- Notochord present at some stage of life, in most cases replaced by backbone.
- Dorsal tubular nerve cord.
- Gill slits present at some stage of life (larva or adult).
- Body with a head and trunk and two pairs of appendages.
- Subphylum Urochordata
- Subphylum Cephalochordata
- Subphylum Vertebrata
The subphylum vertebrata has two super classes - Agnatha (jawless vertebrate) and Gnathostomata (jawed vertebrata).
Class 1: Chondrichthyes
Chondro means cartilage and ichtyes means fish
Class 2: Osteichthyes
Os means bone and ichthyes means fish
Class 3: Amphibia
Amphi means double or both and bios means life. It refers to life on land as well as in water
Class 4: Class Reptilia
Reptere means to crawl. They are four-legged or legless crawling animals whose body is covered by scales. They lay eggs on land.
Class 5: Aves
Avis means Bird
Class 6: Mammalia
Mamma means breast
Birds and mammals have a constant body temperature. The are termed homoiothermal.