AP®BiologyCollege BoardExam QuestionsUnit 7: Natural SelectionEvolution

Evolution (College Board AP® Biology): Exam Questions

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Evolution

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1
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Which of the following states how the fossil record provides evidence for evolution?

  • The fossil record indicates that all organisms appeared suddenly without any transitional forms.

  • Extinct species are shown in the fossil record to be unrelated to modern species.

  • Older fossils are found in deeper rock layers, showing gradual changes over time.

  • It can be seen in the fossil record that genetic variation does not influence evolution.

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2
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Which of the following best describes the information represented in a phylogenetic tree?

  • The physical size differences between species.

  • Evolutionary relationships based on common ancestry.

  • The exact lifespan of each species.

  • Similarities in the physical traits of species.

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3
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The global decline of amphibian populations over recent decades has been linked to habitat destruction, climate change and the spread of fungal infections. Scientists have observed that some amphibian species with small population sizes and limited genetic diversity are at a higher risk of extinction.

Which of the following is most likely to present the highest risk of extinction for amphibian populations?

  • Competition from non-native species.

  • Predation.

  • Rapid environmental change.

  • The creation of new ecological niches.

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4
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A population of island-dwelling finches was divided, creating two geographically isolated groups. Over many generations the populations developed distinct mating behaviors and beak shapes, adapting to different food sources. When scientists brought individuals from both populations together the finches did not recognize each other as mates and failed to reproduce.

Which of the following is the most likely explanation for these finches being considered to be separate species?

  • They live in different environments and consume different food sources.

  • They are reproductively isolated due to their different behaviors.

  • They have different beak shapes.

  • They evolved through gradual change over many years.

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5
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A population of fish in a large lake becomes divided when a new dam is built, separating the population into two isolated groups. Over many years these groups experience different environmental conditions and selective pressures, eventually leading to the formation of two distinct species.

Which of the following identifies the process that has occurred in this scenario?

  • Sympatric speciation

  • Artificial selection

  • Convergent evolution

  • Allopatric speciation

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1
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The Amur leopard (Panthera pardus orientalis) is a critically endangered big cat native to southeastern Russia and northeastern China. Figure 1 shows the effect of reducing leopard numbers on the genetic diversity of the population.

Graph showing a downward trend of genetic diversity as population size decreases, with a logarithmic scale on both axes. Points are marked along the line.
Figure 1. Graph showing the effect of reducing leopard numbers on the genetic diversity of the population

Which of the following statements provides the best explanation for the data shown in Figure 1?

  • As population size increases, genetic diversity increases.

  • Adaptability is not impacted by decreasing population numbers.

  • Decreasing population size removes alleles from the population making the species vulnerable to environmental changes.

  • Inbreeding results in increased mutations in the DNA which counteracts any loss of genetic diversity due to small population size.

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2
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Paleontologists discovered a series of fossils in sedimentary rock layers, representing a lineage of marine invertebrates. The fossils show gradual changes in shell shape over millions of years, with occasional rapid shifts in morphology coinciding with periods of significant environmental change.

Which of the following evolutionary models best fits this fossil record?

  • Punctuated equilibrium

  • Gradualism

  • Divergent evolution

  • Allopatric speciation

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3
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Modern whales possess small pelvic bones, despite not using legs for walking or movement on land. Scientists have identified these structures as vestigial, but their presence in fully aquatic animals raises questions about their evolutionary significance.

Which of the following conclusions best explains why whales have these pelvic bones?

  • Whales have evolved from ancestors that walked on land, and the pelvic bones are remnants of their terrestrial past.

  • Whales evolved from fish, which also have pelvic bones.

  • The pelvic bones help whales swim faster, making them an advantageous trait.

  • The pelvic bones are necessary for whale reproduction.

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4
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The mitochondrial genome is maternally inherited, meaning that all mitochondria in an individual are inherited from the mother. Because of this, mitochondrial DNA (mtDNA) is often used to study evolutionary relationships.

Which of the following best explains why mitochondrial DNA is useful for studying the evolutionary relationships between species?

  • Mitochondrial DNA mutates faster than nuclear DNA.

  • Mitochondrial DNA undergoes recombination, allowing for the mixing of genes between generations.

  • Mitochondrial DNA does not undergo recombination, preserving ancestral genetic information.

  • Mitochondrial DNA is specific to certain species.

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1
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The image below shows a cladogram.

phylogenetic, evolutionary tree_canis

Which of the following conclusions can be drawn from this cladogram?

  • C.simensis shares a common ancestor with C.anthus, C.latrans, C.lupus and C.lupus familiaris.

  • The DNA of C. adustus and C. mesomelas is less similar than the DNA of C.adustus and C.Alpinus.

  • C. adustus and C. mesomelas evolved more recently than C.lupus.

  • C.alpinus evolved from L. pictus.

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2
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Several species of lava lizards, of the genus Microlophus, are endemic to the Galápagos Islands. A group of scientists recorded the mating displays of male lava lizards in different parts of the Galápagos, using wave amplitude to represent the height and length of head-bobbing behavior. Figure 1 shows variations in these displays among different species currently living on different islands.

Map of the Galápagos Islands showing locations and head bobbing behaviours of different lizard species: M. pacificus, M. habeli, M. albemarlensis, M. jacobi, M. indefatigabilis, and M. grayii.
Figure 1. Wave amplitude used to represent the height and length of head-bobbing behavior in Lava lizards.

Which of the following conclusions about the evolution of Galápagos lava lizards is best supported by the data?

  • Mating displays remain identical among all individuals of the same species, ensuring reproductive success.

  • The variation in mating displays suggests reproductive isolation, supporting the idea that allopatric speciation has occurred.

  • The differences in mating displays are random and unlikely to contribute to reproductive isolation.

  • The observed variation is an example of convergent evolution, where unrelated species develop similar traits due to shared environments.

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3
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A biologist studying a population of beetles in a rapidly changing environment recorded changes in allele frequencies for a gene associated with pigmentation over 10 years.

The beetles inhabit a region affected by increasing industrial pollution, which has darkened the landscape. The table below shows the observed allele frequencies for a light-colored (l) recessive allele and a dark-colored (L) dominant allele:

Table 1: Allele frequencies in a beetle population

Year

Frequency of L (p)

Frequency of l (q)

1

0.45

0.55

5

0.68

0.32

10

0.89

0.11

Which of the following provides the most likely explanation for the data?

  • The light-colored beetles are likely to become extinct if environmental conditions remain unchanged, reducing the genetic diversity of the population.

  • Genetic drift has eliminated the recessive allele, showing that random chance plays a greater role than selection in determining evolutionary outcomes.

  • The population is not in Hardy-Weinberg equilibrium, as changes in allele frequency over generations indicate that evolutionary forces are acting on the population.

  • Natural selection is acting on the population, as dark-colored beetles have a selective advantage in the polluted environment.

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4
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Cytochrome C is a protein common to all organisms, and the gene that codes for it is often studied when constructing phylogenetic trees.

The table shows the number of nucleotide differences in the cytochrome C genes of several different species.

Human

Chicken

Mouse

Rat

Yeast

Fruit fly

Human

X

61

32

36

112

89

Chicken

61

X

61

61

119

94

Mouse

32

61

X

10

119

77

Rat

36

61

10

X

115

84

Yeast

112

119

119

115

X

124

Fruit fly

89

94

77

84

124

X

Which of the following shows the correct order of the organisms when arranged from the most closely related to humans, to the the least closely related?

    1. Chicken

    2. Fruit fly

    3. Yeast

    4. Mouse

    5. Rat

    1. Rat

    2. Mouse

    3. Fruit fly

    4. Yeast

    5. Chicken

    1. Mouse

    2. Rat

    3. Chicken

    4. Fruit fly

    5. Yeast

    1. Yeast

    2. Fruit fly

    3. Chicken

    4. Rat

    5. Mouse

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5
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The point in time at which a species diverged from its most recent ancestor can be determined by measuring the percentage difference in DNA bases, as the rate at which differences accumulate is constant. 

There is a 0.7 % difference between the DNA of the pygmy chimpanzee and common chimpanzee, which diverged 3 million years ago. Human DNA differs from both the pygmy chimpanzee and common chimpanzee by 1.6 %. 

Which of the following correctly states how long ago the ancestor of humans diverged from the ancestor of chimpanzees?

  • 3.9 million years ago

  • 1.3 million years ago

  • 6.9 million years ago

  • 6.4 million years ago

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