section_path: Suitable geological environments
section_name: Suitable geological environments
paragraph_text: Suitable geological environments
  
  A variety of geologic and environmental settings have been proposed for an origin of life. These theories are often in competition with one another as there are many differing views of prebiotic compound availability, geophysical setting, and early life characteristics. The first organism on Earth likely looked different from LUCA. Between the first appearance of life and where all modern phylogenies began branching, an unknown amount of time passed, with unknown gene transfers, extinctions, and evolutionary adaptation to various environmental niches. One major shift is believed to be from the RNA world to an RNA-DNA-protein world. Modern phylogenies provide more pertinent genetic evidence about LUCA than about its precursors.
  
  The most popular hypotheses for settings for the origin of life are deep sea hydrothermal vents and surface bodies of water. Surface waters can be classified into hot springs, moderate temperature lakes and ponds, and cold settings.