Fish classification

Question 1

What are the characteristics of Chondrichthyes?

Answer 1

• flexible skeleton made out of cartilage
• paired fins
• hard scales
• 2 chambered hearts
• most species have 5-7 gills slits on each side of the body
• 1 pair of nostrils
• some species produce egg cases , others give birth to live young

Question 2

What are Chondrichthyes?

Answer 2

• cartilaginous fishes
• includes sharks, skates , rays and chimaeras (ghost shark)
• there are around 1,000 species in this class of fish

Question 3

What are Agnatha?

Answer 3

• jawless fish
• Lampreys and hagfish are in this class
• the earliest vertebrate

Question 4

What are the characteristics of Agnatha?

Answer 4

• do not have paired fins or a stomach
• adults and larvae have a chord that provides the main support for the body of an organism during its embryonic stage
• skeleton made of cartilage and seven or more paired gill pockets
• they have a light sensitive pineal eye: A pineal eye is a third eye in front of the pineal gland
• fertilisation of eggs take place outside the body

Question 5

What are Osteichthyes?

Answer 5

• largest class of vertebrates
• have bones instead of cartilage
• over 29,000 species of bony fish found in freshwater and marine environment

Question 6

What are the characteristics of Osteichthyes?

Answer 6

• they have a swim bladder
• paired pectoral and pelvic fins
• they have a dorsal, anal and caudal fins
• have an operculum ( the bony flap that protects the gills from harm )
• have scales
• most species have a fusiform body design, meaning that their bodies are rounded and tapered at both ends
• bony fish have a lateral line that runs across the side of their body