Deep-sea Microorganisms Are Found Relatively Unchanged Over More Than 2 Billion Years

Figure 1: Comparison among three microscopic samples 

According to a UCLA’s report today (Feb, 3rd, 2015), scientists have recently discovered a type of deep-sea microorganisms that are believed not to have any evolutionary changes in the past 2 billion years. This is considered the “greatest absence of evolution ever reported”. Researchers also claimed that the discovery of this microorganism’s lack of evolution significantly contributes to the interpretation of Darwinism. 

In this research, a 1.8 billion-year-old microscopic sulfur bacterial fossil found in rocks from West Australia’s coast was examined and compared with two other samples, including a fossil found in the same region of Australia from 2.3 billions years ago and a currently living sulfur bacteria found in the Chile’s sea mud, South America. After several examinations using cutting-edge technology, scientists has announced that the ancient bacteria in the two fossils found in Western Australia are identical. More interestingly, they are also “indistinguishable” from the modern microbes found in Chile. These results suggest that these microorganisms have remained unchanged in the past 2.3 billion years.

             Figure 2: Regions where the living sample was collected in South America

 Figure 3: Regions where two fossilized samples were collected in Australia

 In order to establish the explanation for the lack of evolution in these organisms, UCLA scientists performed several techniques including Raman spectroscopy and confocal laser scanning microscopy to three-dimensionally analyze the chemistry and composition of the fossils. Results have dated these fossils back to 2.2 billion and 2.4 billion years ago, exactly when the Great Oxidation Event occurred. During this event, oxygen was largely produced by the ocean and stored in the atmosphere, resulting in a major increase in sulfate and nitrate in the ocean. Fortunately, sulfate and nitrate are essential nutrients needed for the survival of these microorganisms that allow them to survive and reproduce. Scientists also believe that these bacteria are capable of performing photosynthesis, a process of converting CO2 and water to oxygen that also permit them to live in the oxygen poor environment. UCLA’s geographic records also show that the extreme environment in which these microorganisms live has remained essentially stable or even unchanged for the past 3 billion years.

Professor Schopf, a UCLA professor, said: “The rule of biology is not to evolve unless the physical or biological environment changes, which is consistent with Darwin”. At this point, it is important to recall the theory of Darwinian evolution, which states that all species of organisms adapt to the surrounding environment through natural selection of small, inherited variations that induce their abilities to compete, survive and reproduce. Since there has been no change in the physical environment, the organism’s biology should also remain unchanged consequently. “If they were in an environment that did not change but they nevertheless evolved, that would have shown that our understanding of Darwinian evolution was seriously flawed”, said professor Schopf. In conclusion, although collected evidences have proved the lack of evolution in these microorganism, further examinations of other ancient fossils from similar environments are required to consider if the organisms have remained absolutely unchanged. 

-Posted by Phi Duong (Group A)