About Lesson
Characteristics of Class Pisces
- Have gills for gaseous exchange.
- Body is covered by scales.
The scales protect the fish from mechanical damage;
They also prevent osmotic loss of water through their permeable body surfaces.
- Have fins for locomotion.
- Have muscle blocks called myotomes on either side of the body, which assist in swimming.
- Have a sensory lateral line, which detects vibrations in water.
- Have a streamlined body to reduce resistance of water while swimming.
- Are poikilothermic, i.e. their body temperature fluctuates depending on that of the environment.
- The eyes have a nictitating membrane.
- Have a single circulatory system with a 2 chambered heart (1 auricle and 1 ventricle)
- Fertilisation is external, in water.