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3800 Mya
Earliest life on earth

It is not known with any certainty exactly how or where life started, but the earliest fossil evidence shows bacterial mats – ‘biomats’. These form stromatolites that consist of domes of biomats interlayered with fine sediments.

However, these are not thought to represent the sites for the origin of life. It is not known with any certainty exactly how and where this happened, but there are a number of potential concepts. Charles Darwin came up with the idea of a "warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc., present, that a protein compound was chemically formed ready to undergo still more complex changes.”

This idea changed somewhat when, for instance, in 1953 an experiment was conducted to attempt to emulate what was thought to be the environment of the early earth.

Stanley Miller and his supervisor Harold Urey devised this apparatus. Ocean, and the postulated atmosphere were derived and electrical discharges to emulate lightning were instigated. The resultant chemicals found in the ‘ocean’ were found to contain a number of chemicals important to natural life.

It was subsequently found that the initial gases may not have been present in fact, but the principal was established that organic chemical compounds that were vital to life forming processes could be synthesized.

1979 it was discovered that along some of the mid oceanic ridges where new ocean crust was being generated, there were huge upwellings of hot mineral rich waters.

These were acidic and contained hydrogen sulphide. They formed what became known as “black smokers” as they appeared to be dark clouds emanating from the ocean floor at great depth. They were not formed of smoke, but as mineral laden water came into contact with ocean waters the minerals precipitated out, largely producing sulphur with various metals.

It was found that huge biomes were in place around these vents all with no reliance on the sun for energy. The base of the food cycle were bacteria who derived energy from the metabolization of sulphur. These bacteria were then predated by many other organisms including eyeless shrimps and metre long ‘tube worms’ which had no digestive system and subsisted on the waste products of the bacteria in a close symbiotic life.

It was thought that these black smokers could be the remnants of the places and processes that gave rise to the first life.

There were a number of questions that arose in the scientific world about this. One of which was the lack of a process to form the cell walls that Bacteria and Archaea developed.

It was then that another form of hydrothermal vent was examined. These are the so-called ‘white smokers’ or ‘champagne vents ‘. These were alkaline and contained many other minerals.

They were situated away from the mid oceanic ridges and formed mineral ‘towers’ that were formed of microscopic pores that may have emulated cell walls and allowed the cell functions to develop.

3800 Mya Earliest life on earth

3800 Mya
Earliest life on earth