Q: Radiometric dating is used to determine the age of fossils. Which equation correctly represents the relationship between the amount of a radioactive isotope remaining and the number of half-lives elapsed?

$$N = N_0$ \times (\frac{1}{2})^n$$

Question 1

Which of the following best describes macroevolution?

Accepted Answer

The broad pattern of evolution above the species level, including the origin of new taxonomic groups and mass extinctions.

Question 2

A paleontologist discovers a fossil in sedimentary rock. Which of the following is a limitation of using fossils to study macroevolution?

Accepted Answer

Fossilization is a rare event, so the fossil record is incomplete and biased toward organisms with hard parts.

Question 3

Radiometric dating is used to determine the age of fossils. Which equation correctly represents the relationship between the amount of a radioactive isotope remaining and the number of half-lives elapsed?

Accepted Answer

$$N = N_0$ 	imes (\frac{1}{2})^n$$

Question 4

Why do scientists use different isotopes for dating fossils of different ages?

Accepted Answer

Because isotopes with longer half-lives are needed to date older fossils, as shorter-lived isotopes would have decayed away.

Question 5

Which of the following events occurred first in Earth's history?

Accepted Answer

Appearance of single-celled prokaryotes

Question 6

According to the theory of plate tectonics, what is continental drift?

Accepted Answer

The movement of continents due to the shifting of Earth's plates over geological time.

Question 7

How does continental drift promote allopatric speciation?

Accepted Answer

By physically separating populations, leading to genetic divergence and the formation of new species.

Question 8

Which of the following best explains why the fossil record is compared to wallpaper in an old house?

Accepted Answer

Because, like wallpaper, the fossil record is layered, with newer fossils on top of older ones, revealing a sequence of historical events.

Question 9

Which group of organisms has been present on Earth the longest, according to the geological record?

Accepted Answer

Single-celled prokaryotes

Question 10

What is adaptive radiation, and what is a real-world example?

Accepted Answer

The rapid evolution of diverse species from a common ancestor, such as the diversification of mammals after the extinction of dinosaurs.

Question 11

How many mass extinction events have occurred in Earth's history, and what is a likely cause of the current high extinction rate?

Accepted Answer

Five mass extinctions; current extinctions are likely due to human activities such as habitat destruction and climate change.

Question 12

After a mass extinction event, how long does it typically take for a diverse community of organisms to recover?

Accepted Answer

Millions of years

Question 13

What is heterochrony, and which of the following is an example?

Accepted Answer

A change in the timing or rate of developmental events, such as the retention of juvenile features in adult salamanders (paedomorphosis).

Question 14

What are Hox genes, and how can changes in these genes lead to speciation?

Accepted Answer

Genes that control the placement and organization of body parts; mutations can result in major changes in body form, potentially leading to new species.

Question 15

Which of the following statements best reflects Francois Jacob's idea that 'evolution is like tinkering'?

Accepted Answer

Evolution modifies existing structures for new functions, rather than inventing new ones.

Question 16

Which isotope is commonly used to date fossils less than 75,000 years old, and why is it not useful for older fossils?

Accepted Answer

Carbon-14; because its half-life is too short to detect in older fossils.

Question 17

Which of the following best describes a homeotic gene?

Accepted Answer

A gene that controls the identity and arrangement of body parts during development.

Question 18

Which of the following is a challenge when dating older fossils using radiometric methods?

Accepted Answer

The original radioactive isotopes may no longer be present, and the surrounding rocks must be dated instead.

Question 19

Which of the following is the correct order of classification from most inclusive to least inclusive?

Accepted Answer

Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 20

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

Accepted Answer

The opening of ecological niches, leading to adaptive radiations among surviving lineages.

AP Biology – Chapter 23: Broad Patterns of Evolution – Guided Study

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