But a look back through history shows that geological processes have been key to the evolution of life on Earth. Geology has shaped biology by creating favourable conditions, and indeed the basic “ingredients”, for life’s emergence and evolution.
And now there is growing evidence that this also works in reverse: life has shaped our planet’s atmosphere, oceans and landscapes in many ways.
Let’s take a walk back through time.
Our planet is a living organism
Early in the 20th century, Russian scientists posited that living organisms shape their environment in a way that allows life to be sustained. In the 1970s, a similar idea known as the “Gaia hypothesis” emerged in the Western world, thanks to scientists James Lovelock and Lynn Margulis.
Life started shaping the planet as soon as it appeared, possibly as early as 3.7 billion years ago. Back then radiations from the Sun were not as strong as today and without a little help, the whole planet should have remained frozen.
That little help may have come from bacteria producing the heat-trapping gas methane, with significant amounts of this greenhouse gas released into the atmosphere.
Much later – some 200 million years ago – a similar relationship happened in reverse. At this time, more complex lifeforms may have prevented a runaway build-up of carbon dioxide in the atmosphere (as seen on Venus) by trapping CO₂ in the skeleton of marine organisms like plankton. These then later became buried at the bottom of oceans to form limestones.
We are made of star dust
The chemical elements that compose our body were made in the explosion of a star – we are made of star dust! We share the origin of our atoms with everything around us, including rocks.
But forces deep within planet Earth also shape life.
Weathering of mountains, and continents in general, also delivers essential nutrients to marine lifeforms. One example is phosphorus, which is released into rivers and oceans by weathering of the mineral apatite found in continental rocks. Phosphorus is also a building element of DNA molecules, and of adenosine triphosphate (ATP), the “rechargeable battery” responsible for energy transfers in our cells.
The first widespread emergence of continents could have been key to the first oxidation of the atmosphere (called the Great Oxidation Event, about 2.4 billion years ago). By providing essential nutrients like phosphorus, weathering of the first continents would have allowed photosynthetic cyanobacteria that make up stromatolites to thrive and release oxygen into the atmosphere.
Source: https://theconversation.com/unpacking-the-history-of-how-earth-feeds-life-and-life-changes-earth-103162#:~:text=Geology%20has%20shaped%20biology%20by,and%20landscapes%20in%20many%20ways.
