The Brittle Starfish Essay, Research Paper
Marine Institute of Memorial University
& # 8220 ; The Life of a Brittle Starfish & # 8221 ;
Course: Biology 1100
Teacher: Keith Rideout
Due Date: November 3, 2000
Student # : 961687
Table of Contentss
Page #
1.0 Introduction 1
2.0 General characteristics 1-2
2.1 Stereom 2
2.2 Water Vascular System 2
3.0 Habitat 3
3.1 Aggregation 3
4.0 Food Procurement 3-4
4.1 Food Source 3
4.2 Marauders 4
5.0 Development 4
6.0 Decision 4
7.0 Pictures 5-9
7.1 Structures of Brittle Starfish 5
7.2 Digestive System 6
7.3 Picture # 1 of Brittle Starfish 6
7.4 Picture # 2 of Brittle Starfish 7
Bibliography 8
1.0 Introduction
The type of marine being, which will be reported on within the undermentioned text, is the Brittle Stars. The Brittle Star is besides called the snake star and a common name for a big group of echinoderms closely related to the sea star. These beings make up the category Ophiuroidea ; another common name for Ophiuroidea is snake stars. These beings can be found in all oceans but are more abundant in the Tropics. Brittle stars can come in different colourss.
2.0 General Features
Their organic structures have a cardinal disc that is demarcated from five weaponries, unlike true sea star. Their five weaponries can be broken off quite easy, but will renew themselves. These weaponries are normally forked and spinous. The brickle star includes about 2000 species, and the weaponries are about 20 centimeters in length. The cardinal disc is about 1 inch across. Unlike the traditional sea star which uses tubing pess to creep and attach itself to objects. The brickle starfish uses his tube pess to take a breath and to convey nutrient to it & # 8217 ; s oral cavity, they do non utilize the tubing pess as a suction mechanism. The brickle starfish moves their weaponries to swim and creep. The brickle starfish contains a oral cavity on the bottom of its organic structure and their tubing pess are chiefly used as sense variety meats for observing visible radiation and olfactory property. The most common type of brickle star is the long-armed type, which is a grey or blue species that is luminescent. Brittle stars with many branched weaponries are called basket stars. Some brickle stars may reproduce by interrupting across the center of the organic structure disc, with each of the halves turning it & # 8217 ; s losing half and corresponding weaponries. Brittle stars lack unfastened Grovess on the lower surface of their weaponries. Each arm contains a series of jointed bonelike home bases, or bonelets, which determine the freedom of arm motions. They can travel in any way and really rapidly. They besides have a skeleton composed of legion home bases of Ca carbonate.
2.1 Stereom
The home bases that compose brickle sea star, ophiuroids and echinoderms is calcite along with other organics. Though each home base is a individual crystal of calcite, it doesn & # 8217 ; Ts take a typical crystalline signifier. Below is a image of the tooth socket, notice the holes.
2.2 Water Vascular System
Possibly non as obvious is the H2O vascular system, another trait common to all echinoderms. By analyzing the unwritten underside side of a brickle star, one will be able to see 100s of bantam pess normally arranged into several rows on each extremity of the star. These are the tube pess, or dais, and are filled with saltwater in brickle stars. The H2O vascular system within the organic structure of this species is besides filled with saltwater. By spread outing and undertaking Chamberss within the H2O vascular system, the brickle star can coerce H2O into certain tube pess to widen them. The animate being has muscles in the tubing pess, which are used to abjure them. By spread outing and abjuring the right tubing pess in the proper order, the animal can walk. Many echinoderms can besides organize chumps on the terminals of their tube pess. These chumps can be used to capture and keep quarry, or to keep onto stones in a fleet current or tide.
3.0 Habitat
Brittle stars can be found in the warmest and coldest of the universe & # 8217 ; s seas and have a wide geographic scope. Brittle stars can be found at assorted deepnesss of the ocean and tend to cleaving to sway for privacy. They can non be found on land or fresh H2O. These beings are non frequently seen because they live under stones or in coral, seaweed and they burrow into the clay or sand.
3.1 Collection
These marine beings tend to aggregate in big Numberss and eviden
tly besides did so in the yesteryear. Fossil beds dwelling about entirely of big Numberss of one or a few species are known from every bit early as the Lower Cambrian. In present twenty-four hours these species including most echinoderms may cover big countries of the seafloor. The ground behind collection seemingly is a response to one or more environmental factors, chiefly nutrient. Large Numberss of ophiuroids including brickle star and crinoids occupy countries in which strong currents carry big sums of plankton. A brickle starfish raises some of his weaponries in the H2O to capture the plankton and utilizing the bing weaponries to keep on to other brickle stars. They do this so that they will non be swept off by the current.
4.0 Food Procurement
Brittle starfish obtain nutrient by utilizing its long weaponries to convey nutrient to its oral cavity ; the tubing pess bring little atoms of nutrient to its oral cavity.
4.1 Topographic point in the Food Chain
Some brickle starfish are scavengers, eating works or carnal stuff that they come across. Many of these species develop relationships with sponges or corals. They clean the host of dust and in return get a safe topographic point to populate. Some brickle starfish are marauders as they catch shrimp, as they get older they catch bigger beings such as calamari and fish.
4.1 Food Beginning
Brittle stars eat many things. A brickle star & # 8217 ; s diet can include cirripeds, snails, sea urchins, boodles and mussels. They besides eat little animate beings and plankton. Many brickle stars eat mussels and boodles. They besides feed on debris and little life or dead animate beings. After they get large plenty they will in fact gimmick and eat fish anchorites and condylactis windflowers.
4.2 Marauders
Marauders known to devour a batch of brickle stars are bottom brooding fish such as tap, American plaice, haddock and Norway lobsters. These marauders do non by and large consume the full toffee star but acquire their arm as the brickle star will interrupt off it & # 8217 ; s ain arm as a defence mechanism.
5.0 Development
Scientists speculate that the deficiency of Precambrian dodos of echinoderms indicate that in earlier old ages they lacked a calcite skeleton and therefore did non fossilise. Ancient echinoderms exhibited a assortment of eccentric organic structure signifiers, the earliest signifiers seem to hold been experimenting with different organic structure signifiers and feeding mechanisms. They were adapted to life on difficult or Soft Ocean floor and evolved the burrowing wont. Anatomy and palaeontology surveies suggest that they may hold developed from a crinoidlike ascendant.
6.0 Decision
In decision the brickle sea star is a really alone being, as it possesses the undermentioned features:
& # 183 ; Will interrupt off it & # 8217 ; s ain weaponries as a defence mechanism towards marauders, the marauder will eat the arm and the brickle sea star will regrow the arm.
& # 183 ; Has evolved over the old ages to develop a spinal chord.
& # 183 ; Some brickle starfish are marauders and really gaining control and eat the undermentioned runt, plankton, calamari and fish.
& # 183 ; Has a H2O vascular system that consists of fluid-filled vass that are pushed out from the organic structure surface as tube pess, and other constructions, which is used in centripetal perceptual experience.
& # 183 ; Will aggregate in big Numberss on coral, away fast traveling current so that they can work as a squad to capture plankton that gets swept through the current. One brickle star captures the plankton with a twosome weaponries and uses the staying weaponries to keep on to another brickle star so that it won & # 8217 ; t be swept off.
Who would hold thought that the brickle sea star could be so complex?
7.0 Pictures
7.1 Structures of The Brittle Star
7.2 Digestive System
7.3 Picture # 1 of Brittle Starfish
7.4 Picture # 2 of Brittle Starfish
Bibliography
1. & # 8220 ; Introduction to the Asteroidea & # 8221 ; *http: //www.ucmp.berkeley.edu/echinodermata/asteroidea.html* ( 18 Oct 2000 ) .
2. & # 8220 ; The Ophiuroidea & # 8221 ; . *http: //home.att.net/~ophiuroid/home.html* ( 18 Oct 2000 ) .
3. & # 8220 ; Introduction to the Echinodermata & # 8221 ; *http: //www.ucmp.berkeley.edu/echinodermata/echinodermata.html* ( 18 Oct 2000 ) .
4. & # 8220 ; The Echinodermata & # 8221 ; . *http: //www.ldeo.columbia.edu/users/gregory/echinodermata.html* ( 18 Oct 2000 ) .
5. & # 8220 ; Brittle Star & # 8221 ; . *http: //lycoskids.infoplease.com/ce5/CE007562.html* ( 23 Oct 2000 ) .
6. & # 8220 ; The Ophiuroidea & # 8221 ; . *http: //www.ucmp.berkeley.edu/echinodermata/ophiuroidea.html* ( 23 Oct 2000 ) .
7. & # 8220 ; The Brittle Star & # 8221 ; . *http: //lycos.infoplease.com/ce5/CE007562.html* ( 23 Oct 2000 )
