There are so many different creatures and plants on this planet, that scientists have spent years trying to organise them.
This is called classification: the organisation of different organisms into groups.
One of the earliest ways that scientists categorised species was designed by Carl Linnaeus in the 1700s:
He created the Linnaean system, which divides living things by the characteristics that make them unique from each other, starting with kingdoms - like the plant kingdom versus the animal kingdom.
Afterwards, the groups get more specific:
Kingdom ⇒ Phylum ⇒ Class ⇒ Order ⇒ Family ⇒ Genus ⇒ Species!
Here are some easy ways to remember the order:
However, over time, inventions like the microscope increased scientific understanding about structures inside organisms and how they are made to be so unique.
This meant scientists realised they needed to start organising living things in a different way.
It seems like lots of Carls have an interest in biology, because, in the 1990s, Carl Woese classified beings using a ‘three-domain system’, which uses 3 groups called domains as headings:
Archaea (primitive bacteria)
Eukaryote (protists, fungi, plants and animals)
Now let's have a go at answering some classification questions!
Note: Jot down any descriptions or explanations that help you understand key concepts, to help you now and during revision!