1. Fish

2. What are fish? Aquatic vertebrates Most have
Paired fins
Scales
Gills
Wide range of characteristics
Belong to different classes

3. Fish Evolution First fishes: armored bodies, no jaws
Cambrian period (510 mya)
505 mya to 410 mya: Adaptive Radiation of fishes – variation increased (no armor v. armor; jaws v. jawless)

4. Fish Evolution
Jaw evolution and paired fins seem to have come about together
Made out of bone or cartilage
Paired fins
More control during swimming
Tail fins
More muscle mass along trunk of body

5. Fish Evolution Fish evolved into two groups: Class Chondrichthyes
Superclass Osteichthyes
Lobe finned (Class Sarcopterygii)
evolutionary links point to the lobe finned fish sharing a common ancestor with early amphibians
Ray finned (Class Actinopterygii)

6. Orders of Bony Fish Anguilliformes Order Salmoniformes Order
Cypriniformes Order
Siluriformes Order
Perciformes Order
Use your computers to research characteristics of one order (body layout, habitat, types of food eaten, modes of feeding, examples).
You will present your findings to the class.

7. Fish Order: Body layout: Habitat Types of food eaten Modes of feeding
Examples:

8. Fish Form and Function Adaptations for life in water
Methods of feeding
Gills
Paired fins

9. Feeding Display all modes of feeding
Herbivores, carnivores, omnivores, parasites, filter feeders, detritus feeders
Depending on type of food available
Some fish are highly specialized (barracuda - carnivore)

10. External Fish Anatomy
Fins:
Dorsal
Pectoral
Pelvic
Anal
Caudal

11. External Structures Fins Lateral Line Operculum Nares
steering, propulsion through water
Lateral Line
Operculum
covers/protects gills
Nares
Nasal openings

12. Lateral Line Senses changes in the water NO external ear
Current
Electrical
Heat
NO external ear
Utilizes lateral line for detecting sound vibrations

13. Key: External Fish Anatomy
Nares
Eye
Fins:
Dorsal
Pectoral
Pelvic
Anal
Caudal
Operculum
Mouth
Lateral Line

14. Skeletal System Consists of bone and cartilage Skull Vertebrae Ribs
Rays – within the fins

15. Skeletal System

16. Muscular System Tail and Trunk Muscle Jaw Fin
Myotomes – blocks of muscle that run up and down the fish’s body
Separated by myosepta
Jaw
Fin

17. Digestive System Mouth Pharynx Esophagus Stomach Liver and pancreas
Short, expandable (to enable swallowing of large food)
Stomach
Gastric glands
Pyloric ceca
Finger-like projections responsible for most digestion
Liver and pancreas
secrete enzymes to help with digestion
Intestines
majority of food absorption, length differs in herbivores a carnivores
Gizzard

18. Digestive System

19. Digestive System Labeling
Mouth
Pharynx
Esophagus
Liver
Gall bladder
Intestine
Anus
Stomach

20. Respiratory System Gills on either side of the pharynx
Made up of filaments
Feathery structures with large number of capillaries for increased gas exchange
Pull water in through the mouth, over the gills, out the openings on the side of the pharynx

21. Specialized Respiratory Systems
Exception: Lungfish – need to go to surface of water to fill air sac (“lung”)
Oxygen poor water

22. Respiratory System Afferent blood vessels Efferent blood vessels Gills
Operculum
Heart
Dorsal aorta
Ventral aorta

23. Also, describe how fish breathe.
What happens to the operculum?
What is the purpose of afferent/efferent blood vessels?

24. Nervous System VERY simplified Brain
3 lobes
Forebrain (smell)
Midbrain (vision, learning, motor receptors)
Hindbrain (medulla oblongata and cerebellum)
Coordination
Movement
Balance
Spinal cord – serves rest of the body

25. Nervous System - Brain

26. Circulatory System Closed circulatory system Single loop around body
4 part heart: (but considered 2 chambered)
Sinus venosus
Atrium
Ventricle
Bulbus arteriosus

27. Circulatory System – Blood Flow
Sinus venosus receives unoxygenated blood from the body
Valve at the end of the sinus venosus opens into the atrium
Atrium has thick, muscular walls
Atrium receives unoxygenated blood and pumps it into the ventricle
Ventricle is the largest and most muscular chamber of the heart
Ventricle fills with blood it constricts and forces the blood through the bulbus arteriosus

28. Circulatory System – Blood Flow
Bulbus arteriosus is a valve or series of valves that control blood flow out of the ventricle and into the ventral aorta.
Blood passes through the bulbus arteriosus to the ventral aorta.
From the ventral aorta, blood flows to the gill filaments, where it is oxygenated.
Blood flows out of gills through the dorsal aorta and through the fish’s body.

29. Label the heart of a fish
Sinus venosus
Atrium
Ventricle
Bulbus arteriosus
Vein
Ventral Aorta
Also, draw in direction of blood flow.

30. Circulatory System
Red blood cell production
Spleen
Kidney
Bones

31. Blood Flow

32. Excretory System Release nitrogenous waste as ammonia
Gills
Kidneys filter blood to excrete liquid waste
Kidneys allow fish to maintain salt balance
Salt water fish
Fresh water fish
Cloaca

33. Reproduction External fertilization
Oviparous – completely separate from both parents
Females release eggs into water
Males release sperm
Ovoviviparous
One parent carries fertilized eggs until they hatch – no direct connection to the parent (yolk sac is nourishment)
Viviparous
Carry fertilized eggs internally – direct connection between mother and offspring (no yolk sac)
Live birth
Sharks

35. Growth and Development
Fish are able to live independently when hatched
Some species build nests, care for young for long periods of time
Aquatic life – minimal strain on organs, bone, muscle
Can grow large
Limits on circulatory system, brain function

36. Life Cycle of Bony Fish Egg Larval fish/Alevin Fry Juvenile Adult
Spawning adult

37. Other Structures Swim Bladder Between the stomach and the spine
Allows for buoyancy
Fills with air to keep fish afloat
If the fish does not have a swim bladder, they will sink if they stop swimming

38. Dissection of the Perch

39. You will need to sketch and label the following systems:
External fish anatomy
Respiratory system
Reproductive system
Digestive system
Heart
I expect these to be turned in with the dissection packet and questions.

40. Also… You will be removing organs from your perch.
Throughout the dissection I will be circulating to see which organ(s) we will save for future comparisons.
You will be graded on the dissection as well as the post-dissection packet.
I will collect 1 packet from each person
The answers to the questions throughout the procedure should be on a separate sheet of paper – these can be completed after the dissection
Each group will receive a dissection grade.

41. Dissection of the Perch

42. Dissection of the Perch