A team of researchers are uncovering new information about ancient microorganisms on Earth using fossils that are billions of years old. The team has identified similar patterns of growth in modern microbial mats and fossils that are 2.8 billion years old. Ultimately, the patterns are linked to photosynthesis and could help scientists better understand when microorganisms first started using photosynthesis to derive energy from sunlight. The origin of photosynthesis had profound effects on the global climate and biosphere of Earth by dramatically increasing the amount of oxygen in the atmosphere. This work was supported in part by the NASA Astrobiology Institute (NAI).