Turtle
A turtle, which belongs to the order Testudines, is a reptile with a body covered by a hard bony shell. While many animals, including mammals, have developed shells, none of them have a structure quite like the one that turtles have. The turtle’s shell has an upper section known as the carapace and a lower section called the plastron.
Habitat
Turtles have adapted to a variety of environments.Most species are aquatic, living in bodies of water that range from small ponds to large lakes and rivers.
Physical Characteristics
Turtles have a very hard shell that is made of keratin that protects them from their predators. Their shell has 13 large scutes, or plates, on top of it. The bottom shell is called a plastron. They have a soft inner body with skin that looks like scales and a tail. Turtles have rigid beaks, and some have razor-sharp serrated edges instead of teeth. Unlike the other reptiles, turtles cannot extend their tongue. They have keen senses of sight, smell, and direction, but also have poor hearing. Additionally, they can hold their breath underwater for up to 4 to 7 hours.
Adaptation
All turtles are well adapted to life in both sea and land: they have strong armors against predators. Long, stiff foreflippers pull them through the water while the hindflippers steer. Their large eyes allows them to gather light in dark waters.
Theory of Evolution
The DNA hypothesis suggests that turtles were a sister group to the archosaurs. A second hypothesis proposes that turtles were more closely related to lizards. A third hypothesis suggests that turtles appear as anapsid.
Natural selection
Overproduction is one cause of natural selection in which an organism has so many offspring that not all of them can survive. This phenomenon is true in the Leatherback turtle populations. A female turtle can lay up to 100-150 eggs at one time (natural selection) but is lucky if half her offspring make it to the sea when they hatch. The baby turtles climb over each other, sometimes struggling to reach the surface of their nest. Those who make or reach it to the surface and get the opportunity to head towards the sea face other challenges. When it comes to baby leatherbacks, “the tiniest variation in size and shape can determine who lives and who dies” (The Origin of Turtles). The turtles with strong flippers who can get to the water line without being picked off by the predators are the ones who reproduce and create the future generation of leatherbacks. This is how the species of the leatherback turtle keeps strong flippers in its genes. The ones who reproduce it have them.
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