Question 1

Which of the following best describes the sequence of events hypothesized to have led to the origin of life on early Earth?

Accepted Answer

Abiotic synthesis of small organic molecules, joining into macromolecules, packaging into protocells, origin of self-replicating molecules

Question 2

The Miller-Urey experiment provided evidence for which hypothesis about the origin of life?

Accepted Answer

Organic molecules can be synthesized abiotically under conditions similar to early Earth's atmosphere

Question 3

Which molecule is thought to have been the first genetic material, and what property supports this hypothesis?

Accepted Answer

RNA; it can act as a catalyst and self-replicate

Question 4

What evidence supports the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Their inner membranes are similar to prokaryotic plasma membranes

Question 5

During the 'oxygen revolution' approximately 2.7 to 2.4 billion years ago, what was a major consequence for life on Earth?

Accepted Answer

Extinction of many anaerobic prokaryotes due to rising oxygen levels

Question 6

Which event is most closely associated with the Cambrian explosion?

Accepted Answer

Rapid diversification of hard-bodied animals and predator-prey interactions

Question 7

Which of the following is a direct consequence of mass extinction events?

Accepted Answer

Adaptive radiations, where surviving groups diversify to fill new niches

Question 8

The end-Permian extinction, also known as 'The Great Dying,' was primarily caused by which factor?

Accepted Answer

Massive volcanic eruptions releasing greenhouse gases

Question 9

Which adaptive trait was crucial for the colonization of land by plants and animals?

Accepted Answer

Adaptations to resist desiccation and reproduce on land

Question 10

Which of the following best explains why the fossil record of early life is limited?

Accepted Answer

Early life forms were microscopic and lacked hard parts, making fossilization unlikely

Question 11

If the atmospheric oxygen concentration increased from 0.001% to 10% over a period of 300 million years, what was the average rate of increase per million years? (Assume a linear increase; use the formula $$	ext{Rate} = \frac{	ext{Final} - 	ext{Initial}}{	ext{Time}})$$

Accepted Answer

$$\frac{10 - 0.001}{300} = 0.0333\%$$ per million years

Question 12

Which of the following is NOT evidence supporting the endosymbiotic origin of mitochondria?

Accepted Answer

Mitochondria are surrounded by a single membrane

Question 13

Which mass extinction event is associated with the asteroid impact that led to the collapse of the food web and a 'nuclear winter'?

Accepted Answer

End-Cretaceous extinction

Question 14

Which process is most responsible for the formation of banded iron formations in ancient rocks?

Accepted Answer

Precipitation of iron oxide due to oxygen produced by photosynthetic organisms

Question 15

Which of the following is an example of morphological innovation that led to adaptive radiation?

Accepted Answer

Evolution of seeds in plants, allowing colonization of new habitats

Question 16

Why did the evolution of photosynthesis have a major impact on the history of life?

Accepted Answer

It increased atmospheric oxygen, enabling aerobic respiration and diversification of life

Question 17

Which event in Earth's history is most closely linked to the appearance of stromatolites?

Accepted Answer

First evidence of life in the fossil record

Question 18

Which of the following statements about adaptive radiation is TRUE?

Accepted Answer

It can occur after the evolution of a key trait that allows organisms to exploit new resources

Question 19

Which of the following best explains why recovery of biodiversity after a mass extinction can take millions of years?

Accepted Answer

Ecological communities and habitats must be rebuilt, and new species must evolve to fill vacant niches

Chapter 25: The History of Life on Earth – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards