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This chapter covers the evolution of life on Earth starting from three and half billion years ago and tries to give a possible explanation to why the following sequence of events was possible.

On the west Australian coast, there is a remote location called Shark Bay. Here, about three and half billion years ago, life started manifesting itself on Earth. To prove the happening of this event there are ancient type of rock formations called Stromatolites. These are layered mounds, columns, and sheet-like sedimentary rocks. They were originally formed by the growth of layer upon layer of cyano bacteria, a single-celled microbe that lives today in a wide range of environments ranging from the shallow continental shelves to lakes, rivers, and even soils.

Cyano bacteria are prokaryotic cells (the simplest form of modern carbon-based life) and they lack a DNA-packaging nucleus. Bacteria, including the photosynthetic cyano bacteria, were the only form of  life on Earth at that time and their DNA floated loosely inside their cell wall.  Instead the DNA-packaging nucleus is called this way because it packs the DNA like spools of thread and allows a DNA a hundred times more complex to be enclosed  in a cell wall about the size of the cyano bacteria.

The photosynthetic cyano bacteria was, for two billion years, the only life in existence on Earth. During this period it was producing oxygen, therefore increasing the amount of  oxygen in the Earth atmosphere. With this action, it was allowing the next evolutionary step to take place.

About seven hundred million years ago, a more sophisticated form of life takes place. This new type of life was the molds. Molds have a DNA about 100 times more complex than the cyano bacterias. Their DNA is packed in a nucleus and required oxygen to thrive.  Molds are the first example of intelligent life on Earth. They are considered intelligent because of their capability of finding their way in and out of a labyrinth or finding the shortest path between two or more points. Moreover they have the capacity to hack other living

creature's DNA, insuring their own survival. (The next chapter will cover a story based on their DNA hacking ability).

About one hundred million years after their creation, molds, when mixed in the clay, were able to create the first hard-shelled animals.  Clay is made of layers, only a few nanometers of thickness, capable of sliding on top of each other and giving it a viscous property. The outside edges of the layers are rich in silica. The molds used the silica strata converting them into the shell of the first animals appearing on earth. The molds, even now, still retain their ability to transform their DNA, the same way they created the first shelled animals. Soon after, animals like the trilobites started a population explosion everywhere on Earth.

Darwinian evolution proceeded then to create, in five hundred million years, all the other species on Earth.

The evolution from the cyano bacterias to the molds took an amazing amount of time, about one fourth the age of the Universe. Inside this time span, the history of the Western Civilization, from ancient Rome to the present, would fit a million times. It took so long because the DNA had to become a hundred times more complex during this evolution. In contrast, about one half of man's DNA is similar to a dinosaur's DNA and therefore a smaller time span was required for man's evolution.

We appear to be the final product of this evolution on Earth and, maybe, we are the only species capable of admiring the beauty and the mystery of the Universe.

UPDATES

NASA on May 2018 has reported that the Mars land rover, after four years of search, has been able to find only simple organic molecules such as methane on this planet. Since Mars, millions of years ago, was covered with water, finding Stromatolites could have been a proof that life was pervasive in the Universe. It appears that the creation of even basic life requires conditions not easily found on other planets.

Marcello VENEZIANO

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