I: | They have feathers and most of them can fly. |
II: | They possess beak. |
III: | They have scales on the forelimbs and hindlimbs are modified into wings. |
IV: | They have dry skin without glands except the oil gland at the base of the tail. |
V: | They possess a fully ossified (bony) endoskeleton. |
VI: | They have long bones that are solid without air cavities (pneumatic). |
1. | 3 | 2. | 4 |
3. | 5 | 4. | 6 |
I: | Alimentary canal and reproductive tracts open into a common chamber called cloaca which opens to the exterior but the urinary system has a separate opening to the exterior. |
II: | Respiration is by gills, lungs and through skin. |
1. | Vertebrata is a subphylum; Agnatha is a division and Pisces is a super-class |
2. | Vertebrata is a supraphylum; Agnatha is a phylum and Pisces is a super-class |
3. | Vertebrata is a subphylum; Agnatha is a division and Pisces is a class |
4. | Vertebrata is a subphylum; Agnatha is a super-class and Pisces is a class |
I: | The most unique characteristic is the presence of mammary glands. |
II: | Skin is unique in possessing hair. |
III: | Heart is unique in being four-chambered. |
IV: | Viviparity is a unique feature. |
I: | are exclusively marine and mostly asymmetrical animals. |
II: | have cellular level of organisation. |
III: | have a water transport or canal system. |
IV: | have extracellular digestion. |
A | B | C | D | |
1 | Nerve cord |
Notochord | Gill slits | Terminal anus |
2 | Notochord | Nerve cord | Gill slits | Post anal tail |
3 | Nerve cord |
Notochord | Gill slits | Post anal tail |
4 | Notochord | Nerve cord | Muscle myotome |
Terminal anus |