latitudes, depths, and conditions in the sea. They achieve most astounding diversity in reef conditions but at the same time are broad on shallow shores, around the shafts — refugia where crinoids are at their most rich.

Although, all through the profound sea, where base staying and tunneling ocean cucumbers are basic. Once in a while representing up to 90% of creatures.

sea urchin

While all echinoderms are benthic — that is, they live on the ocean bottom — some ocean lilies can swim at awesome speed for brief timeframes, and a couple of remote ocean cucumbers are completely gliding.

A few crinoids are pseudo-planktonic, joining themselves to skimming logs and flotsam and jetsam, despite the fact that this behavior was practiced most broadly in the Paleozoic, before rivalry from such living beings as barnacles limited the degree of the conduct.

The hatchlings of echinoderms, particularly ocean urchins and starfish, are pelagic, and with the guide of sea, streams can be transported for incredible separations, strengthening the worldwide dissemination of the phylum.


Grown-up echinoderms display pentaradial symmetry. Although, they have a calcareous internal skeleton, which is made of ossicles. Despite the fact that the early larval phases of all echinoderms have two-sided symmetry.

The endoskeleton is created by epidermal cells and may have cells with pigments, giving distinctive hues to these creatures, and in addition, cells loaded down with poisons. Gonads are available in each arm of this type.

In echinoderms like ocean stars, each arm bears two columns of tube feet on the oral on the side. The tube feet support in connection to the substratum.

These creatures have a genuine coelom that is altered into a special circulatory framework called a water vascular framework. A fascinating element of these creatures is their capacity to recover, even if more than 75 percent of their mass is lost in their bodies.


Echinoderms are only marine. They happen in different living spaces from the intertidal zone down to the base of the remote ocean trenches and from sand to rubble to coral reefs and in chilly and tropical oceans.

Food habits of Echinoderm

Almost all Echinoderms are carnivores or detritivores, however, some of them are suspension feeders. Little fish arriving on the upper surface might be caught by pedicellaria.

Besides this, a dead creature matter might be hunted however the primary prey things are living spineless creatures, for the most part, bivalve mollusks.

To eat one of these, the starfish moves over it, appends its tube feet and applies weight on the valves by bending its back.

At the point when a little hole between the valves is framed, the starfish embeds some portion of its stomach into the prey. Then discharges its digestive enzymes and gradually melts the delicate body parts.


As the adductor muscle of the shellfish unwinds, more stomach is embedded and when processing is finished, the stomach is reverted to its standard position in the starfish with its presently melted bivalve feast inside it.

The same everted stomach process is utilized by other starfish to eat detritus, ocean anemones, corals, algal films and sponges.


Echinoderms lives in Aquatic habitat or Brackish water

Life history of Echinoderm

Furthermore, echinoderms have enhanced in various ways of life. A few, in the same way as other starfish, are predators. Besides this, sand dollars, ophiuroids and holothurians frequently feed on debris. Crinoids are channel feeders.

Moreover, ocean urchins rub green algae from rocks. Moving towards ocean urchins and starfish, they might be common in extremely shallow water, while the floor of the remote ocean may swarm with holothurians or ophiuroids.

Reproduction in this type of species is usually done by external fertilization. The eggs and sperm are unreservedly released into the water.

A couple of ocean urchins brood their eggs in uncommon pockets. However, most of them give no parental consideration. Furthermost, many echinoderms experience a few planktonic larval stages before settling down.


The average lifespan of echinoderms is 4 years. Other types of echinoderms also live for 8-10 years.



A few echinoderms are meat eaters (for instance starfish) others are planktonic feeders (for instance basket stars) or waste foragers (for instance some ocean cucumbers).

Reproduction is completed by the release of eggs and sperms into the water. Most species deliver pelagic (free gliding) planktonic larvae which feed on tiny fish. These hatchlings are respectively symmetrical, not at all like their folks. When they settle to the base they change to the usual features of an echinoderm.

Communication and Reception

Researchers have discovered that starfish communicate through chemical signals. Starfish can discharge synthetic compounds into the water to send messages to others of their class.

A reproduction procedure of echinoderms

As far as sexual reproduction is concerned, starfishes are much the same as most different creatures. Where a male and a female will need to mate in order to create a baby. The male and the female starfishes really look basically the same as one another with regards to the outer physical attributes.

Moreover, when they spawn, their inward gonads will be uncovered and their sex can be distinguished. A few animal varieties also have both male and female sex organs which implies that they can reproduce on their own.

starfish mate

The greater part of the time, the male starfish discharge their sperm while the females discharge their eggs in the ocean. Fertilization normally happens externally.

However, a few types have been found to fertilize inside their bodies. At the point when the eggs are prepared, they either stick to rocks or buoy in the ocean until the point when they incubate to end up larvae.

Known Hazards

Known Hazards of starfish are given below:

  • Echinoderms wounds cause exceptional pain. It causes bluing of skin and sometimes vomiting and nausea. Spicules held in the skin cause stubborn cysts which are very painful.
  • Starfish can extend in size from a couple of crawls to a couple of feet in measurement. Contact with human beings happens just during deep Ocean diving, or when a starfish gets washed aground.
  • Starfish don’t assault people, however, can commit painful and difficult stings with the discharge of venom. When they are incidentally handled (grabbed) or stepped upon. It is chiefly the deep ocean divers who are in danger.

Similar species

Seastar (Asteroidea)

Sea urchins (Echinoidea)

Brittle stars(Ophiuroidea)

Feather stars, sea lilies (Crinoidea)

 Sea cucumbers (Holothuroidea)

Fun Facts

Apart from all the hazards, there are also some fun facts about the Echinoderm:

funfacts of star

Although, these fun facts are quite interesting yet there are some dangers as well.



Aymen Nizam

Aymen Nizam

I am IT (Graduate) from Bahria University Islamabad currently writing blogs on animals and plants, I am a content writer by profession and passionate about writing all information about living things. TapeDaily has provided me a chance to share my expertise with you.

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