"If we find life on another planet, it's likely going to be microbial," said Ashley Manning-Berg, assistant professor in geology at The University of Tennessee in Chattanooga. "So a lot of the focus for evidence for life is not just to learn about the ecosystems on early Earth, it's a way of telling us that if life evolved and then died on Mars, what do we look for? Manning-Berg is studying how billion-year-old fossils of microorganisms were preserved on Earth, so we can know what to look for on