Description
Mammals are an outstanding example of adaptive radiation, the process by which organisms evolve into a multitude of new forms. This poster explores that subject, and it shows the results. It begins with the first tetrapods (terrestrial vertebrate), then it shows and explains how they evolved into three basic groups based on skull characteristics. The synapsids were the last group to evolve, and they were the most advanced. They evolved around 324 million years ago. They are often referred to as the “stem-mammals” or “proto-mammals.” They
were the dominant and largest terrestrial vertebrates during the Permian, 299 to 251 million years ago. Changes in the planet resulted in their mass extinction. The reptiles adapted to fill the ecological niches they left behind. The result was a world dominated by dinosaurs. The earth changed again around 65 million years ago, and the dinosaurs became extinct. The few surviving synapsids adapted into modern mammals, which are also classified as synapsids.
