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Birth of the Earth

How and when did the complex living system we call 'soil' evolve?

The soil hasn't always been here. Yet many people, including evolutionary biologists, seem to think that life just landed - on the land. Like this video. Yet the soil is the land...but how and when did it get there?

At first there was probably only rocks, water and sediment. That was how it was fro the nine tenths the life of this planet - we call earth. The evolution of this soil ecosystem - earth - required the transformation of rock into complex organisms within 10 million years (it sounds a lot but a mere glance in geological speak). As continents collided, the chemistry, botany and zoology came together. The plants needed the animals to help colonise the land to access the mineral, and in the process, became 'higher plants'. However they were the washed to the sea, until mites came along to make the most of the debris and transform that back into nutrients. That was the crucial process that transformed inanimate rock into animated soil..

My Theory

We need to explain the role of small soil creatures in creating the fragile living soil structure, and how these co-evolved and now co-exist. My theory is that soil evolved between 350-375 million years ago. That evolution comprises three main elements - the role of soil animals, physio-chemical aspects, and essential elements.


Five main aspects of the formation of soil

Soil Animals 

I make the prediction that the soil evolved around 350 mya. This is based on the animals found in the soil - they are relatively -primitive' and predate insects.  Soil would not exist, but for the soil mesofauna. Soil does not merely “harbour” soil animals. They are part of what makes soil – as opposed to the inorganic clay/minerals/sediment/sludge - a living entity.

Collision Course

Two continents collided to create new land. Plants did not just drop on the land. One of the properties pertinent to the 'invasion of land'/'creation of soil' appears to be the evolution of desiccation resistance. The small soil creatures like oribatid mites and springtails survive in this dryness in different ways. Springtails spring out of the way. Oribatid mites roll up in a ball.

Essential Elements

Volcanic dust provides all the essential elements for plants. It is hard to see how plants could have evolved anywhere else as there would not be that distribution of elements in say sand. If plants started to evolve in the stuff, then the little soil animals will come in and recycle those essential minerals when the plant died.