Binomial nomenclature: the scientific name

A name with two parts

You have a given name and a family name. Together they tell us who you are, and nobody else in your class has the same two names. A scientific name works in the same way. It has two parts. This is called binomial nomenclature, from the Latin for "two names".

Binomial nomenclature was introduced by Carolus Linnaeus (Carl Linnaeus), a Swedish naturalist of the 18th century.

For the mango, the scientific name is Mangifera indica Linn.

• Mangifera is the genus. Like your family name, it tells you the group.
• indica is the specific epithet. Like your given name, it tells you the kind within the group.
• Linn. is the author, a short form of Linnaeus. It says that Linnaeus first described this species.

The rules

1. Biological names are in Latin, or made to look like Latin (Latinised), whatever language they come from.
2. The first word is the genus. The second word is the specific epithet.
3. In print, both words are in italics. By hand, each word is underlined separately. This shows that they are Latin.
4. The genus starts with a capital letter. The specific epithet starts with a small letter.
5. The name of the author comes at the end, in short form, for example Linn. It is not in italics.

You should find only one correct form: Musca domestica, with a capital M and a small d. Every other choice shows a red message.

Two codes

Who decides that a name is correct? There are international rules.

• Plants, algae and fungi follow the International Code of Nomenclature for algae, fungi and plants. Older books call it the ICBN.
• Animals follow the International Code of Zoological Nomenclature (ICZN).

The codes make sure that each species has one correct name, and that no two species have the same name.

Names that tell you something

Many names are descriptions. In Mangifera indica, "indica" means "of India". In Homo sapiens, "sapiens" means "wise". In Musca domestica, "domestica" means "of the house", and the housefly lives in houses.

When two organisms have the same genus, the genus tells us that they are close relatives.

The lion, the tiger and the leopard are three species of one genus. The potato, the tomato and the brinjal look different, and they are cousins.

Once you have written the genus in full, you may shorten it in the same text: P. tigris, P. pardus.

Try it in Python

A computer cannot see italics, but it can check the other rules. This program checks six names.

Practise with new numbers

Common mistakes

• Mangifera Indica: a capital letter in the epithet.
• mangifera indica: a small letter in the genus.
• Homo: only one word. A species name needs both.
• A name written in plain letters in a notebook, with no underline.

Remember these

• A scientific name has two words: the genus and the specific epithet. This is binomial nomenclature.
• It was introduced by Linnaeus. The names are in Latin.
• In print the name is in italics. By hand, each word is underlined separately.
• The genus starts with a capital letter, and the epithet with a small letter. The author comes last, in short form.
• Organisms with the same genus are close relatives.

Check yourself

Try each one on your own first. If you are stuck, open a hint. Then check with Show the answer.

1. In Panthera tigris, which word is the genus?

2. What is wrong with "Solanum Tuberosum"?

3. What does the last word in Mangifera indica Linn. tell us?

4. How should you write the scientific name of the housefly by hand?