KINGDOM: Animals

Bilaterally symmetrical animals

SUPERPHYLUM: Deuterostomes

PHYLUM: Chordates

SUBPHYLUM: Vertebrates

The subphylum known as vertebrata contains all chordates that have definite backbones or spinal columns during their development. 

Vertebrates are also known as craniates because they all have a definite cranium, although the hagfish exists as an exception to this rule as it is a craniate but not a vertebrate.

Vertebrates also have some form of gut for the purpose of the digestion process.

Vertebrates have a mouth at the front and an anus at the back, but all will have had at some point a tail.

The tail is basically an extension of the backbone beyond the anus.

It is supposed that the first form of known vertebrate would have been the Myllokunmingia which is reckoned to have lived around 525 million years ago.  As with many primitive fossils, this was discovered in the proximity of China.  Its length would have only spanned the width a modern £2 coin.

Vertebrates contain familiarly known fish, amphibians, reptiles, birds and mammals.

The vertebrata subphylum can be split into jawed and jawless animals.

Jawed vertebrates make up the vast majority of this superphylum, however jawless vertebrates are represented in today's world by the lamprey.

Jawed vertebrates are grouped into an infraphylum called gnathostomata.  You may wish to skip to this section if you wish to find out more about today's popular zoo animals.

There have been many classes of jawless vertebrates established.  Classes are the next categorisation down in the life hierarchy to phyla.

Classes of jawless vertebrates include conodonta, pteraspidomorphi, thelodonti, anaspida, galeaspida, pituriaspida and osteostraci which are all understood to be extinct.  The class of cephalaspidomorphi contains the lamprey which is alive in today's world.  This class is also understood to categorised as jawless vertebrates.

Humans are gnathostomes.