Question

Differentiate between chordates and non-chordates.

Answer 1

Hint:Animals can be distinguished on the basis of the existence of a backbone. Animals with a backbone or notochord are called chordates whereas non-chordates are animals lacking a backbone or notochord.

Complete answer:
Chordata is a phylum that comprises species such as mammals, fish, birds, reptiles and amphibians (all vertebrates); sea squirts (tunicates); and lancelets (cephalochordates). All chordates have a notochord, a dorsal nerve cord, and pharyngeal slits at some point in their life. Notochord is a flexible skeletal rod composed of cartilage. It passes between the digestive tract of the animal and its nerve cord, providing protection to the body. In certain species of phylum chordata, it is present only in the larval tail and in some it is present throughout their lifespan from head to tail.

Some differences between chordates and non-chordates are:

Chordates	Non-chordates
The chordates are bilaterally symmetrical.	The body of non-chordates can be radial, cylindrical, bi-radial.
Notochord is present at some stage in its life.	Notochord is absent in non-chordates.
Chordates respire through gills or lungs.	Non-chordates take respire through their body surface, gills or trachea.
There is a post-anal-tail at some stage in the life cycle of chordates.	Non-chordates do not have a post-anal-tail.
The pharyngeal gill slits occur in the early embryonic stages or adult stage.	Pharyngeal gill slits do not occur in non-chordates.
Chordates possess endoskeleton and exoskeleton.	Non-chordates only have an exoskeleton.

Note:All chordates are vertebrates, but not all vertebrates are chordates. The key distinction between chordates and vertebrates is that certain chordates do not have a vertebral column, whereas all vertebrates have a vertebral column. In vertebrates, the nerve cord is surrounded and protected by the vertebral column.