PHYLUM CHORDATA Vertebrates Fish, amphibians, reptiles, birds and mammals

GENERAL TRAITS OF CHORDATES 1.Bilateral symmetry 2.Complete digestive system 3.Closed circulation with a ventral heart 4.Dioecious

5.These traits present during some part/stage in their life: a. Notochord- becomes spine b. Dorsal nerve cord- becomes spinal cord c. Pharyngeal gill slits d. tail

GENERAL TRAITS OF FISH 1. Streamlined bodies 2. Mucus covered bodies 3. Paired fins help with steering & balance. 4. Maintain buoyancy 5. tissues & bones not as heavy

6. Respiration- gills; water enters mouth, passes over gills, gases exchange, water leaves w/CO 2 thru gill slits. 7.Circulation- 2 chambered heart a. 1 atrium & 1 ventricle b.Path of Blood= body-atrium-ventricle- afferent arteries-gills- efferent arteries-body

8. Nervous- brain & spinal cord 9. Sensory- a. Good sense of smell b. Poor eyesight c. Lateral Line System- sensory pits in skin attached to fluid filled canals under skin; can detect movement.

10.Excretory System- 2 kidneys a.Osmoregulation- regulation of water & ions (salt) in body. b.Freshwater fish- water moves into blood due to osmosis; urinate a lot to remove excess water c.Saltwater fish- water moves out of blood into salty water; urinate very little to retain water.

11.Digestive System- a.Teeth- modified scales for grasping prey b.Swallow prey whole or in large chunks. c.Large stomach for storing infrequent meals.

THREE CLASSES OF FISH

CLASS AGNATHA 1.EX: hagfish & lamprey 2.Jawless fish w/smooth skin- no scales 3.No paired fins 4.Cartilage skeleton 5.Gills open to water 6.Fertilization- external 7.Oviparous- lays eggs externally

8.Lamprey- a. Suckerlike mouth b. Teeth & rasping tongue scrape scales off host. c. Suck blood of fish

9.Hagfish- a. Live buried in sand & mud b. Mouth with 4 pairs of tentacles c. Enter dying/dead fish thru mouth d. Eat contents of body, leaving sack of skin & bones e. Secretes green slimy mucus to deter predators

CLASS CHONDRICHTHYES 1.EX: sharks, skates, rays 2.jaws 3.Paired fins 4.Cartilage skeleton 5.Gills open to water- gill slits 6.Dermal placoid scales- “dermal denticles” a. Point backward- reduces friction in water b. feels like and used to be used as sandpaper. 7. Buoyancy- oily livers

8. Special Digestive Adaptations: a. Teeth in rows 1. ratchet forward when one is lost. 2. New row of teeth develop every 7-8 days b. Rugae- folds in stomach that expand to hold large meals c. Spiral valve- increases absorption of nutrients (like human villi)

9. Special Respiratory Adaptations: a. Ram Ventilation- some sharks 1. Swim with mouth open to force water into mouth over gills.

b. Spiracles- holes behind eyes 1. Used for breathing while eating.

10. Special Sensory Adaptations: a. Lateral Line system b. Ampullae of Lorenzini- 1. pits in snout that detect impulses or electrical currents in water. 2. Used to find prey, mates, identify predators. 3. Helps sense in murky or turbulent water

11. Fertilization- internal a. Males have penis- like structure called clasper for inseminating female.

Male shark Female shark

b. Development of eggs 1. Oviparous- lays eggs 2. Ovoviviparous- eggs hatch inside mother –No placenta so babies that have hatched sometimes eat other eggs &/or siblings that have hatched. –EX: Great whites & nurse sharks 3. Viviparous- “Pups” are attached to mother by placenta 1. EX: bull shark, mako, whale shark, hammerheads

12. Smallest- dogfish shark (1 meter) 13. Largest- whale shark (10 meters & filter feeds)

14. Skates & rays find food along bottom.

LABEL THE DIAGRAM OF THE EXTERNAL FEATURES OF SHARK ON BACK OF PAGE 1 STOP HERE! WE WILL GO OVER THE PARTS OF THE SHARK NEXT CLASS BEFORE THE DISSECTION!

CLASS OSTEICHTHYES 1.EX: tuna, bass, bluegill, seahorse 2.Bony fish 3.Jaws 4.Paired fins 5.Bony skeletons 6.Gill openings covered with operculum- muscular plate that pulls water into mouth.

7.Buoyancy- swim bladder a. Increase air- fish rises b.Decrease air- fish sinks 8. Special Sensory Adaptations: a. Ossicles/otoliths- pick up vibrations in water for hearing

9.Reproduction: a. Fertilization- external b. Oviparous c. Males create nest. Females lay eggs. Males fertilizes eggs. Sometimes female protects eggs until hatching. d. Spawning- return to river born in to reproduce (salmon)

10. Scales- a. Can be used to identify fish b. Can estimate age of fish with rings (annuli) on scales. 1. Cosmoid2. Ganoid 3. Cycloid4. Ctenoid

1.Shark skin was once used for a. Sand paper b. Clothing c. Writing utensils 2.Bony fish belong to the class a. Agnathab. Chondrichthyesc. osteichthyes 3.Sharks reproduce using ___ fertilization a. Externalb. internal 4.Which type of fish has placoid scales? a. Bassb. Stingrayc. hagfish 5.The structure in bony fish that maintains buoyancy is a. Operculumb. Swim bladderc. Oily liver