Understanding The Essential Requirements For Life

The Hadean Bioscience researchers suggest that in order to understand how life began on Earth, we need to understand the specific environmental requirements that must be satisfied to allow this to occur. They identified nine specific conditions and unless all these environmental requirements are met, life cannot be born.

  1. For prebiotic life to begin, a powerful energy source is required. Energy from the Sun alone is not enough to break down inorganic compounds such as nitrogen (N2), carbon dioxide (CO2) and water (H2O) and convert them to complex organic molecules. However, a natural nuclear reactor would provide more than enough energy to drive the required reactions.

  2. A supply of major elements is another condition for the formation of life, as most organisms on earth are made up of carbon, hydrogen, oxygen and nitrogen. The early Earth crust, along with the atmosphere and ocean, can supply these.

  3. As well as the elements that form the building blocks of organic compounds, there must also be a ready supply of the nutrients that sustain life. The nutrient source on early Hadean Earth would have been the rocks on the Earth's surface, which were rich in iron and phosphorus as well as rarer elements like potassium and uranium.

  4. A high concentration of gases containing compounds such as ammonia and methane is another key requirement. An enclosed space, such as an underground chamber occurring in the plumbing of a nuclear geyser, would collect a sufficient concentration of these gasses.

  5. The team have also identified that dry-wet cycles are another essential environmental condition for the emergence of life. Alternating between hydration and dehydration can generate more complex organic molecules from amino acids, such as RNA.

  6. For life to begin, water must be clean and non-toxic. The early oceans were highly acidic and very salty, and life would not have emerged nor survived here. This suggests that life would have formed in a watery environment on land, such as pool or wetland.

  7. Water must also be poor in sodium and rich in potassium. We know this as modern cells contain little sodium, suggesting that life formed in an environment where this was relatively unavailable.

  8. A cycle between day and night is another vital condition for the birth of life. Day-night cycles allow variations in temperature, with low and high temperatures driving different types of reactions, and encouraging self-replication of DNA sequences.

  9. Finally, a diverse environment is necessary to emerge life. Variations in pH, salinity and temperature will help to drive different types of reactions, leading to more complex and varying organic molecules. Diverse environments would occur across the Earth's landmass through plate tectonics, but not within its oceans.