Question

1. List four distinguishing characteristics that members of Phylum Chordata share.

1.

2.

3.

4.

2. What anatomical feature do the lancelets and tunicates lack, which are found in all other chordate specimens in this lab?

3. For each of the following organisms on display, determine which class they belong to

DEMO	Name of organism(s) on display	CLASS
A
B
C
D
E
F
G

Answer the following questions about the classes listed in the table above.

4. Which classes are represented by organisms with no jaws?

5. Which class is represented by organisms with jaws, a skeleton primarily made up of cartilage and no swim bladder?

Which class is represented by organisms with jaws, a bony endoskeleton and a swim bladder?

Answer 1

1) *Presence of a notochord.

*A dorsal hollow tubular nerve chord

*Presence of pharyngeal slits.

*They have a endostyle or thyroid gland.

*Presence of a post -anal tail.

2) No: name of the organism class

A lampreys,hagfishes   Cyclostomata

B shark,rays    Chondrichthyes

C Tuna    Osteichthyes

D Frogs   Amphibia

E Lizards    Reptila

F Ducky birds   Aves

G cow,goat    Mammalia

3) a)class cyclostomata is classsified as jawless fishes.They have jawless mouths with horny epidermal structures that function as teeth,and branchial arches that are internally positioned instead of external as in jawed fishes.

b)chondrichthyes is the class that contains the cartilaginous fishes.They are jawed vertebrtaes with paired fins,paired nares,scales,a heart with its chambers in series and skelton made of cartilage and are devoid of swim bladder.

c)ostiechthyes is the class of bony fish ,whose skelton is primarily composed of bone rather than cartilage.In most forms there unique feature is the presence of a swim bladder,an air filled sac to give buoyancy,gill covers,gill chamber,bony platelike scales,a skull with sutures, and external fertilization of eggs.