Strange sharks, giant insects, and a new and improved egg During the carboniferous, forests and swamp dominated the landscape. In the oceans, strange new sharks appeared. Giant insects walked amongst the trees while the first reptiles and early ancestors of what would become mammals hid inside rotted stumps. Here are a couple of videos on how chickens make their eggs. How an Egg is Made Chicken anatomy and egg formation Here’s a video about how bird babies get air while they’re still inside the egg. How Birds Get Oxygen Inside Their Eggs Here’s an article about the first known reptile. Hylonomus: The Earliest Reptile Here’s an article about finding tiny fossils inside carboniferous tree stumps. Tiny Animals Trapped in Fossil Trees Help Reveal How Fauna Moved Onto Land Here’s an article about an early ancestor of what one day would become the mammals. Archaeothyris