chapter 40 section 2

Question 1

notochord

Answer 1

A notochord is a stiff, flexible rod of cells that runs
the length of the body near the dorsal surface of a
chordate

Question 2

atriopore

Answer 2

An atriopore is an opening through which water

leaves the body of a lancelet

Question 3

In most chordates, the function of the notochord is taken over by the

Answer 3

vertebral column

Question 4

The gill chambers of aquatic chordates evolved from the

Answer 4

pharyngeal pouches

Question 5

A lancelet feeds by

Answer 5

d. filtering food particles from the water that passes through its pharynx

Question 6

. Unlike adult lancelets, adult tunicates

Answer 6

are usually sessile

Question 7

List the chordate characteristics that lancelets have as adults

Answer 7

a notochord, a dorsal nerve cord, pharyngeal

pouches, and a postanal tail

Question 8

How do lancelets use their tail?

Answer 8

Lancelets use their tail to swim weakly and to

wriggle backward into the sand.

Question 9

What behavior do tunicates exhibit when touched?

Answer 9

They squirt out a stream of water when touched

Question 10

How does the structure of a larval tunicate differ from that of an adult tunicate?

Answer 10

A larval tunicate has all four chordate characteristics,
but an adult tunicate has only one: a pouchlike
pharynx with slits

Question 11

How are most adult tunicates similar to sponges, and how are they different
from sponges?

Answer 11

Like sponges, most adult tunicates are sessile animals
that feed by filtering food from the water;
they are also hermaphrodites, as are most
sponges. Unlike sponges, tunicates have true tissues
and organs; water enters an adult tunicate
through a single opening, while it enters a sponge
through numerous pores