Introduction

Evolutionary biology is the study of how life on Earth has changed over time. But to understand how flora and fauna have changed across millions of years, we first need the bigger context — how the Earth itself formed, how stars formed, even how the universe itself came to be. What follows is the longest and most speculative story in this book: the story of how life originated and how life forms evolved into today's biodiversity, set against the backdrop of the Earth's own formation and the universe's.