What organisms appeared first on the barren rock?

The first organisms to appear on barren rock were likely simple, single-celled microorganisms, such as bacteria and archaea. These microorganisms were able to thrive in harsh conditions and played a crucial role in soil formation and the establishment of ecosystems. Early forms of cyanobacteria contributed to the process of photosynthesis, which gradually altered the atmosphere and paved the way for more complex life forms.