The following Outline of the History of Life on Earth, and Human Evolution was written by my friend HWPTRA, a Life Sciences scholar. This outline history is a list of some of the significant events during the 4.5 billion years of Earth’s history. Any one of the entries in this list is itself a vast topic with an enormous literature (both scientific and popular) behind it; the brief descriptions here are little more than labels pointing the interested reader toward that literature (as on the Internet) for all the details.
The years and periods listed for the events are always to be taken as very approximate. As science advances, the time or period estimated for a listed event can be found to be different than previously thought, sometimes significantly different, and the sequence of events can even change as a result of new knowledge. So, this list is a snapshot of our knowledge today, where we understand that there are limits to the precision of that knowledge. Even so, it is a fascinating and enlightening presentation, which can help us gain a bare-bones yet integrated overview of the natural history that eventually produced us, Homo sapiens sapiens.
Following the outline history of life on Earth, I post a Histo-Map of human civilizations, compiled by John B. Sparks in 1931. To help the reader, I have posted six images of this map: one of the entire map, and five of sequential sections of the map. Also, I list a link to a website that shows a “big” version of the entire map. In all cases you will find lots of tiny print, and may wish to expand an image for easier reading (until it becomes fuzzy due to the low resolution of the original). The Histomap covers the interval of 2000 BC to 1930 AD, perhaps half of human history, and a very late 0.86 millionths of Earth’s history. Enjoy.
Outline of the History of Life on Earth, and Human Evolution
If the entire 4.5 billion years of Earth’s history were compressed into a single year:
1. January and February: it was too hot for any life to evolve.
2. March 1st to July 25th: bacteria were the only life forms on the planet.
3. July 25th: oxygen in the atmosphere was finally at near modern levels, and oxygen-using eukaryotic cells evolved.
4. November 20th: animals with backbones appeared.
5. December 22nd: first placental mammals appeared.
6. December 29th: the first apes appeared.
7. December 31st, 6:00 PM: Homo erectus appears.
8. December 31st, 11:46 PM: Homo sapiens (modern man) appears.
9. December 31st, from 11:59 PM to 12:00 AM (midnight): all of human history.
Addendum (1 March 2017)
Earliest evidence of life on Earth ‘found’
1 March 2017