Scientists have discovered ancient microfossils in Western Australia, providing new insights into the emergence of complex life during the Great Oxidation Event. These discoveries, which show similarities to algae, could redefine our understanding of the evolution of life and the potential for complex life in the universe.
Microfossils discovered in Western Australia suggest a huge leap forward in the complexity of life during the Great Oxidation Event, suggesting the early evolution of complex organisms such as algae.
Microfossils from Western Australia may capture a leap in the complexity of life that coincided with an increase in oxygen in Earth’s atmosphere and oceans, an international team of scientists says.
The survey results were published in a magazine geobiology, provides a rare window into the Great Oxidation Event, about 2.4 billion years ago, when oxygen concentrations on Earth increased and the planet’s surface fundamentally changed. This event is thought to have caused a mass extinction and opened the door to the development of more complex life, but until the discovery of new microfossils, little direct evidence existed in the fossil record. said the scientists.
![Microfossils in black chert](https://scitechdaily.com/images/Microfossils-Within-Black-Chert-777x583.jpg 777w,https://scitechdaily.com/images/Microfossils-Within-Black-Chert-400x300.jpg 400w,https://scitechdaily.com/images/Microfossils-Within-Black-Chert-768x576.jpg 768w,https://scitechdaily.com/images/Microfossils-Within-Black-Chert.jpg 1500w)
Microfossils are contained within black chert like the one seen here.Credit: Erica Barlow
First direct evidence linking environmental change and complex life
“What we show is the first direct evidence linking environmental changes during the Great Oxidation Event to the increase in complexity of life,” said lead author and affiliated research professor in the Department of Earth Sciences at Penn State University. said one Erica Barlow. “This is a hypothesis, but we haven’t been able to test it because the fossil record is so sparse.”
Comparison with modern organisms and algae
Compared to modern organisms, the microfossils more closely resembled a type of algae than the simple prokaryotes (organisms such as bacteria) that existed before the Great Oxidation Event, the scientists said. Algae, like all other plants and animals, are eukaryotes and are more complex life forms whose cells have a nucleus surrounded by a membrane.
More research is needed to determine whether the microfossils were left behind by eukaryotes, but the possibility could have significant implications, the scientists said. That would set back the known eukaryotic microfossil record by 750 million years.
![Hammersley Ranges Western Australia](https://scitechdaily.com/images/Hamersley-Range-Western-Australia-777x583.jpg 777w,https://scitechdaily.com/images/Hamersley-Range-Western-Australia-400x300.jpg 400w,https://scitechdaily.com/images/Hamersley-Range-Western-Australia-768x576.jpg 768w,https://scitechdaily.com/images/Hamersley-Range-Western-Australia.jpg 1500w)
The researchers conducted their study in the Hamersley Mountains, a mountain range in Western Australia.Credit: Erica Barlow
“The microfossils have striking similarities to a modern family called Bolbocaidae,” Barlow says. “This suggests that this fossil may be that of an early eukaryote. This is a big claim and requires further work, but it is an exciting claim that the community can build on and test.” It’s raising issues.”
Barlow discovered the fossil-bearing rocks while doing undergraduate research at the University of New South Wales (USNW) in Australia, and his current research was carried out as part of his doctoral research at UNSW and then at Penn State University. I went there while conducting research as a researcher.
Implications and future research
“These particular fossils are surprisingly well preserved, allowing us to study their combination of morphology, composition, and complexity,” said Penn State professor of geosciences and co-author of the study. said one Christopher House. “These results provide important clues about changes in the biosphere billions of years ago.”
Scientists analyzed the chemical and carbon isotopic composition of the microfossil and determined that the carbon was produced by living organisms, confirming that the structure was indeed a living fossil. They also revealed insights into microbial habitat, reproduction, and metabolism.
Barlow compared the sample to microfossils from before the Great Oxidation Event, but found no comparable organisms. The microfossils she discovered were larger and featured more complex cell arrangements, she said.
“This record seems to reveal an explosion of life. The diversity and complexity of this fossilized life that we are discovering is increasing,” Barlow said.
Compared to modern organisms, Barlow said microfossils have clear similarities to algal colonies, including the shape, size and distribution of the colonies and individual cells, and the membranes surrounding the cells and colonies.
“They have striking similarities, so when you compare them that way you can say that these fossils were relatively complex,” Barlow said. “Although there’s nothing like them in the fossil record, they have very striking similarities to modern algae.”
Broad implications for understanding life on Earth and beyond
The discovery raises questions about how long it took for complex life to form on early Earth (the earliest undisputed evidence of life is 3.5 billion years old) and how much time ago the solar system The scientists said this has implications both for what the search for life elsewhere reveals.
“When you find such large and complex fossils so early in the history of life on Earth, I think it raises certain questions. If life is found elsewhere, it’s probably just a bacterial species. “It may not be a prokaryote,” Barlow said. . “Maybe there’s something more complex preserved. Even if it’s still microscopic, it could be something slightly higher order.”
Reference: “Unique microfossils support early Paleoproterozoic uplift in complex cellular organization” Erica V. Barlow, Christopher H. House, Ming-Chang Liu, Maxwell T. Wetherington, Martin J. Van・Author Kranendonck, October 6, 2023, geobiology.
DOI: 10.1111/gbi.12576
Pennsylvania State University scientist Maxwell Weatherington also contributed. Ming-Chang Liu, staff scientist at Lawrence Livermore National Laboratory; Martin Van Kranendonck, Professor at the University of New South Wales, Australia.
Australian Research Council; NASA And the National Science Foundation funded this research.