1.3 - Species & Naming

Species and scientific naming

• A species is the smallest group organisms are sorted into.
• It's a group of similar organisms that can reproduce with one another to give fertile offspring - offspring that can themselves go on to reproduce.
• This makes a species a natural unit: its members breed together, while members of different species generally don't produce fertile offspring.

The binomial system

• Because there are so many species, each is given its own scientific name using the binomial system - an internationally agreed, two-part naming system, mostly in Latin.
• The two parts are:
  1. Genus - The first part, shared with closely related organisms, giving information about ancestry
  2. Species - The second part, the species itself
• Example: humans are Homo sapiens - Homo is the genus and sapiens is the species.
• Writing conventions:
  • The whole name is written in italics
  • Only the first letter of the genus is capitalised

Why the system is used

• The point is consistency.
• The same organism is often given many different common or local names in different places and languages - over a hundred plant species are commonly called raspberries, for instance - which causes confusion.
• A single agreed scientific name means scientists anywhere in the world refer to a species by exactly the same name, so there's no doubt about which organism is meant.