Question 1

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

Accepted Answer

Fossil evidence did show intermediate morphology, but it could not definitively confirm that this was solely due to interbreeding. Other factors such as convergent evolution could not be ruled out.

Question 2

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

Accepted Answer

Homo sapiens have a larger cranium, which houses a larger brain, but with reduced brow ridges. They also have a less pronounced chin and smaller teeth compared to Homo heidelbergensis.

Question 3

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

Accepted Answer

The revised model of human evolution states that Homo sapiens emerged from Africa around 200,000 years ago, not 10,000 years ago. Therefore, option C is not a feature of the revised model of human evolution.

Question 4

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?

Accepted Answer

The answer of The phylogeny illustrated in the figure shows...

Question 5

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

Accepted Answer

The figure shows a clear reduction in the size of canines and overall tooth size in modern humans compared to other hominins and apes, indicating an evolutionary trend towards less emphasis on biting and more on processing food with tools and cooking.

Question 6

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

Accepted Answer

The hypothesis suggested by Richard Green et al. was based on the fact that Neanderthals had a Eurasian range and modern humans migrated out of Africa. Therefore, they expected that humans who descended from Europeans and Asians (who migrated out of Africa and into Eurasia) would share more alleles with Neanderthals than humans descended from African populations.

Question 7

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

Accepted Answer

The answer of Briefly describe how the changed ecology of...

Question 8

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

Accepted Answer

The answer of What is the primary distinction between the...

Question 9

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

Accepted Answer

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Question 10

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
$\begin{array} { | l | c | c | c | c | c | c | } 
\hline \text { Population } & \mathrm { R } & \mathrm { PD } & \mathrm { LS } & \mathrm { HS } & \text { LO } & \mathrm { F } \
\hline \text { \% heterozygosity } & 23 & 91 & 42 & 15 & 21 & 86 \
\hline
\end{array}$

Accepted Answer

The serial founder effect predicts that populations established more recently will have lower genetic diversity due to a smaller number of founding members. The order from highest to lowest \% heterozygosity (indicative of genetic diversity) is PD, F, LS, R, LO, HS, which matches option B.

Question 11

What skull characteristics distinguish Paranthropus from other hominin lineages?

Accepted Answer

Paranthropus is distinguished by its robust skull features, including large muscle attachment areas for chewing muscles, pronounced sagittal crests (distinctive top ridges), and prominent cheekbones, which supported their strong jaws and large teeth.

Question 12

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?

Accepted Answer

The correct skeletal changes associated with bipedal locomotion include the alignment of the foramen magnum directly beneath the skull, a shortened and broadened pelvis, and an arched foot with the loss of an opposable toe. However, the femur in bipedal locomotion becomes longer and is angled inward (not outward) to accommodate pelvic changes, which helps in maintaining balance during walking.

Question 13

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

Accepted Answer

Richard Wrangham hypothesized that the use of fire to cook food provided large energetic stores that are easily consumed and processed, reducing the nutritional challenge and leading to distinct morphological changes, including a large increase in brain size.

Question 14

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?

Accepted Answer

The researchers found distinct genetic clusters in H. pylori that corresponded to continent scale geography, but these genotypes revealed a continuous gradation of genetic composition from one region to the next, rather than sharp divisions as seen in the human genotypes.

Question 15

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?

Accepted Answer

Homo floresiensis fossils found on the island of Flores in Indonesia have been dated to have lived as recently as 50,000 years ago, which is much later than the extinction of other Homo species.

Question 16

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?

Accepted Answer

The answer of If the population of the last common...

Question 17

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

Accepted Answer

The answer of Based on the figure, is the common-language...

Question 18

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

Accepted Answer

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Question 19

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

Accepted Answer

The figure shows a clear, inverse relationship between heterozygosity of H. pylori and distance from the geographic origin in East Africa. Heterozygosity is highest in East Africa, where the bacterium originated, and decreases as it spreads further from this region.

Question 20

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

Accepted Answer

The first hominins had a small cranial capacity and an opposable big toe, which are features more similar to the panin lineage (chimpanzees and bonobos) than to later hominins.

Quiz 19: Human Evolution