The theme of how life and its environment have coevolved together for about four billion years on Earth is explored in this chapter. The major evolutionary events that unfolded in the Archean eon (4 to 2.5 billion years ago), Proterozoic eon (2.5 to 0.539 billion years ago), and the Phanerozoic eon (0.539 billion years ago to present) are outlined, such as the origin(s) of multicellularity, eukaryotes, complex multicellular organisms, and humans. By drawing on this evolutionary timeline, theoretical paradigms for understanding and grouping the notable evolutionary events are sketched (e.g., major transitions in evolution). The next part of the chapter illustrates the intricate interplay between life and its environment by chronicling the rise in molecular oxygen levels, its possible causes and profound consequences, and its potential connections with key geological changes like the putative Snowball Earth episodes. Lastly, the ‘Big Five’ mass extinctions that transpired in the Phanerozoic, along with their triggers and ramifications, are described.