Which of the following is a characteristic of all chordates at some
point during their life cycle?
B) post-anal tail
C) four-chambered heart
Why do adult urochordates (tunicates) lack notochords, even though
larval urochordates have them? Larvae use notochords to _____.
A) aid in swimming; adults are sessile and thus no longer propel themselves.
B) stiffen their bodies; in adults, the notochord is replaced by a column of bone.
C) induce tissue differentiation; in adults, tissue is already differentiated.
D) organize their nervous systems; adults' nervous systems are fully developed and do not change.
If a tunicate's pharyngeal gill slits were suddenly blocked, the
animal would have trouble _____.
D) respiring and feeding
Chordate pharyngeal slits appear to have functioned first as
A) the digestive system's opening
B) suspension-feeding devices
C) components of the jaw
D) sites of respiration
Which of the following statements would be LEAST acceptable to most
A) The first fossils resembling lancelets appeared in the fossil record around 530 million years ago.
B) Recent work in molecular systematics supports the hypothesis that lancelets are the basal clade of chordates.
C) The extant lancelets are the immediate ancestors of the fishes.
D) Lancelets display the same method of swimming as do fishes.
Which extant chordates are postulated to be most like the earliest
chordates in appearance?
B) adult tunicates
Vertebrates and tunicates share _____.
A) jaws adapted for feeding
B) a high degree of cephalization
C) the formation of structures from the neural crest
D) a notochord and a dorsal, hollow nerve cord
All chordates studied to date, except tunicates, share a set of
A) 13 Hox genes
B) 5 Dlx genes
C) 9 Otx genes
D) 7 FOXP2 genes
Which of the following characteristics is shared by a hagfish and a
A) a rasping tongue
B) paired fins
D) a well-developed notochord
A new species of aquatic chordate is discovered that closely
resembles an ancient form. It has the following characteristics:
external armor of bony plates, no paired lateral fins, and a
suspension-feeding mode of nutrition. In addition to these, it will
probably have which of the following characteristics?
B) no jaws
C) an amniotic egg
The earliest known mineralized structures in vertebrates are
associated with _____.
A team of researchers has developed a poison that has proven
effective against lamprey larvae in freshwater cultures. The poison is
ingested and causes paralysis by detaching segmental muscles from the
skeletal elements. The team wants to test the poison's effectiveness
in streams feeding Lake Michigan, but one critic worries about
potential effects on lancelets, which are similar to lampreys in many
ways. Why is this concern misplaced?
A) Lamprey larvae and lancelets have very different feeding mechanisms.
B) Lancelets do not have segmental muscles.
C) Lancelets live only in saltwater environments.
D) Lancelets and lamprey larvae eat different kinds of food.
To reproduce, many plants produce seeds-structures containing
embryonic offspring along with nutrients inside a tough case. These
offspring develop after being released by the parent plant. To which
animal reproductive strategy is seed production most
A) oviparous reproduction
B) ovoviviparous reproduction
C) viviparous reproduction
Why do skates and rays have flattened bodies, while sharks are
A) Sharks are more closely related to the tubelike lampreys than skates and rays are.
B) Skates and rays need enlarged pectoral fins to help them stay level in turbulent water, while sharks do not.
C) Skates and rays exchange gases across their skin and thus require a high surface-area-to- volume ratio, while sharks use gills to respire.
D) Sharks are streamlined for active swimming off the bottom, while skates move about mostly on the ocean bed.
Which of these statements accurately describes a similarity between
sharks and ray-finned fishes?
A) They are equally able to exchange gases with the environment while stationary.
B) They are highly maneuverable due to their flexibility.
C) They have a lateral line that is sensitive to vibrations.
D) A swim bladder helps control buoyancy.
The presence of a swim bladder allows the typical ray-finned fish to
stop swimming and still _____.
A) effectively circulate its blood
B) use its lateral line system
C) use its swim bladder as a respiratory organ
D) not sink
Which shark structure is closest in function to a swim bladder full
A) its lateral line system
B) its spiral valve
C) its liver
D) its gills
If a ray-finned fish is to both hover (remain stationary) in the
water column and ventilate its gills effectively, then what other
structure besides its swim bladder will it use?
A) its pectoral fins
B) its lateral line system
C) its caudal (tail) fin
D) its opercula
How did the evolution of the jaw contribute to diversification of
early vertebrate lineages?
A) It allowed for smaller body size.
B) It was the first stage in the development of a bony skull.
C) It made additional food sources available.
D) It increased the surface area for respiration and feeding.
It is believed that the coelacanths and lungfish represent a crucial
link between other fishes and tetrapods. What is the major feature in
these fish in support of this hypothesis?
A) Like amphibians, they are tied to the water for reproduction.
B) Their fins have skeletal and muscular structures similar to amphibian limbs.
C) They have highly evolved nervous and circulatory systems.
D) They have lungs and are able to breathe air when water is scarce.
Jaws first occurred in which extant group of fishes?
C) ray-finned fishes
Which of these might have been observed in the common ancestor of
chondrichthyans and osteichthyans?
A) a mineralized, bony skeleton
C) a spiral valve intestine
D) a swim bladder
Arrange these groups in order from most inclusive (most general) to
least inclusive (most specific).
A) 4, 3, 1, 5, 2
B) 4, 3, 2, 5, 1
C) 3, 4, 1, 5, 2
D) 3, 4, 5, 1, 2
Suppose, while out camping in a forest, you found a chordate with a
long, slender, limbless body slithering across the ground near your
tent. This critter could be _____.
A) a lampreys
B) a mammal
C) an amphibian
D) a skate
While on an intersession course in tropical ecology, Kris pulls a
large, snakelike organism from a burrow (the class was granted a
collecting permit). The 1-meter-long organism has smooth skin, which
appears to be segmented. It has two tiny eyes that are hard to see
because they seem to be covered by skin. Kris brings it back to the
lab at the field station, where it is a source of puzzlement to the
class. Kris says that it is a giant oligochaete worm; Shaun suggests
it is a legless amphibian; Kelly proposes it belongs to a snake
species that is purely fossorial (lives in a burrow).
The class decided to humanely euthanize the organism and subsequently dissect it. Having decided that it was probably not a reptile, two of their original hypotheses regarding its identity remained. Which of the following, if observed, should help them arrive at a conclusive answer?
A) presence of moist, highly vascularized skin
B) presence of lungs
C) presence of a nerve cord
D) presence of a digestive system with two openings
The organism was found to have two lungs, but the left lung was much
smaller than the right lung. Kelly added that the herpetology
instructor had said that in most snakes, the same condition exists. If
the size difference between the lungs in this organism is not a shared
ancestral characteristic with its occurrence in snakes, then its
existence in this organism is explained as which of the
1. a result of convergent evolution
2. an example of homologous structures
3. a similar adaptation to a shared lifestyle or body plan
4. a result of having identical Hox genes
A) 1 only
B) 1 and 3
C) 2 and 3
D) 3 and 4
Which of the following could be considered the most recent common
ancestor of living tetrapods?
A) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
B) an armored, jawed placoderm with two pairs of appendages
C) an early ray-finned fish that developed bony skeletal supports in its paired fins
D) a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes
A trend first observed in the evolution of the earliest tetrapods was
A) the appearance of jaws
B) feet with digits
C) the mineralization of the endoskeleton
D) the amniotic egg
Fossils of the earliest tetrapods should _____.
A) show evidence of internal fertilization
B) show evidence of having produced shelled eggs
C) indicate limited adaptation to life on land
D) feature the earliest indications of the appearance of jaws
Terry catches a ray-finned fish from the ocean and notices that
attached to its flank is an equally long, snakelike organism. The
attached organism has no external segmentation, no scales, a round
mouth surrounded by a sucker, and two small eyes. Terry thinks it
might be a marine leech, a hagfish, or a lamprey.
Terry saved some of the tooth-like objects within the hagfish's round mouth to analyze their composition in his mentor's biochemistry research lab. Terry will find that they are composed of the same protein found in tetrapod _____.
What is believed to be the most significant result of the evolution
of the amniotic egg?
A) Tetrapods were no longer tied to the water for reproduction.
B) Tetrapods can now function with just lungs.
C) Newborns are much less dependent on their parents.
D) Embryos are protected from predators.
Which structure of the amniotic egg most closely surrounds the
A) the chorion
B) the yolk sac
C) the allantois
D) the amnion
The evolution of similar insulating skin coverings such as fur, hair,
and feathers in mammals and birds is a result of _____.
A) shared ancestry
B) convergent evolution
D) evolutionary divergence
Which of the following characteristics evolved independently in
mammals and birds?
A) amniotic eggs
Suppose you traveled back in time and located the first animals to
have evolved feathers. You found that these animals were tree-dwelling
ectotherms, able to run quickly but unable to fly. You also noticed
that only males had feathers. Which hypothesis of feather evolution
would these data most support? Feathers initially evolved in a role
associated with _____.
C) sexual selection
Mammals and birds eat more often than reptiles. Which of the
following traits shared by mammals and birds best explains this
C) amniotic egg
Which characteristic is common to all the modern representatives of
all major reptilian lineages (turtles, lepidosaurs, crocodilians, and
A) presence of teeth
B) presence of four walking limbs
D) presence of a notochord
Which of these are amniotes?
Due to its system of air sacs connected to the lungs, the respiratory
system of birds is arguably the most effective respiratory system of
all air-breathers. Upon inhalation, air first flows into posterior air
sacs, then into the lungs, and then into anterior air sacs on the way
to being exhaled. Thus, there is one-way flow of air through the
lungs, along thousands of tubules called parabronchi.
If the inner lining of the air sacs is neither thin nor highly vascularized, then what can be inferred about the air sacs?
A) They must not belong to the respiratory system.
B) They cannot be derived from endoderm.
C) They are not efficient sites of gas exchange between air and blood.
D) They cannot effectively moisturize the air before it reaches the lungs.
The one-way flow of air along parabronchi makes what type of gas
exchange mechanism possible, at least theoretically?
A) the same as that occurring in fish gills
B) the same as that occurring in insect tracheae
C) the same as that occurring in mammalian lungs
D) the same as that occurring in echinoderm skin gills
Which of these characteristics added most to vertebrate success in
relatively dry environments?
A) the shelled, amniotic egg
B) the ability to maintain a constant body temperature
C) two pairs of appendages
D) a four-chambered heart
Which of the following are the only extant animals that descended
directly from dinosaurs?
During chordate evolution, what is the sequence (from earliest to
most recent) in which the following structures arose?
1. amniotic egg
2. paired fins
4. swim bladder
5. four-chambered heart
A) 2, 3, 4, 1, 5
B) 3, 2, 4, 5, 1
C) 3, 2, 1, 4, 5
D) 2, 1, 5, 3, 4
Which clade does NOT include humans?
Primate evolution and behavior, such as hunting skills, have been
directed in part by the development of depth perception. What
anatomical change made depth perception possible?
A) a larger brain
B) the formation of compound eyes
C) movement of the eyes to the front of the head
D) diurnal activity
What group of mammals have (a) embryos that spend more time feeding
through the placenta than the mother's nipples, (b) young that feed on
milk, and (c) a prolonged period of maternal care after leaving the
Which of the following represents the strongest evidence that two of
the three middle ear bones of mammals are homologous to certain
A) They are similar in size to the reptilian jawbones.
B) They are similar in shape to the reptilian jawbones.
C) The mammalian jaw has fewer bones than does the reptilian jaw.
D) These bones can be observed to move from the evolving jaw to the evolving middle ear in mammalian embryos.
Which of the following is the most inclusive (most general) group in
which all of the members have fully opposable thumbs?
Which of these would a paleontologist most likely do to determine if
a fossil represents a reptile or a mammal?
A) Look for the presence of milk-producing glands.
B) Look for the mammalian characteristics of a four-chambered heart and a diaphragm.
C) Use molecular analysis to look for the protein keratin.
D) Examine the teeth.
Female birds lay their eggs, thereby facilitating flight by reducing
weight. Which "strategy" seems most likely for female bats
to use to achieve the same goal?
A) limit litters to a single embryo
B) refrain from flying throughout pregnancy (about six weeks long)
C) give birth to underdeveloped young, and subsequently carry them in a pouch that has teats
D) feed multiple embryos internally using placentas
Unlike eutherians, both monotremes and marsupials _____.
A) lack nipples
B) have some embryonic development outside the uterus
C) lay eggs
D) are found in Australia and Africa
On the back of your skull you can feel a small bump, below which is
an opening where the spinal cord enters the skull. The location of
this opening toward the bottom of the skull is significant in
evolutionary biology for what reason?
A) It allowed for the hominin brain to grow much larger than other primates.
B) It provided greater protection for the spinal cord.
C) It occurred as a result of the change to a bipedal stance.
D) This change was necessary for the increase in size from prosimian forms to anthropoid forms.
Brown et al. and Morwood et al. reported in 2004 that they had found
skeletal remains of a previously unknown type of hominin, now dubbed
Homo floresiensis, on the Indonesian island of Flores. These hominins
were small (approximately 1 meter tall) with small braincases
(approximately 380 cubic centimeters) as compared with other hominins.
The remains of H. floresiensis were found alongside handmade stone
tools and the remains of dwarf elephants that also inhabited the
island, suggesting that H. floresiensis was able both to make tools
and to coordinate the hunting of animals much larger than itself. H.
floresiensis is estimated to have lived at the site where the remains
were found from at least 38,000 years ago to 18,000 years
Refer to the paragraph on Brown et al. and Morwood et al. Which would be the most feasible method of figuring out to which other hominin species H. floresiensis was most closely related?
A) Compare the type of prey hunted by H. floresiensis to that hunted by each of the other hominin species.
B) Compare the average body size of H. floresiensis to that of each of the other hominin species.
C) Compare the skeletal morphology of H. floresiensis to that of each of the other hominin species.
D) Compare the estimated life span of H. floresiensis to that of each of the other hominin species.
In what respect do hominins differ from all other
A) lack of a tail
B) eyes on the front of the face
C) bipedal posture
D) opposable thumbs
The table above is a comparison of several characteristics of H.
floresiensis to those of nine other hominin species (arranged roughly
from oldest to most recent). What do these data suggest?
A) A large brain is not necessarily required for toolmaking.
B) Body mass and braincase volume are completely unrelated.
C) Hominins first evolved in and then radiated out from Asia.
D) Homo floresiensis is most closely related to Australopithecus afarensis or A. africanus.
Refer to the paragraph on Brown et al. and Morwood et al. It is
speculated that H. floresiensis and H. sapiens may have lived on
Flores concurrently. Suppose researchers obtained mitochondrial DNA
samples from the H. floresiensis remains, amplified a 1000-base-pair
sequence via PCR, and compared it to that of several currently living
H. sapiens native to Indonesia, North Africa, and North America. Also
suppose H. floresiensis were found to differ from the average
Indonesian H. sapiens in 28 base pairs, from the average North African
H. sapiens in 51 base pairs, and from the average North American H.
sapiens in 53 base pairs, while two randomly selected H. sapiens
differed from each other in an average of 21 base pairs. What would
you surmise from these data?
A) H. floresiensis and H. sapiens probably did not live on Flores concurrently.
B) H. floresiensis and H. sapiens probably lived on Flores concurrently but did not interact.
C) H. floresiensis and H. sapiens probably lived on Flores concurrently, and H. sapiens killed and consumed H. floresiensis.
D) H. floresiensis and H. sapiens probably lived on Flores concurrently and interbred to some degree.
Arrange the following taxonomic terms in order from most inclusive
(most general) to least inclusive (most specific).
A) 5, 1, 4, 2, 3
B) 5, 4, 1, 2, 3
C) 5, 4, 2, 1, 3
D) 5, 2, 1, 4, 3
Which of these traits is most strongly associated with the adoption
A) enhanced depth perception
B) shortened hind limbs
C) opposable big toe
D) repositioning of foramen magnum
Which of the following statements about human evolution is
A) Modern humans are the only human species to have evolved on Earth.
B) Human ancestors were virtually identical to extant chimpanzees.
C) Human evolution has occurred within an unbranched lineage.
D) The upright posture and enlarged brain of humans evolved separately.
With which of the following statements would a biologist be most
inclined to agree?
A) Humans and other apes represent divergent lines of evolution from a common ancestor.
B) Humans represent the pinnacle of evolution and have escaped from being affected by natural selection.
C) Humans evolved from chimpanzees.
D) Humans and other apes are the result of disruptive selection in a species of chimpanzee.