Turtle

Sea turtles are reptiles which mean that they lay eggs, cold blooded and have scale on their legs and breaths through their lungs. The size of sea turtles can range anywhere from 29 inches to 75 inches. Male and female sea turtles are almost the same in size. Depending on the species, the color can range between black, green and yellow. Sea turtles have remained unchanged for the past 120 million years. Sea turtles, unlike other turtles cannot retract their head and feet inside their shells. They can weigh anywhere from 36 kg to 900 kg. The life span of sea turtles can be up to 80 years. Sea turtles can be found in warm climate oceans such as the Pacific Ocean. The most well-known sea turtle is the green sea turtle. The green sea turtles are so ancient that lived when the dinosaurs still existed. Green sea turtles weigh up to 300 kilograms and are the largest sea turtles in the world. Their average life span is around 80 years and their size is 5 feet. They are named ‘green’ sea turtles not only because of their color of their shells, but also because of the color of their skin. However, unlike all the other sea turtles, juvenile green sea turtles eat invertebrates such as crabs and jellyfish in order to develop their body strength. Adult green sea turtles, however, are herbivores and only eat algae and seaweed. Male are slightly larger in size than females, and also has a longer tail. Green turtles are one of an endangered species, regardless of this; they are still hunted for their eggs and meat which are used for human consumption. Also, a number of green sea turtles are killed by boat propeller, fishnets and also human attack.
 * Green sea turtle **
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Habitat Green sea turtles are located in open warm ocean, and depending on their stages of life, their habitat differ. Adult green sea turtles spend most of their time in shallow water where there are coral reefs such as the blue coraland sea plants such as algae and seaweed. Adult green sea turtles must lay their eggs on beaches, but other than this, they do not leave the water. Hatchling and juvenile green sea turtles prefer to live away from shore and in the open ocean, as they eat invertebrates such as jellyfish in order to develop a strong shell and body. However, this can be very dangerous as they are defenseless against large predators. As illustrated on the map above, green sea turtles tend to live near the coast of Africa, the Atlantic Ocean and also the Pacific Ocean. To be more precise, many of the green sea turtles live in the Mediterranean Sea which connects South Europe, North Africa and West Asia, as there are many coral reefs to be found there. The green sea turtles select their habitat, and factors that affect their choice are: a) Whether they can find food b) Whether there are protections c) Whether it is near shore d) Whether there are many large predators living there


 * The structure of the lungs **

Sea turtles have a metabolic system. This is good because it allows the turtles to stay under water for a very long period of time. A green sea turtle can stay under water for over 5 hours without breathing in oxygen. Their lungs are highly elastic, and an additional bronchi which enables them to have a high lung capacity. This allows rapid air exchange, allowing them to swim over longer distances for longer durations. These adaptions of their lungs are important in marine life. Sea turtles are vertebrates, just like humans and many other land animals, however they do not need to breathe while they swim or exercise. Humans do. They hold their breaths and rely on their oxygen within their lung to supply oxygen form tissues. When their ‘oxygen tank’ ever runs out, sea turtles come above the surface to breathe in again.


 * The structure of the strong shell **

Sea turtles have a hard outer shell protecting their internal body from predators such as shark. The shell is made of hard bone plates, covered with scutes which are substances in the human hair that are made of keratin. The outer layer of the shell is formed by scutes, but what is forming the shape is the bone layer. The bone layer is connected with the bone structure of the turtle as with all vertebrates. The vertebrae of the sea turtles are interesting as it allowed the sea turtles to swim flexibly throughout the ocean floor, which is an important feature. However, the disadvantage of having a shell for sea turtles is that, if the scutes are destroyed or breached, it can cause infections or injuries to spread through the turtle’s body, which can eventually lead to death. Although shells are useful under water, it slows them down when they are hatching their eggs onshore, which makes them weak against land predators and [|seagulls].


 * Laying eggs on beaches **

Sea turtles lay their eggs on shore, most preferable a sandy beach. Many female sea turtles have a //homing instinct// that is, returning to the same beach where they were born to hatch their eggs. It is extremely difficult for female sea turtles to move on shore, as their heavy shell restricts their mobility. A female sea turtle finds a spot that will be safe even when the high tides come. After she finds a good spot to hatch her eggs, she then digs and lay her eggs inside it. She will then cover it with sand, and finally when she finishes laying her eggs, she goes back to the water. The //homing instinct// allows sea turtles to lay their eggs safely as they know that the specific beach in which she was born is safe, in other words, for safety. The disadvantage of this is that female sea turtles lay a clutch, a nest for turtle eggs of around five or six per season which is approximately 400 eggs. The //homing instinct// applies to all 400 sea turtles, which can result in over population of sea turtles which can affect the food chain. Also, female turtles unintentionally destroy a clutch, as sometimes there are many eggs. Land animals such as raccoons would dig up the eggs and eat them and sometimes there are eggs as many as 500 in the same area!


 * Forelimbs **

Their forelimbs are has adapted into long, paddle like flippers for swimming. With their mobility under water, the green sea turtle has only two predators. They are: sharks and humans. Its forelimbs are good adaptions, making them strong swimmers because their forelimbs has modified into a paddle like shape, therefore making them push along the water faster and easier. It allows them to run away faster from larger predators. It has adapted to this because there was an increase in global warming, making the sea currents strong. From this adaption, they can swim up to 1.5 miles per hour.


 * Salt secretion **

Sea turtles are able to live in sea water without the need for freshwater. Green sea turtles have salt gland which enables them to get rid of excess salt obtained from seawater. The salt gland is found on the turtle’s skull and helps maintain salt balance, and at the same time allows marine vertebrates to drink sea water. The gland helps empties salt from their eyes, thus making them look as if they are ‘crying’ when on land. This adaption may have occurred because green sea turtles are now officially a marine animal and for every reptile that lives under water, salt secretion is required. Another benefit that salt secretion gives, besides maintaining salt balance and allowing them to drink sea water, is that it helps females to prevent sand going into its eyes when digging to lay her eggs.

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Geographic. (n.d.). Green Turtles, Green Turtle Pictures, Green Turtle Facts - National Geographic. //Animals, Animal Pictures, Wild Animal Facts - National Geographic//. Retrieved June 25, 2011, from [] HistoryKing. (n.d.). Sea Turtle Adaptation. //History, American History, World History, Music History, Art History, Biography, Ancient Greece History, Mthology, World War//. Retrieved June 25, 2011, from [] Inc. (n.d.). Sea Turtle Evolution. //Sea Turtle Facts and Information//. Retrieved June 25, 2011, from []