Classification
The first rank in the classification system is called a kingdom. There are five kingdoms, based upon what an organism's cells are like:
- animals (all multicellular animals)
- plants (all green plants)
- fungi (moulds, mushrooms, yeast)
- prokaryotes (bacteria, blue-green algae)
- protoctists (Amoeba, Paramecium).
There are several further ranks before we reach a particular species. In order, these are:
- kingdom
- phylum
- class
- order
- family
- genus
- species
This video shows the classification hierarchy
Difficulties with Classification
It can be difficult to classify a species e.g. we are Homo Sapiens
| rank | classification | notes |
|---|---|---|
| kingdom | animals | |
| phylum | chordates | animals with backbones |
| class | mammals | animals that are warm-blooded, have lungs and body hair, produce milk and give birth to live young |
| order | primates | ape-like animals |
| family | hominids | human-like animals |
| genus | homo | humans |
| species | sapiens | modern humans |
It can also be difficult to classify a certain organism. For example, the single-celled organism called Euglena has some confusing characteristics. It has:
- chloroplasts, like a plant
- no cell wall, like an animal
- a flagellum to swim with, like some bacteria
A fifth kingdom, called the protoctists, was made for organisms like Euglena.
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