However, today many scientists build phylogenetic trees to illustrate evolutionary relationships and the taxonomic classification system is expected to reflect evolutionary relationships Historically, organisms were organized into a taxonomic classification system.

Each group of organisms went through its own evolutionary journey, called its phylogeny. To build phylogenetic trees, scientists must collect character information that allows them to make evolutionary connections between organisms.

class — the category in the taxonomic classification system that falls within phylum and includes orders. phylogenetic tree — diagram used to reflect the evolutionary relationships between organisms or groups of organisms. phylogeny — evolutionary history and relationship of an organism or group of organisms. taxon — a single level in the taxonomic classification system.