From the earliest forms of life in the sea to the first dinosaurs that ruled the land, early life on Earth took many strange forms. Explore how life grew, adapted, and changed across a span of 275 million years from the Cambrian through the Triassic Period. Engaging images and informative graphics help explain the development of life on Earth, while an encyclopedic-entry-style format makes the text approachable and highly browsable. Final comprehension questions encourage reflection on what readers have learned.