Systematics is the broader field concerned with studying the diversity of organisms and their evolutionary relationships. It involves the classification of organisms into hierarchical groups based on shared characteristics and evolutionary history. Systematists use various methods, including morphological, molecular, and genetic data, to reconstruct evolutionary trees (phylogenies) that depict the evolutionary relationships among different species.
Taxonomy, on the other hand, is a specific aspect of systematics focused on naming and classifying organisms. Taxonomists categorize organisms into hierarchical groups called taxa (such as kingdom, phylum, class, order, family, genus, and species) based on their shared characteristics. The goal of taxonomy is to provide a universal system of nomenclature to organize and identify organisms systematically.