Overview- The green turtle or the Chelonia Mydas, is a large, weighty sea turtle with a wide, smooth carapace, or shell. It inhabits tropical and subtropical coastal waters around the world and has been observed clambering onto land to sunbathe. The green turtle is one of the Seven Species that have been around for over 110 million years, surpassing that of the great dinosaurs. Over its many years inhabiting this earth, the green turtle has developed a great variety of adaptations, allowing it to survive against predators and natural causes alike.
Environment- Although the Turtle has had to relocate countless times over its extended time on this planet, it has never strayed too far from the oceans and coastal waters in which it inhabits, Green sea turtles are found in the Pacific, Atlantic and Indian oceans (Worldwide in seas where temperature do not fall below 20 degrees). They are sensitive to heat and cold and prefer the warmer parts of the oceans. Males will never leave the water, but females must swim to the shore in order. to lay their eggs.
Abiotic Factors- Throughout the countless years that the Green Turtle has been on this planet a variety of abiotic factors have threatened its survival, whether they be general oceanic dangers or factors exclusive to the Green Turtle itself. Oceanic dangers threatening the Turtle include, rocks, sand, oxygen, and harsh and rough waves or a combination of some or many of these, whereas factors threatening the Turtle itself include the marine animals on top of the food chain.
Challenges- Many challenges face the Green Turtles survival, from the time they hatch until the time they die. Of these threats many of them are human related, some examples of hatching challenges include proprietorial animals such as lizards, seagulls and other birds, as well as inconsiderate humans may attack and kill the newly hatched turtles as they make their long voyage to the ocean shore, these hatchlings are killed for meat and their shells, however it is not just he newly born turtles that are effected by these predators, fully grown turtles may also be killed for their meat and or shells, however it is generally females that are killed by humans due to them being the only one that makes their way out of the ocean, males are normally killed by marine predators.
Another challenge that faces Green Turtles are Habitat Loss and ingestion of, and entanglement in, marine debris, Humans have left a substantial mark on the Natural Habitats of many animals, Green Turtles included, litter floats among the waves and as a result the Turtle ( and many other marine animals ) may ingest these, mistaking them for jelly fish and or other marine animals they may eat.
Adaptations- Due to these dangers the Turtle has had to develop a great deal of different adaptations in order to survive the factors that threaten its survival. These adaptations fall into three separate categories, Structural, Physiological and Behavioural. A structural adaptation of the Sea Turtle are their forelimbs and neck, the forelimbs are modified into long, paddle-like flippers for swimming, it allows the Green Turtle to maintain its speed whilst travelling in the ocean. The neck is also non retractile, The shell adaptations necessary for retractile limbs would impede rapid swimming, thus taking away its speed in the water. Another Structural Adaptation is the mouth of the turtle, it has no teeth, Their jaws are powerful and shaped like a bird’s beak. Most sea turtles are carnivore eating crabs, sponges, clams, molluscs and other marine invertebrates, therefore they have no problem eating their allocated cuisine. A behavioural adaptation of the Green Sea Turtle is how adult females return to the same region where they were hatched. It is not known exactly how they are able to navigate back to their natal beaches. Researchers think they may use a number of clues including ocean currents, the earth’s magnetic field, and water chemistry. And finally a Physiological Adaptation of the Green Turtles - Thermoregulation, because most sea turtles are ectothermic or “cold blooded,” it means that they cannot regulate their internal body temperature. Their metabolism is dependent on the surrounding environment. Being ectothermic had some advantages. It enables them to lower their metabolic rate, so they need less oxygen and can stay submerged for longer periods of time, allowing them to both eat and avoid being eaten.
Rythmic Pattern- For a Green Sea Turtles nest to successfully house and incubate a batch of eggs the temperature must be exactly right, if it is too hot the Turtles may die in the egg before they are hatched, if it is too cold the eggs will not successfully incubate, this is why it is so important that we keep beaches at a safe level, otherwise the turtles will cease to reproduce and cease to exist.
If coastal waters are not at the expected temperature then Green Turtles will travel many miles in order to find one that is. Dr David Pike, a leading expert on Marine life says that
“Because sea turtles must nest on land, they must be able to continue nesting in areas that will produce hatch-ling turtles.
“If sea turtles are unable to find suitable nesting beaches, they may be unable to adapt to changing environmental conditions and decline as climate change takes hold.”
As Dr Pike says, if we do not take hold of climate change then there is no doubt that the population of the Green Sea Turtles will decline and eventually falter.