Der Ursprung des Lebens : „Die“ Herausforderung der Wissenschaft
Kein Mensch kann die unendlich erscheinende Zeitspanne ermessen, die das biologische Leben auf unserem Planeten umfasst. Dennoch ist es möglich, fast von Beginn an die Auswirkungen des letzten gemeinsamen Vorfahrens aller Lebewesen zu verstehen. Allein es fehlt die Kenntnis seines Ursprungs.
Research on the origin of life presents a unique challenge as it deals with a singular and possibly unique event which occurred approximately four billion years ago. Not only the processes leading to the first living cells, but even the conditions under which they evolved are inaccessible to scientific observation and therefore highly speculative. However, a single terrestrial environment is more open to detailed consideration: the early Earth’s crust. In this most outer layer of the planetary body, tectonic fault zones – systems of interconnected cracks and cavities which were filled with volatile media like water and carbon dioxide – must have existed. These systems offered large temperature and pressure gradients, a constant supply of hydrothermally formed organic compounds, and efficient protection against destructive external influences. All in all, they may have presented the ideal environment for the formation of protocells and the early stages of life. In a recent research project at the UDE, an analysis of inclusions in quartz crystals which formed in this environment exhibited a large variety of organic compounds which could have formed the basis for prebiotic chemistry. In connection with these results, experiments were performed which prove the formation of key cellular ingredients and of primitive cell-like structures under the conditions of fault zones. Moreover, the most recent experiments prove a beginning molecular evolution which can lead to stabilizing and potentially functional units in the “cell” membranes.