The Value of Biosphere Earth, pt. 1: The Life Timeline

Chris Searles/BioIntegrity
2 min readSep 26, 2021


This series explores Earth’s life support system and how it affects the climate solution. Here is part 1. Science’s timeline of Life’s history.

Microbial Earth, “The Pale Orange Dot” (NASA, 2017) and modern Earth, “The Blue Marble” (NASA, 2000).
Click for larger graphic.

Biosphere Earth began forming more than 4 billion years ago.
Modern human beings first appeared about 300 thousand years ago.

4+ Billion Years in the Making. Earth’s viability as the container for modern human existence and economics took an unfathomable length of time to establish. According to the current scientific record, Earth’s life-support system began forming with the advent of microbial life, roughly 4.4 billion years ago.[1] It took perhaps three billion years for “simple” microbial life to achieve pervasive coverage of planet Earth. Earth’s microbial community gave birth to larger “complex life”, plants and animals, nearly four billion years after the first microbes, roughly 600 million years before present day.[2] Since then Earth’s planetary biosphere, capable of supporting both micro- and macro-life simultaneously, has taken form several times.[3] In each iteration Earth’s biosphere reformed with a greater diversity of organisms and attributes.[4]

Today’s Civilization. Today’s human life-support system began forming roughly 65 million years before evidence of the first modern humans.[5] Current science tells us the first anatomically modern humans, Homo sapiens, emerged in Africa roughly 300,000 years ago and dispersed across the planet about 180,000 years ago.[6] Just 12,000 years ago the last Ice Age ceased. Humans in Europe came out of their caves and human beings similar to people today began cultivating crops and domesticating animals on a temperate-climate Earth.[7] Today’s civilization, “the economic society”, began perhaps 6,000 years ago with the material wealth-based monarchies and oligarchies of Sumer and Egypt.[8]

What Can You Do?

Engage in historical thinking about the history and value of life on Earth.

“Biosphere Earth” is our most powerful and essential climate stabilization resource. Over the next 16 weeks, this series will talk about why.

Read part 2 of this series.
Listen a podcast about this post.
Listen to a podcast introduction to this series.

For a complete list of scientific citations for this post, click here.