Chapters: 3
Fish, Amphibians, Reptiles and Birds
Phylum Chordata (Chordate)
 All have backbone
 Vertebrates – subphylum
 Shared Characteristics:
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Notochord
Dorsal nerve chord
Gill slits
Endoskeleton
Closed circulatory system
1. Notochord
 Rod of cells above the
central nervous system
(CNS)
 Most chordates have as
embryos
 Develops into
backbone
2. Dorsal Nerve Cord
 Becomes a brain and
spinal chord
 hollow
3. Gill Slits
 In embryo stage
 Disappear except in
fish
4. Endoskeleton
 Internal skeleton
 Advantage – ability to
grow without molting
5. Closed Circulatory System
 2, 3,4 Chambered
hearts
 Benefit – more oxygen
 Blood contained in
blood vessels
5b. Chambered hearts
6. Other characteristics of
Chordates
 Complex nervous
system
 Varied locomotion
 Tail extends beyond
anus
 Gills or lungs
Vertebrate Classes
Fish
 Fish characteristics:
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Aquatic (fresh and Salt)
Paired fins for
movement
Scales
Gills
Various feeding
methods (herbivores,
carnivores, parasites,
filter feeders)
Fish Digestion
 Pathway of food:
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Mouth
Esophagus
Stomach (partially
broken down)
Pyloric cecum – secrete
digestive enzymes and
absorption
Fish Digestion continued
 Food does not pass
through
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Liver –
Pancreas –
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Both secrete chemicals to
break down food
Fish Circulation
 Closed circulatory
system
 2 chambered heart
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Atrium – oxygen poor
blood from body
Ventricle – pumps
blood to gills
Fish sense organs
 Have a well-developed
brain
 Eyes – color vision
 Strong sense of taste
and smell
 Lateral line – sense
motion of other fish
Groups of Fish
 Group 1:Jawless Fish
 examples- lampreys and
hagfish
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- simplest
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- cartilage
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- tubular
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- sucker mouth
 Nostrils – only one
 Produce slime
 7 gills – not covered
 parasites
Group 2: Cartilaginous Fish
 Examples: sharks and rays
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- cartilage skeleton
Tooth-like scales on skin
- jaws with 1000’s of teeth
- acute senses of vision,
smell, and vibrations
 - breathes by swimming
 - internal fertilization
 Skates and Rays
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Bottom feeders
Filter feeders
Vacuum like mouths
Group 3: Bony Fish
 largest group of fish
 - skeleton of bone
 - swim bladdermaintains depth
 - external fertilization
(spawning)
Importance of Fish
 ecology of water
 - food source (Fish are
friends not food-BruceFinding Nemo)
 - hobby and sport
Amphibians
“Double Life”
Characteristics of Amphibians
 Live in water when
young and to reproduce
 Live on land as adults
 Breath through skin
 No scales
 Have lungs
 External fertilities!
Additional Amphibian
Characteristics
 Ectotherms –
organisms whose body
temp is controlled by
the outside temp. (cold
blooded)

Dormant in cold
environments
More amphibian characteristics
 Amphibians are the
link between land and
water animals
Groups of Amphibians
 Frogs and Toads
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Short, broad bodies
Sing to attract males
Sticky tongue to catch
food
Acute vision
Hearing – tympanic
membrane,
Powerful hind legs
Toads
 Found in dryer environments
Life cycle of frogs and toads