Phylum Chordata
Chordate: animals that have a
notochord in the embryonic form
Notochord: a flexible rod that extends
the length of the body
Notochord
4 Characteristics of Chordates
1. Dorsal nerve cord
2. Notochord
3. Pharyngeal gill slits
4. Tail
Subphylum Vertebrata: animals whose dorsal nerve
cord is protected by a series of bone
Characteristics
1. Endoskeleton
2. Skull and Backbone
4. Vertebrae that
encloses/protects the nerve cord
3. Hinged Jaw
Fish: most primitive vertebrates
Ichthyology: study of fish
-first jawed vertebrates
-evolved during the
Devonian Period (350
MYA)
-fins/scaled/gills
-two chambered heart
with a closed circulatory
system
Fish Heart
1. Atrium: a chamber
that holds blood
before pumping it into
the ventricle
2. Ventricle: muscle
chamber responsible
for pumping blood
throughout the body
Fish external anatomy
Fish Taxonomy
Fish
Class Agnatha
(jawless)
Class
Chondrichthyes
(cartilagenous)
Class
Osteichthyes
(bony)
Class Agnatha: “no jaws”
-circular mouth with teeth
-freshwater parasites
-elongated bodies
Ex. Lamprey
Class Chondrichthyes: sharks and rays
-cartilage skeletons
-lack gill cover
-detect electric fields from
muscle contractions
-swim to keep from
sinking
Ex. Nurse shark, sand
skate
Class Osteichthyes: bony fish
-ossified (boney) skeleton
-operculum: protective
gill cover
-skin glands that secrete
slimy covering
Ex. Box fish, walleye,
largemouth bass,
porcupine puffer,
piranha, black molly,
catfish
Class Amphibia: “double life”
Introduction:
-linked to water for
reproduction
-evolved in the
Carboniferous period
-ecosystem was all
wetlands
Class Amphibia: “double life”
Characteristics:
-aquatic larval stage with
gills (tadpoles)
-four legs - tetrapods
-herbivores as larva;
carnivores as adults
-respiration with lungs
and through skin
-external ear drums
-three chambered heart
Specimens
-grass frog (Rana pipiens)
-bull frog
-american toad
-red-spotted newt
-red eyed tree frog
-African clawed frog
-poison dart frogs
Class Reptilia
• First terrestrial
quadriped
• Amniotic egg (oviparous
reproduction)
-body covered with scales
-breath entirely with lungs
- “3.5” chambered heart
Specimens
-
King snake
Ball python
Reticulated python
Water mocassin
Snapping turtle
Map turtle
Leatherback sea turtle
Eastern painted turtle
- Anole
- American alligator