Sharks-+Alvinlol+Syrett

=Shark - Alvin Syrett = Sharks are a type of fish, which live all around the world. Sharks belong in the group of fish called Elasmobranch. Along with Stingray, they have 5 to 7 gills and have skeletons made of cartilage. There are about approximately 440 species of sharks, most live in the sea, with a few species living in fresh water. Most sharks prefer to live in areas where there are rocks at the bottom of the ocean. The earliest known shark species are dated back more than 420 million years ago. Different species of shark hunt many different prey, but all sharks are carnivorous. They eat different types of fish and mammals. Most sharks live in the ocean but a few species live in both fresh water an seawater. Depending on the species of the shark, the preferred temperature of the water will change, but most sharks prefer warm water. Since sharks are at the top of the food chain in the sea, they have no reason to hide from predators and so they are free to go wherever they want, but they must stay close to areas where there is food. Seals are favorite food for many species of shark. Since seals usually swim close to the surface, sharks prefer to stay near the surface when searching for food. Almost all sharks stay above 2000 meters of sea depth.
 * __Modern animal __**
 * Overview **
 * H****abitat **

Most sharks have 2 main colors. Black/grey and white. The top of the shark is a grey and black color and the bottom is a white color. This helps a lot in the survival of many sharks. Having a dark color tone on top helps the shark camouflage because the dark tone of color will match the bottom of the ocean, such as rocks and sand. The white underside of the shark will help it camouflage against the sunlight streaming into the water, and so they will be hard to spot if you are looking up at a shark. This is why some sharks that live in Pacific region seas have darker skin tones than other sharks in order to blend in to the rocks at the bottom of the ocean.
 * Adaptation **
 * 1) **Color **[[image:http://surf.transworld.net/files/2009/01/26/tiger-shark-roger-horrocks.jpg width="330" height="220" align="right" caption="A Tiger shark’s white underside and grey top"]]

Almost all sharks use their electroreception ability to hunt for prey. Electroreception is the ability to pick up and understand electric currents. Small movement of animals and the movement of water current send out tiny electrical signals. Sharks have special pores on their bottom jaws that contain conductive jelly that helps pick up that electrical current. This helps sharks a lot in searching for food because prey such as small mammals and fish can be located with ease. Weak or injured prey is easier to detect because they usually send out a stronger e lectrical current as they are struggling and have more irregular movements. Scientists believe that Hammerhead sharks are better at sensing electric current than other sharks because they have a bigger head. Bigger heads mean more surface area, and so more electroreception pores are spread out in a larger area, helping Hammerhead sharks find prey easier. This makes Hammerhead sharks the ultimate predator of the ocea n.
 * 2. Special electroreception ability **

Sharks have a unique sense of smell. Their nostrils are not connected to their breathing, so they can carry on smelling without breathing out. Since they can smell continuously, it is easier for them to get live updates on where the scent is coming from and if the scent is getting stronger. This helps sharks smell bleeding and wounded prey from hundreds of meters away. This makes the sharks efficient hunters in the sea.
 * 3. Smell **

<span style="font-family: Arial,sans-serif;">The skin on all sharks are composed of small, hard scales that look like teeth. These plates are made of protein. These scales are hard and durable, and they also act as armor for the sharks, or an exoskeleton. These also help the shark swim faster because of the streamlined shape of the plates, which helps sharks be able to catch fast agile prey, such as seals.
 * <span style="font-family: Arial,sans-serif;">4. Skin **


 * <span style="font-family: Arial,sans-serif;">5. Tails **

<span style="font-family: Arial,sans-serif;">Shark tails have adapted for different purposes. Unlike fish, sharks cannot swim backwards. This means that sharks need to have special shaped tails to compensate for the loss of agility. Different tail shapes changed the amount of thrust, endurance and agility. Sharks that hunt for fast fish, seals,and in some cases, Dolphin need to have tails that are shaped so that the shark can achieve fast acceleration for catching its prey. Less aggressive sharks such as the Porbeagle hunt groups of fish such as mackerel; therefore need specially shaped tails <span style="font-family: Arial,sans-serif;"> that help it keep up with fast prey.

<span style="font-family: Arial,sans-serif;">Megalodon is a prehistoric shark that lived approximately 1.6 million years ago. Fossils of the teeth of this animal have been found all over the world, such as in America and Europe. It is one of the largest and most powerful predators of the invertebrate species. Scientists think that the Great White shark is similar to the Megalodon, just smaller. They fed on whales and types of mammals such as pinnipeds.
 * __<span style="font-family: Arial,sans-serif;">Prehistoric Animal- Megalodon __**
 * <span style="font-family: Arial,sans-serif;">Overview **


 * <span style="font-family: Arial,sans-serif;">Habitat **

<span style="font-family: Arial,sans-serif;">Megalodon are thought to have lived in all areas of seas because their teeth have been found all <span style="font-family: Arial,sans-serif;"> over the world. They lived in deeper <span style="font-family: Arial,sans-serif;">waters instead of shallow areas because their massive size. Since they are so closely related to modern Great White sharks, scientists think that they used to live where Great White sharks live now. They preferred warmer water to cold, and 1.6 million years ago, the sea was warmer than it is now, therefore Megalodon could survive in most places.

<span style="font-family: Arial,sans-serif;">When the world started cooling, before the extinction of many animals and the Megalodon itself, Megalodon needed special enzymes that could cope with colder temperatures. These special enzym <span style="font-family: Arial,sans-serif;">es helped the muscles function and helped digest food. Without these enzymes, the Megalodon may have become extinct earlier, because the change of temperature of the sea.
 * <span style="font-family: Arial,sans-serif;">Adaptations **
 * 1) **<span style="font-family: Arial,sans-serif;">Special enzymes **

<span style="font-family: Arial,sans-serif;">2**. Bite force** <span style="font-family: Arial,sans-serif;">After an experiment in 2008, the results showed that the Megalodon had one of the most powerful bite forces in history at approximately 180,000 to 200,000 newtons, which is over 10 times more powerful th <span style="font-family: Arial,sans-serif;">an its distant relative; the Great White Shark. Since the Megalodon was so big, it needed a powerful jaw in order to cope with chewing and biting big animals, such as whales.

<span style="font-family: Arial,sans-serif;">The tail of the Megalodon is similar to the modern Great White shark. This is because the Great White shark and the Megalodon have similar diets, such as small mamm <span style="font-family: Arial,sans-serif;">als such as pinnipeds and seals. To hunt these animals, short bursts of speed are needed; therefore, this special type of tail is used. Without this tail shape, the shark will not be able to achieve great speeds in order to chase fast prey such as fish. The Great White shark and the Megaldon also had a similar shaped body, and so similar tail shapes would be appropriate.
 * 3. <span style="font-family: Arial,sans-serif;">Tail **

<span style="font-family: Arial,sans-serif;"> <span style="font-family: Arial,sans-serif;">Compared to the modern Great White shark, the size of the Megalodon is massive. There are a number of reasons for this. First of all, the Megalodon hunted whales and medium sized mammals. A big body and big jaw is needed in order to successfully hunt these animals, while in modern time, Great White sharks hunt squid, seals, and some fish. Compared to Great Whites, Megalodons eat bigger prey, meaning a bigger body and jaw is needed. A bigger body is also useful for defending itself against other predators
 * <span style="font-family: Arial,sans-serif;">4. ****<span style="font-family: Arial,sans-serif;">Size **

<span style="font-family: Arial,sans-serif;">Fossil evidence has shown that Megalodon had more efficient hunting strategies compared to Great White sharks. When attacking a whale, the Megalodon focused on immobilizing bony areas such as the ribcage, shoulders, or spine. Great White sharks usually avoid these areas, and they usually focus on other areas of the bo <span style="font-family: Arial,sans-serif;">dy. Evidence has also shown that Megalodon also focus on breaking the ribcage, and damaging important internal organs in the process. This is the most likely reason why the Megalodon needs such a big body and jaw. Fossils of small animals have shown that they have been rammed from below, possibly breaking bones or instantly killing on impact. During the Pliocene time period, new animals such as bigger whale starting to appear. Fossil evidence has shown that Megalodon have targeted the flippers of these whales. This would have helped immobilize the whale because the whale would no longer be able to swim and escape.
 * <span style="font-family: Arial,sans-serif;">5. Hunting strategies **

<span style="font-family: Arial,sans-serif;">Between the mid-Miocene and the Plio- <span style="color: black; font-family: Arial,sans-serif;">Pleistocene period, many changes happened on Earth in terms of temperature. The temperature of the sea changed significantly, and continents shifted. At the same time, the Ice Age began, which is the main reason why the Megalodon could not survive. Since Megalodon weren't used to such cold water temperatures, they could not survive during the Ice Age. Whales, the Megalodon’s favorite food, either migrated to Polar Regions or became extinct. Without their main food source, many Megalodon died out. Since so much water froze during the Ice Age, the water levels dropped drastically, make breeding harder for the Megalodon because of less breeding grounds and also increasing the chances of Megalodon pups being hunted by predators, since the pups usually stay in shallow areas in order to hide from predators such as whales, other carnivorous fish and also other Megalodon.
 * <span style="font-family: Arial,sans-serif;">Extinction **


 * __<span style="font-family: Arial,sans-serif;">Future animal- Great Great Black Shark __**

<span style="font-family: Arial,sans-serif;">The Great Great Black Shark is a descendant of the Great White Shark. It is similar to the Megalodon in size. It has a darker shade of skin, which is useful for camouflage. The Great Great Black Shark can survive in a wide range of water temperatures, and also survive high pressure. This helps the shark dive deeper than past sharks could. This also helps the shark hunt for a wider range of food sources such as giant squid, and other deep sea fish. Also, having a bigger body helps it be able to eat bigger animals, such as bigger whales. It also helps defend itself against other shark species.

<span style="font-family: Arial,sans-serif;">In 50 million years, many continents will bump into each other, making bigger continents. This will create bigger area of sea, and there will be less differen <span style="font-family: Arial,sans-serif;">ce in sea temperature in the world. The Great Great Black Shark will be able to live in most parts of the world, except for very cold areas. The species of shark will swim around freely in search of food, such as whales and mammals. The spread of animals around all parts of the globe may be a bad for the Great Great Black Shark, because food will have to be shared among more animals and competition may arise, such as more powerful marine animals.
 * <span style="font-family: Arial,sans-serif;">Habitat **


 * <span style="font-family: Arial,sans-serif;">Adaptations **

<span style="font-family: Arial,sans-serif;">The color of the Great Great Black Shark is a darker tone compared to other sharks. <span style="font-family: Arial,sans-serif;">This helps it camouflage at deeper sea levels because of low light conditions. This helps it sneak up on prey such as whales and mammals such as seals. <span style="font-family: Arial,sans-serif;">Also, since darker colors attract heat, the darker skin color can also help the shark keep warmer at the surface of the water.
 * 1) **<span style="font-family: Arial,sans-serif;">Color **



<span style="font-family: Arial,sans-serif;">The Great Great Black Shark is bigger than the Great White Shark, and a bit smaller than the Megalodon. <span style="font-family: Arial,sans-serif;">This is a big advantage for the shark for many reasons. One reason is because the shark is capable of eating
 * <span style="font-family: Arial,sans-serif;">2. Bigger size **

<span style="font-family: Arial,sans-serif;"> bigger animals, such as killer whales, one of the only Great White predators. This can ensure a longer life for most of the Great Great Black Shark. Another reason is because having a bigger body help <span style="font-family: Arial,sans-serif;">s the shark swim faster, and so helping it hunt faster prey such as dolphins and other types of mammals. Having a bigger body also helps defend itself from other species of shark.

<span style="font-family: Arial,sans-serif;">Similar to the Megalodon, the shark has special enzymes in its body that helps muscles in the body function properly at high pressure. This helps the shark dive down to deeper levels and so helps it escape from Killer Whales, one of its only predators, and also hunt other varieties of fish, such as deep sea creatures. The enzymes also helps the shark’s muscles function normally in cold waters, which is something the Megalodon had, but wasn’t developed enough in order to help it survive the Ice Age. This will ensure that the Great Great Black Sharks will survive during another Ice Age.
 * 3. <span style="font-family: Arial,sans-serif;">Ability to tolerate high pressure and change in temperature. **

<span style="font-family: Arial,sans-serif;">The ability to see better in low light conditions are important for this species of shark, especially since it can dive down to deep water. Since there is little light in deep <span style="font-family: Arial,sans-serif;">water, it will be hard to see without this special ability. This ability also helps the shark hunt for squid and other deep sea creatures that live only near the bottom of the sea.
 * <span style="font-family: Arial,sans-serif;">4. Ability to see better in low light conditions **

<span style="font-family: Arial,sans-serif;">Since the Great Great Black Shark is so massive, it needs a special tail shape in order to sustain agility and speed. This will help it catch fast prey such as big fish, whales and agile mammals. Without a special tail sha <span style="font-family: Arial,sans-serif;">pe, the massive shark will not be able to handle its own weight, and may not be able to catch its prey. This is an important part of its body that may help this species of shark avoid extinction.
 * <span style="font-family: Arial,sans-serif;">5. Special tail shape **

<span style="font-family: Arial,sans-serif;">As more competition arises and less food for all species of marine life, the Great Great Black Shark will have to evolve even further to tolerate the lack of food. At the same time, because of global warming, the Earth is getting warmer. This will lead to melting ice in the arctic. Over thousands of years, this will increase the sea level significantly, flooding some land masses. After thousands of millions of years, another Ice Age will start. When the sea level decreases, many species of marine life will either die off or become extinct. This may be good or bad for the Great Great Black Shark because its competition may die off, or its prey may become extinct. If all its prey dies off or become extinct, the Great Great Black Shark may have to adapt to become smaller to scavenge for scarce food sources.
 * <span style="font-family: Arial,sans-serif;">Extinction **

Shark - Wikipedia, the free encyclopedia. (n.d.).//Wikipedia, the free encyclopedia//. Retrieved June 26, 2011, from []
 * Biliography**

Martin, R. A. (n.d.). Adaptations of the Great White Shark. //ReefQuest Centre for Shark Research Home//. Retrieved June 26, 2011, from [] What are 3 adaptations of the shark for life in the water? - Yahoo! Answers. (n.d.). //Yahoo! Answers - Home//. Retrieved June 26, 2011, from [] Megalodon - Wikipedia, the free encyclopedia. (n.d.).//Wikipedia, the free encyclopedia//. Retrieved June 26, 2011, from []

Megalodon - Shark Glossary - EnchantedLearning.com. (n.d.).//ENCHANTED LEARNING HOME PAGE//. Retrieved June 26, 2011, from []

Reconstructing Megalodon. (n.d.). //ReefQuest Centre for Shark Research Home//. Retrieved June 26, 2011, from []