These chemical and metal-rich environments possibly provided the necessary ingredients for life to emerge not once, but twice. How life began on Earth is a question that’s puzzled scientists, philosophers, and theologians since humanity was conscious enough of its own existence to wonder how we came into being. But since the beginning, humans have conceived of a singular moment when life emerged from a series of chemical reactions. The second group, eukaryotes, can be larger, multi-celled, and comprise the rest of life on Earth, including human beings. In the new study, scientists investigated genomes, protein structures, and chemical reactions that make up the earliest phases of microbial evolution.