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270
In deuterostomes, the blastopore develops into an anus.
Cleavage is radial, and an enterocoelom develops.
The echinoderms have evolved radial symmetry,
an internal skeleton, gills, a nerve ring, and a water vas-
cular system. The sea star is a major echinoderm show-
ing these specializations.
Chordates have evolved a notochord, a dorsal hol-
low nerve cord, and pharyngeal pouches at some point in
their life history. Only lancelets show all of these char-
acteristics as adults. The vertebrates develop a verte-
bral column in place of a notochord.
Vertebrates are divided into superclasses: the ag-nathans (jawless fishes) and the gnathostomes (jawed
vertebrates). There are six classes of jawed vertebrates:
cartilaginous fishes (e.g. shark); bony fishes (e.g. trout,
cod, tuna); amphibians (e.g. frogs and salamanders); rep-
tiles (e.g. snakes, lizards, turtles); aves (birds); mam-
mals (e.g. dogs, cats, humans).
The evolution of vertebrates is still being studied.
The hagfishes and lampreys are descendants of the orig-
inal jawless fishes. Sharks are modern representatives
of the cartilaginous fishes. The original bony fishes di-
verged into two groups: the ray-finned fishes and the
lobe-finned fishes.
Amphibians, which evolved from lobe-finned fishesduring the Devonian period, reached their greatest size and
diversity in the swamp forests of the Carboniferous pe-
riod. Most amphibians return to the water to reproduce.
Reptiles, which are believed to have evolved from
the amphibians, have a shelled amniote egg. A shelled egg
along with extraembryonic membranes makes repro-
duction on land possible. Stem reptiles gave rise to di-
nosaurs and birds. The mammals trace their ancestry to
another reptilian line of descent.
While amphibians and reptiles are ectothermictheir
body temperature is the same as that of the environment
both birds and mammals are homeothermicthey meta-
bolically produce a constant body temperature. Adaptations
of birds include feathers and hollow bones, both adap-
tations for flight. Mammals have evolved hair and mam-
mary glands. Monotremes are egg-laying mammals, and
marsupials are pouched mammals which give birth to very
immature young. While the young of placental mammals
are more developed at birth, they still require parentalcare to survive.
Among mammals, primatesprosimians, mon-
keys, apes, and humansare adapted for living in trees.
Monkeys leap but apes swing from limb to limb. This
may have been an adaptation that led to bipedalism in
hominids. The first hominid (humans and immediate an-
cestors) wasA. afarensis, which could walk erect but had
only a small brain. Later-appearing australopithecines
may have manufactured stone tools, but H. habi lis cer-
tainly did.H. erectus was the first fossil to have a brain
size of more than 1,000 cc. H. erectus migrated from
Africa into Europe and Asia. They used fire and may
have been big-game hunters.Most likely,H. sapiens evolved in Africa but then
migrated to Europe and Asia, where this species sup-
planted the archaic humans living there. One of these
species was H. sapiens neanderthalens is . The Nean-
derthals did not have the physical traits of modern humans,
but they did have culture.
31ANIMALS: PART II
CH A P T E R RE V I E W
STUDY EX E R C I S E S
Study the text section by section as you answer the questions that follow.
31.1 ECHINODERMS (P. 644) Echinoderms (e.g., starfish) and chordates (e.g., vertebrates) are both deuterostomes.
In deuterostomes, the second embryonic opening becomes the mouth, and the coelom develops by
outpocketing from the primitive gut.
Echinoderms have radial symmetry and a unique water vascular system for locomotion.
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1. Complete the following table to describe the characteristics of echinoderms:
Characteristic Description
type of symmetry
skeletal system
respiration
nervous system
water vascular system
2. Label this diagram of a sea star with the following terms (some are used more than once):
ampulla
anus
arm
cardiac stomach
central disk
coelomic cavity
digestive gland
endoskeletal plateseyespot
gonads
pyloric stomach
radial canal
sieve plate
skin gill
spine
tube feet
3. Trace the path of water in the water vascular system: sieve plate to a.____________________canal
tob.
____________________canal to radial canal toc.
____________________feet . Each of these feet hasa(n) d.__________________. The function of the water vascular system is e.__________________.
4. A sea star has a two-part stomach. Describe how the sea star feeds on a clam, mentioning both parts of the
stomach.
31.2 CHORDATES (P. 646)
All chordates have a notochord, a dorsal hollow nerve cord, and pharyngeal pouches sometime during their
life history; in vertebrates, the notochord is replaced by the vertebral column.
27
e.
f.
g.h.
d.
c.
b.
a.
r.
q. p.
o.
n.
m.
l.
k.
j.
i.
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5. Label this diagram with the three primary chordate characteristics, plus another that also distinguishes
chordates.
272
c.
d.
a.
b.
6. Which two chordate characteristics do hemichordates have? a._____________________________
and b._____________________________
What evidence suggests that hemichordates and echinoderms are related? c.
8. Complete the following table to describe the invertebrate chordates:
Name Chordate Characteristics Appearance
tunicates
(subphylum Urochordata)
lancelets
(subphylum Cephalochordata)
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273
8. Complete this evolutionary tree of the chordates by filling in the name of the subphylum/class in the
arrowheads. Place these terms in the ovals: limbs, mammary glands and hair, jaws, lungs, amnion, feathers,
vertebrae
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274
31.3 VERTEBRATES (P. 649)
There are three groups of fishes. One group is jawless, but the other two groupsthe cartilaginous and bony
fishes (ray-finned and lobe-finned)have jaws.
Amphibians (e.g., frogs and salamanders) evolved from lobe-finned fishes and have limbs, an adaptation for
locomotion on land.
The shelled egg of reptiles, which contains extraembryonic membranes, is an adaptation for reproduction on
land.
Both birds, which can fly, and mammals, which have hair and mammary glands, evolved from reptiles and are
able to maintain a constant body temperature.
9. Place a check in front of the characteristics that distinguish the vertebrates.
a. bilaterial symmetry in all
b. radial symmetry in some
c. tube-within-a-tube plus coelom
d. segmented
e. vertebral column replaces embryonic notochord
f. open/closed circulatory system
g. cephalization with compound eyes
h. living endoskeleton
Fishes (p. 950)
10. Associate each statement below with the three living classes of fishes:jawless fi shes (JF),cartilaginous fishes (CF), and bone fishes (BF)
a. have jaws (choose two)
b. are parasitic
c. sharks, rays, and skates
d. hagfishes and lampreys
e. ray-finned and lobe-finned
11. In bony fishes, what is the purpose of
a. lateral line sys tem _______________________________________________________________________________
b. swim bladder ___________________________________________________________________________________
c. gills ___________________________________________________________________________________________
d. single circulatory loop ___________________________________________________________________________
e. pai red fins _____________________________________________________________________________________
Amphibians (p. 651)
12. Describe each of these features of amphibians.
skin a.__________________________________________
lungs b.__________________________________________
body temperature c.__________________________________________
life cycle d.__________________________________________
heart e.__________________________________________
13. Describe each of these features of reptiles.
skin a.
lungs b.
body temperature c.
type of egg d.
heart e.
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275
14. How do the following characteristics of birds contribute to their ability to fly?
feathers a.
horny beak b.
keel c.
four-chambered heart d.
one-way flow of air in lungs e.
15. Match the types of mammals to the following descriptions (some descriptions are used more than once):
1 All have hair and mammary glands.2 All lay eggs.
3 All have pouches.
4 All have internal development to term.
a. monotremes
b. marsupials
c. placental mammals
16. Name a type of mammal adapted to each of the following:
flying in air a.
running on land b.
swimming in the ocean c.
preying on other animals d.
living in trees e.
31.4 HUMAN EVOLUTION (P. 659)
Primates (e.g., prosimians, monkeys, apes, and humans) are mammals adapted to living in trees.
Human evolution diverged from ape evolution in Africa about four million years ago. The australopithecines
were the first hominids.
Homo habil is could make tools,Homo erectus migrated out of Africa and was a big game hunter.
Cro-Magnon is the name given to modern humans who made sophisticated tools and definitely had a culture.
17. List an adaptation for arboreal life in relation to the following:
vision a.
digitsb.
brain size c. _______________________________________________________________________________________
birth number d. ____________________________________________________________________________________
Hominids (p. 660)
18. Australopithecines were the first a.______________. The oldest one, dated about 4.4 MYA in the fossi l record
and known as b.______________, represents a transitional stage between c.______________ and
d.______________. Australopithecines walked e.______________, but their brain was f.______________. They
exhibit mosaic evolution, meaning that their g.
The next australopithecine in the fossil record is h.______________, who was a common ancestor for the rest of
the australopithecines and i.______________.A. afarens is andA. africanus are termed gracile because they are
slight in appearance. j.______________ and k.______________ are termed l.______________ because they had
larger facial bones, most likely due to larger teeth and chewing muscles.
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276
OFFICE BUILDING ONE
A fourteen story office building is possible.
Key Onea. Protozoa
b. Porifera
c. Cnidaria
d. Platyhelminthes
e. Nematoda
f. Annelida
g. Mollusca
h. Arthropoda
i. Echinodermata
1. sea star (starfish)
2. clitellum
3. flame cells
4. eggnymphadult
5. organ system level of organization6. ampulla
7. fluke
8. jellyfish
9. leech
10. octopus
11. jointed appendages
19. Match theHomo species with the following phrases that describe their way of life (numbers can be used more
than once):
1 brain size less than 1,000 cc
2 brain size 1,000 cc or larger
3 more likely scavenged meat
4 more likely hunted animals
5 certainly had speech and culture
6 most likely had speech and culture
7 perhaps had speech and culture
8 made tools9 had upright posture
Homo habil is a.______________
Homo erectus b.______________
Neanderthals c.______________
Cro-Magnons d.______________
20. Which hypothesisthe out-of-Africa hypothesis or the multiregional continuity hypothesisstates thatH.
erectus and then, later on, humans left Africa? a.______________ Which hypothesis states thatH. erectus left
Africa and that then modern humans simultaneously arose in Europe, Asia, and Africa? b.______________ With
which hypothesis would you expect more similarity between fossils dated between 300,000 BP and 100,000
BP? c.______________ The fossil record shows several varieties of humans in Asia and Europe dated prior to
100,000 BP. These are called d. ______________H. sapiens . One example of an archaicH. sapiens is
e.______________.
Constructing Office Buildings
The object of this game is to construct an office building by matching the numbered terms with the organisms in the
key (some numbers should be matched to more than one letter). Five correct answers in a row gives you one story.
Any wrong answer is a natural disaster that forces you to start from the ground again.
12. tube feet
13. elephantiasis
14. soft body
15. five hearts16. bilateral symmetry
17. muscles
18. water vascular system
19. medusa
20. cellular level of organization
21. muscular foot
22. five arms
23. earthworm
24. nerve net
25. clam
26. setae
27. Trichinella
28. ladder-type nervous organization
29. horseshoe crab30. stone canal
31. pseudocoelom
32. coelom
33. mesoglea
34. pore bearers
35. polychaete
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277
36. squid
37. segmentation
38. closed circulatory system
39. open circulatory system
40. mesoderm
41. collar cells
42. trachea
43. trochophore larva
44. hydra
45. Hirudo46. Malpighian tubules
47. mantle
48. Dirofi lariafilarial worm
49. nematocysts
50. metamorphosis
51. gills
52. typhlosole
53. Ascaris
54. sieve plate (madreporite)
55. hermaphroditic
56. acoelomate
57. pseudocoelomate
58. pyloric stomach
59. worms60. molting
61. nephridia
62. visceral mass
63. cephalization
64. spicules
65. green gland
66. exoskeleton
67. wings
68. sessile
69. sac body plan
70. tube-within-a-tube
How many s tories is your building? _______
OFFICE BUILDING TWO
An eight-story office building is possible.
Key Two
a. sponge
b. hydra
c. planarian
d. Ascaris
e. clam
f. earthworm
g. lobster
h. sea star
i. grasshopper
j. Obelia
1. diploblastic
2. coelomate
3. segmented
4. nematocyst
5. sac body plan
6. tube-within-a-tube body plan
7. bilateral symmetry
8. radial symmetry
9. organs
10. closed circulatory system
11. insect
12. belong to the same phylum
13. flame cells
14. Malpighian tubules
15. green gland16. nephridia
17. tracheal tubes
18. gills
19. body wall for respiration
20. skin gills
21. spicules
22. shell
23. carapace
24. spiny skin
25. planula larva
26. metamorphosis
27. nymph
28. molt
29. ovipositor30. asexual reproduction
31. alternation of generations
32. clitellum
33. bilateral larva but radial adult
34. nerve ring
35. ganglia in foot and visceral mass
36. dorsal hollow nerve cord
37. ventral solid nerve cord
38. no nervous system
39. nerve net
40. ladder-type nervous organization
How many s tories is your building? _______
OFFICE BUILDING THREE
A ten-story office building is possible.
Key Three
a. jawless fishes
b. cartilaginous fishes
c. bony fishes
d. amphibians
e. reptiles
f. birds
g. mammals
1. four-chambered heart
2. frogs and salamanders
3. air sacs
4. lampreys and hagfish
5. infant dependency
6. Chondrichthyes
7. hair
8. smooth, nonscaly skin
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CH A P T E R TE S T
9. ectothermic
10. two-chambered heart
11. differentiated teeth
12. some are parasitic
13. highly developed brain
14. feathers
15. fish, but no operculum
16. evolved from amphibians
17. homeothermic
18. snakes, lizards19. primates
20. epidermal placoid (toothlike) scales
21. shelled egg
22. whales and dolphins
23. class Aves
24. lateral line system
25. mammary glands
26. some are filter feeders
27. metamorphosis
28. sharks, rays, and skates
29. marsupials
30. Osteichthyes
31. ray-finned fishes
32. monotremes
33. scales of bone
34. dinosaurs
35. operculum
36. evolved from reptiles
37. lobe-finned fishes
38. double circulatory loop
39. paired pelvic and pectoral fins
40. one-way path through lungs41. three-chambered heart
42. lungs
43. expandable rib cage
44. gills as an adult
45. wings
46. single circulatory loop
47. molt
48. usually four limbs
49. amniote egg
50. cartilaginous skeleton
How many s tories is your building? _______
278
OBJECTIVE QUESTIONS
Do not refer to the text when taking this test.
1. Each is a vertebrate characteristic EXCEPT
a. bilateral symmetry.
b. coelom development.
c. open circulatory system.
d. segmentation.
2. The earliest vertebrate fossils came from the
a. amphibians.b. bony fishes.
c. cartilaginous fishes.
d. jawless fishes.
3. Modern humans are more closely related to
a. monkeys than apes.
b. African apes than Asian apes.
c. Neanderthals than Cro-Magnon.
d. whales than prosimians.
4. The skin of amphibians functions mainly for
a. circulation.
b. excretion.
c. reproduction.
d. respiration.
5. The extraembryonic membrane in the reptile egg
promotes
a. additional reinforcement from drying out.
b. complete independence from the water for re-
production.
c. enhanced elimination of wastes from the
embryo.
d. increased hardness to prevent breakage.6. Bird feathers are modified
a. fish fins.
b. mammalian hair.
c. reptilian scales.
d. vertebrate teeth.
7. The hair of mammals is an adaptation for
a. camouflage in all species.
b. control of body temperature.
c. faster locomotion.
d. regulation of waste elimination.
8. The most successful mammals are the
a. marsupials.
b. monotremes.
c. lancelets.d. placentals.
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9. Which is true of echinoderms?
a. contain a dorsal hollow nerve cord
b. have internal organs in a visceral mass
c. move by a water vascular system
d. All of these are true.
10. Which is found only among echinoderms?
a. deuterostome developmental pattern
b. radial symmetry
c. exoskeleton
d. tube feete. ventral mouth
11. Which feature is NOT found among fishes?
a. endoskeleton
b. closed circulatory system
c. warm blood
d. dorsal hollow nerve cord
12. The most important reason amphibians are in-
completely adapted to life on land is that
a. they depend on water for external
fertilization.
b. they must reproduce in water.
c. the skin is more important than the lungs for
gas exchange.
d. their means of locomotion is poorlydeveloped.
13. A four-chambered heart is seen among
a. fishes.
b. amphibians.
c. birds.
d. mammals.
e. Both c and dare correct.
14. Which pair of statements correctly contrasts birds
and mammals?
a. Birds are cold-blooded. Mammals are warm-
blooded.
b. Birds are egg-laying. No mammals are egg-
laying.c. Birds have air sacs in addition to lungs. Mam-
mals have no such sacs.
d. Birds lack a septum between the ventricles.
Mammals have such a septum.
15. What do echinoderms and chordates have in
common?
a. radial symmetry
b. pharyngeal pouches
c. second embryonic opening is the mouth
d. All of these are correct.
16. Extraembryonic membranes
a. are found during the development of all
vertebrates.
b. are found during the development of reptiles,
birds, and mammals.
c. have exactly the same function in all vertebrates.
d. Both a and c are correct.
e . Both a and b are correct.
279
17. Which is NOT a distinguishing feature of ver
tebrates?
a. dorsal notochord
b. jointed internal skeleton
c. extreme cephalization
d. open circulatory system
e. efficient respiration
18. The type of mammal that lays eggs while nour
ishing its young with milk is called
a. a monotreme.b. a marsupial.
c. placental.
d. hermaphroditic.
19. Which is NOT true of echinoderms?
a. external skeleton
b. tube feet
c. skin gills
d. gonads in arms
20. Which is NOT an echinoderm?
a. sea l ily
b. sea urchin
c. sea cucumber
d. sea horse
21. Australopithecinesa. were apelike below the waist and humanlik
above the waist.
b. were humanlike below the waist and apelik
above the waist.
c. were generally apelike.
d. were generally humanlike.
22. The out-of-Africa hypothesis says that
a. Homo etectus migrated out of Africa and re
placed archaic human species in Europe an
Asia.
b. no interbreeding took place between differen
types of humans.
c. modern humans arose in Africa in several different places.
d. Neanderthals, and alsoH. erectus, migrate
out of Africa.
e. all of these
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AN S W E R KE Y
280
STUDY EXERCISES
1.
Description
radial
spine-bearing, calcium-rich plates in an
endoskeleton
gas exchange across skin gills and tube feet
central nerve ring plus radial nerves
a series of canals that ends at tube feet; a means of
locomotion
2. See Figure 31.2b, page 645, in text. 3. a. stone b. ring
c. tube d. ampulla e. locomotion 4. The sea star evertsits cardiac stomach, puts it in the shell, and secretes en-
zymes; partly digested food is taken up, and digestion is
completed in the pyloric stomach. 5. See page 646 in
text. 6. a. dorsal nerve cord in collar and trunk
b. gill slits in pharynx c. The larvae of hemichordates and
echinoderms are similar.
7.
Chordate Characteristics Appearance
all three (larva); gill slits thick-walled, squat
(adult) sac
all three lancet
8. 2. See Figure 31.3, page 647, in text. 9. a, c, d, e, h
10. a. CF, BF b. JF c. CF d. JF e. BF 11. a. senses pres-
ence of other organisms b. buoyancy c. respiration
d. movement of blood to gills first e. balancing and pro-
pelling body in water 12. a. smooth, nonscaly, and used
for respiration b. small and poorly developed c. ec-
tothermic d. undergo metamorphosis from tadpole to
adult e. three chambers 13. a. thick, dry, scaly b. moredeveloped than in amphibians c. ectothermic d. am-
niote e. nearly or completely four chambered 14. a. pro-
vide broad, flat surfaces b. reduces weight c. attaches
flight muscles d. provides good delivery of oxygenated
blood to muscles e. provides good oxygenation of blood
15. a. 1, 2 b. 1, 3 c. 1, 4 16. a. bat b. horse c. whale
d. lion e. monkey 17. a. eyes forward with stereoscopic
vision b. nails, not claws, and opposable thumb c. large,
well developed d. single offspring at a time 18. a. hominids
b.A. ramidus c. apes d. humans e. erect f. small g. body
parts evolved at different rates h.A. afarensis i. humans
j.A. robustus k.A. boisei l. robust 19. a. 1, 3, 7, 8, 9 b. 2,
4, 6, 8, 9 c. 2, 4, 6, 8, 9 d. 2, 4, 5, 8, 9 20. a. out-of-
Africa b. multiregional continuity c. multiregional con-tinuity d. archaic e. Neanderthal
OFFICE BUILDING ONE
1. i 2. f 3. d 4. h 5. d, e, f, g, h 6. i 7. d 8. c
9. f 10. g 11 . h 12 . i 13 . e 14 . c, d, f, g
15 . f 16 . d, e, f, g, h 17 . d, e, f, g, h, i 18 . i
19 . c 20 . a, b 21 . g 22 . i 23 . f 24 . c 25 . g
26. f 27. e 28. d 29. h 30. i 31. e 32. e, f, g,
h, i 33 . c 34 . b 35 . f 36 . g 37 . f, g, h 38 . f
39. g, h, i 40. d, e, f, g, h, i 41. b 42. h 43. f, g, h
44 .c
45 .f
46 .h
47 .g
48 .e
49 .c
50 .h51 . g, h, i 52 . f 53 . e 54 . i 55 . d, f 56 . b, c
57. e 58. i 59. d, e, f 60. h 61. f 62. g 63. d, h
64 . b 65 . h 66 . g, h 67 . h 68. b, c 69 . c, d
70. e, f, g, h, i
THOUGHT QUESTIONS
Answer in complete sentences.
23. Compare the success of chordate evolution to arthropod evolution. What are the similarities and differences?
24. Compare the adaptations of amphibians and reptiles to a land existence.
Test Results: ______ Number right 24 = ______ 100 = ______ %
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OFFICE BUILDING TWO
1. b, j 2. d, e, f, g, h, i 3. f, g, i 4. b 5. b, c 6. d,
e, f, g, h, i 7. c, d, e, f, g, i 8. b, h, j 9. c, d, e, f, g,
h, i 10. f 11. i 12. b and j; g and i 13. c 14. i
15. g 16. f 17. i 18. e, g, h 19. f 20. h 21. a
22 . e 23 . g 24 . h 25 . b 26 . i 27 . i 28 . g, i
29 . i 30 . b 31 . j 32 . f 33 . h 34. h 35 . e
36. none 37. f, g 38. a 39. b, j 40. c
OFFICE BUILDING THREE
1. e, f, g 2. d 3. f 4. a 5. g 6. b 7. g 8. a, d
9. a, b, c, d, e 10 . a, b, c 11 . g 12 . a 13 . g
14 . f 15 . a, b 16 . e 17 . f, g 18 . e 19 . g
20 . b 21 . e, f 22 . g 23 . f, g 24 . b, c 25 . g
26 . b, g 27 . d 28 . b 29 . g 30 . c 31 . c 32 . g
33. c 34. e 35. c 36. f, g 37. c 38. c, d, e, f, g
39. c 40. f 41. d 42. d, e, f, g 43. e, f, g 44. a, b, c
45 . f 46 . a, b, c 47 . e 48 . d, e, f, g 49 . e, f
50. a, b
CHAPTER TEST
1. c 2. d 3. b 4. d 5. b 6. c 7. b 8. d 9.
10 . d 11 . c 12 . a 13 . e 14 . c 15 . c 16 .
17. d 18. a 19. a 20. d 21. b 22. a 23. Eac
phylum contains numerous diversified species adapted t
a variety of environments. Arthropods have more species
24. Amphibians reproduce in the water and have a larva
stage that develops in the water. The skin must be kep
moist because it supplements the lungs for gas exchangeReptiles reproduce on land because they lay a shelle
egg with extraembryonic membranes. The skin can pre
vent desiccation because it is dry and scaly. The lungs ar
moderately developed, and a rib cage helps ventilate th
lungs.
28