Fish…our friends in the water
Porcupine Fish
Great White Shark
Barreleye
Characteristics of Fish• 20,000 species• Found in all types of water• i.e: Fresh, salt, sunless, polluted,
warm, cold, etc.• Ectothermic
Respiration
• Respire using gills• H2O enters mouth. • Water passes over gills• Water then passes out slits on side of
fish• O2 and CO2 are exchanged through
capillaries (small blood vessels) in gills
Circulation• Two-chambered heart• 1-chamber received deoxygenated
blood• 2nd-chamber pumps blood to gills. • Oxygen picked up and dispersed to rest
of body• Carbon dioxide is released• Slow process
Nervous/Reproductive System
• Lateral line---mechanism that detects movements and vibrations.
• Some fish can smell
• Two sexes (male and female)• External fertilization
3 Classes of Fish
•Jawless (Agnatha)•Cartilaginous (Chondrichthyes)
•Bony (Osteichthyes)
Jawless Fish• Sharp teeth used to “drill” hole in
animal• Blood sucked out of hole• Endoskeleton made of cartilage• No scales or paired fins
• Examples: Lamprey, hagfish
Cartilaginous Fish• Endoskeleton made up of cartilage• Skilled predators (typically found near
floor of water source)• Electroreception• Scales
• Examples: Sharks, rays
Bony Fish• Endoskeleton made up of bones• Lateral line system (pressure change and
swim with no light)• Swim bladder (allows fish to float)• Scales (reduces friction)• Majority of fish
• Examples: Salmon, Trout, Catfish
Top Related