Vertebrates (subphylum vertebrata)

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Vertebrates (subphylum vertebrata)

• Possess a backbone (aka vertebral column, spine)
• VertebraeDorsal row of hollow skeletal elements
  (usually bone)
• Nerve cordspinal cord, protected by vertebrae,
  (part of nervous system), ends in brain
• Bilateral symmetry, endoskeleton

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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

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Global Habitats
41.2
58.2
39.9
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Fish importance

• Appeared gt 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

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Fish Morphology

• Skin
• Color
• Bioluminescence
• Swimming Locomotion
• Fins
• Muscles

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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 ? 10-30 cell layers
• Range 20 ?m 3 mm
• Dermis

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Fish Skin

• Function
• Hold fish together
• Serves as barrier against abrasive agents
• Osmoregulation (what does this mean?)
• Permeable ? respiratory function
• Biomechanical properties in sharks

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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

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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

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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

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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

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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

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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)

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Coloration
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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

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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)

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Coloration Social roles
Cleaner Fishdistinctive markings recognized by
larger fish
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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
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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
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Bioluminescence

• Most luminous fish found 300-1000 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

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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

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Fins

• Types of fins
• Paired fins pectoral and pelvic
• Median fins dorsal, caudal, anal, adipose

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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

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Fins
Soft rays vs. Spines

• Spines
• Usually hard and pointed
• Unsegmented
• Unbranched
• Solid

• Soft rays
• Usually soft and not pointed
• Segmented
• Usually branched
• Bilateral, w/left and right halves

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Fish Muscles

• Muscles provide power for swimming
• Myomersbands of muscle, run along sides of body,
  attached to backbone
• Constitute up to 80 of the fish itself
• Much hardly used except during emergencies
• Dont 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

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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

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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
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Isolate and move only fin(s)
pectoral
Rajiform - pectoral
Labriform -pectoral oscillate
Diodontiform - pectoral
anal
Gymnotiform -anal
dorsal
Tetraodontiform analdorsal
Balistiform analdorsal
Amiiform -dorsal
Ostraciform-rigid body, caudal main propulsion
Flex caudal portion, fast swimmers
Thunniform-rigid body, caudal main propulsion
Carangiform
Subcarangiform
Undulate the body eels, elongate fish
Anguilliform
(Wavelike)
(fanlike)
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http//www.oceanfootage.com/stockfootage/Titan_Tri
gger_Fish//?DVfSESSCKIE7305db92882366fd26c463edc2
09393f8e25bdc9
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Tuna Ultimate Living Swimming MachineSwim
continuously feeding, courtship, rest,
reproduction
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Tuna Ultimate Living Swimming Machinehydrodynami
c 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 dont 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

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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.
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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)

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Fish
Three Classes Agnatha Chondrithyes Osteicthyes
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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

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Class Agnatha
Hagfishs mouth
http//www.soest.hawaii.edu/oceanography/faculty/c
smith/index.html
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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

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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

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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.

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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

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Scales- use slides

• Draw
• Placoid
• Ganoid
• Cycloid
• Ctenoid