Lesson 1 - Identifying, Naming, and Classifying Species

Species = a group of organisms that can interbreed in nature and produce fertile offspring

About 2 million species have been identified on Earth to date

o Estimated to be between 5 million to 20 million

Not just biologists need to know the identity of different species

o Doctors, border inspection officials (invasive species), farmers, zoo keepers

Identifying and Naming New Species

Three species concepts are used to help define species

o Each one focuses on a different aspect of an organism

Morphological species concept focuses on morphology – body shape, size, and other structural

features

Biological species concept define species on the basis of whether two organisms can produce fertile

offspring

Phylogenetic species concept examines the phylogeny, or evolutionary history, of organisms

Naming Species

Most familiar organisms have been given several names that differ from continent to continent, country

to country, and often region to region within the same country

o E.g. in English-speaking N.A. alone, groundhog = woodchuck = whistle pig = forest marmot

Taxonomy = the branch of biology that identifies, names, and classifies species based on natural

features

o Father of Taxonomy is Carolus Linnaeus

o Developed the system for naming species: binomial nomenclature

Name of the organism is known as the species name or the scientific name

Binomial nomenclature = the system of giving a two-word Latin name to each species

o first part is the genus

o second part is the species

scientific name is italicized, when typed, with first letter of genus name capitalized and species in lower

case

o E.g. humans = Homo sapiens

If hand written, entire scientific name is underlined

Classification of species requires a set of rules or criteria to be followed

o Linnaeus developed the basis of the system of classification used today

Classification = the grouping of organisms based on a set of criteria that helps to organize and

indicate evolutionary relationships

Hierarchial classification = the method of classifying organisms in which species are arranged in

categories from most general to most specific

Typically a species is classified by placing it in one of eight nested categories

Each of these categories is known as a rank

o E.g. phylum or order

The name of each rank is called a taxon

E.g. Rodenta or Chordata