What is the three domain system?

The three-domain system is a taxonomic classification framework that divides all cellular life into three primary domains: Archaea, Bacteria, and Eukarya. This system was introduced in 1990 by Carl Woese and his colleagues, marking a significant shift from the traditional five-kingdom model. The classification is based on molecular data, particularly the sequences of ribosomal RNA (rRNA), rather than solely on morphological characteristics. This approach revealed that prokaryotes are not a single group but consist of two distinct lineages, leading to the establishment of Archaea and Bacteria as separate domains. The three-domain system provides a more accurate representation of the evolutionary relationships among living organisms.