Life Science
Chapter 11
Fishes, Amphibians, and Reptiles
By Ben Williams and Graham Bacon
Section 11.2
Clown Fish
• Fishes
Characteristics of Fishes
• In addition to living in water and having fins, most fishes are
ectotherms, obtain oxygen through gills, and have scales
largest group of vertebrates and been around the longest
• Obtaining Oxygen
– Water enters mouth passes through gills and oxygen is
filtered into blood
– CO2 goes from blood to water and both exit through gills
• Circulatory System closed
– Oxygen travels throughout body from gills O2 rich blood
pumped into the heart
– Heart pumps the O2 poor blood back to vessels in gills
Channel Catfish
Characteristics of Fishes (cont.)
• Movement
– Swim using fins primarily for obtaining food but some
for reproduction
• Reproduction
– Most external male spreads sperm over eggs outside
body
– Some internal eggs are fertilized inside female body
(sharks, guppies)
• Nervous System
– Aid to find food and avoid predators
– Must have keen sense of touch, smell and taste
Trout Eggs
Jawless Fishes
• The major groups of fishes are jawless fishes, cartilaginous
fishes, and bony fishes.
• Jawless fishes are unlike other fishes in that they have no jaws
and no scales.
• Hagfishes and lampreys only one that exist today
• Have mouths for scraping, stabbing, and sucking food
• Hagfish crawl into dead or dying fish to eat
• Lamprey parasites
– Attach to suck tissue and blood
Hagfish
Cartilaginous Fishes
• Examples sharks, rays, ad skates
• Obtaining Oxygen
– Sharks constantly swim to pass water over gills sleep in currents
to make water pass through
– Rays/Skates holes behind eyes takes in water water exits
through gill openings on underside
• Obtaining Food
– Rays/Skates feed on the ocean floor crushing mollusks,
crustaceans, and small fish with it’s teeth
– Sharks will attack most anything great smell but poor eyesight
• Use two rows of teeth to eat multiple rows behind are
replacements
Great White Shark
Ray
Bony Fishes
• A bony fish has jaws, scales, a pocket each side of the head
that holds the gills, and a skeleton made of hard bones.
• Swim bladder adjusts at different depths
• 95% of all fish species fresh and salt water
• Environments dark depths, light-filled waters, and coral
reefs
Bony Fish
Assignment
• Read Section 11.3
• Do Key Terms
• Chapter WS 308 & 317