Wings appeared by the Late Carboniferous. First appeared Late Devonian Aquatic or semi-aquatic Eggs and young in water Broad spectrum of shapes, sizes, and modes of life. The key feature in the origin of reptiles is the development of the amniotic egg . Eliminated need to lay eggs in water, allowing vertebrates to live and reproduce on dry land for the first time. Amniotic egg probably evolved in Carboniferous.
General trends show a necessity to build the food chain.