Chapter 15

Question 1

The primary function of the notochord is

Answer 1

support

Question 2

Cladistics shows that the chordates contain paraphyletic groupings such as

Answer 2

reptiles and birds.

Question 3

In terrestrial vertebrates, which of the following structures did not arise from the pharyngeal pouches?

Answer 3

intervertebral discs

Question 4

Pharyngeal gill slits first evolved for

Answer 4

filter feeding.

Question 5

One chordate characteristic found in adult ascidians is the

Answer 5

pharyngeal slits.

Question 6

An unusual chordate morphological feature of ascidians is that

Answer 6

their blood travels in both directions.

Question 7

Cephalochordates are similar to higher fish in that they possess a

Answer 7

closed circulatory system.

Question 8

The primary support system in vertebrates is the

Answer 8

living endoskeleton.

Question 9

The earliest ostracoderms could be characterized in this way:

Answer 9

placoderms without jaws.

Question 10

Of the early fish, which led to the extant fish of today?

Answer 10

acanthodians

Question 11

Garstang introduced the theory of ________, which stated that the juvenile characteristics of the ascidian led to the vertebrates.

Answer 11

paedomorphosis

Question 12

The origin of the jaw in the gnathostomes is the

Answer 12

gill arch.

Question 13

It is relatively safe to say that your closest evolutionary relative is a(n)

Answer 13

echinoderm

Question 14

Zoologists consider ____ the closest living relative of vertebrates.

Answer 14

cephalochordates