Scientists say that in the ancient past, there were no reptiles upon the land. As was the case with life in general, the earliest reptiles lived in the sea. The scarcity of food forced them to come over to land. More than 250 million years ago, they journeyed to the shore in search of food. On the land, there were forests of ferns and other vegetation then.
The presence of vegetation helped the proliferation of plant-eating insects and the early reptiles moved to the land in search of these insects. The competition for life in the sea may also have forced them to make the shore their home. These reptiles developed legs for walking around, lungs for breathing air and scales for protection. Gradually they evolved into reptiles fully adapted for life on land.
How do we know about these facts when no one was actually present to watch the evolution of reptiles then? We examine fossils, the remnants of prehistoric animals and plants and come to conclusions. Scientists argue about the order in which separate adaptations such as the legs and the lungs appeared. However, they all agree that the most important adaptation was with regard to laying eggs.
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