This paper examines the green sea turtle (Chelonia mydas), one of Earth's oldest reptile species, now critically endangered due to human activity. It covers the turtle's scientific classification, physical characteristics, reproductive behavior, diet, and habitat. The paper then outlines the major threats to the species — including hunting, incidental capture, marine debris, oil spills, habitat degradation, and fibropapillomatosis — before discussing the ecological roles green sea turtles play in ocean and beach ecosystems. It concludes with an overview of current legal protections and recovery efforts in Hawaii and the southeastern United States.
The paper demonstrates cause-and-effect analysis at both the species and ecosystem level. Rather than simply listing threats, it traces how each threat — from incidental bycatch to disease — feeds into population decline, and then shows how that decline ripples outward to damage two distinct ecosystems. This layered reasoning gives the essay argumentative depth beyond a simple informational report.
The paper opens with taxonomy and classification, moves through physical biology and life-cycle reproduction, then shifts to habitat and diet. The central section catalogs human and environmental threats in detail. The paper closes by articulating the turtle's ecological value and surveying protective legislation, ending with a call-to-awareness conclusion. This funnel structure — from organism to ecosystem to policy — is well-suited to environmental science writing at the high school level.
The green sea turtle is an endangered species of reptile and one of the few animals alive today that witnessed the age of the dinosaurs. Sea turtles have existed for approximately 200 million years, and they are now on the verge of extinction largely due to human activity.
The scientific classification of the green sea turtle is as follows:
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Cheloniidae
Genus: Chelonia
Species: C. mydas
Binomial Name: Chelonia mydas (Linnaeus, 1758)
There are seven remaining species of sea turtles: the green sea turtle, the leatherback, the hawksbill, the olive ridley, the flatback, the loggerhead, and Kemp's ridley. Of these, only the first four are found in Hawaiian waters, while the flatback turtle is found exclusively along the northern coasts of Australia.
Green sea turtles, like the majority of modern reptiles, are cold-blooded — their body temperature is not constant but depends on the surrounding environment. They are covered by a bony shell that protects them from predators. This shell covers both the belly (ventral) and the back (dorsal), providing essential defense for animals that are slow-moving on land and have no other protective mechanism.
Although sea turtles must crawl their heavy bodies across land, they are remarkably fast swimmers. Their front and rear limbs have evolved into flippers, allowing them to reach speeds of up to 35 mph underwater. Their shells are also lighter and more streamlined than those of land turtles, making them well adapted to aquatic life.
Sea turtles can remain underwater for more than two hours while asleep, as their respiratory system allows them to store higher concentrations of oxygen in their blood and muscles, along with elevated levels of carbon dioxide. When active, however, they must surface more frequently. In young sea turtles, this ability is not yet fully developed, so hatchlings sleep afloat at the water's surface.
Beyond breathing and locomotion, sea turtles possess an ingenious system for managing salt intake: a salt gland located behind their eyes allows them to excrete excess salt by shedding what appear to be tears.
Baby turtles weigh only about one ounce at birth, but adults can grow to weigh between 400 and 500 pounds and measure up to 4 feet in length. The largest of all sea turtle species — and the largest of all reptiles — is the leatherback, which can grow to over 200 pounds, though it does not nest in Hawaii.
The exact lifespan of sea turtles is unknown, but they are believed to easily reach 150 years. One of the factors contributing to their endangered status is the extraordinarily long time it takes them to reach sexual maturity — between 20 and 50 years.
Scientists believe that nesting female sea turtles return to their natal beach — the beach where they were born — to lay their eggs. This journey can require migrating up to 800 miles from their feeding grounds. Migration generally takes place in late spring. The most frequented nesting beaches in Hawaii are on French Frigate Shoals, where an estimated 90% of Hawaiian green turtles mate and lay eggs. Males accompany females and mate with them offshore. Females nest only once every two to four years, and they come ashore only at night. Within a two-week period, a single female can lay as many as nine clutches, each containing between 75 and 200 eggs.
The incubation period lasts between 45 and 75 days depending on temperature. When ready to hatch, baby turtles use a small protuberance on their beaks called an egg tooth to chip their way out of the shell.
After hatching, the baby turtles dig their way to the surface in a collective effort that can take several days. An individual hatchling would not be strong enough to reach the surface alone. When the group gets to within about an inch of the surface, they pause to check the temperature of the sand. If the sand feels hot, indicating daytime, they wait — daytime exposure increases their risk of predation. Once the sand cools, signaling nightfall, they emerge and head toward the sea, guided by the brightest point on the horizon.
This natural orientation system has become a serious problem in recent decades: artificial lights from coastal development confuse hatchlings and lead many of them away from the ocean, where they die of exhaustion or heat. After reaching the water, young turtles must swim continuously for approximately two days. They do not come ashore again for about a year.
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