DEFINING A CHORDATE:
Which organ system has been chiefly responsible for giving the phylum its eminence among animals?
List the 5 characteristics common to all
chordates (at least at some time in their lives)
1.
2.
3.
4.
5.
How do the protochordates differ from the "higher" chordates?
Name two structures that protochordates lack in comparison to chordates.
What is the function of the notochord? How does its structure give it its stiffness?
What is a nephridia? What system does it belong it?
A. Using the pie chart in your lab manual, calculate the percentage of each group within the phylum Chordata:
Actinopterygii_________ __________
_________
Reptila Myxini
__________
__________
__________
_________
_________
A. Where are tunicates found?
B. Name the pathway as water is pumped through a tunicate. Begin with the incurrent siphon →

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Exercise 17: Phylum Chordata: A Deuterostome Group
D. What is the tunic? What is it made of?
E. Obtain a preserved adult tunicate and observe it under a dissecting microscope.
Diagram and label this specimen using the terms: excurrent & incurrent siphon, pharynx, stomach, adhesive pad
F. What type of circulatory system do tunicates have? Describe the system.
G. The free swimming larvae of tunicates are called __________________.
A. What two new structures are seen in lancelets that tunicates did not have?
B. Where are lancelets found?
C. Which structures in the lancelet exhibit segmentation?
D. Obtain a preserved lancelet and observe it under a dissecting microscope.
Diagram and label this specimen using the terms: rostrum, oral hood, oral cirri, gill slits, nerve cord, notochord, and the three fins (caudal, ventral & dorsal).
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Exercise 17: Phylum Chordata: A Deuterostome Group
E. Does it have a distinct anterior side?
F. Where photoreceptors located in a lancelet?
G. What aspects of the circulatory system of lancelets have been modified in
"higher" chordate groups?
H. Describe two locations where gas exchange occurs in the lancelet?
I. In lancelets, water that has filtered across the gill bars and has picked up metabolic waste products from the nephridia exits the body through the
______________, while undigestible food is released from the body through the
_________________.
J. Diagram a cross-section
of a lancelet (Amphioxus) and label it below.
K. Diagram a longitudinal-section
of a lancelet (Amphioxus) and label it below.
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Exercise 17: Phylum Chordata: A Deuterostome Group
View the Shape of Life video describing the evolution of chordates, taking notes as you watch. Answer the following questions.
Notes:
A. What is the ancient basic body design that was passed along in the evolution of
chordates?
B. What secrets do amphioxus hold to our own evolution? Describe the traits that
C. What allowed vertebrates to get larger and more complex?
D. Name two evolutionary adaptations that appeared with the advent of fish and
other
Using the internet, answer the following questions:
A. Although rarely eaten by humans, tunicates are an important link in the food chain and thus indirectly provide humans with a source of food. Give an example of how they serve this function.
B. Tunicates contain some unusual chemicals, and some of these may prove to be useful as drugs. Give an example of a chemical and its use.
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