1. Vertebrates (subphylum vertebrata)
Possess a backbone (aka vertebral column, spine)
Vertebrae=Dorsal row of hollow skeletal elements (usually bone)
Nerve cord=spinal cord, protected by vertebrae, (part of nervous system), ends in brain
Bilateral symmetry, endoskeleton

2. Fish Form & Function Goals for this lab
Learn about fish: Topics
Skin/scales
Coloration
Locomotion
Fins
Muscles
Discuss 3 classes of fish
Dissect different fish- up to 3 different forms
Write paper comparing different fish forms
Due next Monday/Tuesday
Details to follow

3. Global Habitats
41.2%
58.2%
39.9%

4. Fish importance Appeared > 500 mya
Comprise half of vertebrate species
Feed on all types of marine organisms
some organisms previously discussed use fish as their home (bacteria to crustaceans)
Some animals eat fish
Most economically important marine organism
Vital source of protein to millions of humans
Ground up for chicken feed, fertilizer, leather, glue, vitamins obtained from them
Some kept as pets

5. Fish Morphology Skin Color Bioluminescence Swimming Locomotion Fins
Muscles

6. Skin Organ of the body Consists of connective tissue
Muscles pull against skin tissue & skeleton
Key component of the muscle-tendon-tail fin system
Layers
Epidermis
Typically 250 m thick  cell layers
Range 20 m – 3 mm
Dermis

7. Fish Skin Function: Hold fish together
Serves as barrier against abrasive agents
Osmoregulation (what does this mean?)
Permeable  respiratory function
Biomechanical properties in sharks

8. Fish Skin Derivatives: Mucous formed in epidermis cells
Protect against infection
Constantly shed to remove bacteria and fungus
Ex. Clingfish lack scales, protect their bodies by a thick layer of mucous
Bone is also skin derivative
scales, most important

9. Fish Scales First appear as dermal bone
Found in fossil of Cambrian period (570 mya)
Layered bone, solid armor-constrained movement
Evolved smaller and reduced into scales
5 types of scales (examples with images to follow)
Placoid
Cosmoid
Ganoid
Cycloid
Ctenoid

10. Fish Scales: Placoid Found in elasmobranchs (sharks & rays)
“teeth like”, same composition
As fish grows, do not increase in size, instead new scales are added

11. Fish Scales: Cosmoid
In the Sarcopterygii (fish with fleshy lobe fins), primitive fish
Less evolved than Elasmobranchs and Actinopterygii (fish with rayed fins)
Scales found in fossil record but not in any living fish,
Except in simplified version of coelocanth and lungfish

12. Fish Scales: Ganoid In primitive Actinopterygii
Found in reedfish, polypterus, gar, bowfin, and sturgeons
Were thick heavy scales when first appeared
Rhomboid-shaped
Developed into teleost scales

13. Fish Scales: Teleost scales
Two types:
Ctenoid-higher fish
Cycloid-soft-rayed, anchovies, sardine
Mineralized surface layer & inner collagenous layer
Scales surrounded by dermis, in dermal pockets
Grow from top, bottom, and insides; overlap lower part
Scales grow with fish
Characterized by concentric ridges (growth increments)
Ctenoid scales
Cycloid scales

14. Coloration

15. Coloration Fish display a multitude of patterns involving
2 or more colors,
in many tints and shades,
arranged in spots, stripes, patches, and blotches
3 Types of coloration predominant in oceans
Silver – pelagic, upper zone
Red – deeper zone (~ 500 m)
Black or violet – deep sea
Countershaded near shore and colorful in coral reefs

16. Coloration Chromatophores
Colored cells from which light is reflected off
Located in the skin (dermis), eyes
Various colors/hues-combination of different chromatophores
Functional Roles of Colors in Fishes-examples of each to follow
Social Roles
Advertisement
Mimicry
Hiding
Protection from sun (especially larvae)

17. Coloration: Social roles
Cleaner Fish: distinctive markings recognized by larger fish

18. Coloration: Advertisement: Bright, bold and showy males indicate:
Reproductive availability, either permanently or seasonally, e.g. cichlids, wrasses, minnows, sunfish
Unpalatable or venomous, e.g. lionfishes
Mimicry – Disguise:
Disguises: look like something in habitat, e.g. leaffish, sargasso fish
Mimicry: mimic distasteful species

19. Coloration: Concealment
General color resemblance – resemble background
Variable color resemblance – change with background, e.g. flatfish
Obliterative shading – countershading, dark above, light below (invisible fish)
Disruptive coloration – disruptive contours that breakup outline; bold stripes, bars, false eye spots
Coincident disruptive coloration – joining together of unrelated parts of the body to reduce recognition; e.g. sea dragon

20. Bioluminescence
Most luminous fish found m depths, few shallow
3 Types of light producing methods:
Self-luminous (on/off)
Symbiotic bacteria nurtured in special glands
Acquire from other bioluminescent organisms- diet contains light-emitting compounds
Function:
Concealment by counter-illumination - ventral placement matches background from above, against attack from below
Dorsal photophores safeguard against predators from above
Advertisement for courting, maintaining territory, to startle and confuse predators, and feeding

21. Fish Locomotion Means of Locomotion:
Simplest form: Passive drifting of larval fish
Some can:
Burrow
Walk, hop, or crawl
Glide
Fly
Most can:
Swim in a variety of ways

22. Fins Types of fins: Paired fins: pectoral and pelvic
Median fins: dorsal, caudal, anal, & adipose

23. Fins
Main functions:
Swimming – increase surface area w/o increasing mass
Stabilizers – yaw, stability-dorsal and anal fins
- brake, pitch, roll, reverse -pectoral/pelvic
thrust with caudal fin
Modifications in fins:
Defense – spines, enlarge fish
Locomotion – modified for crawling, flying, gliding
Hunting – lures, sensory organs
Respiratory organ – lungfish, supply oxygen to eggs

24. Fins Soft rays vs. Spines Spines: Soft rays: Usually hard and pointed
Usually soft and not pointed
Segmented
Usually branched
Bilateral, w/left and right halves
Spines:
Usually hard and pointed
Unsegmented
Unbranched
Solid

25. Fish Muscles Muscles provide power for swimming
Myomers=bands of muscle, run along sides of body, attached to backbone
Constitute up to 80% of the fish itself
Much hardly used except during emergencies
Don’t have to contend with same effect of gravity
Fish muscle arrangement not suitable on land
Cow: 30% muscle/wt
Tuna: 60% muscle/wt
Contraction causes oscillation of body and tail
Body bends as one side contracts b/c of an incompressible
notochord or vertebral column
Caused by bands of muscle = myomeres

26. Fish Muscles Major fibers (see handout): Red, pink, and white
Pink intermediate between red and white
Muscle types do not intermingle
Different motor systems used for different swimming conditions
Red – cruising
White – short duration, burst swimming
Pink – sustained swimming, used after red and before white

27. Fish Locomotion Swimming classified into 2 generic categories:
Periodic (or steady or sustained)- e.g. running marathons, for covering large distance at constant speed
Transient (or unsteady) – e.g. like running sprints, used for catching prey or avoiding predators

28. Isolate and move only fin(s)
pectoral
Rajiform - pectoral
Labriform -pectoral oscillate
Diodontiform - pectoral
anal
Gymnotiform -anal
dorsal
Tetraodontiform – anal+dorsal
Balistiform – anal+dorsal
Amiiform -dorsal
Ostraciform-rigid body, caudal main propulsion
Flex caudal portion, fast swimmers
Thunniform-rigid body, caudal main propulsion
Carangiform
Undulate the body: eels, elongate fish
Subcarangiform
Anguilliform
(Wavelike)
(fanlike)

29. http://www. oceanfootage. com/stockfootage/Titan_Trigger_Fish//

30. Tuna: Ultimate Living Swimming Machine Swim continuously – feeding, courtship, rest, reproduction

31. Tuna: Ultimate Living Swimming Machine hydrodynamic adaptations
Big size-high performance engine
Streamlining-spindle shaped & rigid body
Small structures at various parts of the body to improve swimming efficiency and reduce drag, e.g.
Eyes flush with body – don’t protrude
Adipose eyelid - smooth, reduce drag
Depression grooves for dorsal, pelvic, & pectoral fins at high speed
Keeled peduncle - cutting through water
Finlets for cross-flow - delayed separation

32. Tuna: Ultimate Living Swimming Machine
Must swim to survive:
No gas bladder, rigid body, ram ventilation
High blood volume, large heart, maintain warm core (25oC)
School to utilize vortices generated by other fish (~like race car driver who “slipstreams” and then slingshots past leading car)
Adopt swim-glide for energy savings (like birds)
High narrow tails – propulsion with least effort, used to design efficient propulsion systems for ships
Slipstream: The area of reduced pressure or forward suction produced by and immediately behind a fast-moving object as it moves through air or water.

33. Fish-mouth types (some)
Large mouth with teeth (e.g. barracuda)
Long snout/small mouth (e.g. butterfly fish)
Protrusible mouth (e.g. slipmouth)
Beak-like mouth (e.g. parrotfish)
Large mouth (e.g. herrings)

34. Fish
Three Classes:
Agnatha
Chondrithyes
Osteicthyes

35. Class Agnatha Jawless fishes Ex. Hagfish, lampreys No paired fins
Gill holes, no slits or operculum
Large sucking mouth with teeth
Scavengers
As a defense mechanism, secrete slime then tie itself in knots to escape predators
Also tie in knots for pulling food off carcasses, and cleaning slime from body

36. Class Agnatha Hagfish’s mouth

37. Class Chondricthyes Sharks and rays Skeleton = cartilage, not bone
Paired fins-efficient swimming
Gill slits exposed,
no operculum
Large oil-filled liver
Heterocercal tail (upper longer than lower lobe)
Placoid scales-skin like sandpaper

38. Class Osteichthyes Bony fish Largest group of living vertebrates
Bones for skeletons
Gill covering (operculum)
Swim bladder (balloon-like)
Homocercal tails (even)
Cycloid & Ctenoid scales

39. Dissection Worksheet Working in groups of 2 or 3 people,
dissect 1 fish following the worksheet and writing the answers to the questions in your notebook as you go.
Need to draw 3 external illustrations in your notebooks
1 of the fish you are dissecting, before you dissect it
2 others that have specialized mouths and caudal fins
label the type of mouth and caudal fin each has
Label the following structures on each illustration:
gill cover, pectoral fins, pelvic fins, dorsal fin,
anal fin, adipose fin (if present), lateral line
give the head length, total length, and the fork length (of the dissected one ONLY, see handout)
look at a scale under a microscope and draw it.

40. Dissection Worksheet continued
Cut through body cavity
Find the following
Heart
Liver
Stomach/intestines
Swim bladder (if applicable)
Spine
Cut cross section, 2/3 down the body
Red muscle
White muscle

41. Scales- use slides
Draw
Placoid
Ganoid
Cycloid
Ctenoid