Q: A fossilized skull contains $$\frac{1}{64} of $$its original carbon-14. If the half-life of carbon-14 is 5,700 years, what is the approximate age of the fossil?

$$5,700 \times 6 = 34,200$$ years

Question 1

Which of the following best describes the four-stage hypothesis for the origin of life on Earth?

Accepted Answer

The abiotic synthesis of small organic molecules, the joining of these molecules into polymers, the packaging of these molecules into protocells, and the origin of self-replicating molecules.

Question 2

Stanley Miller’s 1953 experiment was significant because it demonstrated that:

Accepted Answer

Organic molecules could be synthesized abiotically under conditions thought to resemble those of early Earth.

Question 3

Why do 3.5-billion-year-old stromatolites suggest that life originated before 3.5 billion years ago?

Accepted Answer

Because stromatolites are formed by prokaryotes, indicating that life must have existed to create them.

Question 4

Which of the following changes would most likely be made to Miller’s apparatus to reflect current evidence about Earth’s early atmosphere?

Accepted Answer

Replace the reducing gases with a mixture containing more neutral gases such as $$CO_2$$ and $$N_2.$$

Question 5

Why is the formation of protocells considered a key step in the evolution of life?

Accepted Answer

Protocells can maintain an internal environment different from their surroundings, a basic property of life.

Question 6

Radiometric dating is based on which of the following principles?

Accepted Answer

The decay of radioactive isotopes at a constant rate.

Question 7

A fossilized skull contains $$\frac{1}{64} of $$its original carbon-14. If the half-life of carbon-14 is 5,700 years, what is the approximate age of the fossil?

Accepted Answer

$$5,700 	imes 6 = 34,200$$ years

Question 8

Which event is most closely associated with the end of the Cretaceous period?

Accepted Answer

A mass extinction likely caused by an asteroid impact, leading to the extinction of most dinosaurs.

Question 9

How does plate tectonics influence macroevolution?

Accepted Answer

By altering the distribution and diversification of organisms through the movement of continents.

Question 10

Which of the following best explains why marsupial mammals underwent more diversification in Australia than elsewhere?

Accepted Answer

Australia’s isolation limited competition from placental mammals, allowing marsupials to diversify into many ecological niches.

Question 11

Which of the following is an example of an exaptation?

Accepted Answer

Feathers that originally evolved for insulation later being used for flight in birds.

Question 12

Which statement best distinguishes between homologous and analogous structures?

Accepted Answer

Homologous structures are inherited from a common ancestor, while analogous structures arise from convergent evolution.

Question 13

Which of the following is the correct order of classification categories from most specific to most general?

Accepted Answer

Species, genus, family, order, class, phylum, kingdom, domain

Question 14

In cladistics, what is a clade?

Accepted Answer

A group consisting of an ancestral species and all its descendants.

Question 15

Why is hair not a useful character for distinguishing a particular clade of mammals within the larger clade Mammalia?

Accepted Answer

Because hair is a shared ancestral character for all mammals.

Question 16

How do molecular clocks help track evolutionary time?

Accepted Answer

By estimating the time required for a given amount of genetic change based on the assumption of a constant rate of mutation.

Question 17

Which of the following best describes the concept of parsimony in constructing phylogenetic trees?

Accepted Answer

Choosing the tree that requires the fewest evolutionary changes.

Question 18

Which domain includes organisms with eukaryotic cells?

Accepted Answer

Eukarya

Question 19

Which of the following is a consequence of mass extinctions?

Accepted Answer

They are often followed by adaptive radiations, where new species rapidly evolve to fill vacant ecological niches.

Tracing Evolutionary History: The Origin and Diversification of Life on Earth

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