Turtle
by John T.
Artwork by Conor A.
The turtle is a reptile with a shell on its back made up of a ton of bones fused together. Turtles can be found a lot of places, including Massachusetts. Depending on the species, it can be very vibrantly colored, as the painted turtle is, whereas the snapping turtle is a much plainer turtle for camouflage reasons. A cool thing about the turtle is that it lives in four totally different environments- the more forested wetlands and marshes, along with the shores of rivers and lakes, the open ocean, and the very hot and arid desert.
Over time, the turtle, like many animals, evolved different traits. These traits are described on our cladogram. The first trait that was evolved was a spine and a skull case, known as becoming a vertebrate. Next it evolved a jaw, and was then considered a gnathostome. After that, it became a tetrapod, or a creature with four limbs. Next to be evolved was the ability to lay water-tight eggs, which enabled them to lay eggs on land. Animals with this trait are known as amniotes. The last evolution of the turtle was becoming a sauropsid, meaning it has two palatal openings in the roof of its mouth. The purpose of this trait is a puzzle to scientists.
The turtle’s most recent common ancestor node is that of sauropsids. When you trace the turtle’s line down on the cladogram, you’ll see that all the animals that come out from the other side of the branch are its closest relatives. Those animals are everything from the cryptocleidus to the triceratops. I used the cladogram to figure this out by first learning that all the animals who come out of your animal’s most recent node are its closest relatives. Next, I looked at the cladogram and traced out from the other side of the turtle’s most advanced trait node and found all the animals that share its trait (sauropsids).
Last updated April 7, 2007.