Question

13. How do isotopic signatures provide evidence for early life? summarize in one paragraph

Answer 1

Isotopic signatures offer critical evidence for early life by revealing distinct patterns in the ratios of stable isotopes, such as carbon (C), nitrogen (N), and sulfur (S), in ancient rocks and fossils. Biological processes, such as photosynthesis and respiration, preferentially utilize certain isotopes, leading to characteristic isotopic ratios that differ from those found in abiotic processes. For example, a high ratio of carbon-12 to carbon-13 in ancient sediments can indicate biological activity, as early organisms tended to preferentially take up lighter carbon isotopes. By analyzing these isotopic signatures in geological records, scientists can infer the presence of early life forms and gain insights into the conditions and environmental contexts in which they existed, thereby contributing to our understanding of the origins and evolution of life on Earth.