Deck 23: Chordates

Question 1

Cephalochordates

A)are small fish-like,freshwater animals.
B)have a notochord only in their immature stage.
C)digest food in a hepatic cecum or liver diverticulum.
D)have a ventral nerve cord.
E)have a heart that circulates blood cells with hemoglobin in a closed system.

Answer 1

C

Question 2

Reproduction in sea squirts is

A)asexual,with new individuals budding off the adults.
B)hermaphroditic with internal fertilization.
C)hermaphroditic with external fertilization.
D)with separate sexes and internal fertilization.
E)with separate sexes and external fertilization.

Answer 2

C

Question 3

The urochordates are

A)called tunicates.
B)marine animals.
C)sessile as adults,but tadpole-like as larvae.
D)often abundant in intertidal organisms.
E)All of the choices are correct.

Answer 3

E

Question 4

Chordates typically have

A)a notochord.
B)radial cleavage.
C)the anus derived from the blastopore.
D)a coelom that is either enterocoelous or schizocoelous.
E)all of the choices are typical chordate features.

Question 5

The central definition of a monophyletic group focuses on:

A)Do we have evidence of transitional fossils in the geological record?
B)Do we have the majority of species described in each higher taxon?
C)Are all of the species described actually real species?
D)Do all higher taxa contain all known descendants of their single common ancestor?
E)Do all of the taxa fit into the seven ranks of the Linnaean taxonomic hierarchy?

Question 6

Adult ascidian tunicates have

A)a notochord.
B)pharyngeal slits.
C)a dorsal heart.
D)a nerve cord and the beginning of an advanced brain.
E)all of the choices are adult ascidian features.

Question 7

The difference(s)between the traditional and cladistic classification of chordates and their extant sister groups is a difference in

A)the addition of new and comparative rRNA and DNA molecular sequence data.
B)fossil evidence that clearly shows that the traditional classification is simply wrong.
C)the insistence in traditional systematics that all taxa be paraphyletic.
D)the insistence in cladistics that all taxa be monophyletic.
E)all of the choices are points of argument.

Question 8

Although several invertebrate groups have been proposed as chordate ancestors,most zoologists now believe the embryological evidence indicates the chordates have probably descended from ancestors nearest the ___________ lineage.

A)Arthropoda
B)Cnidaria
C)Annelida-Mollusca
D)Lophophorate
E)Echinodermata

Question 9

The extant group likely to be the most closely related to the basal chordates are the echinoderms because

A)there is direct fossil evidence for a lineage from sea stars to tunicates.
B)tunicates are advanced echinoderms.
C)early embryonic development of echinoderms is similar to that of chordates.
D)although there are few similarities between echinoderms and chordates,there are even fewer between chordates and any other group.
E)new molecular evidence shows they are nearly identical at the rRNA level.

Question 10

Modification of the pharyngeal slits for first use in respiration occurred in early

A)fish with the development of gills.
B)amphibians with the development of external gills.
C)reptiles with the development of the modern lung.
D)lophophorates well before we reach the chordates.
E)echinoderms as a new respiratory apparatus.

Question 11

All chordates have

A)a single,dorsal,tubular,nerve cord.
B)a ventral heart.
C)pharyngeal slits.
D)a postanal tail as some stage.
E)all of the choices are chordate features.

Question 12

One example of why a cladist is not satisfied with the traditional classification scheme is because it

A)includes too many levels of classification.
B)includes humans among the mammals.
C)includes birds with the reptiles.
D)does not include birds with the reptiles.

Question 13

Appendicularians

A)are sexually mature individuals that have retained the larval body form.
B)are pelagic.
C)build a delicate,transparent,and hollow sphere of mucus to trap food.
D)replace feeding houses every 3-4 hours.
E)All of the choices are correct.

Question 14

Organisms that retain the larval form of their evolutionary ancestors when they are sexually mature are called

A)Larviparous.
B)Paedomorphic.
C)Nymphogenic.
D)Precocial.

Question 15

A dorsal tubular nerve cord is

A)another name for the notochord.
B)a strip of cartilage that forms a back and tail.
C)primitive tissue that forms bone vertebrae.
D)an early nerve cord that enlarges at one end to form the brain and also extends through vertebrae.
E)None of the choices is correct.

Question 16

The name Urochordata means literally

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

Question 17

The phylum Urochordata includes the classes

A)Ascidiacea,Cephalaspidomorphi,and Myxini.
B)Appendicularia,Cephalochordacea,and Myxini.
C)Ascidiacea,Myxini,and Thaliacea.
D)Thaliacea,Cephalaspidomorphi,and Calcichordata.
E)Ascidiacea,Appendicularia,and Thaliacea.

Question 18

The perforated pharynx of chordates first evolved as a device for

A)support.
B)respiration.
C)suspension or filter feeding.
D)detecting odors.
E)All of the choices are correct.

Question 19

A notochord is most correctly defined as

A)a primitive spine.
B)the tissue that becomes the dorsal nerve.
C)a flexible stiffening rod extending the length of the body.
D)embryonic tissue that develops into bone and cartilage.
E)any tissue that functions in the role of a dorsal tubular nerve cord.

Question 20

Salps in the class Thalacea

A)are barrel-shaped open-ocean organisms.
B)have larger transparent bodies.
C)may be luminous at night.
D)may occur singly or in long chains.
E)All of the choices are correct.

Question 21

The urochordates are enclosed in a nonliving cellulose-containing structure called a _________ or test.

Question 22

Of the five chordate hallmarks,adult tunicates have only two,the _______ _______ and the endostyle.

Question 23

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

Question 24

The lancelets or Branchiostoma are found

A)very rarely and are about extinct.
B)as parasites inside the tracts of fish.
C)commonly in the sandy bottoms of coastal waters around the world.
D)in tropical freshwater streams.
E)near deep ocean thermal vents.

Question 25

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

Question 26

The ostracoderms

A)are the adult form of the ammocoete.
B)were the first vertebrate to have jaws.
C)are an extinct group of heavily armored,jawless fish.
D)were the first fish with paired fins that led to paired appendages.
E)were the first jawed animals.

Question 27

Development of the vertebrate head and sense organs was largely the result of two innovations:

A)Appearance of an outer epidermis and an inner dermis
B)Neural crest and ectodermal placodes
C)Living endoskeleton and highly differentiated brain
D)10 to 12 pairs of cranial nerves and an autonomic nervous system
E)Pharynx and endocrine system

Question 28

While several invertebrate groups (phyla)have in the past been proposed as chordate ancestors,embryological evidence indicates the chordates are most probably a sister group to the _____________.

Question 29

Lancelets belong to the subphylum __________.

Question 30

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

Question 31

The lancelet reproduces

A)by asexual processes alone.
B)by budding.
C)sexually with both sex organs on the same organism,similar to earthworms.
D)sexually but with separate sexes and internal fertilization.
E)sexually but with separate sexes and external fertilization.

Question 32

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

Question 33

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

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

Question 34

The ammocoete larvae is important in zoology since it

A)is the "missing link" between chordates and vertebrates.
B)represents the features of the most advanced chordate that is not a vertebrate.
C)represents the features of the first vertebrates that are not obscured by advanced vertebrate development.
D)is identical to the earliest Burgess shale fossil vertebrate.
E)possesses all features found in derived vertebrates,and evolution from this point forward was a matter of losing different features.

Question 35

Walter Garstang's hypothesis of vertebrate evolution could be described as the

A)annelid-vertebrate hypothesis.
B)echinoderm-vertebrate hypothesis.
C)amphioxus-vertebrate hypothesis.
D)ascidian larva-vertebrate hypothesis.
E)ammocoete larva-vertebrate hypothesis.

Question 36

What feature(s)can be found in the ammocoete that are lacking in amphioxus,that are found in vertebrates?

A)A true liver with a gallbladder
B)A two-chambered heart
C)A three-part brain
D)Eyes,nostrils,and auditory vesicles
E)All of the choices are ammocoete features lacking in the amphioxus lancelet

Question 37

Pelagic tunicates with barrel-shaped bodies and complex life histories belong to the class _________.

Question 38

Tunicates belong to the subphylum ______________ (Tunicata).

Question 39

The larva of the freshwater lamprey,that closely resembles the amphioxus lancelet,is the

A)Ammocoete.
B)Branchiostoma.
C)Cephalaspidomorph.
D)Heterostracan.
E)Ostracoderm.

Question 40

In the chordates,the __________ forms in the vicinity of the embryological blastopore.

Question 41

The oldest jawed fishes are extinct and are called ____________.

Question 42

The development of a new vertebrate head was largely the result of two embryonic innovations: the neural crest and _________ ___________.

Question 43

Outline the five chordate features.What is the fate of the endostyle in the higher vertebrates?

Question 44

Larval and adult tunicates look virtually nothing alike.How can you explain this dramatic metamorphosis in evolutionary terms?

Question 45

The closest model for the vertebrate ancestral stock is something similar to the _______ _______.

Question 46

One overriding advantage of the endoskeleton of vertebrates,as compared to the invertebrate exoskeleton is that it permits __________ without the necessity of molting.

Question 47

The earliest known vertebrate fossil,from the Burgess Shale of British Columbia,is an amphioxus-like creature called _______.

Question 48

Outline the process that may explain how vertebrates evolved jaws.Be sure to discuss Meckel's cartilage and the significance of that structure.

Question 49

Explain why fossil specimens of Haikouella lanceolata offer many clues to understanding the evolution of vertebrates from cephalochordates.

Question 50

Usually we think of evolution acting on organisms with different structures.How could evolution select the developmental pattern seen in paedomorphosis?

Question 51

The early vertebrate fossils belong to an extinct group of jawless fishes known as ____________.

Question 52

Are the jawless ostracoderms a real taxon (that is,are they a monophyletic group)?

Question 53

Describe the core difference between the traditional and cladistic classification systems as they relate to chordates.

Question 54

Why are traditional grouping such as Reptilia and Agnatha not recognized in cladistics? Explain why that does or does not make evolutionary sense.

Question 55

Discuss the contention that the ammocoete larva of lampreys is a successful model of the primitive vertebrate body plan.

Question 56

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

Question 57

The characteristics of the chordates and the characteristics of the vertebrates are not the same.List the features that distinguish these two groups.