Homo sapiens Lesson

Lake Turkana is located in a region with most of the fossil record of early human origins and contains sediments that can be used to study past climate fluctuations. (T/F)

True

Humans are more closely related to Gorillini (gorillas) than to Pan (chimpanzees and bonobos). (T/F)

False

Which statement is true? A. Savannas are desert-like ecosystems composed of shrubs and xerophytes common in East Africa. B. The proposed hypothesis of variability selection states that the key events in human evolution were shaped by environmental instability and the flexibility of our ancestors in what they ate and where they lived. C. The savanna hypothesis states that Hominin speciation was driven by abrupt and fast climate fluctuations of wet-dry cycles. D. Human ancestors with more diverse diets were more likely to go extinct during times when environmental conditions change.

B. The proposed hypothesis of variability selection states that the key events in human evolution were shaped by environmental instability and the flexibility of our ancestors in what they ate and where they lived.

Match the event and the time in history: Homo sapiens first emerged in Africa

200,000 years ago

Match the event and the time in history: The last glacial maximum

25,000 years ago

Match the event and the time in history: Global temperatures became more variable

3 million years ago

Match the event and the time in history: Global temperatures were higher

50 million years ago

Why did Homo survive whereas Paranthropus went extinct? A. Homo became more versatile in response to short-lived large swings between drier and wetter climate. B. Paranthropus was not adapted to handle a long-term trend towards grassland-dominated savanna.

A. Homo became more versatile in response to short-lived large swings between drier and wetter climate.

What evidence allowed scientists to refute (disprove!) the hypothesis that bipedalism and increased brain size were driven by a single, gradual long-term trend towards increased aridity and the expansion of the savanna? A. Plant wax biomarkers in sediments. B. Adaptations of Bovids (African antelopes) in the fossil record. C. Paleo diet research of fossil tooth isotopic data. D. Layers from deep-sea sediment cores. E. Carbon 13/12 isotopic ratios of C4 grasses versus C3 woody plants in sediments. F. All of the above

F. All of the above

Savannas are:

They are open tropical ecosystems composed of grasses and sedges, sometimes spotted with clusters of woody trees.

The "variability hypothesis" is:

adaptation to a more variable climate

"savanna hypothesis" is:

adaptation to the long-term drying trend