Scientists Probe 1.7-Billion-Year-Old Fossils to Trace Complex Life's Origin

1 articles · Updated · ScienceDaily · Aug 18

Researchers are examining some of Earth’s oldest rocks for microscopic fossils about 1.7 billion years old that may capture the transition from simple microbes to the first eukaryotes.
That search targets a major gap in evolution: eukaryotic cells—with nuclei and organelles—are considered Earth’s earliest complex life and the ancestors of plants, animals and fungi.
A roughly 100-sq.-km area near Svalbard and ancient coastal deposits in Australia are key hunting grounds because clay-rich, lightly sampled rocks can preserve fragile soft-bodied microfossils.
The work is difficult because organisms older than 500 million years lacked shells or skeletons, and billions of years of geological alteration have degraded the tiny remains.
By showing which environments preserve early life on Earth, the fossil hunt could also sharpen the search for biosignatures on Mars and icy moons such as Europa and Enceladus.