| Author: | Stefano |
|---|---|
| category: | Evolution |
Today I was taking a look at this page, and in particular to the geological clock image
Of course there's uncertainty on the correctness of the actual moments in time, but assuming these values are more or less correct it is quite interesting to note that it took only 500 million years to go from a highly destructive event like the formation of the moon (which is thought to be occurred via an impact event) to the first "protolife" able to replicate and improve itself, definitely something quite complex.
Only 500 million years were then needed to start photosynthesis, another quite complex affair. With this process started, it took almost 2 billion years to increase the oxygen level sensibly (testifying the diffusion of life forms on the Earth), and for Prokaryotes to start collaborating and create Eukaryotic cells: 2 billion years of pure Prokaryote evolution, from protolife to something complex enough to start a superior organism. A lot of time, in particular considering that it was only some thousands of years ago that a new subspecie of Lactobacillus, the Bulgaricus, become specialized in fermented milk environment (see also here), and many bacteria develop strong antibiotic resistance in a very short time, leading to a race between humans and pathogens, or better, humans and evolution.
This looks amazing, and quite puzzling. The development of a complex mechanism like photosynthesis, or even the generation of a protolife able to evolve by itself, took less than a third of the time needed for the Prokaryotic/Eukaryotic step, a period of time where an incredible amount of mutations, lateral transfers, reductions ad rearrangements happened on their genetic code.
Further aggregation to multicellular organisms took other 700 million years. After other 800 million years, the first animals, and in only 300 million years we have the Cambrian explosion. Then everything skyrockets. In the remaining 600 million years we have plants, insects, reptiles, mammals, and the man.
Edit: rewrote wrongly written statement.