Reptilia — dry skin, dry land
This is the class of reptiles, very well adapted to the terrestrial environment. They live in terrestrial, fresh water and sea water environments.
Figure to be added
- They bear a dry skin free of glands. The skin has scales.
- Pentadactyl limbs are present for movement.
- The heart has two atria and an incompletely divided ventricle.
- Respiration is carried out by lungs.
- They are poikilothermic.
- They practise internal fertilisation.
Dry skin bought their freedom
An amphibian needs a moist skin; a reptile does not. A dry scaly skin without glands stops water being lost, and internal fertilisation means reproduction needs no water either. Between them, those two set reptiles wholly free on land.
| Amphibians | Reptiles | |
|---|---|---|
| Skin | Thin, moist, glandular | Dry, scaly, glandless |
| Heart chambers | 3 | 3 (ventricle incompletely divided) |
| Fertilisation | Needs water | Internal |