Phylum Hemichordata and Invertebrate Chordates Notes Organizer – Chapter 17
1. Evolutionary Perspective
a. Describe the evidence for the statement “Echinoderms, Hemichordates, and Chordates are derived from
a common (yet undiscovered) ancestor.”
b. What characterizes a chordate?
c. Which characteristics are shared by both chordates and hemichordates?
d. Describe the conclusions zoologists have drawn from these shared characteristics.
e. The ____________________ body forms and lifestyles present in these phyla support the generalization
that chordates and hemichordates probably diverged from widely separated points along the
deuterostome lineage.
2. Phylogenetic Relationships
a. Draw the phylogenetic tree shown in Figure 17.2 which illustrates the evolutionary relationships
between echinoderms, hemichordates and chordates.
Figure 17.2 on pg. 279
3. Hemichordate Characteristics
a. Hemichordata means “ ___________________
______________________ . “
b. Includes the:
-
Which live in or on marine _______________________________ .
c. What are the five identifying characteristics of the Phylum Hemichordata?
4. Phylum Hemichordata Classification
a. Construct a simple chart which shows the classes, characteristics, and members of Phylum
Hemichordata. You may find a summary of this information in Table 17.1 on pg. 280.
Class Name:
Characteristics:
Members:
Class Name:
Characteristics:
Members:
Class Name:
Characteristics:
Members:
5. Class Enteropneusta
a. Basic description, number of species and size:
b. Where can you find members of this class?
c. Why are members of this class known as “Acorn Worms?”
d. Draw and label the major parts of an Acorn Worm as seen in Figure 17.3.
Figure 17.3
e. Describe the pathway food takes in acorn worms.
6. Class Pterobranchia
a. Means “ _______________________ ___________________________ “
b. Basic description, number of species and size:
c. Where can you find members of this class?
d. Draw and label the external structures of the Pterobranch as seen in Figure 17.5.
Figure 17.5
e. Describe the pathway food takes in pterobranchs.
7. Phylum Chordata Characteristics
a. List the five characteristics of the Phylum Chordata:
b. Phylum chordata is named after the notochord present in its members. Describe the notochord:
c. Identify the structure and function of pharyngeal slits:
d. What is considered largely responsible for the success of chordates? Why?
e. Define postanal tail:
8. Subphylum Urochordata
a. Members of Subphylum Urochordata:
b. Describe the structure and lifestyle of sessile chordates:
c. What is the “tunic” of tunicates? What is it made up of?
d. Describe the pathway water and food take as they move through urochordates.
e. Draw and label the pathway of water through Tunicates as seen in Figure 17.9(a).
Figure 17.9 (a)
9. Subphylum Cephalochordata
a. Members are called ____________________________________.
b. Basic description, number of species and size:
c. Where will you find members of Cephalochordata?
d. Cephalochordata means “Head Cord.” Why is this name appropriate?
e. Contrast the notochord of lancelets with other chordates.
f.
Draw and label the major structures found in lancelets as seen in Figure 17.10.
Figure 17.10
10. Deuterostome Phylogeny
a. Illustrate the Interpretation of Deuterostome Phylogeny as seen in Figure 17.11 on pg. 286 which
demonstrates the evolutionary relationships between hemichordates and the members of the three
chordate subphyla.
Figure 17.11
11. Hemichordate and Invertebrate Chordate Comparison
a. Use Table 17.1 on page 280, along with Figure 17.11, to fill in the following Venn Diagram which
compares the three major groups.
Phylum Hemichordata
Subhylum Urochordata
Subhylum Cephalochordata