Deck 19: Human Evolution

Question 1

What do the two diagrams (A and B) illustrate regarding human evolution?

A) the multiregional hypothesis and the out-of-Africa hypothesis, respectively
B) the out-of-Africa hypothesis and the multiregional hypothesis, respectively
C) coexistence of multiple hominins throughout the evolutionary history of Homo sapiens and the existence of a single hominin throughout the evolutionary history of Homo sapiens, respectively
D) the existence of a single hominin throughout the evolutionary history of Homo sapiens and coexistence of multiple hominins throughout the evolutionary history of Homo sapiens, respectively

Answer 1

A

Question 2

Which of the following evidence does NOT support the out-of-Africa hypothesis?

A) Differences among modern human populations are due to geographic separation for 2 million years.
B) the replacement of other hominin species by Homo sapiens expanding beyond Africa approximately 60,000 years ago
C) The coalescence time for human mitochondrial DNA is between 120,000 and 230,000 years ago, while the coalescence time for non-African mtDNA is only about 38,500 years ago.
D) the existence of greater mitochondrial diversity in Africa than in the rest of the world combined

Answer 2

A

Question 3

When using host-pathogen coevolution to study patterns of human migration, why do researchers study human-specific pathogens that transmit vertically as opposed to laterally?

A) Vertical transmission (parent to offspring) provides a shared evolutionary history between host species and pathogen; the evolutionary history of the pathogen should reflect the human population it infects. Lateral transmission can be movement to an unrelated individual or an entirely different population or nonhuman reservoir.
B) Vertical transmission (from population to population) provides an evolutionary history between the host species and the pathogen, reflecting a broad range of evolution within the human population. Lateral transmission (parent to offspring) only provides information on a single lineage within the population.
C) Vertical transmission (sibling to sibling) provides a shared evolutionary history between host and pathogen; the evolutionary history of the pathogen should reflect the human population it infects. Lateral transmission can be movement to other subpopulations, distorting the data within the larger population.
D) Vertical transmission (between unrelated individuals) provides a broad evolutionary history of the population due to high rates of transmission of the pathogen within the population. Lateral transmission is movement to an entirely different population or nonhuman reservoir, so it would not provide a history of migratory patterns.

Answer 3

A

Question 4

What did Richard Green et al. conclude from their study about interbreeding between Neanderthals and modern humans?

A) They found that genomes of African humans do not contain Neanderthal-derived DNA, indicating that Neanderthals did not interbreed with modern humans after moving out of Africa.
B) They found that genomes of African humans do not contain Neanderthal-derived DNA, but 1% to 4% of the genome of typical non-African humans is derived from Neanderthals, indicating interbreeding.
C) They found that genomes of African humans contain 1% to 4% Neanderthal DNA, indicating that Neanderthal speciation occurred after humans left Africa and there was no interbreeding with modern humans.
D) They found no distinguishing differences in African and non-African DNA comparisons, indicating that Neanderthals were simply a phenotypically different population of modern humans and should not be considered a separate species.

Question 5

How did the ecology of the African tropics change about 6 million years ago?

A) This area experienced warming temperatures and regular rainfall patterns, resulting in a shift to tropical forest.
B) This area experienced warming temperatures and significantly reduced rainfall, resulting in the formation of the Sahara Desert.
C) This area experienced warming temperatures and a significant increase in rainfall, resulting in a shift to swampland.
D) This area experienced cooling temperatures and seasonal patterns of rainfall, resulting in a shift to savanna.

Question 6

As an archaeologist, a colleague asks you to confirm her identification of some fossilized burial remains of a hominin. The fossils were discovered relatively undisturbed, deep in a cave where the body was protected from scavengers. The hands of the skeleton were deliberately folded across the chest and a crude flute was clasped between the hands. The skull had a greatly reduced brow ridge and a flat face. Charcoal remains near the entrance of the cave included charred bones of a large game animal that date to approximately the same time as the skeleton; the bones were clearly scored by a tool. As which species of hominin would you identify the remains?

A) Homo sapiens
B) Homo neanderthalensis
C) Homo floresiensis
D) Homo naledi

Question 7

What did the discovery of Neanderthal DNA in modern human genomes tell us about gene flow as Homo sapiens emerged from Africa?

A) All of the human variation that exists today was derived from the variation that existed in the population of Homo sapiens that first emerged in Africa; there is no evidence of interbreeding with other hominin populations.
B) Very little human variation is derived from what was present in the population of Homo sapiens that first emerged in Africa; a significant amount of variation was introduced after interbreeding with Neanderthals and Denisovans.
C) Human variation is largely derived from what was present in the population of Homo sapiens that first emerged in Africa, but a limited amount of variation has been passed from Neanderthals and Denisovans through interbreeding after Homo sapiens emerged from Africa.
D) Although DNA extraction techniques continue to improve, there are not enough data to provide conclusive evidence about whether modern humans interbred with Neanderthals.

Question 8

Which statement accurately reflects the order of relationship between humans and the other apes, going from most closely related to most distantly related?

A) Sister taxa with chimpanzees, then bonobos, gorillas, orangutans, and gibbons
B) Sister taxa with chimpanzees and bonobos, then gorillas, orangutans, and gibbons
C) Sister taxa with chimpanzees and gorillas, then bonobos, orangutans, and gibbons
D) Sister taxa with chimpanzees and bonobos, then gibbons, gorillas, and orangutans

Question 9

Why does the process of deep coalescence result in incomplete lineage sorting?

A) The coalescent event between alleles results in incomplete separation of the lineages.
B) The coalescent event between alleles predates the speciation event separating the lineages.
C) The coalescent event between alleles occurs simultaneously with the separation of the lineages.
D) The coalescent event between alleles postdates the speciation event separating the lineages.

Question 10

What is the underlying assumption of the "structure" method for analyzing multiple loci at the same time?

A) It assumes that the number of genotypes under consideration comes from an unspecified number of distinct groups, each with its own characteristic allele frequencies.
B) It assumes that an undetermined number of genotypes come from a specified number of distinct groups, each with different allele frequencies.
C) It assumes that the set number of genotypes under consideration comes from a specified number of distinct groups, each with its own characteristic allele frequencies.
D) It assumes that the set number of genotypes under consideration comes from a specified number of distinct groups, each with different characteristic allele frequencies.

Question 11

As a result of the ecological changes that occurred in the African tropics ~ 6 million years ago, the Hominina moved on to the savanna while chimpanzees and gorillas remained in the forest. One of the early adaptations by Hominina was the evolution of bipedal locomotion. Which of the following is NOT a hypothesis for why bipedal locomotion was favored?

A) Bipedal locomotion was more energetically efficient than knuckle walking.
B) Bipedal locomotion resulted in the evolution of larger brains and language.
C) Bipedal locomotion may have helped hominins keep cool in the direct sunshine of the savanna by reducing exposed body surface area.
D) Bipedal locomotion frees the hands for carrying items and harvesting fruits from small trees.

Question 12

What was the major transition from archaic hominins to the genus Homo?

A) increase in tooth size
B) increase in brain size
C) evolution of bipedalism
D) evolution of skull ridges

Question 13

What is meant by describing modern human global migration as a "serial founder effect"?

A) With each successive wave of migration into a new geographic area, each new population accumulated unique mutations, resulting in increased genetic diversity with distance from the population of origin.
B) With each successive wave of migration into a new geographic area, each new population represented a completely different set of unique alleles relative to the source population.
C) With each successive wave of migration into a new geographic area, each new population carried the same set of alleles, diverging from the source population only after accumulating unique mutations.
D) With each successive wave of migration into a new geographic area, each new population was a subset of the previous population, which resulted in reduced genetic diversity in the newly colonized region relative to the source region.

Question 14

What are the distinguishing features of the hominin lineage?

A) bipedalism and dentition
B) bipedalism and big brains
C) big brains and dentition
D) big brains and tool use

Question 15

Who was "mitochondrial Eve" and how does she support the out-of-Africa hypothesis?

A) She is the nuclear DNA ancestor of all living humans; her origins trace back to Africa, indicating an African origin for modern humans and supporting the out-of-Africa hypothesis.
B) She is the mtDNA coalescent of living humans; the timing of coalescence indicates greater mitochondrial diversity in the rest of the world as compared to Africa, supporting an African origin for modern humans as genetic diversity increases over time.
C) She is the mtDNA coalescent of living humans; the timing of coalescence indicates greater mitochondrial diversity in Africa than the rest of the world, supporting an African origin for modern humans.
D) She is the nuclear DNA coalescent of the hominoids; the timing of coalescence indicates an earlier split between modern humans and chimpanzees with greater genetic diversity in Africa than the rest of the world, supporting the out-of-Africa hypothesis.

Question 16

Deep coalescence in molecular data is most likely when branches are ________ and population sizes are ________.

A) short; large
B) short; small
C) large; large
D) large; small

Question 17

What does this figure tell us about diversification and effective population size in the Y chromosome and mtDNA?

A) Y chromosome diversity and effective population size decreased dramatically during the migration out of Africa, followed by a significant increase in effective population size. mtDNA diversity and effective population size dramatically increased and is significantly larger than that of the Y chromosome.
B) Y chromosome diversity and effective population size increased dramatically during the migration out of Africa, followed by a severe restriction in effective population size. mtDNA diversity and effective population size dramatically increased and is significantly larger than that of the Y chromosome.
C) Both diversity and effective population size increased steadily and significantly for the Y chromosome and mtDNA during the migration out of Africa and are now approximately equivalent to each other.
D) Y chromosome diversity and effective population size decreased during the migration out of Africa and then recovered to become approximately equivalent to mtDNA.

Question 18

Gene trees for modern human populations were constructed using blood group data, mtDNA, and the Y chromosome. What did the research using mtDNA and Y chromosome data determine that the blood group data did not about the origin of modern humans?

A) The mtDNA and Y chromosome data both indicated multiple origin points for modern humans, which supports the multiregional hypothesis.
B) The mtDNA and Y chromosome data both indicated primarily European origin points for modern humans as they migrated across the globe.
C) The mtDNA and Y chromosome data both indicated an African origin point; the blood group data indicated a European point of origin.
D) The mtDNA and Y chromosome data both indicated an African origin point for the migration of modern humans across the globe.

Question 19

How do Neanderthals physically differ from modern humans?

A) Neanderthals were lighter and faster, with a more pronounced brow ridge and larger eyes.
B) Neanderthals were heavier, stronger, and stockier, with a more pronounced brow ridge and larger eyes.
C) Neanderthals were significantly shorter and stockier, with large feet that lacked a raised arch.
D) Neanderthals were significantly shorter, with large feet that lacked a raised arch and a flat face with reduced dentition.

Question 20

Which of the following most accurately describes the hominoids (members of the superfamily Hominoidea)?

A) humans and the extinct species more closely related to humans than to chimpanzees
B) modern humans only
C) modern humans, chimpanzees, and bonobos
D) all of the apes: orangutans, gorillas, chimpanzees, humans, and gibbons

Question 21

Why was the fossil evidence for interbreeding between Neanderthals and Homo sapiens inconclusive?

A) The fossil evidence was very scant and incomplete.
B) Fossil evidence appeared to show morphological characters intermediate between H. sapiens and H. neanderthalensis, but could not determine if that was solely due to interbreeding.
C) Many researchers argue that H. sapiens and H. neanderthalensis are the same species, so the fossil evidence is not applicable.
D) Researchers were unable to extract DNA from Neanderthal fossils.

Question 22

Which of the following describes how Homo sapiens skulls differ physically from Homo heidelbergensis?

A) Homo sapiens has a rounded cranium with larger brain size, a less pronounced chin, larger teeth, and reduced brow ridges.
B) Homo sapiens has a rounded cranium with smaller brain size, a pronounced chin, smaller teeth, and reduced brow ridges.
C) Homo sapiens has a rounded cranium with smaller brain size, a pronounced chin, smaller teeth, and prominent brow ridges.
D) Homo sapiens has a rounded cranium with larger brain size, a pronounced chin, smaller teeth, and reduced brow ridges.

Question 23

Which of the following is NOT a feature of the revised model of human evolution?

A) Modern human variation is largely derived from what was present in the population of Homo sapiens that first emerged from Africa.
B) Different populations of humans have inherited different amounts of genetic material from different sources, such as from Neanderthals and Denisovans.
C) Homo sapiens emerged from Africa 10,000 years ago.
D) Not all genetic variation has been lost from Homo species that diverged prior to the emergence of Homo sapiens in Africa.

Question 24

The phylogeny illustrated in the figure shows the relationships among 53 modern humans based on mitochondrial DNA. How does this phylogeny support the out-of-Africa hypothesis?

Question 25

Based on the figure, which statement most accurately describes the evolutionary changes in hominin dentition over time?

A) a reduction and then loss of large canines in modern humans as compared to other apes, with overall reduction in size of teeth
B) overall spread of upper jaw with increased prominence of the canines in modern humans
C) wider spread of jaw with increased prominence of molars in modern humans
D) an increase in the size of the canines in modern humans with a wider lower jaw

Question 26

How did migration patterns factor in to Richard Green et al.'s hypothesis about interbreeding among Neanderthals and modern humans?

A) Neanderthals had a Eurasian range, and since modern humans migrated out of Africa, they expected humans who descended from Europeans and Asians to share more alleles with Neanderthals than humans descended from African populations.
B) Neanderthals had an Asian range, and since modern humans migrated out of Africa, they expected humans who descended from Asia to share more alleles with Neanderthals than humans descended from African or European populations.
C) Neanderthals had a western European range, and since modern humans migrated out of Africa, they expected humans who descended from western Europeans to share more alleles with Neanderthals than humans descended from African populations.
D) Neanderthals had a North African range, and since modern humans migrated out of Africa, they expected Neanderthals to share more alleles with Africans than humans descended from other populations.

Question 27

Briefly describe how the changed ecology of the African tropics may have favored the evolution of bipedalism in hominins.

Question 28

What is the primary distinction between the multiregional hypothesis for human evolution and the out-of-Africa hypothesis for human evolution?

A) The multiregional hypothesis suggests that hominins left Africa and colonized the rest of the Old World in two to three waves, while the out-of-Africa hypothesis suggests that hominins left Africa and colonized the rest of the Old World once.
B) The multiregional hypothesis suggests that hominins evolved in multiple regions of the Old World, as evidenced by multiple branches in hominin phylogeny, while the out-of-Africa hypothesis suggests that hominins left Africa and colonized the Old World in two to three waves.
C) The multiregional hypothesis suggests that hominins left Africa and colonized the rest of the Old World once, while the out-of-Africa hypothesis suggests that hominins left Africa and colonized the Old World in two to three waves.
D) The multiregional hypothesis suggests that hominins evolved in multiple regions in both the Old World and New World, while the out-of-Africa hypothesis suggests that hominins left Africa and colonized the Old World once.

Question 29

What are the specific, distinguishing characteristics of the hominin lineage?

Question 30

As humans have migrated across the globe, establishment of new populations have resulted in the "serial founder effect." Given what you have learned about allele frequencies and the founder effect, list the following human populations in order from the first to migrate out of Africa to the most recently established population. Population
$\begin{array} { | l | c | c | c | c | c | c | } \hline \text { Population } & \mathrm { R } & \mathrm { PD } & \mathrm { LS } & \mathrm { HS } & \text { LO } & \mathrm { F } \\\hline \text { \% heterozygosity } & 23 & 91 & 42 & 15 & 21 & 86 \\\hline\end{array}$

A) HS, LO, R, LS, F, PD
B) PD, F, LS, R, LO, HS
C) LO, R, LS, F, PD, HS
D) LS, F, PD, HS, LO, R

Question 31

What skull characteristics distinguish Paranthropus from other hominin lineages?

A) huge muscle attachment regions, distinctive top ridges, protruding cheekbones
B) reduced muscle attachment regions, distinctive top ridges, flatter cheekbones
C) huge muscle attachment regions, reduced top ridges, flatter cheekbones
D) lack of muscle attachment regions, distinctive top ridges, protruding cheekbones

Question 32

As the African tropics changed to savanna, hominins moved onto the savanna while other apes remained in the forest. A major adaptation to the savanna was the evolution of bipedal locomotion. Which of the following is NOT a skeletal change associated with bipedal locomotion?

A) direct alignment of foramen magnum directly beneath the skull
B) shortened and broadened pelvis
C) shorter femur angled outward to accommodate pelvic changes
D) arched foot with loss of opposable toe

Question 33

What did Richard Wrangham hypothesize about how the use of fire shaped the course of hominin evolution?

A) The use of fire increased winter survival, leading to larger populations and greater genetic diversity.
B) The use of fire to cook food (as opposed to eating raw food) provided large energetic stores that are easily consumed and processed; this reduced nutritional challenge led to distinct morphological changes, including a large increase in brain size.
C) The use of fire enabled early hominins to prevent predator attacks, leading to higher survival rates. It also enabled them to clear large tracts of forest in tropical Africa, leading to the increased use of agriculture and a more reliable food supply.
D) Wrangham argues that the use of fire was insignificant in shaping human evolution and that the evolution of more sophisticated tools is what led to more successful hunting and a more reliable, higher-protein food supply. Increased dietary protein led to the evolution of increased brain size.

Question 34

Researchers studied the genetics of Helicobacter pylori, a stomach bacterium that is present in about half of the world, to see if H. pylori geographic patterns reflect those of their human host. What were the results of their study?

A) They found ambiguous genetic clusters that roughly corresponded to continent scale geography; genotypes revealed a continuous gradation of genetic composition from one region to the next.
B) They found distinct genetic clusters corresponding to continent scale geography; genotypes revealed sharp gradation from region to region rather than continuous gradation as seen in humans.
C) They found distinct genetic clusters corresponding to continent scale geography; genotypes revealed a continuous gradation of genetic composition from one region to the next rather than sharp divisions as seen in the human genotypes.
D) Although there was congruence in the migratory patterns revealed in each data set, the divisions in the human data were not as sharp from one region to the next as the H. pylori data were.

Question 35

Other than Homo sapiens, all Homo species went extinct by 30,000 years ago. However, a recent fossil discovery indicates one species may have survived until more recently. Which species is it?

A) Homo habilis
B) Homo neanderthalensis
C) Homo naledi
D) Homo floresiensis

Question 36

If the population of the last common ancestor of humans, chimpanzees, and gorillas was very large, and humans split from chimpanzees very quickly after the gorilla lineage diverged, how might this influence the relationship between gene trees and species trees in this clade?

Question 37

Based on the figure, is the common-language practice of referring to chimpanzees as monkeys accurate? Are monkeys a monophyletic group?

Question 38

What is the advantage of using DNA sequences from many genes to reconstruct the evolutionary history of humans?

Question 39

What does this figure tell us about the relationship between heterozygosity of H. pylori and its geographic origin?

A) Heterozygosity varies widely, although it is greatest at the midpoint of the geographic distribution of H. pylori.
B) There is not a significant relationship between heterozygosity and geographic origin.
C) Heterozygosity increases with distance from geographic origin in East Africa.
D) Heterozygosity decreases with distance from geographic origin in East Africa.

Question 40

What physical features of the first hominins are more like the panin lineage rather than the hominin lineage?

A) larger cranial capacity, fully bipedal locomotion
B) smaller braincase, dental anatomy
C) skull orientation, dental anatomy
D) small cranial capacity, opposable big toe

Question 41

What do these data on mean haplotype heterozygosity from 938 human samples from around the world tell us about human migration?

Question 42

Briefly describe the multiregional hypothesis and the out-of-Africa hypothesis. What is the key distinction between them?

Question 43

What are the primary difficulties of host-pathogen coevolution studies?

Question 44

List the distinguishing cultural features of Homo sapiens.

Question 45

How have the recent advances in sequencing ancient DNA altered our understanding of the evolutionary history of the hominin clade?

Question 46

Relate the pattern of modern human migration to the results of Green et al.'s research on interbreeding between Neanderthals and modern humans.

Question 47

What did the identification of "mitochondrial Eve" tell us about human origins?

Question 48

What is the "serial founder effect," and what are the dynamics of genetic diversity as each new population is established?

Question 49

How does the use of fire change the nutritional challenge for humans, and how did this possibly affect human evolution?