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Green Sea Turtle
The Green Turtle (Chelonia mydas) is one of the many species of turtles that inhabits the vast oceans. The green turtle is named for the greenish color of it’s fat found under its shell. It is a large, heavy reptile, usually about 0.7-1.0 m in shell length and about 90-140 kg in weight. The maximum length and weight are about 1.2 m and 375 kg respectively. (1) The green turtles upper shell is smooth and wide, the animal is brown, but when the light from the sun hits it, the green color from the fat is visible. The green turtle is found in warm, coastal waters around the world. (2) Sea turtles, in adaptation to an aquatic life, have limbs modified into flippers for efficient swimming. It feeds mainly on marine grasses. Most female sea turtles leave the water only when it is breeding season because the female needs to dig a nest on the land and deposit her eggs. But an unusual characteristic of the green turtle is that it will often emerge onto land to enjoy the sun. (2)
The green turtle is classified as follows:
(3) And (4)
In this paper the classification and origin of the green turtle will be discussed further. Their diet, mating habits, offspring, senses, and their economic value will also be discussed.
Classification and Origin
There are four characteristics that have played a role in discussion of the relationship and classification of turtles. The characteristics include the dermal armor, the acromion process on the scapula, the astragalus-calcaneum complex, and the hooked fifth metatarsal. (1) The dermal armor (shell) is the interlocking osteoderms that are found lying above the vertebral column and the ribs. The acromion process in the turtle is an extension medioventrally on the scapula. (1) This unique characteristic allows for different muscle attachments in the turtle and accounts for the awkward positioning of the frontal limbs for walking or swimming. The astragalus-calcaneum complex has to do with the fusion of these two junctions to from a mesotarsal joint. (1) The hooked fifth metatarsal is evidence of a delay in ossification compared to the other metatarsals.
It is predicted that the origin of the turtle had to have been around the around the Germanic Basin of southern China and the western United States in about the Lower Permian time, about 280 millions of years ago. (4)
Throughout time the turtle has been whimsically portrayed as a slow moving creature. A unique feature to the turtle is that it exists as both a creature of the sea and a creature of the earth. The reputation that it holds as being a slow moving creature on the earth is true, but gliding in the water is another story. The marine green turtle (Chelonia mydas) has been known to swim three hundred miles in ten days. (3)
The green turtles are found distributed throughout the world’s oceans. There are found in the eastern and western hemispheres and on beaches throughout the Atlantic, Pacific and Indian Oceans. (5) The Pacific Green turtle and the Atlantic Green sea turtle are of the same species, they have basically the same length and weight. Since these two are over 3,000 miles away from each other combined with the centuries of separation, evolution has left the two of them with slightly different internal structures. Not only is their coloring a little bit different but also the Pacific green turtle's limbs are much longer. (5)
When food is available, the turtle will eat, but characteristic to all reptiles, the turtle can survive long fasts, they can live on weekly or monthly feedings. Their water is stored in cloacal bladders, which allow them to survive long droughts. (3)
The Green Turtle like most turtles, prefers a varied diet. They usually enjoy small invertebrates such as worms, snails, slugs, insects, thin-shelled bivalves and crayfishes and other crustaceans. (3) Many sea turtles love to eat jellyfish. Plastic bags are therefore very hazardous because they look similar to jellyfish, especially since the bags tend to float near the surface. (6) The larger aquatic turtles occasionally catch fish and sometimes birds or small mammals. Marine grasses and plants are also eaten but the fibrous parts are avoided, the green sea turtle does not have a well-developed jaw that is sharp enough to cut and grind. Turtles have been left to fend with out teeth for more than 150,000,000 years. The more modern types have semi-sharp and jagged edges of their jaws to function as teeth. (3) Their food is chewed and with the use of the forelimbs for manipulation of the often cumbersome meal. The floor of the throat is lowered; the head thrusted forward and the mouth opened as wide as possible, water rushed in to assist in the prey moving down. (3)
A courtship that is highly characteristic for each species or related group of species precedes copulation. The male's contribution in the mating display includes various types of head-waving, lunging at the female while roaring, and gracefully swimming backward in front of her while stroking her lores (cheeks) with his extremely long nails located on his forelimbs. The turtle has a single penis unlike other reptiles like snakes and lizards. (3). One of the unique characteristics of turtle reproduction is the ability of the female turtle to lay fertilized eggs years after a single mating.
The female green sea turtle will lay her eggs on land. Many studies have been done to determine what characteristics of a beach the female will choose to lay her eggs. Some hypotheses claim that the spot for nesting is random, based on topography on the beach, the vegetation, the amount of pollution, thermal cues, interspecies competition or the amount of human disturbance. The studies have been condu
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