classification

Classification

The grouping of objects or organisms based on a set of criteria.

Taxonomy

The discipline of identifying, naming, and classifying organisms.

Linnaeus

Swedish botanist who developed the system of naming organisms.

Binomial Nomenclature

A two-part naming system using genus and species.

Genus

First part of a scientific name; a group of closely related species.

Species

Second part of a scientific name; refers to a group of organisms that can breed and produce fertile offspring.

Taxon (plural: Taxa)

A named group of organisms.

Hierarchy of Biological Classification (from broadest to most specific)

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Domain

Broadest taxonomic group including Bacteria, Archaea, and Eukarya.

Kingdom

Second broadest taxon; includes groups like Animalia and Plantae.

Phylogeny

Evolutionary history of a species or group of organisms.

Cladistics

Method of classifying organisms based on common ancestry.

Cladogram

Diagram that shows evolutionary relationships.

Derived Character

Trait that appears in recent parts of a lineage but not in its older members.

Molecular Clock

Model that uses DNA comparisons to estimate the length of time two species have been evolving independently.

Eubacteria

Kingdom of unicellular prokaryotes whose cell walls are made up of peptidoglycan.

Archaebacteria

Kingdom of unicellular prokaryotes that have cell walls without peptidoglycan and often live in extreme environments.

Protista

Kingdom composed of eukaryotic organisms that are not classified as plants, animals, or fungi.

Fungi

Kingdom composed of heterotrophs; many obtain energy and nutrients from dead organic matter.

Plantae

Kingdom of multicellular, photosynthetic autotrophs that have cell walls containing cellulose.

Animalia

Kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls.