Time calendar

Flowering plants appear on last day

The Earth is approximately 4.55 billion years old. If that age were represented as a month of time divided into 30 days, each "day" would equal 150 million years. It would be only on day 8 that the first life forms--types of prokaryotic cells--would have likely appeared, and the first fossils of these cells (bacteria and blue-green algae) date to day 10. However, the first eukaryotic cells would not have appeared until day 24.

The first land plants would have appeared on day 28, and cycads and gymnosperms would have appeared on day 29. It would not be until day 30 (actually in the latter half-day) that both flowering plants and mammals would have appeared through evolution. Humans would have appeared late in the last day.