Primates: Classification and a quick note on word endings

There are so many species of living things on Earth, zoologists have to classify and categorise not only to make sense of things but also to aid identification. Talk to a gardener from China about snap dragons and they most likely won't know what you're talking about. However, mention Antirrhinum majus and you're talking the same language!

The classification system used today is based on the system introduced by the Swedish scientist Linnaeus.

However, any system is not fixed and zoologists are constantly "tweaking" the system to reflect new knowledge. And they don't always agree! Which is not surprising considering the complexities of life on Earth, living and extinct. And it is also why you might see minor differences in classification when researching.

The generally accepted way of classifying all life is as follows:

Three examples:

You can use the Primates Tree we have prepared to trace these particular classifications.

Classification	Human	Red Uakari	Chimpanzee
Kingdom	Animalia	Animalia	Animalia
Phylum	Chordata	Chordata	Chordata
Sub-Phylum	Vertibrata	Vertibrata	Vertibrata
Class	Mammalia	Mammalia	Mammalia
Order	Primates	Primates	Primates
Sub Order	Anthropoidea	Anthropoidea	Anthropoidea
Infra Order	Catarrhini	Platyrrhini	Catarrhini
Super Family	Hominoidea	Ceboidea	Hominoidea
Family	Hominidae	Cebidae	Pongidae*
Genus	Homo	Cacajao	Pan
Species	Homo sapien	Cacajao rubicundus	Pan troglodytes

*Recently there have been moves to include the great apes within the family Hominidae. In this scheme Homininae is a subfamily of Hominidae, and includes Homo sapiens and some extinct relatives, as well as the gorillas and the chimpanzees (not orangutans).

To distinguish between humans, chimps and gorillas, another term Hominini, which refers to a Tribe (this occupies the space between family and genus), is used to describe all the human species that have ever lived but which doesn't include chimps and gorillas. 

If this all sounds like complicated madness, the reason is that recent DNA sequencing has shown that the ancestors of chimps, gorillas and humans split from the orang-utan line first. Next came the chimp/human and gorilla split. Finally chimp and human ancestors split to produce the 3 species alive today.

Diagrammatically, it looks something like this, with time going from past to present, with the oldest common ancester located at the top of the diagram.

If you look at the primate family tree, you will notice we have used the old classification, simply becasue it is the most commonly used one at present.

However, if you look closely you will see that it doesn't really represent the evolutionary relationship between the great apes and humans as shown above.

Further reading on classification:

Palomar College has prepared a very readable classification of living things. Flashcards and crossword puzzles also included.
Animal Diversity Web. Another very good site. Includes pictures, sounds, information and classification.
Primates.com Excellent fact sheets and articles on individual primates as well as a classification table.
Carl Linnaeus Biography
The Franklin Institute Readable explanations and activity ideas.
PlantExplorers for information on plant classification.
Enchanted Learning for a simple treatment for younger children
Rediscovering Biology for a detailed treatment suitable for A level onwards.

Word Endings:

When zoologists assign names to families there is a set of rules they follow. The following applies to animal classification.

Note the suffix -oid is from the Greek and means resembling. The prefix homo means man, therefore the word hominoid means man like.