Sea+Urchin

**The Purple Sea Urchin** WENDY YIP 10C The Micraster Corbovis - Extinct Sea Urchin The Disguised Sea Urchin- Future Sea Urchin



**__ THE PURPLE SEA URCHIN __** Strongylocentrotus purpuratus is famously known as the binominal name of the Purple Sea Urchin which means “spiny hedgehog” in old English. The purple sea urchin has appeared around 450 million years ago and able to live up to 70 years. They are invertebrate, dioecious  and nocturnal. They contain spines that are around 1.5 inches long that are attach ed to its rounded body with the diameter around.5 inches called the “test”. Their body color is green when they were young and turn purple in adulthood. Their general temperature range is around 5-23.5 degree. The purple sea urchin can be found in the Pacific Ocean especially from Alaska’s coast line all the way down to the Mexico’s coastline. They can be easily found living in shallow water, sandy areas and rocky shores. **__ SCIENTIFIC CLASSIFICATION __**


 * ===Kingdom === || ===Animalia === ||
 * ===Phylum === || ===Echinodermata === ||
 * ===Class === || ===Echinoidea === ||
 * ===Subclass === || ===Euechinoidea === ||
 * ===<span style="font-family: 'Comic Sans MS',cursive;">Superorder === || ===<span style="font-family: 'Comic Sans MS',cursive; font-size: 16px;">Echinacea === ||
 * ===<span style="font-family: 'Comic Sans MS',cursive;">Order === || ===<span style="font-family: 'Comic Sans MS',cursive; font-size: 16px;">Echinoida === ||
 * ===<span style="font-family: 'Comic Sans MS',cursive;">Family === || ===<span style="font-family: 'Comic Sans MS',cursive; font-size: 16px;">Strongykicentrotidae === ||
 * ===<span style="font-family: 'Comic Sans MS',cursive;">Genus === || ===<span style="font-family: 'Comic Sans MS',cursive; font-size: 16px;">Strongylocentrotus === ||
 * ===<span style="font-family: 'Comic Sans MS',cursive;">Species === || ===<span style="font-family: 'Comic Sans MS',cursive; font-size: 16px;">Strongylocentrotus Purpuratus === ||

<span style="font-family: 'Comic Sans MS',cursive;">**__ ECHINODERMATA __** <span style="font-family: 'Comic Sans MS',cursive;"> The Purple Sea Urch in is known as one of the five classes that belong to the Phylum Echinodermata. The Phylum Echinodermata is divided into five classes. Each class is represented by a marine animal. The Purple Sea Urchin are classified as the member of the class “echinoidea” The Phylum Echinodermata refers to animals with “Spiny Skin” such as sea cucumbers, sand dollars, sea stars, sea urchin etc. The animals of the phylum echinodermata have skeletons that are made of bony plates. They also have tiny feet and hollow tubes inside their body which is filled with seawater.

<span style="font-family: 'Comic Sans MS',cursive;">**__ HABITAT __** <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">All types of sea urchin cannot survive in fresh water but can survive under any water tem ﻿ perature. Coral reefs and kelp beds can also be the homes of the sea urchins along with ocean rocks and sandy lagoons. In urchin beds, th ﻿ ousands of sea urchins can be stored. Sometimes, when there were too many sea urchins overcrowding, they turn into cannibals and cannibalism happens. The purple sea urchin can be found in the Pacific Ocean around North America especially from Alaska’s coast line all the way down to the Mexico’s coastline. They can be easily found living in shallow water, sandy areas and rocky shores.

<span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">Marine animals such as sea otters, crabs, wolf eels, sunflower stars, spiny lobsters and some birds are classified as the purple sea urchins’ predators. Unfortunately, most of the predators are located near the habitat of the Strongylocentrotus purpuratus, so it makes them more difficult to survive. But most importantly, human kinds are the biggest predators of the purple sea urchin because their organs especially their reproductive organs (call “uni” by Japanese) are used for sushi. For their predators, they will first break off all the spines and then tear the shell apart to eat their organs inside. The purple sea urchin eats mussels, barnacles, plankton, dead fish, sponges, kelp (favorite food) and algae as their main prey. The purple sea urchin has an important role in maintaining the ecosystem. They can eat algae really fast which can help keep the healthy algae population level.

<span style="font-family: 'Comic Sans MS',cursive;"> Every animal have their own area or environment which is suitable for them to live. The purple sea urchin is nocturnal and has good smelling and hearing senses. They hide in kelp forests, urchin beds, coral reefs or rocks in day time. In night time, they start searching food for feeding. Despite the fact that purple sea urchins can live in either sea bed or intertidal zone, most of them can be easily found in shallow water or rocky shores than in deep water with the dept of 35m. They find it difficult to live in really warm or hot water because the warm temperature can create stress for the sea urchin. Due to the large carbon dioxide released into the atmosphere, the sea water is absorbing much carbon dioxide. When carbon dioxide is absorbed, the sea water will become acidic which damages many of the marine animal’s habitats including the purple sea urchin. The acidic water can badly affect the growth of the purple sea urchin larva. Which in the result, that in the future majority of the purple sea urchin do not have a full grown skeleton and can affect the next generation. The average water temperature for the purple sea urchins habitat is between -1 to 15 degree.



<span style="font-family: 'Comic Sans MS',cursive;">**__ STRUCTURAL ADAPTATION #1 __** <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">The spines play a very important role for the purple sea urchin. The main role of the spines is used for protection. Poisonous liquid is released from the pedicellarines if the spines detected something is coming near them. If something sharp touched their body, the spines will poked towards that area. Also the spines are used for helping the purple sea urchins to build homes in rocky area. The sea urchins will use the spines to dig holes inside limestone or move objects for their homes. They spent years rubbing their spines to dig hole against the limestone. Beside kelp forests and coral reefs, sea urchins will hide inside the rocks which create a better protection from the predators. The spines can be also used to spear food and feeding. Some of the purple sea urchins will hide in the holes, and will wait for food to come near them.

<span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">Possible explanation can be made to discuss to the appearances of this adaptation. Since all intestines are placed together closely inside the body, many protection would be needed because a round body can easily be damaged by predators. Also, there’s not much area on the surface for the sea urchin to grow arms or legs, so spines were added for the function of protection and for the function of moving. Therefore, the spines are needed for multipurpose use because not much features can be added due to the size of the sea urchin.

<span style="font-family: 'Comic Sans MS',cursive;">**__ STRUCTURAL ADAPTATION #2 __** <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">Each of them contain around 50-75 tube feet with the function of eating, moving and respiration. For protection, they will use their tube feet to move rocks, bits of shells or seaweed to cover them. Another wording is that they can blend in with their surroundings to camouflage. Next, the tube feet can allow the purple sea urchin to move by sticking it along with the ocean floor. Despite the fact that the tube feet is for moving, the tube feet can also be used as the tool for feeding itself. Firstly, the purple sea urchin will use their spines to hunt for their prey and then they will pass their prey towards the tube feet. The tube feet are attached to the mouth of the purple sea urchin. Therefore, that’s how the prey can be delivered to the mouth from the tube feet. Lastly, the tube feet also contain the function of primary respiration. In the tube feet, primary gas exchanges happen. Tube feet help minor respiration while the external gills are the main organs for respiration.

<span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">The environmental pressure that could have given rise to this adaptation is similar to the spines. Due to the small size of the sea urchin, not much features can be added on the outside. Since the spines contain a lot of functions in order to help surviving, the tube feet were developed too. If the spines are damaged, that symbolizes that the sea urchin is going to die because most of the surviving function are lost. Therefore the tube feet are needed.The purple sea urchin is a slow moving marine animal due to the size of their tube feet <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">Since the shape and the function of the spines make difficulties for the sea urchin to move, so they need to use the tube feet which are located between spines to move. Continuing on, another reason that they are slow movers it to protect themselves. Once they feel any object coming by, they will stop then stay on the sea floor. If they stay still when any object pass by, it can decrease the chances of being discovered by the predator that is passing by quickly.

<span style="font-family: 'Comic Sans MS',cursive;">**__ PHYSIOLOGICAL ADAPTATION #1 __** <span style="font-family: 'Comic Sans MS',cursive;"> The purple sea urchin own two circulation functioned system. The two systems are the water vascular system and the hemal system. The hemal system is where blood is contained in the latter. The water vascular system is used on the echinoderms which the system can be defined as a hydraulic system that contains the function of transporting food or waste, minor respiration and moving. The main circulatory fluid fills the body crater which the fluid contains phagocytic coelomocytes. The phagocytic coelomocytes can pass through both systems which is a necessary part of blood clotting. Also the phagocytic coelomocytes can seal injured or damaged spines. If the spines are damaged or broken, the purple sea urchin has the ability to grow new spines within 75 days. Same to the axolotl, both animals has the ability to regenerate damaged body parts. It also collects waste and pass down to the gills and the tube feet for removal. <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">The environmental pressure that could have given rise to this adaptation is to increase the surviving chance of the sea urchin. The spines are important for the sea urchin because the spines can protect them from their predators. If these two systems are not developed, sea urchins can die very easily. Large marine animals such as the otter can easily break of the spines of the sea urchin; therefore these two system ﻿ s can regenerate the spines and can help blood clotting to increase the lives of the purple sea urchins.

<span style="font-family: 'Comic Sans MS',cursive;">**__ PHYSIOLOGICAL ADAPTATION #2 __** <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">The nervous system of the purple sea urchin is build up with a simple layout where they do not contain a brain. The purple sea urchin has a simple layout of the nervous system because their body size is too small to hold to many organs. Therefore all the organs have multiple functions. The centre that controls the whole purple sea urchin is a huge nerve circular shape. The huge nerve ring forms a circle around the mouth. In the nerve rings, there are five nerves that then separate into numbers of small nerves to control the other organs such as the tube feet, spines and inner organs. The five nerves are located under the radial canvas.

<span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">One of the environmental pressures that assigned to this adaptation is for protection. Since there are too many functions in every structural adaptation, the main control centre is really important. The nerve ring is located in the centre because it is surrounded by a lot of organs and protective adaptations. Also the five nerves are developed because it is easier for messages to be transport to the organs. If there are no nerves, then other organs need to be the messenger. Messengers should be separated with other functions because it can decrease the chance of messages being mixed up with other functions in the organs.

<span style="font-family: 'Comic Sans MS',cursive;">**__ BEHAVIOURAL ADAPTATION #1 __** <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">The purple sea urchin contains 7700 genes inside their body. 100-150 eggs can be produced by the purple sea urchin every time. The purple sea urchin is a dioecious marine animal. Eggs can be created without any sexual intercourse. The gametes are released by the male sea urchin and the female sea urchin will fertilized randomly with the help of the surf. But the gametes can be damaged by strong, big surf. Male sea urchin usually has 5 gonads that are located under the test. The gonad is surrounded by muscles which allow gametes to be squeezed through the single duct which can be found in the gonad. <span style="color: black; font-family: 'Comic Sans MS',cursive; font-size: 16px;">There’s a possible explanation to this adaptation which can have occurred during years of revolution. This behavior occurs as a result due to the body shape is hard for any sea urchin to have any contact when they are spiky without any flat area. In addition, the reproductive organs are located inside the test for protection protected; therefore it is easier to release gametes separately into the sea. However it is important that gametes can be easily damaged by the surf or whether the male gametes can be delivered to the female gametes, so pressure is still on for this marine animal to release their gametes into the ocean.

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