Our group which consists of Tom mullaney, Jack warburton, Alisdair mcneil and isaac dawson are researching the topic Echinoderms.

an echinoderm is a phylum of marine animals. Echinoderms are found at every ocean depth from the intertidal zone to the abyssal zone.The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates.

Ophiuroidea= brittlestars

Crinoidea= feather stars

Asteroidea= sea star or starfish

Holothuroidea= Holothurians or sea cucumbers

Echinoidea= Sea urchins

Ophiuroidea/Brittle stars

Brittle stars, or ophiururoids, are echinoderms, closely reated to star
fish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to 60 centimetres in length on the largest specimens. They are also known as serpent stars.

Brittle stars contain 2 large clades, brittle stars and Euryalia (basket stars). Many of the ophiuroids are rarely encountered in the relatively shallow depths normally visited by humans, but they are a diverse group.

There are some 1,500 species of brittle stars living today, and they are largely found in deep water more than 500 metres down.

Brittle stars are fully grown in 3-4 years and live up to 5 years.Basket stars are usually confined to the deeper waters. These animals are even known from abyssal (6000 m) depths.


Crinoids/feather star

Crinoids are marine animals that make up the class crinoidea of the echinoderms .Crinodea comes from the greek word krinon, They live both in shallow water and in depths as great as 6,000 metres. Sea lillies refer to the crinoids which, in their adult form, are attatched to the sea bottomby a stalk, feather stars or comatulids refer to the un stalked forms.

Crinoids are characterized by a mouthon the top of the surface that is surrounded by feeding arms. They have a U shaped gut , and their anus is located next to the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognized, most crinoids have many more than 5 arms, Crinoids usually have a stem used to attach them selves to a subtrate, but many live attached onlyas juveniles and become free swimming as adults.

There are only a few hundred known modern forms , but crinoids were much more numerous both in species and numbers in the past. Some thick limestone beds dating to the mid-to-late paleozoic are almost entirely made up of dis articulated crinoid fragments.


Asteroidea= Star fish/sea stars

Marine scientists have undertaken the difficult task of replacing the beloved star fish's common name with sea star because, well, the star fish is not a fish. It's an echinoderm.

There are some 2,000 species of sea star living in all the worlds oceans, from tropical habitats to the cold seafloor. The five arm varieties are the most common, hence their name, but species with 10,20 and even 40 arms exist.

They have bony, calcified skin, which protects them from most predators, and many wear striking colours that camaflauge them or scare of potetial attackers. Purely marine animals , there are no fresh water sea stars, and only a few live in brackish water.

Beyond their distinctive shape, sea stars are famous for their famous ability to regenerate limbs, and in some cases, entire bodies. They accomplish this by housing most or all of their vital organs in their arms. Some require the central body to be intact to regenerate, but a few species can grow an entirely new sea star just from a portion of severed limb.

Most sea stars also have the remarkable ability to consume their preyoutside their bodies. Using tiny, suction-cupped feet, they pry open clams or oysters, and their sack-like cardiac stomach emerges from their mouth and oozes inside the shell. The stomach then envelops the prey to digest it, and finally withdraws back into the body.


Holothuroidea= sea cucumbers

There are some 1,250 known species, and many of these animals are indeed shaped like soft-bodied cucumbers. All sea cucumbers are ocean dwellers, though some inhabit the shallows and others live in the deep ocean. They live on or near the ocean floor-sometimes partially burried beneath it.

Sea cucumbers feed on tiny particles like algea which they gather in with 8-30 tube feet that look like tentacles surrounding their mouths. Sea cucumbers particularly eggs are prey for fish and other marine animals. They are also enjoyed by humans, especially in Asia, and some species are farmed as delicacies. When threatnened, some sea cucumbers discharge sticky threads to ensnare their enemeis. Others can mutilate their own bodies as a defence mechanism. They violently contract their muscles and jettison some of their internal organs out. The missing body parts are quikely regenerated.


If you want to know more about echinoderms watch this video below.