Although Most Red-Eared Sliders Can Live Up to 45-60 Years, Most WILL NOT Survive Two Years! Chris Johnson 2014
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Red Eared Slider Secrets Although Most Red-Eared Sliders Can Live Up to 45-60 Years, Most WILL NOT Survive Two Years! - CHRIS JOHNSON - www.redearedslidersecrets.com 3
Bonus 3 The History of Turtles Like all other animals throughout history and still living today, turtles are the product of an evolutionary process that spans millions of years. Environmental changes and certain conditions can trigger mutations, and if the mutations prove better for the survival of the species, the changes become spread throughout the species. Eventually, the species has changed so much that it has become something else entirely. Because of their heavy shells and thick skulls, the remains of turtles were better able to endure through harsh conditions and stood a better chance of becoming fossilized. Turtle fossils, therefore, have been found far more often than fossils of other animals of similar sizes, allowing paleontologists to get a better idea of the ancestry of the modern turtle. Reptile Evolution Long before the dinosaurs walked the earth, there was a group of prehistoric amphibians known as the Labrynthodonts. It is from this group that paleontologists believe all reptiles are descended, coming about with the development of the amniote egg. Although animals have been laying eggs for millions of years prior to the Labrynthodonts, they had to be laid in the water to prevent them from drying out. Even today, some animals still have to do this, including fish and amphibians. However, an amniote egg is able to be laid on dry ground, and they are laid by animals that include birds, reptiles, dinosaurs and some rare mammals like the platypus. These eggs have a water-tight shell and fluid-filled membranes that protect and nourish the young. By being able to be laid on land, they free the animal from the necessity of having to return to the water. The oldest egg found dates to the lower Permian period, more than 275 million years ago. 4
Reptiles have been around for longer than that, however. The earliest known animal that can be readily identified as a reptile is a small creature known as the Hylonomus, found in fossilized tree stumps in Nova Scotia. It dates back to the Carboniferous period some 360 to 290 million years ago, and it was part of the group of reptiles known as the Cotylosaurs, also known as the stem reptiles from which all modern reptiles are believed to be descended. The Turtles Early Ancestors Currently it is unknown what group of stem reptiles gave rise to the turtles, although there are some possible candidates that have been debated. One such early on was known as the Eunotosaurus who had wide, paddle-shaped ribs that some paleontologists believe to be the forerunner of the modern shell. Today, that has been discarded, since it is now known that the shell isn t a part of the ribs but a series of plants in the skin. Eunotosaurus is no longer considered a possible ancestor. Because of the skull structure of turtles, which completely lack fossae as mentioned in chapter two, they were considered to be directly related to primitive ancestors with similar features, known as anapsids. It should be noted that diapsids, in contrast, have two distinct holes in the skull through which jaw muscles are attached. Still, other groups of scientists considered the Pareiasaurs as the true ancestors of turtles due to their heavy bodies. They appeared in the early Triassic period, about 248 to 206 million years ago, when the dinosaurs were beginning to roam the earth. Many Pareiasaurs were armored with a layer of bony plates in 5
the skin, which greatly resembled the plates on an alligator s back, and they had heavy, solid skulls like modern turtles. Today, paleontologists have begun to use DNA sequencing to help them identify the ancestors of modern reptiles. By comparing the DNA of living reptiles with those of fossilized reptiles, biologists made numerous startling discoveries. Turtles are not related to the primitive anapsids as once believed, but they are descended from later diapsids, and the bones in their skulls filled in through evolution. Through DNA tests, it was revealed that turtles are more closely related to crocodiles than to any other reptilian group. Although no fossils of the earliest turtle ancestor have been found, the search continues. The earliest recognizable turtle is a specimen called Proganochelys, dating about 225 million years ago, and it was similar in appearance to the modern Snapping turtle. Unlike the Snapper, this Triassic turtle lived on land like a tortoise. Turtles began to rapidly diversify during the Jurassic period, about 206 to 144 million years ago. During this time, dinosaurs were the dominant life forms on earth. Sea turtles included such species as Plesiochelys, which was found in Europe, and the Archelon, which measured 12 feet long and is known to be the largest turtle that ever lived. Several features unique to the ancient turtles are not found in their modern descendents. The ancient reptiles had a series of bony projections from the vertebrae in the neck which made it impossible for them to retract their heads into their shells. They also had a larger number of vertebrae than any modern turtle. Because of these features, it s quite possible that paleontologists have only found side branches of the turtle family which died out without any descendents, and the direct, true ancestors of modern turtles have yet to be found. 6
Modern Appearance of Turtles Red Eared Slider Secrets Despite not knowing who the exact ancestor of the modern turtle was, it s become apparent that at some point in the early developmental history of the species, they divided into two separate groups that focused on different arrangements of the vertebrae in the neck. The first group, called the Cryptodirans, is the most easily recognizable, and from this group the redeared sliders are descended. They have the ability to pull their heads back into their shells, accomplishing this by bending their necks into a vertical S-shaped curve. The other group is rarer in modern times, known as the Pleurodirans, which translates to side-necked. This group is unable to pull their elongated necks back into their shells, and for a defense, they instead curl their necks and heads alongside their bodies, beneath the margin of the shell. This group of turtles has now become such a minority that they do not appear in North America at all. The most primitive of the turtles living today appear to have evolved in North America shortly after the dinosaurs went extinct some 65 million years ago, at the end of the Cretaceous period. This group includes the Mud and Musk turtles, closely related to the Snappers. The most ancient fossils of Snappers have been found throughout Europe, Asia and Africa, dating more than 15 million years ago. When it comes to the land turtles, the tortoises, they are known as the Testudo group, and they appeared first in Africa and grew to be a very diverse group in the dry, arid areas of the sub-sahara. The heat of these desert regions allowed for a boosted metabolism and plentiful growth. The varied Softshell family began evolving in eastern Asia, but today their descendents are found all over the world. Although tortoises are a diverse group, the Emydid family is even more so. This group includes the Painted turtles, Sliders including the red-eared sliders and River Cooters. Unlike the other families, this group appears to only just be beginning its evolutionary diversification process, and the most recent of the 7
groups to appear are the North American box turtles. They ve only just recently given up their aquatic lifestyle, in geological time. Chelonian Ecology All of nature maintains a balance, and in most ecosystems, the greatest amounts of living organisms are the plants. They use a system called photosynthesis to manufacture food for themselves from sunlight, using carbon dioxide and producing oxygen. Because of this, ecologists call them producers. Animals then feed upon the plants and other animals, taking in oxygen and producing carbon dioxide. Dead matter from the bodies of animals and plants are then recycled into materials that plants use for more nourishment. Turtles play a vital role in this system. Being both predator and prey animals, they help to control populations of fish and frogs while helping to sustain larger predators like alligators, crocodiles and jaguars. In many habitats like deserts and riverbanks, turtles and tortoises are the most abundant of the mid-level predators, animals that are located in the middle of the food chain. 8
Written By - Chris Johnson - Red Eared Slider Secrets 9
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