Sea+Urchin-+Micraster+Corbovis

__**The Micraster Corbovis**__ Modern Animal- The Purple Sea Urchin_   **Future Animal-The Disguised Sea Urchin **



__**SCIENTIFIC CLASSIFICATION**__

 * **Kingdom** || Animalia ||
 * **Phylum** || Echinodermata ||
 * **Class** || Echinoidea ||
 * **Subclass** || Euechinoidea ||
 * **Superorder** || Echinacea ||
 * **Order** || Echinoida ||
 * <span style="font-family: 'Comic Sans MS',cursive;">**Genus** || <span style="font-family: 'Comic Sans MS',cursive;">Micraster ||
 * <span style="font-family: 'Comic Sans MS',cursive;">**Species** || <span style="font-family: 'Comic Sans MS',cursive;">Micraster Corbovis ||

<span style="font-family: 'Comic Sans MS',cursive;">The earliest sea urchin fossil appeared in the <span style="font-family: 'Comic Sans MS',cursive;">Ordovician Period which is around
<span style="font-family: 'Comic Sans MS',cursive;">488.3–443.7 million years ago.<span style="font-family: 'Comic Sans MS',cursive;">The Micraster Corbovis existed during the Cretaceous Period of the Mesozoic Era. The word Cretaceous refers to“chalk” and is abbreviated as “K”. Micraster Corbovis was one ancestor of the Purple Sea Urchin. They belonged to the forbes. The Cretaeous Period was around 145.5–65.5 million years ago. [image 1] The colored section is the most probably location of where the Micraster Corbovis was located. The location is determined due on the location of where the fossils were discovered. ====<span style="font-family: 'Comic Sans MS',cursive;">The Cretaceous Period was after the Jurassic Period and was after the Palogene Period that belongs to the Cenozoic Era. Due to the warm climate and relatively high eustatic sea level in The Cretaceous, many now extinct animals such as dinosaurs, ammonites, marine reptiles, rudists were living in the oceans and the seas. New species of birds and mammals were created during that period. The Micraster Corbovis fossils were discovered around the shore side in Germany and France, which has mentioned before as the probably location of where the Micraster Corbovis was located in the Cretaceous Period. ====

====<span style="font-family: 'Comic Sans MS',cursive;">It is suggested that the Micraster Corbovis lived around warmer areas compare to other area in the Cretaceous Period. The fossil found in Germany and France was in the location where ocean temperature was warmer compare to other areas. However the temperature now might be different compare to 145.5-65.5 million years ago since global warming or any radiation did not happened in that period. Therefore it is a possible answer that the Micraster Corbovis lived in that similar weather temperature. ==== ====<span style="font-family: 'Comic Sans MS',cursive;"> ====

====<span style="font-family: 'Comic Sans MS',cursive;"> From image 2, the fossil showed that the Micraster Corbovis did not grow any spines. Only the tube feet and the mouth were clearly shown. Therefore, it is believed that the Micraster Corbovis did not have any spines in the Cretaceous Period. From the information stated above, it is possible that the Micraster Corbovis only lived in the ocean bed and not on rocky shores or inside rocks because spines did not appear during that period. It is suggested that the Micraster Corbovis can only stayed in the ocean floor or lived inside sea plants such as coral reefs to camouflage for protection. So the Micraster Corbovis had a different habitat comparing to the Purple Sea Urchin. ====

====<span style="font-family: 'Comic Sans MS',cursive;">Even though the Micraster Corbovis had similar body size compare to the Pur<span style="font-family: 'Comic Sans MS',cursive;">ple Sea Urchin, it is believed that Micraster Corbovis only ate algae and kelps in the Cretaceous Period. Extincted animals like the Pygmy Water Buffalo, Prehistoric Llama and the Paeleolama mirifica was herbivores like the Micraster Corbovis. Since the Purple Sea Urchin only eat sea plants, so it is suggested that the Micraster Corbovis only ate plants instead of other animals. Predators of the Micraster Corbovis could be teleost fish, cartilaginous fish, jawed fish, sharks, skates and rays families which were also extinct animals. However those information were just suggestions since it happened 145.5-65.5 million years ago. ====

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<span style="font-family: 'Comic Sans MS',cursive;">__**STRUCTURAL ADAPTAION#1**__
====<span style="font-family: 'Comic Sans MS',cursive;">The teeth of the Micraster Corbovis were bigger compare to the Purple Sea Urchins. The teeth helped to chew prey down to the esophagus. The teeth were located inside the mouth which was surrounded by softer tissue. It was believed that the Micraster Corbovis had more teeth than the Purple Sea Urchin. The Micraster Corbovis were born with sharp teeth. Since the Micraster Corbovis did not have any spines, they used their sharp teeth to dig holes in limestone rarely. ====

====<span style="font-family: 'Comic Sans MS',cursive;">The most likely environmental pressure that created this adaptation was that the Micraster Corbovis could not use the tube feet to break down food or to dig holes. The tube feet were too small for food to pass into the internal body; therefore teeth were needed to chew food. Also the tube feet were not sharp enough to dig limestone holes and spines did not exist. So teeth were used to dig holes because the teeth were the sharpest organ of the Micraster Corbovis. ====

<span style="font-family: 'Comic Sans MS',cursive;">__**STRUCTURAL ADAPTATION #2**__
====<span style="font-family: 'Comic Sans MS',cursive;">The Micraster Corbovis had a peach shaped test instead of a rounded shape like Purple Sea Urchin. The internal organs were protected by the hard peach shaped test. The peach shaped test was more stable compare to the rounded shape because in the Cretaceous Period, the Micraster Corbovis did not have any spines to balance themselves. The peach shaped test had a flat side while the other side was round, so the flat side was to help the Cretaceous Period to balance on the sea floor. ==== ====<span style="font-family: 'Comic Sans MS',cursive;">The main environmental pressure of this adaptation was that the Micraster Corbovis needed a suitable test shape to protect its internal organs and was easier for locomotion. They could not have any quadrilateral shape because it was hard for them to fit into limestone or to camouflage. With the shape of one side flat and one side round, it gained benefits for the Micraster Corbovis to camouflage behind rocks or inside sea plants. ====



<span style="font-family: 'Comic Sans MS',cursive;">__**PHYSIOLOGICAL ADAPTATION#1**__
====<span style="font-family: 'Comic Sans MS',cursive;">The Micraster Corbovis were nocturnal. They were only active in night times and were resting during day time. The Micraster Corbovis was really sensitive if object touched them, lights or any chemicals. Therefore Micraster Corbovis only moved at night time. When they were moving at night time, it gave them advantages to hunt for prey because they have strong sense if any object is coming nearby ﻿ ====

====<span style="font-family: 'Comic Sans MS',cursive;">The possible environmental pressure of this adaptation was to gain advantages for Micraster Corbovis to hunt and to survive. Since the Micraster Corbovis was sensitive to lights, chemicals or any touches, they could only move at night time where there’s no natural sunlight. Also the Micraster Corbovis did not have any eyes to see, which all the organs and the test were combined as one eye. In night time, it was dark enough, that it was difficult to see anything, therefore the Micraster Corbovis should only move at night time since it had no eyes. ====

<span style="font-family: 'Comic Sans MS',cursive;">__** BEHAVIOURAL ADAPTATION#1 **__ ====<span style="font-family: 'Comic Sans MS',cursive;">The reproduction process of the Micraster Corbovis was similar to the Purple Sea Urchin. Even though the Micraster Corbovis did not have spines, both of the female and male released their gametes into the ocean. The surf will then help both the gametes joined together. Same as the Purple Sea Urchin, the male released their gamete<span style="font-family: 'Comic Sans MS',cursive;">s through the gonad. 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="font-family: 'Comic Sans MS',cursive;"> <span style="font-family: 'Comic Sans MS',cursive;">Possible explanation can be made to discuss this adaptation. Eggs were created when gametes from both parents were released. Since the female Micraster Corbovis only had the ova inside their internal body, therefore both parent needed to release gametes into the ocean due to the lack of organs in the female’s body. ====

<span style="font-family: 'Comic Sans MS',cursive;">__** BEHAVIOURAL ADAPTATION#2 **__ ====<span style="font-family: 'Comic Sans MS',cursive;">From the Micraster Corbovis fossil, it is believed that Micraster Corbovis hid in sea plants to camouflage themselves that is similar to the Purple Sea Urchin. The main reason that they camouflage themselves was for protection. Another reason that Micraster Corbovis hid in sea plants was that it was easier for them to hunt for prey. Since they did not have any spines to hunt for preys, they needed to hid themselves and wait for prey to come nearby which is similar to nowadays sea urchin. ==== ====<span style="font-family: 'Comic Sans MS',cursive;">From the fossil picture, it showed that the Micraster Corbovis did not have any spines therefore, they have less protection compare to the Purple Sea Urchin. Therefore they need to protect themselves from their predator by camouflage. ====

<span style="font-family: 'Comic Sans MS',cursive;">__**EXTINCTION**__
====<span style="font-family: 'Comic Sans MS',cursive;">In Earth history, it marked that one of the largest mass extinctions happened in The Cretaceous period- the K-T extinction. In the K-T extinction, many species were disappeared and extinct such as non- avian dinosaurs, large marine reptiles and pterosaurs. This extinction happened around approximately 65.5 million years ago. There were several predictions that led to this extinction from scientists. The scientists believed that this extinction was led by massive asteroid destruction, increasing volcanic activity, lack of sunlight and photosynthesis and change in climate and sea level. Approximately 98% of the marine invertebrates were extinct in this extinction. Invertebrates that lives in warm and could be found in shallow water were recorded as extinct animals including the Micraster Corbovis. Therefore it is believed that the main cause that led to the extinction of the Micraster Corbovis was due to the K-T extinction. ====

=__**BIBLIOGRAPHY**__=

Discovery Channel, (2011), Cretaceous, Retrieved 24th June 2011, from []

Exploring Earth, (2011), K-T extinction, Retrieved 25th June 2011, from []

Geofinder, (2011), Cretaceous, Retrieved 23rd June 2011, from []

Geology Rocks(2011), Micraster Evolution, Retrieved 23rd June 2011, from [imgurl=http://www.geologyrocks.co.uk/system/files/images/micraster.gif&imgrefurl]

Wikipedia, (2011), Cretaceous, Retrieved 23rd June 2011, from []

Wikipedia, (2011), K-T extinction, Retrieved 24th June 2011, from []