Prokaryotic organisms, encompassing bacteria and archaea, exemplify the simplest life forms and exhibit remarkable evolutionary endurance and adaptability. This chapter explores the pivotal innovations in prokaryotic agency, including secretion, motility, and the emergence of life cycles, which enhanced metabolic and genetic complexity. These mechanisms underscore the adaptability of prokaryotes, enabling them to thrive in diverse environments and contributing to their evolutionary success. Despite their impressive capabilities, prokaryotes face inherent constraints in achieving structural complexity. We conclude by contextualizing these adaptations within a broader evolutionary scenario, highlighting the transition from prokaryotic simplicity to eukaryotic complexity.