Question 1

Briefly describe the "out of Africa" and "multiregional" views to describe the transition from Homo erectus to Homo sapiens .

Accepted Answer

Early modern humans evolved from a single woman in Africa, whose offspring then migrated from Africa, perhaps as recently as 100,000 years ago, and populated Europe and Asia, driving the earlier hominid populations to extinction. Alternatively, early modern humans did not have an isolated origin in Africa, but rather they established separate colonies throughout Eurasia. Occasional contact and interbreeding between these populations enabled our species to maintain its overall cohesiveness while still preserving physical differences in people that we observe today.

Question 2

What are stromatolites and why are they important in Earth history?

Accepted Answer

Stromatolites are blue-green algae that trap sediment. They are common in some Proterozoic rocks, but the oldest are in 3.3 to 3.5 billion-year-old rocks. Stromatolites are important in understanding Earth's history because the atmosphere of the Paleoarchean had no free oxygen, but stromatolites release oxygen as a by-product of photosynthesis thereby increasing the levels of oxygen in the Earth's atmosphere.

Question 3

Describe bird evolution as known from the fossil record.

Accepted Answer

The ancestor of birds was probably a small theropod, and some species have been discovered in China that had a featherlike covering. The birdlike Archaeopteryx had dinosaur-like teeth, tail, brain size, and hindlimb structure, but had feathers and a wishbone, typically observed in birds.

Question 4

Briefly state the problems that animals faced in their adaptation to land.

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Question 5

What happened to marine invertebrates during the mass extinction that occurred at the end of the Permian Period, and what caused it?

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Question 6

What were pterosaurs? What adaptations did they have for their unique ability?

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Question 7

How did eukaryotic cells evolve, and why was this advance so important in life history?

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Question 8

Briefly state some of the problems that plants had to overcome as they adapted to land and how they accomplished that.

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Question 9

Briefly state why the development of the amniote egg was so significant in the evolution of the reptiles.

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Question 10

What do the Ediacaran fauna represent, why are they important, and what is their relationship to later life forms?

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Question 11

What characterized the Ordovician in terms of invertebrate life, and how does that relate to what was happening geologically at the time?

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Question 12

How did transgressing and regressing seas affect the quantity and diversity of life forms in the Paleozoic?

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Question 13

What was the first line of evidence that the Cretaceous Mass Extinctions were caused predominantly by a large meteorite impact?

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Question 14

Describe the evolution of fish in the Paleozoic.

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Question 15

What are the differences between saurischian and ornithischian dinosaurs, and what was their common ancestor like?

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Question 16

What is the evidence that dinosaurs were endotherms? What is the evidence that they were ectotherms? What is the conclusion?

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Question 17

What is the prehistoric overkill hypothesis, and what evidence supports overkill as the reason for the Pleistocene extinctions? What is the alternative hypothesis?

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Question 18

How were hominids different from other primates?

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Question 19

What evidence of life was there on Earth prior to stromatolites?

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Question 20

What is the Cambrian explosion? Is their appearance sudden? Why is it sudden, or why does it seem so?

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Quiz 18: Life History