Question

Distinguish between Nonchordata and Chordata.

Answer 1

Nonchordates	Chordates
1. Notochord is absent in them	1. Notochord is present in them at some of their developmental stage.
2. Their central nervous system is solid and ventral	2. Their central nervous system is hollow and dorsal.
3. Heart, if present in them, is dorsal in position.	3. Heart is always present and it is ventral in position.
4. Their circulatory system is of open or closed type.	4. Their circulatory system is of closed type.
5. Respiratory pigment, the haemoglobin, if present, is dissolved in plasma of blood.	5. Haemoglobin is present in their red blood cells or corpuscles.
6. Pharyngeal gill slits are absent in them.	6. Pharyngeal gill-slits are present in them.
7. They contain anus at posterior end of body, so post-anal tail is not present.	7. Their anus is not located at posterior tip of body, so contain a post-anal tail.