6 Questions
What is the characteristic of the scales in Pisces' exoskeleton?
The scales are overlapping and mesodermal.
What is the significance of the notochord in Pisces?
The notochord is partially or completely replaced by vertebrae.
What is the function of the neuromast organs in Pisces?
They are used to perceive movement and pressure changes in the surrounding water.
What is the characteristic of the heart in Pisces?
It is a tubular venous heart with unpaired chambers that are always filled with deoxygenated blood.
What is the characteristic of the digestive system in Pisces?
It has a well-developed stomach and pancreas.
What is the characteristic of the eggs in Pisces?
They are heavily yolked and embryonic membranes are absent.
Study Notes
Characteristics of Pisces
- Pisces have a cold-blooded, aquatic, and gill-breathing body plan
- They possess an exoskeleton composed of mesodermal scales
- They are oviparous vertebrates, meaning they lay eggs
Body Structure
- Boat-shaped and streamlined body covered by an exoskeleton of overlapping mesodermal scales, denticles, and bony plates
- Presence of hinged jaws and paired fins
- Paired nostrils, which do not open to the pharynx, except in Dipnoi and Crossopterygii
Skeletal System
- True teeth are present, derived from dermal denticles
- Vertebrae partially or completely replace the notochord
- Cranium encloses the brain and cranial nerves
Muscular System
- Myotomes are divided into dorsal and ventral portions
Digestive System
- Well-developed stomach and pancreas are present
Circulatory System
- Tubular venous heart with unpaired chambers, always filled with deoxygenated blood, except in lung fishes
Excretory System
- Mesonephros is the adult functional kidney
Nervous System
- Neuromast organs (lateral line organs) are present for perceiving movement and pressure changes in the surrounding water
- Internal ear has three semicircular canals
- Dorsal and ventral spinal nerve roots unite to form a mixed spinal nerve
Reproductive System
- Eggs are heavily yolked and embryonic membranes are absent
This quiz covers the key features of Pisces, including their body structure, respiratory system, and distinguishing characteristics. It is a great resource for students of biology and zoology.
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