Phylum Chordata

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Phylum Chordata

• Fish

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I. Phylum Chordata

• Includes Fish, Reptiles, Birds and Mammals
• A. Characteristics of Chordates
• 1. All have bilateral symmetry
• 2. All have internal skeleton
• 3. Notochord Flexible internal, supporting
  structure backbone

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• 4. all have paired gill slits at some point
  in life (even mammals)
• 5. Have 2 layer body covering scales,
  feathers, hairs, skin,
• 6. Closed circulatory system
• 7. Highly developed nervous system
• 8. Chambered heart 2, 3, or 4
• 9. Dorsal nerve cord spinal cord protected
  by the notochord

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II. Fishes

• A. General Info
• 1. Well developed senses- excellent smell,
  sight (for most)
• 2. Most have scales covering body
• 3. All secrete mucous to protect from bacterial
  and fungal infections

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• 4. Have gills for entire life
• 5. Most have fins used for moving
• 6. Vary in size 12mm to 40ft.
• 7. exothermic body To changes with
  surrounding To cold blooded
• 8. 3 classes of fish

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• B. Class Agnatha
• 1. Jawless fish has no jaw
• 2. Circular mouth
• 3. Eel shaped body long and slender
• 4. Most primitive living fish
• 5. Very smooth skin no scales
• 6. Skeleton made of cartilage

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• 7. Two types of Agnathas
• a. lamprey
• 1) found both freshwater and saltwater
• 2) has become a big problem in the Great
  Lakes
• 3) lampreys are considered parasites

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• 4) has a sucker like mouth with sharp teeth
• 5) drill into their prey sucks out blood
  and fluids vampire fish
• 6) lives up to 9 years
• 7) averages 2ft feet in body length

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• 8) gray in color
• 9) very strong suction ability

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• b. Hagfish
• 1) only found in saltwater
• 2) very slimy -gt slime-eel
• 3) secretes so much mucus
• noses get clog has to sneeze to clear nose
• 4) feed only on dead fish

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• 5) no eyes
• instead uses barbels -gt very sensitive
  extensions can smell up to 2ft away
• 6) grayish/purplish in color
• 7) lives on the ocean bottom
• 8) coils up when resting
• 9) basically no skeleton except for spine

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• 10) gnaws on food with rough tongue

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• C. Class Chondrichthyes
• Includes sharks and rays
• 1. General information
• a. no true bones -gt skeleton made of
  cartilage
• b. very strong jaws, moveable

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• b. mouth on underside cant really see what
  goes into mouth
• c. skin is like sandpaper placoids -gt cover
  entire body Tooth scales
• d. males easy to identify by a set of claspers
  by anal fins for copulation
• e. has internal fertilization
• f. has 5, 6 or 7 open gill slits

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• 2. Sharks
• a. General information
• 1) over 350 species
• 2) only 50 are known to attack man
• 3) Most feared sea creature thanks to
  movies like Jaws

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• 4) More humans are killed and attacked by
  dogs than sharks
• 5) sizes vary from 6 inches- gt cigar shark
  to 40 ft -gt whale shark
• b. Body of shark
• 1) streamlined for fast speeds -gt hydrodynamic

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• 2) Very muscular body, tail moves from side
  to side
• tail fin is called the caudal
• has two parts upper part much longer than
  bottom part
• 3) very pointy nose increases hydrodynamics
  ability nose is very sensitive

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• 4) has lateral lines -gt enhances smell
  ability, run from nose down the sides
• 5) tiny holes found within the lateral lines
• 6) most sharks must keep moving or will
  suffocate
• 7) teeth are very sharp and in rows like a
  conveyor belt, teeth replace every 2-3 wks

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• 8) Very large liver weigh about 1/4 the body
  weight contains oil that humans use for
  vitamin A
• 9) Intestine is spiraled on the inside for
  storing food

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• 10) fins do not bend
• used for braking and steering
• dorsal fin most noticeable -gt keeps shark
  from spinning

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• c. Feeding of sharks
• 1) Carnivores -gt will eat just about
  anything -gtseals, fish bumpers, tin cans
• 2) filter feeders -gt eat plankton small
  marine life
• two largest sharks are plankton feeders
  whale and basking shark

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• d. Types of sharks
• 1) Great White-gt most feared, but rare
  largest carnivore
• 2) Bull -gt fastest shark and very aggressive
  45 m/h
• 3) whale shark -gt largest of all fish very
  shy 6ft wide mouth

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• 4) Megamouth-gt deep sea shark only 8
  discovered
• first found in 1978, 2nd in 1984 off the
  coast of CA
• 5) Hammerhead -gt unusual head very broad
  and flat aggressive
• 6) And many more very interesting ones

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• e. Importance of sharks
• 1) Top of the food chain keeps nature
  balanced
• 2) Used in cancer research
• 3) Used as food shark fin soup shark stakes
• 4) Clothing -gt boots, etc.
• 5) Skin for burn victims, meshes really good

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• 6) Source of vitamins and oils

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• 3. Rays and Skates
• a. General information
• 1) body is flattened
• 2) have wings to swim
• 3) most have a whip -like tail

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• 4) Most live on the bottom in the sand
• 5) very peaceful and shy animals, attack only
  when provoked
• 6) Feed mostly on squid, fish
• 7) Has spiracles to breathe while resting on
  the bottom

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• b. Protection
• 1) barb -gt located on tail whip it right
  into leg, very painful
• 2) battery-packed sting -gt can knock a man
  out, stun prey
• 3) can swim very fast to avoid danger

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• c. Types of rays
• 1) Manta ray -gt largest of all rays 24ft
  wing span
• plankton feeder
• very, very peaceful
• no barbed spine

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• 2) Blue - spotted -gtvery poisonous be
  careful
• 3) Common sting ray -gt shuffle feet when
  entering water to avoid being hit by tail
• 4) live mostly in shallow waters

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• D. Class Osteichthyes
• Includes all bony fish
• 1. General information
• a) largest class of vertebrates
• b) skeleton made of bone (calcium carbonate)

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Heaviest bony fish 5000 lbs
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• c) have protective, overlapping scales
• d) swim using pectoral fins and tail ( sharks
  only use tails)
• e) Most have external fertilization
• f) Most have a air bladder -gt allows them to
  hover or suspend

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• 2. Body plan
• a. tail fins are even -gt
• sharks -gt
• b. most have large eyes
• c. Mouth in front of body sharks underneath
• d. have nostrils used only for smelling NOT
  respiration

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• e. 4 pairs of gills protected by an
  operculum
• f. have retractable fins sharks cannot
  retract fins
• g. mostly made of muscle makes for very fast
  fish
• h. variety of shapes and sizes

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Class Agnatha
No scales
Gill holes
MouthNo jaw
Single long fin
Skeleton made of cartilage
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Dorsal fin
Placoid scales
Uneven caudal fin
2nd dorsal fin
Lateral lines
Gill slits
mouth
Anal fin
Pelvic fin
Pectoral fin
Class Chondrichthyes
Cartilage skeleton
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Skeleton bone
Dorsal fin
Pectoral fin
Caudal fin
Lateral line
Overlapping scales
Class Osteichthyes
mouth
operculum
anal fin
Pelvic fin