Binomial System (OCR A Level Biology): Revision Note

Binomial System

• A species is a group of organisms that are able to reproduce to produce fertile offspring

• Binomials are the scientific names given to individuals species

• Binomials consist of the organism’s genus and species name in modern Latin

• For example, the binomial for humans is Homo sapiens and the binomial for dogs is Canis familiaris

• Binomials are extremely useful for scientists as they allow for species to be universally identified - the binomial for a species is the same across the entire globe

Naming species

• Species are often given common names, but these common names are often differ between countries and do not always translate directly between different languages

• In order to avoid confusion about what group of organisms scientists are talking about, all species are given a two-part scientific name using the binomial system

• This naming convention was developed and established by the Swedish scientist Carl Linnaeus in the 18th Century

• The binomial name is always italicized in writing (or underlined if it is not possible to italicise)

• For example:

  • The most commonly known yeast is Saccharomyces cerevisiae

  • It is common to abbreviate the genus name (e.g. S. cerevisiae)

  • Saccharomyces paradoxus is another species of that is a member of the same genus as cerevisiae