Echinoderms: Unlikely Sessile Marine Mammals

When society thinks about starfish, perch, chordate, and fetal pig they become extremely curious about how their bodies operate because of how they are made up. I will give a brief synopsis of all animals before going into major detail about them. According to the online website named dictionary.com, Starfish are any echinoderm of the class Asteroidea, having the body radially arranged, usually in the form of a star, with five or more rays or arms radiating from a central disk; asteroid (dictionary.com). It is known that a chordate is an animal belonging to the phylum Chordata, composed of true vertebrates and animals having a notochord (dictionary.com). According to research, a fetal pig is an animal in the phylum Chordata and class Mammalia (dictionary.com). A perch is known to be a certain kind of fish with very spiny fins (dictionary). Starfish, perch, chordate, and fetal pig are some very interesting animals that possess some exclusive qualities both similar and different.

Echinoderms such as starfish, sea cucumbers, and urchins are identified by their symmetry and central mouth. This species is found decorating the coral reefs by their variety of color and sizes. Because some of these animals like to burrow in the sand, they can supply oxygen to some of the depths in the ocean. Echinoderms are a staple food in many sea animals diet.

Steele, V.J. 1984. Morphology and ultrastructure of the organ of Bellonci in the marine amphipod Gammarus setosus. Journal of Morphology, 181(1), 97-131.

Chelonibia is a genus of acorn barnacles in the family Chelonibiidae of the subphylum Crustacea, which up until 1830’s was considered in the subphylum molluscs because of their calcareous shell and sessile pattern ( source). Chelonibia members are epibionts that fasten themselves to many marine vertebrates such as whales, manatees, crabs, horseshoe crabs and turtles (source). They have also been documented on sea snakes, alligators and inanimate substrates, but are not typically found on classic barnacle habitat such as boats, rocks, or docks (source). These motile substrates enable epibionts to gather nutrients from the water flow and some of these organism support abundant and diverse epibiont communities (source). Five living species of Chelonibia have been described, Chelonibia ramose, Chelonibia careta, Chelonibia manati, and Chelonibia testudinaria, all of whom are obligate commensal with particular hosts- ranging from custaceans and chelicerates to sea turtles and sirenians (sourece). Not one of these barnacle species occur on all documented hosts; though C. testudinaria is found on all species of sea turtles (source).

This sea cucumber species is easily identifiable by its vibrant yellow color. Some individuals may even have thick, faded gray stripes along the body. They do not grow large in size like some sea cucumbers, but rather grow up to about 2.5-3 inches in length. There are thorn-like protrusions off of their soft, cylindrical body that line five longitudinal ridges of the body thus giving them a pentaradial symmetry. On the underside of the yellow sea cucumber, there are three rows of tube feet that allow for individuals to attach to various surfaces such as rocks and sponges (Figure 1) (“Yellow Sea Cucumber: Colochirus robustus” 2017). These tube feet are controlled through the use of a water vascular system that allows for general movement (Prusch and Whoriskey 1976). At the anterior end of the yellow sea cucumber, or oral end, there are eight feathery feeding tentacles that extend around the mouth (“Yellow Sea Cucumber: Colochirus robustus” 2017).

Research of echinoderm regeneration on the molecular level has been taking a hit because of the lack of critical mass, but this has all changed lately. It is now possible for scientists to experiment echinoderm genome regeneration on the molecular level. The study done by this host of scientists from the University of London has one main goal, and that goal is to identify the genes that are involved in the regeneration process of Echinodermata. To be more specific, they are looking at the processes of neutral regeneration in specific echinoderm species. Echinoderms have been used as a model organism for development over a long period of time, but just recently they have been on the horizon of molecular advances.

Corals, sea anemones, sea urchins, molluscs, crustaceans and worms are all included in the large, diverse group we call marine invertebrates. They are classed as an invertebrate as they all share one common key feature; they do not have a backbone. Invertebrates seem like a simple life form but they are truly beautiful, interesting and complex creatures that roam our oceans. But which is the most interesting invertebrate? Would it be Porifera, Cnidaria, Bryozoans, Vermiforms, Mollusca, Crustacea, Echinodermata or Chordata? With marine invertebrates making up around 97% of the worlds described species it is open for a large debate (Arkive n.d).

Echinoderms are invertebrates, and the majority of them have spiny skin. This group of invertebrates includes starfish, sand dollars, sea urchins, and sea cucumbers, although these are just a few of them. There are actually about 6,000 different species of echinoderms. All echinoderms have one thing in common. They all have radial symmetry. This means that they all have appendages that point outward like the spokes on a bicycle wheel. All echinoderms live in water, whether it is saltwater or freshwater. If you examine the underside of a jellyfish, you can see the hundreds of tiny legs arranged in rows along each of the appendages. Crabs, eels, larger starfish, octopi, fish, and seabirds are all predators of echinoderms. Sea stars

An Echinoderm is any marine animal of the invertebrate phylum Echinodermata, having a radiating arrangement of parts and a body wall stiffened by calcareous pieces that may protrude as spines and including the Echinoderms live in marine habitats although can rarely live washed up on shore. Echinoderms contain of body parts that may protrude as spines and including the starfish, sea urchins, sea cucumbers, etc. Echinoderms get their Greek names meaning “spiny skin”. Most echinoderms have spiny skin, but some do not. This phylum includes animals mainly living in the ocean. All echinoderms have one thing in common and this is radial symmetry. This means that the creatures have appendages (or body construction) which point outward

The terrestrialization of tetrapods was a major evolutionary achievement and the basis for the diversification of all future land vertebrates. Among the most important innovations was the tetrapod limb, which evolved from the fins of ancestral lobbed-finned fish. Most notably, the dermal fin rays and rigid fin fibrils common to all fish species disappeared during limb evolution. Early pectoral fin formation in teleost embryos share many morphological similarities to early limb development. One of the first major differences is the fate of the apical ectodermal ridge (AER). The AER is a thickening of ectodermal cells in the distal bud. It is responsible for mesenchymal survival, proliferation, and bud outgrowth. In tetrapods, the AER regresses

Consequently, society has become exceedingly critical and judgmental of life and matter beyond its boundaries, often confronting the misunderstood. In spite of their vulnerability to human nature, invertebrates boast an impressive 97% of all animal species on Earth, surpassing its counterpart, vertebrates, by nearly 33 times in terms of population. The 7 divisions that form this queer, yet powerful union are known as phyla, and include the orders Coelenterata, Annelida, Porifera, Echinodermata, Mollusca, Arthropoda, and Platyhelminthes. While all invertebrate species share some common characteristics and behaviors, each is unique and different to its own extent. Furthermore, invertebrate paleontologists have concluded through their studies of fossil evidence that the history of these spectacular creatures is just as impressive- One thing to remember: Not even the Tyrannosaurus Rex was as

Sea cucumbers, a type of Echinoderm, can communicate by sending hormone signals throughout the water

Turtles belong to the class Reptilia, the subclass Anapsida, and the order Testudines (Le Buff 1990). Reptiles have repeatedly invaded marine environments with varying success and marine adaptation has been undertaken more than once in the history of the Cheloniidae family. Marine reptiles were particularly successful in the Mesozoic as major predators in the sea. Mesozoic marine reptiles explored a variety of swimming styles and diets that included fish, cephalopods, other vertebrates, and hard-shelled invertebrates (Motani 2009). The earliest marine turtles appeared in the Jurassic and were a marine species of the family Pleurosternidae known as Desmemys bertelsmanni, as well as an entire marine family, the Thalassemyidae. The carapace of

In his book, Understanding fossils: an introduction to invertebrate palaeontology, Peter Doyle writes this about the ongoing, and continuing formation of layers of the Earth:

The arthropods share many characteristics facilitating their mass divergence. First of all they are part of kingdom Animalia; characteristics that make an arthropod an animal consist of being multicellular organism lacking cell walls. Their bodies consist of true tissue for sensory and movement, which aids in activities such as finding food and finding a mate. Arthropods’ bodies have three germ layers, or triploblastic. These germ layers consist of an endoderm, mesoderm, and an ectoderm. The endoderm develops into the digestive organs; the ectoderm develops into muscular tissue, and the ectoderm into the