Biological Classification and Taxonomy

These vocabulary flashcards cover the fundamentals of biological classification, including the history of taxonomy, the binomial nomenclature system, levels of hierarchy, evolutionary relationships, the three domains, and the six kingdoms.

Classification

The science of organizing and naming living things to help understand how all life on Earth is connected.

Taxonomy

A system used by scientists to sort millions of organisms into categories.

Carl Linnaeus

A Swedish botanist ($1707–1778$) known as the "father of modern taxonomy" who developed binomial nomenclature and the hierarchical classification system.

Binomial nomenclature

The formal system of naming species with two-part Latin names consisting of the genus and the species, such as Homo sapiens.

Seven levels of classification

The hierarchy from most general to most specific: Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Kids Prefer Cheese Over Fried Green Spinach

A mnemonic used to remember the seven levels of classification: Kingdom, Phylum, Class, Order, Family, Genus, Species.

Subspecies

A ranked biological classification below species representing geographically isolated populations that differ physically but can still successfully interbreed.

Cladogram

A branching tree showing evolutionary relationships and how species are related based on shared traits from common ancestors.

Derived characters

Specific traits shared by species that have the same ancestor, such as hair and milk production in all mammals.

Molecular Clocks

A tool that uses DNA mutation rates to estimate how long ago two species shared a common ancestor.

Types of molecular clocks

Mitochondrial DNA and ribosomal RNA are the two primary types used to understand evolutionary history.

Domain

The largest and most general classification group of life.

Domain Bacteria

A domain containing unicellular prokaryotes with thick, rigid cell walls made of peptidoglycan.

Domain Archaea

A domain containing unicellular prokaryotes with cell walls that lack peptidoglycan; they are often found in extreme environments and can survive without oxygen.

Domain Eukarya

The domain consisting of all organisms that have a nucleus, including the kingdoms Protista, Fungi, Plantae, and Animalia.

Kingdom Protista

A diverse kingdom of mostly unicellular eukaryotes with cell walls of cellulose; some have chloroplasts and are aquatic.

Kingdom Fungi

A kingdom of multicellular, nonmotile eukaryotes with cell walls made of chitin that act as decomposers.

Kingdom Plantae

A kingdom of multicellular, nonmotile autotrophs with cell walls made of cellulose and chloroplasts used for photosynthesis.

Kingdom Animalia

A kingdom of multicellular heterotrophs that are mostly motile and lack cell walls and chloroplasts.

Dichotomous Key

A scientific tool used to identify organisms through a series of choices between two specific physical characteristics.