Reptiles

Evolution of reptiles
Reptiles arose about 310-320 million years ago during the Carboniferous period. Reptiles are defined as animals that have scales, lay land based hard shelled eggs, andpossessing ectothermic metabolisms. Today reptiles generally rank low in most ecological food chains, containing very few apex predators, but many examples of apex reptiles have existed in the past. Althoughreptiles have lower species variation than in the past, they have an extremely diverse evolutionary history that has led to biological successes such as dinosaurs, mammals, and birds.
First reptilesReptiles first arose from amphibians in the swamps of the late Carboniferous. Increasing evolutionary pressure and the vast untouched niches of the land powered the evolutionary changes in amphibiansto gradually become more and more land based. Environmental selection propelled the development of certain traits, such as a stronger skeletal structure, muscles, and more protective coating (scales)became more favorable; the basic foundation of reptiles were founded. The evolution of lungs and legs are the main transitional steps towards reptiles, but the development of hard-shelled externaleggs replacing the amphibious water bound eggs is the defining feature of the class reptilia (with the exception of certain squamates) and is what allowed amphibians to fully leave water. Another majordifference from amphibians is the increased brain size, more specifically, the enlarged cerebrum and cerebellum. Although their brain size is small when compared to mammals and birds, theseenhancements prove vital in hunting strategies of reptiles. The increased size of these two regions of the brain allowed for improved motor skills and an increase in sensory development.
The origin of thereptiles lies about 320–310 million years ago, in the steaming swamps of the late Carboniferous period, when the first reptiles evolved from advanced reptiliomorph labyrinthodonts.[1] The oldest known...