Tracing the fossils of first organisms in the earth

Rock Sedimentation is the public cemetery of ancient organisms

The puzzle of life began to evolve has been questioning many biologists. When Aristotle stated that the origin of life was composed by four fundamental matters which were fire, earth, air and water, scientist has been setting up experiment and doing observation to find this answer. But, since the experiment conducted by Francesco Redi, the Abiogenesis theory made by Aristotle was replaced by Redi’s theory named Biogenesis. But, the question is who was the first living organisms to start the biogenesis?

Darwin’s evolution theory suggested that to achieve more complex condition of organisms, the living things must have passed the adaptation and natural selection. This theory became one of the most fundamental consideration and the complex living organisms must have been originated from much simpler organisms. And the only one that follows this requirement is bacteria. To our knowledge, bacteria is single cell organism that can do reproduction by multiplying its cell into mitosis process. But, bacteria only produce to make another a single-cell living organisms too. How did it become more complex?

This question apparently leads us to square one, but the losing information can be achieved by observing and analyzing the rocks. During the life cycle, all living organisms must have been dead for certain times and they left trace on the place they were dead. This implies that the “tomb” or “public cemetery” of the first living organisms. Therefore, the missing information about who was the first organisms living in the Earth can be detected by understanding the diagenetic transformation based on chemical and geological aspects. According to Werner [1] which is written in Brocks and Banfield et al., 2009 , this geochemistry factors are related to the biological aspect, and one of the indicators of life is the presence of non-biological addition of hydrogen sulphide to double bounds, followed by reductive desulphurization.

In rock, the DNA of certain organism must have been mixed together. This ancient bacterial DNA had been stayed because of the sedimentation process. During this era, the Earth was in freezing condition and produced the ice not only in poles part but also in the equators too. However, how can these ancient bacteria be able to live, what kind of things did they consume?

The ancient bacteria were a chemoautotrophic organism meaning they obtained energy throughout the oxidation process provided by the environment. The result of extraction from rocks was aromatic carotenoids okenane, implying there were bacteria that consumed Sulphur and this also indicated that the eukaryotic algae did not yet have an essential role during that time [2].

To conclude, sedimentation process happened in the early period of freezing and melting icecap in the Earth is crucial to trace the ancient bacterial life. The tracing started by extracting the chemical compounds from the rocks and analyzing the Sulphur related chemical compounds.

References
[1] J. P. Werne, "Investigating pathways of diagenetic organic matter sulfurization using compound-specific sulfur isotope analysis," Geochmica et cosmochimica acta, no. 72, pp. 3489-3502, 2008.
[2] J. J. Brocks and J. Banfield, "Unravelling ancient microbial history with community proteogenomics and lipid geochemistry," Nature Reviews, vol. 7, pp. 601-609, 2009.
[3] Image is downloaded from www.gcex.com