Rare Fossilized Algae, Discovered Unexpectedly, Fill in Evolutionary Gaps
Published:23 Mar.2021 Source:Geological Society of America
When geobiology graduate student Katie Maloney trekked into the mountains of Canada's remote Yukon territory, she was hoping to find microscopic fossils of early life. Even with detailed field plans, the odds of finding just the right rocks were low. Far from leaving empty-handed, though, she hiked back out with some of the most significant fossils for the time period.
Eukaryotic life (cells with a DNA-containing nucleus) evolved over two billion years ago, with photosynthetic algae dominating the playing field for hundreds of millions of years as oxygen accumulated in the Earth's atmosphere. Geobiologists think that algae evolved first in freshwater environments on land, then moved to the oceans. But the timing of that evolutionary transition remains a mystery, in part because the fossil record from early Earth is sparse.