About Lesson
Phylum Chordata
Comprise of animals possessing a notochord at some stage of their development.
Live in water, on dry land or both. Others live under the soil (burrowers) while others live on trees (arboreal)
General Characteristics of Phylum Chordata
- Possess a notochord (long rod-like structure) at some stage in their development.
- Most possess a post anal tail. In some, the tail is vestigial or rudimentary.
- Have an endoskeleton. The endoskeleton is either bony or cartilaginous.
- Have a dorso-tubular nerve cord.
- Have muscle blocks called myotomes, on either side of their bodies, attached to the endoskeleton to effect movement.
- Have slits perforating the body walls at pharynx called visceral cleftsg. gill operculum in fishes.
- The body is bilaterally symmetrical.
- Have well-developed nervous system.
It consists of the brain (anteriorly enclosed in a cranium) and a long spinal cord (posteriorly enclosed in a vertebral column).
- Have a closed circulatory system with a ventral heart.
The phylum Chordata is sub-divided into 5 main classes;
- Class Pisces
- Class Amphibia
- Class Reptilia
- Class Aves
- Class Mammalia
Join the conversation
