Taxonomy and Classification Unit Vocabulary
Taxonomy - the area of the biological sciences devoted to the identification, naming, and
classification of living things according to apparent common characteristics.
binomial nomenclature - System of naming organisms in which each organism is
indicated by two words, the genus (capitalized) and species (lowercase) names, both
written in italics. For example, the tea rose is Rosa odorata; the common horse is Equus
caballus. The system was developed by Carolus Linnaeus in the mid 18th century. The
number of binomial names proliferated as new species were established and more
categories were formed, and by the late 19th century the nomenclature of many groups of
organisms was confused. International committees in the fields of zoology, botany,
bacteriology, and virology have since established rules to clarify the situation. See also
taxonomy.
Taxon - A taxonomic category or group, such as a phylum, order, family, genus, or
species.
Domain - Any of three primary divisions of living systems, consisting of
the eukaryotes, bacteria, and archaea, that rank above a kingdom in
taxonomic systems that are based on similarities of DNA sequences.
Kingdom - In the Linnaean taxonomic system, the highest taxonomic
classification into which organisms are grouped, based on fundamental
similarities and common ancestry. The Linnaean system designates five
such classifications: animals, plants, fungi, prokaryotes, and protitis.
Phylum - One of the major divisions of the kingdoms of living things;
the second-largest standard unit of biological classification. The
arthropods, chordates, and mollusks are phyla of animals Phyla in the
plant kingdom are often called divisions.
Class - In biology, the classification beneath a phylum and above an
order. Mammals, reptiles, and insects are classes in the animal kingdom
Order - A taxonomic category of organisms ranking above a family and
below a class.
Genus - A taxonomic category ranking below a family and above a
species and generally consisting of a group of species exhibiting similar
characteristics. The Genus of a species is always capitalized.
Species - Subdivision of biological classification composed of related
organisms that share common characteristics and can interbreed.
Organisms are grouped into species according to their outer similarities,
but more important in classifying organisms that reproduce sexually is
their ability to interbreed successfully. To be members of the same
species, individuals must be able to mate and produce viable offspring.
Phylogeny - The genealogical history of organisms, both living and
extinct. Phylogeny represents the historical pattern of relationships
among organisms which has resulted from the actions of many different
evolutionary processes. Phylogenetic relationships are depicted by branching diagrams
called cladograms, or phylogenetic trees. These diagrams show how closely related
organisms are based on shared genes.
Derived character - A feature of an organism that has undergone change from the
ancestral condition. A characteristic an organism has that it does not share with its
parents or any of its ancestors.
Cladogram - A branching, treelike diagram in which the endpoints of the branches
represent specific species of organisms. It is used to illustrate phylogenetic relationships
and show points at which various species have diverged from common ancestral forms.
Archaebacteria - A subkingdom of bacteria, they survive in environments similar to
those found on the young earth: hot springs, sea vents releasing sulfide-rich gases, boiling
muds around volcanos, that sort of place. They include the methane forming, the salt
loving and the heat loving bacteria. They differ from other bacteria (called Eubacteria)
because:
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they are mostly anaerobic
the RNA of their ribosomes is different to that of Eubacteria.
they have no peptidoglycan in their cell walls
their fats are linked together in a different way
Bacteria – Single-celled microscopic organisms that lack membrane bound organelles
and nucleuses. All prokaryotes are bacteria, although they have been split into two
groups: Eubacteria and Archeabacteria.
Eubacteria – A Domain of Bacteria that have cells walls made of peptidoglycan, a chain
made up sugars and proteins that forms a strong wall.
Eukarya (Eukaryotic) – A group of organisms that has a true nucleus and membrane
bound organelles.
Prokarya (Prokaryotic) – A group of single celled organisms that lack a nucleus and
membrane bound organelles.
Protista - are a diverse group of organisms, comprising those eukaryotes that can not be
classified in any of the other kingdoms as fungi, animals, or plants. This Kingdom
includes single celled animal like organisms such as amoebas, plant like organisms such
as algae, and fungus like organisms such as slime molds.
Fungi - Fungi (singular fungus) are a kingdom of eukaryotic organisms. The fungi are
heterotrophic organisms characterized by a chitinous cell wall, and in the majority of
species, filamentous growth (grows in strands); some fungal species also grow as single
cells. They reproduce both sexually and asexually via spores Yeasts, molds, and
mushrooms are examples of fungi. The discipline of biology devoted to the study of fungi
is known as mycology.
Plantae – A kingdom of organism that is capable of producing its own energy. Plants
obtain most of their energy from sunlight via a process called photosynthesis. Plants have
cell walls made of cellulose and are usually green. Example of types of plants include:
trees, flowers, herbs, bushes, grasses, vines, ferns, and mosses.
Animalia – A kingdom of eukaryotic and usually multicellular organisms. They are
heterotrophic, generally digesting food in an internal chamber, which separates them
from plants and algae. They are also distinguished from plants, algae, and fungi by
lacking cell walls. All animals are motile, if only at certain life stages.
Heterotrph -living organism that obtains its energy from carbohydrates and other
organic material. All animals and most bacteria and fungi are heterotrophic.
Autotroph- Organisms that are able to make their own food (in the form of sugars) by
using the energy of the Sun are called autotrophs, meaning "self-feeders”
Carolus Linnaeus – (1707-1778), Swedish naturalist, who developed binomial
nomenclature to classify and organize plants and animals. Linnaeus was also known as
Karl (or Carl) Linné Latinized his name in 1761 to become Carolus Linnaeus.
Dichotomous Key- A dichotomous key is a tool that allows the user to determine the
identity of items in the natural world, such as trees, wildflowers, mammals, reptiles,
rocks, and fish. Keys consist of a series of choices that lead the user to the correct name
of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous
keys always give two choices in each step.