A new study published in the Proceedings of the National Academy of Sciences has revealed that sulphur-loving microbes might have remained more or less unchanged for more than 2 billion years. The researchers suggested that their findings would confirm the theory of evolution.
Fossils of 1.8-billion-year-old rocks
The lead author of the paper, William Schopf, explained that evolution is a process that happens as a response to changes in the physical or biological environment of an organism. According to him, much evidence has been gleaned to explain this aspect of evolution. However, were those conditions to remain unchanged, “the prediction would be that life shouldn’t change” – this is exactly what the new research is all about.
The stable environment mentioned in the study is the ancient and modern sea floor that has remained unmodified because of the absence of factors that could lead to the remodelling of the environment. The sea-floor happens to be isolated from elements like wave action that could change the sediment make-up.
The contribution of researchers from Chile, scientists Victor Gallardo and Carola Espinoza, has been an important part of the new study. The former had discovered thread-like bacteria living in communities beneath undersea mud. The sample was found near the west coast of Central and South America and near the Galapagos Islands. These microorganisms were found to be living in an environment devoid of oxygen. Furthermore, the conditions in which the bacteria were thriving included cold temperatures and the presence of sulphur. The Chilean scientists suggested that these organisms must have been living on our Earth for billions of years.
Now, it seems that Dr. Schopf has come across the same organism as those discovered by the Chilean researchers. Dr Schopf was handed 2.3-billion-year-old rock samples from western Australia. After some discussion, he concluded that the microfossils in the samples that he was given by a geologist were most probably the same as the ones mentioned by Victor Gallardo and Carola Espinoza.
Dr Schopf thereafter verified 1.8-billion-year-old rock samples he had gathered 30 years ago – these samples were also obtained from a rock formation in western Australia. These revealed the same bacteria as well.
Unable to use genetic analyses to determine the links among the different samples of bacteria, the researchers attempted to compare their morphology to draw conclusions. They documented their shapes and sizes, together with the similarities and differences between the rock samples. They also explored the mineral evidence of their environment as well as the physical structure of the populations they made.
The two Chilean scientists also assisted the team of researchers to make the comparisons.
Ultimately, they found that the two ancient populations from the rock samples and the existing ones discovered by the Chileans were essentially the same. Both groups of bacteria flourished in light-free, sulphur-rich environments that were also characterised by the lack of oxygen.
Now, enters the Darwin’s theory of evolution. Other deposits will now have to be analysed. Dr Schopf is of the opinion that they will most likely find organisms of the same type as the one he found throughout geological time.
The team has suggested that these findings might be used to confirm the null hypothesis of Darwin’s theory of evolution.
“Such findings may eventually be regarded as having confirmed the null hypothesis of Darwinian evolution,” wrote the team of researchers.