In this topic of IBDP Biology, we will learn about the Classification Hierarchy.
Classification Hierarchy
Kingdom – largest group of organisms sharing common features
Phylum – major subdivision of a kingdom, consisting of closely related classes.
Class – group of related orders, subdivision of phylum
Order – group of related families, subdivision of class
Family – group of closely related genera, subdivision of order
Genus – group of related species, subdivision of a family
Species – group of organisms capable of interbreeding and producing fertile offspring
When it comes to IBDP Biology, the basis of this hierarchy is evolutionary.
Classifying a modern human (do not learn, but ensure you understand how it works)
- Kingdom = Animalia
- Phylum = Chordata
- Class = Mammalia
- Order = Primates
- Family = Hominidae
- Genus = Homo
- Species = Sapiens

Species name = Homo sapiens
This is written by the binomial system – capital letter for genus, small letter for species typed in italics or underlined if handwritten.
Kingdoms
When it comes to IBDP Biology, all living things can be classified into 5 kingdoms.
- Prokaryotes
- Protoctista
- Fungi
- Plantae
- Animalia
That's the end of this topic.
