First Evidence of Life

4100 million years
or 1000 meters to today

Geolo­gical era: Archean

Biolo­gical evol­u­tion replaces chem­ical evol­u­tion 500 million years after Earth is formed. This marks the begin­ning of the devel­op­ment of life. Traces of the earli­est life forms, micro­scopic tube-shaped fossils, can still be found in certain rocks today.

Life appears at first in water, and spreads out from there. Proto-cells begin to multiply. They pass their most success­ful traits on to their descend­ants. Some­times new changes appear, and these are subject to natural selection.

As you continue walk­ing, try to imagine how incred­ibly long 4100 million years is.

The first atmo­sphere consisted of 80% water vapour and 10% carbon diox­ide and sulphur diox­ide, nitro­gen and other small molecules (hydro­gen, sulphur oxide, carbon monox­ide, meth­ane and ammo­nia). Cool­ing caused the water vapour to condense, result­ing in continu­ous rain and the form­ing of the oceans.

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