Deck 15: Vertebrate Beginnings: the Chordates

Question 1

The development of a _____________ life style by the early vertebrates is believed to have been key in the success of this group.

A)symbiotic
B)predatory
C)herbivorous
D)scavenging

Answer 1

B

Question 2

Vertebrate animals have

A)an endoskeleton.
B)a notochord at some stage of the life cycle.
C)a ventral heart.
D)all of these

Answer 2

D

Question 3

The perforated pharynx of chordates had an ancestral function for

A)support.
B)respiration.
C)filter-feeding.
D)all of the above

Answer 3

C

Question 4

The nerve cord of chordates is solid and dorsal to the alimentary canal.

Question 5

Urochordates have an unusual feature of their circulatory system: their heart pumps blood in both directions.

Question 6

Garstang's hypothesis of vertebrate evolution is the

A)annelid-vertebrate hypothesis.
B)echinoderm-vertebrate hypothesis.
C)amphioxus-vertebrate hypothesis.
D)tunicate larva-vertebrate hypothesis.

Question 7

All chordates have

A)a single,dorsal,tubular,nerve cord.
B)a dorsal heart.
C)pharyngeal gill slits used for respiration.
D)all of these

Question 8

Vertebrates differ from other chordates because they have a brain case.

Question 9

Amphioxus is certainly not the ancestor of modern vertebrates,but researchers believe it more closely resembles the earliest prevertebrate than any other living animal.

Question 10

Cephalochordates have an open circulatory system,and also have a simple heart.
Multiple Choice Questions

Question 11

The urochordates are

A)called tunicates.
B)marine animals.
C)sessile as adults,but tadpole-like as larvae.
D)all of these

Question 12

Pikia,the earliest known chordate collected from the Burgess Shale of British Columbia,closely resembles

A)amphioxus.
B)living sessile tunicates.
C)the ammocoete larva.
D)an adult larvacean.

Question 13

The phylum Urochordata includes the

A)Ascidiacea and Cephalaspidomorphi.
B)Larvacea and Cephalochordata.
C)Ascidiacea and Thaliacea.
D)Thaliacea and Calcichordata.

Question 14

In vertebrates,pharyngeal gill slits are formed by inpocketing of ectoderm and outpocketing of the endoderm.

Question 15

Tunicates are sessile organisms with no larval stages in their life cycle.

Question 16

The name Urochordata means literally

A)"tail chordates."
B)"head chordates."
C)"kidney chordates."
D)"tunic chordates."

Question 17

The ostracoderms are found only in freshwater lakes in the tropics.

Question 18

A notochord is present at some time in the life cycle of all chordates.

Question 19

Chordates probably evolved from the echinoderm-hemichordate assemblage.

Question 20

During the evolution of the vertebrates,gills changed from respiratory organs to filter-feeding structures.

Question 21

The reptiles,as well as the agnathans,are considered to be ____________ taxa because these groups do not contain all the descendents of the most recent common ancestor.

Question 22

The skeletal rod found in all chordates is called a ___________.

Question 23

The jawless vertebrates are called Agnatha,and the jawed vertebrates are called ____________.

Question 24

The bony fishes currently are divided into two groups: the _______________ and the ____________________.

Question 25

In primitive vertebrates,the notochord functions in

A)sensory reception.
B)coelom formation.
C)muscle attachment.
D)respiration.

Question 26

"Sea squirts," the most common kind of tunicate,belong to the class __________.

Question 27

In both tunicates and cephalochordates,the ventral side of the pharynx contains a ciliated,mucus-secreting groove,the ____________.

Question 28

Unlike most invertebrate phyla,the nerve cord of chordates is single,tubular,and located ______ to the alimentary canal.

Question 29

The __________ were jawed fishes which lived at the same time as the placoderms that may have been the ancestors of today's bony fish.

Question 30

Our knowledge of the fossil invertebrate chordates is quite limited because

A)they were very rare.
B)they were soft-bodied.
C)fossils from that period were obliterated by volcanism.
D)they were only freshwater.
Fill in the Blank Questions

Question 31

The most likely candidate for the vertebrate ancestral stock is something similar to the ____________.

Question 32

Of the four chordate hallmarks,adult tunicates have only one,the ____________.

Question 33

Lancelets belong to the subphylum _________.

Question 34

Fossils known as ____________ are very useful in dating Paleozoic sediments,and are now known to be from small marine vertebrates.

Question 35

The post anal tail is seen in humans only as a vestige;the

A)coccyx.
B)sacrum.
C)appendix.
D)caudal vertebrae.