by JACKLIN KWAN
Fossils from Australia provide the first direct evidence that photosynthesis was happening at least 1.75 billion years ago.
The earliest direct evidence of photosynthesis has been discovered in fossils dating back to 1.75 billion years ago.
Scientists collected fossils from Australia, Canada and the Democratic Republic of Congo and found the samples from Australia and Canada contained evidence of cyanobacteria, the oldest known lifeform on Earth. Scientists believe that cyanobacteria first emerged 2 to 3 billion years ago, before evolving to be capable of oxygen-producing, or oxygenic, photosynthesis.
In a study published Jan. 3 in the journal , researchers revealed these cyanobacteria fossils featured photosynthetic structures, known as thylakoid membranes, which contain pigments like chlorophyll that convert light into chemical energy via photosynthesis.
The cyanobacteria were preserved in a mud clay that was compacted over time to become rock. The researchers used a technique called transmission electron microscopy (TEM) to see the membranes and other tiny details preserved in the fossils.
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