At first sight, stromatolites may seem unremarkable. The stromatolite formations found in Shark Bay, Western Australia, do resemble dark, sediment-covered stones resting in shallow waters. However, they are rich in history through their layers of microbial life, whose interactions have occurred over time and are most likely indicative of a major occurrence in the timeline of Earth’s evolution. Stromatolites likely represent not only a cradle for the early evolution of microbial organisms’ interactions with one another, but also a model to understand how complex eukaryotic organisms may have arisen from these interactions in a long-term evolutionary progression. Although this idea as to how complex life originated may be a bold one, it builds on an age-old question. Approximately 2.3 billion to 2.1 billion years ago, it is believed that the first eukaryotic cells came into existence through a close association between an archaeal cell and a bacterium. Eventually, as the bacterial partner became an essential organelle in the eukaryotic cell, the mitochondrion, this close association or cooperation between the two cells directly contributed to the …