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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