Section 2 Jawless and Cartilaginous Fish Chapter 39 Fish Section 2 Jawless and Cartilaginous Fish
Fish Adaptations Stream-lined body & muscular tail Paired-fins allow fish to manuver Secrete mucus around body to help move in water and protect against infections Store lipids (fat) to help aid in buoyancy Use gills for gas exchange
Homeostasis Freshwater fish = hypertonic (higher concentration of solutes than the surrounding water- gain water) Saltwater fish = hypotonic (contain lower concentrations of solutes than their surroundings- lose water)
Sensory Functions Fish can sense light, chemicals, & sound Some can sense electrical & magnetic fields Many fish can see in color, but most cartilaginous fish can not see in color
Sensory Functions Chemoreception- ability to detect chemicals in the environment Sharks have great sense of smell & taste Barbels- whisker-like organs near mouth
Barbels
Sensory Functions Lateral line- allows fish to sense vibration in the water Cartilagenous fish (sharks & rays)- ampullae of Lorenzini- detect weak electrical fields- help locate prey
Lateral Line
ampullae of Lorenzini
Jawless Fishes Hagfish & lamprey Have an eel-like body, cartilaginous skeleton, and unpaired fins Hagfish live in oceans Lampreys live in freshwater
Hagfishes Bottom-dwellers in cold marine water, no jaws Isotonic- same ion concentration as sea water Feed on small invertebrates or dead & dying fish Burrow in dead fish & consume internal organs
Hagfish
Lampreys ½ parasites, ½ free-living Attaches to host with disk-shaped mouth After feeding, lampreys drop off & host may recover, bleed to death, or die from infection Fertilization occurs outside body (external fertilization)
Lamprey
Cartilaginous Fish Class Chondrichthyes Sharks, skates, rays, & ratfish Cartilage- flexible, lightweight material made of cells surrounded by tough fibers of protein Skin is covered with placoid scales- feels like sandpaper
Sharks Whale shark- largest shark (60 feet) Feed on plankton & floating plants & animals Filter water using gill rakers 6 to 20 rows of teeth that point inward
Whale Shark
Sharks One shark uses 20,000 teeth in a lifetime Each tooth is shaped based-on diet
Great White Shark
Hammer Head Shark
Black-tip Reef Shark
Bull Shark
Lemon Shark
Tiger Shark
Rays & Skates Flatten-bodies with wing-like pectoral fins and whip-like tails Rays have diamond or disk-shaped bodies Skates have triangular bodies Bottom-dwellers Feed on crustaceans
Rays
Skates
Ratfishes Deep-water Have gill slits covered by a flap of skin Some have a rat-like tail Feed on crustaceans or mollusks
Ratfish
Adaptions Gas exchange in gills Some sharks need to constantly move in order for gas exchange to occur Rays usually take in water from ventral side, but when on bottom, they use spiracles located behind eye to draw in water
Adaptations Sharks have an oil in their liver called squalene oil that contributes to their buoyancy Convert ammonia to urea which is a less toxic waste
Reproduction Internal fertilization- male transfers sperm to female’s body No cartilaginous fish provides parental care once young are born
REVIEW!!! Identify three characteristics of fish that makes them well suited to aquatic life. Contrast the feeding behavior of hagfish to the feeding behavior of lampreys. Identify the advantages of internal fertilization vs. external fertilization.