Part 1 - Chapter 10 (Inquisitive)

The following anatomical elements have evolved in hominins to support different functions of bipedal locomotion. Drag each one of the functions to the body part that facilitates that function.

- Head: allows a vertical placement of the head on the vertebral column - neck: positions the body trunk's center of gravity above the pelvis - pelvis: provides stability during standing, walking, and running - knee: places feet under the center of gravity - foot: absorbs shock - big toe: supports the body during walking and running

According to Darwin's hunting hypothesis, the expected order of appearance was from left to right:

- bipedal - small canines - large brain - tool use

Identify which features distinguish all hominins from other hominids and which are only characteristic of later hominins.

- bipedal - small canines - large brain - tool use

Place the following important evolutionary events in chronological order. These events define hominins as a group.

- evolution of bipedalism - increase in enamel thickness - regular use of stone tools - enlargement of brain to around 1,4500 cc

Ardipithecus ramidus was a transitional species in many ways, with some features that were apelike, some humanlike, and others that were a mosaic of both. Place "apelike," "humanlike," or "mosaic" on the correct feature.

- humanlike: left side of head & pelvis - apelike: hand & right side of head - mosaic: feet/toes

Which of the following limb features are associated with bipedalism as seen in humans?

Associated with Bipedalism: - valgus knee - non-opposable big toe - length of the leg Not Associated with Bipedalism: - flat feet - C-shaped spine

Using the graphic and the information provided below, identify this hominin by choosing the correct answer.

Australopithecus robustus

Identify the characteristics associated with Australopithecus afarensis in contrast to earlier hominins.

Characteristics of Australopithecus afarensis: - round heels, double arches (front-to-back and side-to-side), and nondivergent big toes - diverse diet indicated by diverse tooth wear - lived in various habitats Not Characteristics of Australopithecus afarensis: - flat face - human-sized brain

Which of the following statements best characterize the patchy forest hypothesis?

Correct Answer(s): - Climate change that occurred millions of years ago led to contraction of forest in favor of grasslands, requiring greater distances to be travelled between food sources. - Bipedalism is more efficient for medium- and longer-distance travel than is quadrupedalism. Incorrect Answer(s): - Quadrupedal apes can travel efficiently between distant forest patches in search for food. - When forests became patchy, hominins stopped eating foods from trees and switched to hunting animals.

Identify the statements that accurately describe both Australopithecus aethiopicus and Australopithecus boisei.

Describes Australopithecus aethiopicus and Australopithecus boisei: - They had very large molars (cheek teeth). - They are also known as robust australopithecines. - They had enormous chewing muscles indicated by the large attachment areas and a pronounced sagittal crest. - They are found in East Africa. Does Not Describe Australopithecus aethiopicus and Australopithecus boisei: - They had very small molars (cheek teeth). - They made stone tools.

Identify the statements that correctly describe Australopithecus platyops.

Describes Australopithecus platyops: - Some suggest it be placed in a different genera and called Kenyathropus. - Australopithecus platyops had a flat face, unlike other australopithecines. - Australopithecus platyops was found in Lomekwi. Does Not Describe Australopithecus platyops: - Australopithecus platyops lived in a unique tropical forest environment. - Australopithecus platyops dates to 4.4 mya. - Australopithecus platyops is one of the best-represented hominins.

Identify the statements that correctly describe Lovejoy's provisioning hypothesis.

Describes Provisioning Hypothesis: - With the freeing of the hands, males could carry food back to the females and offspring, and could contribute to parental investment in their young. - Provisioning by the male allows the female to care for more than one offspring at a time, which in turn allows for faster mating and birth rates. Does Not Describe Provisioning Hypothesis: - Large brains, tool use, and bipedalism evolved together. - Female hominins are able to support more than one infant at a time without male help.

Identify the statements that correctly describe the site of Bouri.

Describes Site of Bouri: - Bouri is located in the Middle Awash, Ethiopia. - Cutmarks and smashed bones have been found here, indicating that stone tools were used. However, the stone tools were never found. - Australopithecus garhi was found here. Does Not Describe Site of Bouri: - Bouri is dated to about 3.5 mya. - Bouri is the only site where Australopithecus africanus is found. - Bouri has a lot of lithic artifacts (stone tools).

Identify the facts that emerged in the twentieth century that falsify Charles Darwin's hunting hypothesis for the origin of hominins.

Falsifies Hunting Hypothesis: - Bipedalism arose early in hominin evolution, while intensive use of chipped stone tools appeared much later. - Each of the characteristics that define hominin appeared at different points of human evolution. - The Piltdown fossil was shown to be a hoax. Does Not Falsify Hunting Hypothesis: - Bipedalism, tool use, and large brains all evolved together.

Identify the features of the pre-australopithecine Orrorin tugenensis.

Features of Orrorin tugenensis - found in the Tugen Hills - hominin canine complex - clear evidence of bipedalism from the femurs - dates to 6 mya Not Features of Orrorin tugenensis: - humanlike finger bones

Identify the important features of the pre-australopithecine Sahelanthropus tchadensis.

Features of Sahelanthropus tchadensis: - probably bipedal - dates to 7-6 mya - very small brain size - the only hominin fossil found in central Africa - prominent browridges Not Features of Sahelanthropus tchadensis: - nearly human-sized brain - honing complex

Many features distinguish modern humans from the nonhuman apes. However, only bipedalism and nonhoning canines define hominins as a group. Identify the reasons why.

The evolution of hominins involved several different changes that happened at different times. Only two of these features evolved early enough to apply to all the hominins.

The events surrounding the Piltdown fossil discoveries provide important lessons for the scientific community. Place in chronological order the events that occurred before and after the excavations at Piltdown Common.

The leading scientific hypothesis was that a large brain was the most important human feature. Piltdown man was found in southern England and is determined to be an early human ancestor. Australopithecus africanus was found in South Africa. Piltdown man was discovered to be a hoax.

Australopithecus anamensis is the oldest species currently known in the genus Australopithecus.

True

You are an anthropologist who has studied early hominin bones, and you argue, based on the finds, that this species was both bipedal and exhibited a high degree of sexual dimorphism in body size. What are the implications of your argument?

Your argument falsifies Owen Lovejoy's provisioning hypothesis because his hypothesis requires a decrease in sexual dimorphism with the evolution of bipedalism.