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Chapter 6
Macroevolution and the Early Primates
MULTIPLE CHOICE
W 1. Which of the following statements about early mammals is correct?
a. Mammals evolved from reptiles between 230 and 280 million years ago.
b. Mammals evolved from reptiles about 65 million years ago.
c. Early mammals were diurnal.
d. The sense most emphasized in early mammals was vision.
e. Reptiles evolved from mammals about 300 million years ago.
W 2. Which of the following statements help to explain why reptiles remained dominant land
mammals even after true mammals evolved?
a. Reptiles occupied most available ecological niches on land by the time true mammals
arrived.
b. Many reptiles were wiped out in a mass extinction that occurred about 65 million
years ago.
c. Because mammals have a constant body temperature, they can remain active and thus
have the advantage against reptiles who are sluggish when the temperature is cold.
d. Mammals require high-quality nutrition to maintain a constant body temperature, and
such foods were limited during the early period of mammalian evolution.
e. both a and d
W 3. Which of the following factors contributed to the success of mammals at the end of the
Cretaceous period?
a. Early mammals emphasized vision, whereas reptiles emphasized hearing and smell.
b. The evolution of flowering plants provided high-quality nutrition.
c. Mammals had variable body temperature and thus were more flexible than reptiles
who had a constant body temperature.
d. Mammals underwent a mass extinction at this time.
e. all of the above
Chapter 6
W 4. Which of the following best describes the environment in which early primates emerged?
a. Flowering plants had evolved, providing high-quality nutrition in the form of fruits,
nuts, and seeds.
b. An early primate could make its way from what is now North Dakota to what is now
France because Europe was still joined to North America.
c. A mild, wet climate supported the growth of an extensive belt of tropical and
subtropical forests.
d. all of the above
e. none of the above
W 5. The _______________ epoch lasted from 55 to 34 million years ago, was characterized
by a warm, wet climate. During this period primates resembling lemurs and tarsiers lived
in North America, Europe, and Asia.
a. Paleocene
b. Eocene
c. Oligocene
d. Miocene
e. Pliocene
6. Which of the following is correct with regard to the Eocene epoch?
a. Primates lived mainly in North, America, Europe, and Asia.
b. A few primates lived in Africa.
c. All primates disappeared from North America by the end of this epoch.
d. The primates initially spread widely and then almost disappeared.
e. all of the above
7. The Oligocene epoch _______________.
a. lasted from about 34 to 23 million years ago
b. was cooler and drier than the Paleocene and Eocene
c. has few fossil primates because their arboreal lifestyle made fossilization less likely
d. all of the above
e. none of the above
Macroevolution and the Early Primates
8. The adaptive radiation of apes seems to have occurred during the _______________
epoch.
a. Eocene
b. Oligocene
c. Miocene
d. Paleocene
e. Pleistocene
9. Most of the skeleton of this primate fossil is known. Species of this genus vary in size
from a smallish monkey to a chimpanzee. The snout has been reduced and the brain case
is fuller, as compared with proto-apes of the Oligocene. The face has monkeylike
features, as does the wrist, but the lower molars have five cusps, its elbow, shoulder, and
foot are similar to those of a chimpanzee, and its lumbar vertebrae are like those of a
gibbon. It was probably an unspecialized, tree-dwelling, fruit-eating hominoid. Its name
is _______________.
a. Proconsul
b. Plesiadapiformes
c. Ramapithecus
d. Aegyptopithecus
e. Dryopithecus
10. The fossil primate Proconsul is interpreted as _______________.
a. the earliest known Old World monkey
b. a late-Miocene ancestor of African apes and humans
c. a descendant of the ramamorphs
d. closely related to tarsiers
e. none of the above
11. The first well-preserved “true” primates appeared about ______________ million years
ago.
a. 55
b. 50
c. 75
d. 25
e. 10
12. Primatologist Matt Cartmill suggests that primate visual and grasping abilities were
promoted through _______________.
a. the relatively small size of early primates
b. a return to the ground by some primates
c. the activity of hunting for insects by sight
d. human intervention
e. competition from predators
13. Stephen Jay Gould describes Darwinian evolution as __________________ change that
occurs by a twofold process of producing variation within a population and passing along
only a biased portion of this variation to the next generation.
a. variational
b. transformational
c. convergent
d. divergent
e. isolating
14. As the forests diminished and the savanna expanded, populations of hominoids living at
the edge of the savanna experienced selective pressures in favor of _______________.
a. the development of cheek pouches to carry food
b. increased number of offspring in a litter
c. bipedal locomotion
d. smaller, more lightweight body build for climbing spindly thorn bushes
e. less flexibility in the arms and hands
15. Which of the following may have contributed to the development of bipedalism among
the Miocene apes?
a. the ability to increase the food supply by getting more seeds, leaves, and pods from
spiny thorn bushes
b. improved ability to carry offspring
c. improvement in the ability to carry food from the open savanna to the safety of the
trees
d. increased ability to spot predators on the savanna
e. all of the above
16. The first Miocene ape fossil remains were found in Africa in the 1930s and 1940s by A.T.
Hopwood and _______________.
a. Ross MacPhee
b. Elwyn Simons
c. K. Christopher Beard
d. David Pilbeam
e. Louis Leakey
17. Over time, as two populations come to differ from one another, speciation occurs in a
branching fashion known as _______________.
a. cladogenesis
b. gene flow
c. anagenesis
d. punctuate equilibria
e. continental drift
18. Paleontologists Stephen Jay Gould and Niles Eldred proposed that speciation occurs in a
pattern of _______________ or alternation between periods of rapid speciation and of
times of stability.
a. macroevolution
b. punctuated branching
c. punctuated equilibria
d. derived evolution
e. divergent evolution
19. The earliest primates had developed by ______________ million years ago and became
widespread in Africa, Eurasia, and North America.
a. 60
b. 100
c. 37
d. 200
e. 50
20. Anatomical structure (e.g., Chihuahua and the Saint Bernard), geographical distance
and/or barriers, miscarriage of offspring, the presence of maladaptive traits that cause
early death of offspring, or the sterility of offspring are all examples of
_______________
a. genetic drift
b. gene flow
c. mutation
d. change barriers
e. isolating mechanisms
21. A gradual directional change over time can occur with in a single lineage, without any
evident branching, is known as _______________.
a. visual predation
b. cladogenesis
c. derivation genesis
d. anagenesis
e. divergent genesis
22. Reproduction involving the production of relatively few offspring with high parental
investment in each is referred to as _______________.
a. d-selected
b. r-selected
c. k-selected
d. l-selected
e. x-selected
23. As mentioned in your textbook, today _______________ are the only “apes” to have
global distribution.
a. chimpanzees
b. gorillas
c. humans
d. siamangs
e. bonobos
Macroevolution and the Early Primates
24. So varied and ubiquitous were the fossil apes of this period that the _______________
has been called by some the “golden age of the hominoids.”
a. Miocene
b. Pleistocene
c. Paleocene
d. Oligocene
e. Neolithic
25. ___________________ is responsible for explaining, “All evolutionary sequences
include…a fortuitous series of accidents with respect to future evolutionary success.”
a. Vicente Fox
b. Vince Sarich
c. Stephen J. Gould
d. A.T. Hopwood
e. Elwyn Simons
26. Using a molecular technique, Sarich proposed a sequence of divergence for the living
hominoids that showed that human, chimp, and gorilla lines split roughly
_______________ million years ago.
a. 100
b. 15
c. 50
d. 5
e. 15
27. A spectacularly complete specimen found in the Potwar Plateau by David Pilbeam
showed that Sivapithecus was undoubtedly the ancestor of living _______________.
a. orangutans
b. chimpanzees
c. bonobos
d. gibbons
e. simiangs
28. _______________ accounts for the re-arrangement of adjacent landmasses through the
theory of plate tectonics.
a. Continental drift
b. Earth movement
c. Drifting faults
d. Floating land masses
e. Continental modification
29. South America, Africa, Antarctica, Australia and the Indian subcontinent were previously
joined together as the super continent _______________.
a. Mesoamerica
b. Gondwanaland
c. Euroland
d. Atlantis
e. Laurasia
30. Two dissimilar forms develop greater similarities, such as birds and bats. This is an example
of _______________.
a. convergent evolution
b. divergent evolution
c. linear evolution
d. genetic drift
e. the Hardy-Weinberg Principle
31. Populations may split up and become geographically separated; changes may occur in the
gene pools of populations that prevent successful development of a fetus produced
through gene flow; populations may have very different social and cultural patterns that
prevent opportunities for gene flow. These are all examples of _______________.
a. factors that lead to convergent evolution
b. isolating mechanisms
c. anthropomorphisms
d. mutations
e. stabilizing selection
32. The first well-preserved “true” primates appeared about 50-55 million years ago at the
start of the _______________ epoch.
a. Cenozoic
b. Triassic
c. Cretaceous
d. Eocene
e. Mesozoic
33. The earliest evidence of primates in South America dates from the _______________.
a. Oligocene
b. Triassic
c. Eocene
d. Cretaceous
e. Mesozoic
34. In Chad in the summer of 2002, a team or international researchers led by
_______________ unearthed a well-preserved skull dated to between 6 and 7 million
years ago. The researchers suggested that this specimen represented the earliest known
ancestor of humans. They nicknamed it “Tourmai.”
a. Stephen Jay Gould
b. Louis Leakey
c. Michel Brunet
d. Vince Sarich
e. Allan Wilson
35. In his obituary in the journal Nature it was stated, “while others concentrated on what
evolution could tell them about molecules, _______________ always looked for ways
that molecules could say something about evolution.”
a. Vince Sarich
b. Michel Brunet
c. Joseph Felsenstein
d. Allan Wilson
e. Mark Stoneking
36. Prosimian primates were once found all across North America and Europe, and now they
have retreated to specialized niches in __________________.
a. Oahu
b. Ceylon
c. Samoa
d. Bora Bora
e. Madagascar
37. In addition to designating species in the fossil record, paleoanthropologists and
paleontologists construct evolutionary relationships between fossil groups. They pay
particular attention to features appearing more recently in evolutionary history that are
unique to a lineage, calling these features _______________.
a. ancestral
b. pre-adapted
c. pre-selected
d. molecular markings
e. derived
38. _______________ helps detect when branching of related species from a common
ancestor took place in the distant past
a. Linear evolution
b. Convergent evolution
c. The molecular clock
d. Isolating mechanisms
e. Adaptive radiation
39. The term used to describe when two distant forms develop greater similarities is
_______________.
a. adaptive radiation
b. linear evolution
c. cladogenesis
d. speciation
e. convergent evolution
40. A sustained directional shift in a population’s average characteristics is known as
_______________.
a. anagenesis
b. cladogenesis
c. macroevolution
d. k-selected
e. convergent evolution
TRUE/FALSE
W 1. Eocene primate remains are found in North and South America and in Africa.
W 2. The Fayum Depression of Egypt is a key Miocene site.
W 3. As pointed out in your textbook, in absence of isolation a species as a whole may evolve
in a linear manner through variational change in response to environmental changes.
W 4. The accumulation of small changes from generation to generation may transform an
ancestral species into a new one.
W 5. Social isolating mechanisms are thought to have been important factors in human
evolution.
6. At present the only primates to be found all over the earth are the chimpanzees.
7. Genes that regulate the growth and development of an organism can have a major effect
on its adult form.
8. Over time, as two populations come to differ from each other, speciation occurs in a
branching fashion known as cladogenesis.
9. Because speciation is a process, it occurs at a stable and predictable rate.
10. Developmental change in the timing of growth and development events, or heterochrony,
is often responsible for changes in the shape or size of a body part.
11. Stephen Jay Gould describes Darwinian evolution as a variational change.
12. In the nonscientific community, evolution is often seen as leading in a predictable and
determined way from one-celled organisms to humans.
13. Sir Robert May expresses his concerns that include emphasizing valid emotional and
ethical argument for conserving biological diversity and sustaining as much as possible of
the biological riches and unaccounted ecosystem services.
Macroevolution and the Early Primates
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MATCHING
Match the period or epoch to its dates.
a. 180-230 million years ago
b. 34-55 million years ago
c. 55-65 million years ago
d. 230-280 million years ago
e. 23-34 million years ago
f. 5-23 million years ago
1. ______ Permian
2. ______ Miocene
3. ______ Triassic
4. ______ Eocene
5. ______ Paleocene
6. ______ Oligocene
Match the term to its definition.
a. when two distant forms develop greater similarities
b. helps detect when branching of related species from a common ancestor to place in the distant
past
c. factors that separate breeding populations
d. a sustained, directional change in a population’s average characteristics
e. rapid diversification of an evolving population as it adapts to a variety of available niches
1. ______ isolating mechanisms
2. ______ convergent evolution
3. ______ linear evolution
4. ______ molecular clock
5. ______ adaptive radiation
SHORT ANSWER
1. What was the impact of continental drift on the primate development of the Miocene
epoch?
Chapter 6
2. What does the term microevolution mean? What is the focus and why is this important to
the understanding of how primates evolved?
3. Why is it important to recreate primate evolutionary history out of ancient, fragmentary
evidence?
4. How can we account for the rapid spread of the mammals after the Cretaceous?
5. What does it meant to say “mammals were preadpated”?
6. Provide an example of an isolating mechanism being social rather than physical and
describe why it is social rather than physical.
7. Social isolating mechanisms are thought to have been important factors in human
evolution. Explain how they continue to play a part in human evolution.
8. Sorting out evolutionary relationships may be complicated by a phenomenon called
convergent evolution in which two distant forms develop greater similarities. Provide
examples of this phenomenon.
9. Under what circumstances does convergent evolution take place? Describe.
10. Why does the 47-million year old female primate known as “Ida” inspire navel-gazing at
our ancestry?
11. What were the physical and behavioral characteristics of earliest mammals?
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12. Describe the primates of the Miocene, and how ere they different from those in the
Oligocene?
13. Why is an understanding of the concept of continental drift important to
paleoanthropologists and paleontologists?
14. Describe the differences between mammals and reptiles in terms of how they maintain
body temperature.
15. Describe some of the ancestral features seen in Eocene and Oligocene primates that are
still seen in prosimians today.
ESSAY
1. How can evolutionary studies be of interest to public audiences, when the public is more
likely to interpret evolution as a steady process of change from one-celled organisms to
humans?
2. The shift from arboreal to savanna habitat has been described as having a significant
impact on human ancestors? Explain.
3. What are some of the problems faced by biologists and paleoanthropologists in talking
about fossil (rather than living) species? How have they attempted to overcome the
constraints our categorization system exerts on our thinking about past evolutionary
developments?
4. With the end of the Eocene, substantial changes took place among the primates, as among
other mammals. Describe the changes that took place.
5. Describe the Eocene primates as represented by fossils from China and Egypt’s Fayum
depression. Based upon the data do you agree that the biological definition of species
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difficult to apply to the fossil record?
6. The punctuated equilibria model of evolutionary change is often contrasted with the
speciation through adaptation. The interpretation evolutionary change changes with
discoveries of new specimens and laboratory analyses. Do you conceive of a different
way to explain human evolutionary history in the future? Explain why all scientific
models are important.
7. Discuss why convergent evolution might complicate the reconstruction of the
evolutionary history of any given species.
8. Mammals are considered k-selected, and reptiles r-selected. What does this mean?
Is it important to know about reptiles in order to understand the human past?
9. What does the fossil evidence indicate about Old World anthropoids?
10. Discuss the factors involved that pulled attention away from the idea that humans
originated in Africa.