Q: A paleontologist finds a fossil with a carbon-14 to carbon-12 ratio that is one-quarter of the ratio found in living organisms. Given the half-life of carbon-14 is $$5,700$$ years, approximately how old is the fossil?

$$11,400$$ \text{ years} = 2 \times 5,700$ (two half-lives, so one-quarter remains)

Question 1

Which of the following best describes Darwin's concept of 'descent with modification'?

Accepted Answer

Species change over generations as traits are inherited and modified, leading to evolution.

Question 2

A population of beetles is exposed to a new pesticide. After several generations, most beetles are resistant. Which step in Darwin's logic does this scenario BEST illustrate?

Accepted Answer

Natural selection resulting in unequal reproductive success

Question 3

Which of the following is NOT a requirement for natural selection to occur?

Accepted Answer

Individuals must adapt their traits during their lifetime

Question 4

Why is antibiotic resistance in bacteria a powerful example of evolution by natural selection?

Accepted Answer

Resistant bacteria survive and reproduce, increasing the frequency of resistance genes in the population.

Question 5

Which of the following statements about the fossil record is TRUE?

Accepted Answer

Older fossils are found in deeper rock layers, showing a progression from simple to complex life forms.

Question 6

A paleontologist finds a fossil with a carbon-14 to carbon-12 ratio that is one-quarter of the ratio found in living organisms. Given the half-life of carbon-14 is $$5,700$$ years, approximately how old is the fossil?

Accepted Answer

$$11,400$$ 	ext{ years} = 2 	imes 5,700$ (two half-lives, so one-quarter remains)

Question 7

Which of the following is an example of homologous structures?

Accepted Answer

The flipper of a porpoise and the arm of a human

Question 8

Which mechanism of evolution is most likely to decrease genetic diversity in a population after a natural disaster?

Accepted Answer

Bottleneck effect

Question 9

A small group of birds from a mainland population colonizes a distant island. Over time, the island population has less genetic variation than the original population. This scenario is an example of:

Accepted Answer

Founder effect

Question 10

Which of the following best defines Darwinian fitness?

Accepted Answer

The number of healthy, reproducing offspring an individual leaves behind

Question 11

Why can't individuals evolve, according to modern evolutionary theory?

Accepted Answer

Evolution is a change in the gene pool of a population, not in individuals

Question 12

Which of the following is NOT a reproductive barrier that maintains species boundaries?

Accepted Answer

Gene flow

Question 13

Which type of speciation is most likely responsible for the formation of new squirrel species on opposite sides of the Grand Canyon?

Accepted Answer

Allopatric speciation

Question 14

Which of the following is a key difference between microevolution and macroevolution?

Accepted Answer

Microevolution involves changes in the gene pool within a population; macroevolution involves the formation of new species or major changes above the species level.

Question 15

Which of the following is an example of artificial selection?

Accepted Answer

Humans breeding dogs for specific traits

Question 16

Which of the following is NOT a line of evidence for evolution outside the fossil record?

Accepted Answer

Mechanical incompatibility

Question 17

A plant species suddenly doubles its chromosome number and can no longer breed with the original population. This is an example of:

Accepted Answer

Sympatric speciation

Question 18

Which of the following best describes punctuated equilibrium?

Accepted Answer

Species remain unchanged for long periods, interrupted by rapid bursts of change.

Question 19

Which of the following correctly lists the taxonomic hierarchy from broadest to most specific?

Accepted Answer

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

Question 20

Which of the following is the best explanation for why mules are considered an example of hybrid weakness?

Accepted Answer

Mules are sterile and cannot produce offspring.

Darwinian Evolution: Mechanisms, Evidence, and Speciation

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