Milestones in Deep Time

Evolution

50 questions on the history of life — from the age of the Earth and the first cells through the oxygen revolution, Snowball Earth, the Cambrian, the Big Five mass extinctions, and the rise of mammals.
Score 80% or higher to earn a certificate.

Deep-time dates get revised. Contested figures are asked as approximate ranges with well-separated options, and the explanations say where the uncertainty lies.