Class (biology)
A taxonomic rank below phylum and above order. It groups related orders within a classification system.
Taxonomy: The practice and science of naming, defining, and classifying organisms. Class is one rank in the hierarchical system taxonomy uses to organize organisms.
Mammalia: The class of vertebrates that includes mammals, characterized by hair and mammary glands. Mammalia is a familiar named class containing diverse mammal orders.
Linnaean taxonomy: A hierarchical classification system developed from the work of Carl Linnaeus, using nested ranks and standardized names. Its ranked framework established the familiar placement of class between phylum and order.
Kingdom (biology): A high taxonomic rank that groups related phyla or their equivalents. Kingdom sits several levels above class in traditional rank hierarchies.
Taxonomic rank: A level in the hierarchy used to classify organisms, such as family, order, or class. This broader idea explains how class relates to ranks above and below it.
Aves: The class of vertebrates comprising birds, living theropod dinosaurs with feathers and beaks. Aves shows how a distinctive group of animals is placed at class rank.
Phylogenetics: The study of evolutionary relationships among organisms, often represented as branching trees. Phylogenetic evidence informs how taxonomists delimit and revise classes.
Subclass: A taxonomic rank below class and above order, used to subdivide some classes. Subclass adds an optional rank between class and order.
Phylum: A taxonomic rank below kingdom and above class in common biological classifications. A phylum contains one or more classes.
Reptilia: A traditional taxonomic class of vertebrates that includes turtles, lizards, snakes, crocodilians, and tuatara. Reptilia illustrates a traditional class whose boundaries are discussed in light of evolutionary relationships.