A microscopic fossil discovered by researchers at Virginia Tech may be essential to understanding how modern plants have evolved into their current form.
About 1 billion years ago, the algae microfossil – a type of algae known as Proterocladus antiquus – is the oldest green algae known to man. The results were published Monday in Nature Ecology and Evolution.
The fossil of P. antiquus, which is about the size of a flea, was discovered by Virginia Tech’s post-doctoral researcher Qing Tang on a rock in a dry area of northern China that was previously the ocean.
He brought the stone to his adviser, geoscience professor Shuhai Xiao. After inspecting their discovery, they found the microfossil on an electron microscope and agreed that the discovery was significant.
Before the discovery of Xiao and Tang, the oldest green algae were found in a rock slab estimated to be around 800 million years old.
“These fossils are found in mudstones and fine-grained silty shales,” said Phoebe A. Cohen, associate professor of geoscience at Williams College. “Think of the mud that has hardened and turned into rock.”
After the organism died, it descended to the seabed – where it was covered and squeezed by the mud, she said. It was particularly well preserved because the sediments in which it was covered had little oxygen.
Many scientists theorize that terrestrial plants evolved from green algae, which moved from the ocean to fresh water, and then adapted to the dry conditions of the earth. Xiao said the study results strongly support this theory.
“These fossils are linked to the ancestors of all modern land plants we see today,” said Xiao. in a report. Land plants, he added, only evolved around 450 million years ago.
Not only does this discovery suggest that green algae evolved to become multicellular at least a billion years ago, said Xiao in the United States TODAY, it shows that it took longer than what ‘We currently understand so that marine plants adapt and evolve in their current terrestrial forms.
“The existence of multicellular green algae 1 billion years ago implies that it took hundreds of millions of years for green algae to find a way to invade the earth, which raises the question of whether why there has been such a long delay, “he said.
Either way, plants and algae are an integral part of life on Earth for food and oxygen – and this discovery adds a key step in the timeline of when green plants entered our biosphere.
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