A turtle in the desert During the Triassic period (about 248 to 199 million years ago), most of Earth's land continued to stick together in one big supercontinent, Pangaea. Because [...]
Tertiary period: Large animals evolved like moose Dinosaurs become extinct The Tertiary period begins with the catastrophe that killed off the dinosaurs at the end of the Cretaceous Period, about 65 [...]
The Quaternary Period includes today - big cities and all When was the Quaternary Period? The Quaternary period began about 1.8 million years ago (1,800,000 years ago), coming after the [...]
Volcano erupting When was the Cretaceous period? During the Cretaceous period, beginning about 145 million years ago, the continents continued to drift away from each other. Plate tectonics Back to [...]
Cave painting of a herd of aurochs (about 14000 BC) When did the aurochs evolve? Around fifty million years ago, after the dinosaurs died, large mammals started to evolve from smaller mammals [...]
Fish eggs: Egg evolution starts with soft eggs like these When did the first eggs evolve? The earliest living creatures made babies by dividing themselves in half, so that one [...]
Evolution of skeletons: Skeleton of a dinosaur Evolution of skeletons From frogs, there evolved reptiles like crocodiles and dinosaurs. Some of these reptiles lived mostly or entirely on land, so [...]
Human hand bones The first fingers and toes evolved from earlier fish fins about 400 million years ago. During the Devonian period, the oceans were very shallow, and some fish [...]
Fish gills The first cells, which evolved about 3.8 billion years ago, needed carbon dioxide to live and not oxygen. They needed the carbon dioxide to help them break down [...]
This is a mouse brain When did the first brains evolve? Flatworms were the first animals to evolve anything like a brain, but it's really just a thickened part of [...]
