Organisms are classified in a biological classification system known as taxonomy. This system organizes living organisms into hierarchical categories based on shared characteristics and evolutionary relationships. The primary ranks in taxonomy include domain, kingdom, phylum, class, order, family, genus, and species. This structured classification allows scientists to communicate effectively about different species and understand their relationships more clearly. Advances in genetics and molecular biology have also refined this classification process, helping to clarify the evolutionary connections between diverse forms of life on Earth.