Phylum Chordata
A.K.A. Chordates
Four Distinguishing Features
1) Single, hollow, dorsal nerve cord
2) Gill or pharyngeal slits (small openings along
anterior part of body or pharynx)
3) Notochord: flexible rod for support that lies
between the nerve cord and gut
4) Post-anal tail: tail that extends beyond the
anus
Chordate characteristics
• http://www.biog1105-1106.org/labs/deuts/chordates.html
Subphylum Urochordata
A.K.A. tunicates
SEA SQUIRTS
• 3,000 species; all marine
• Sessile
• Filter feeders
• Larval form has all four characteristics of
chordates
Subphylum Urochordata
A.K.A. tunicates
SALPS
• Planktonic
• Filter feeders
• Warm water
http://www.flickr.com/photos/31124758@N00
/165884673/
Subphylum Cephalochordata
A.K.A. Lancelets (amphioxis)
• 23 species
• 7 cm long, similar in shape to a fish
• Retains chordate characteristics entire life
• Invertebrate (lack a backbone)
• Filter feeders; inhabit soft
bottoms)
Subphylum Vertebrata
A.K.A. Vertebrates
• Have a backbone; usually made of bone
• Bilateral symmetry
• Endoskeleton
• Complete digestive system
• Closed circulatory system
Include: fish, reptiles, birds and mammals
Types of Fishes
1) Class Agnatha: Jawless fish
2) Class Chondrichthyes: cartilaginous fish
3) Class Osteichthyes: bony fish
Class Agnatha
A.k.a. Jawless fish
• Lack jaws
• Elongated like an eel
• Lack paired fins
• Lack scales
• Mostly parasitic
Examples: hagfish and lampreys
Lampreys
Hagfish
Hagfish
Class Chondrichthyes
A.k.a. Cartilaginous Fish
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Skeleton of cartilage
Movable jaws with teeth
Paired lateral fins for efficient swimming
Placoid scales: similar shape to teeth
embedded into the skin
• Spiracle and gill slits are not covered
Includes: Sharks, Rays, Skates, and Ratfish
Class Chondrichthyes
• Placoid scales; sandpaper-like
Class Osteichthyes
A.k.a. Bony fish
• Skeleton made of bone
• Cycloid, ganoid or ctenoid scales which are
thin flexible and overlapping
• Scales are made of bone and covered by a thin
layer of tissue and mucus
• Operculum that covers and protects the gills
• Swim bladder: fills with air to control
buoyancy
Class Osteichthyes
• Gills covered by an operculum.
Class Osteichthyes
• Have different scales than sharks:
Ctenoid
Cycloid
Ganoid
Fish Adaptations
• You will work in pairs.
• Each pair will have one sheet of paper and each
person should have a different color pen.
• Each person in the pair will answer every other
question in their color pen.
• Answer the following questions:
• Part I: 1, 2, 3, 4, 5, 7 8, 10, 11, 12(read),14, 15,
16, 17 (your fish only)
• PartII: 1, 2 a-c, 3, 5, 7
• Part III: 1, 2, 3, 4, 6