The science of classifying living things is called "taxonomy." It involves organizing species into hierarchical categories based on shared characteristics and genetic relationships. The primary ranks in taxonomy include domain, kingdom, phylum, class, order, family, genus, and species. Taxonomy aids in the identification and naming of organisms, making it easier to study and communicate about biodiversity. This discipline not only encompasses plants and animals but also fungi, protists, and bacteria, illustrating the complexity of life on Earth.