AP Biology Unit 7: Natural Selection Practice Exam

1. Which of the following statements best describes the data presented in the graph?

2. Which of the following best explains the relationship between the change in the seed supply and the change in the finch population's beak characteristics?

3. If a period of prolonged, heavy rains returned to the island, leading to a resurgence of plants that produce small, soft seeds, which of the following would be the most likely predicted effect on the finch population over the next several generations?

4. A population of cheetahs experienced a dramatic reduction in numbers due to overhunting and habitat loss, leaving only a few individuals. Although the population has since rebounded, it exhibits very low genetic diversity. Which of the following is the most likely consequence of this low genetic variation?

5. The phenomenon described in the cheetah population in the previous question is an example of which of the following?

6. The breeding of domesticated dogs from a common wolf ancestor has resulted in hundreds of different breeds with a wide variety of physical and behavioral traits. This is an example of:

7. Which of the following best describes the trend shown in the data?

8. Which of the following is NOT a condition required for a population to be in Hardy-Weinberg equilibrium?

9. In a population of 1000 plants, 640 have red flowers (dominant phenotype) and 360 have white flowers (recessive phenotype). Assuming the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype ($RR$)?

10. In a different population, the frequency of the allele for albinism (a) is 0.05. Assuming Hardy-Weinberg equilibrium, what percentage of the population would be expected to be heterozygous carriers of the albinism allele?

11. The forelimbs of humans, bats, whales, and cats are composed of a similar arrangement of bones (humerus, radius, ulna, carpals, metacarpals, and phalanges). These structures have different functions in each organism. Which of the following claims is best supported by this anatomical evidence?

12. The wings of a butterfly and the wings of a bird serve the same function (flight) but have very different evolutionary origins and internal structures. These are examples of:

13. All eukaryotic organisms possess membrane-bound organelles, such as mitochondria and a nucleus. Which of the following claims does this evidence best support?

14. The presence of introns (non-coding sequences) within the genes of eukaryotes, but not typically in prokaryotes, is considered strong evidence for the common ancestry of all eukaryotes. This is because:

15. Which of the following provides the best reasoning to explain this observation?

16. This scenario is a direct example of which of the following?

17. What is the relationship between the pre-existing variation in the bacterial population and its ability to evolve resistance?

18. Based on the phylogenetic tree, which of the following statements is true?

19. A new fossil is discovered that has vertebrae, a bony skeleton, and four limbs, but it does not have an amniotic egg. Based on the cladogram, where would this organism most likely be placed?

20. Which of the following is a shared derived character for primates and crocodiles?

21. A scientist claims that this phylogenetic tree is a testable hypothesis. Which of the following types of new evidence would be most likely to cause a revision of the tree?

22. The "RNA world" hypothesis proposes that RNA, not DNA, was the first genetic material. Which property of RNA provides the strongest support for this hypothesis?

23. The Miller-Urey experiment was significant because it demonstrated that:

24. A small group of individuals from a large mainland population colonizes a remote island. The new island population has a different allele frequency than the original population. This is an example of:

25. Which of the following statements best describes the relationship between an organism's phenotype and its fitness?

26. What is the ultimate source of all new heritable variation in a population?

27. A population of wildflowers grows on both the sunny side and the shady side of a hill. The two groups of flowers are still able to interbreed. If seeds from the sunny side are frequently carried by the wind to the shady side, how would this process affect the genetic makeup of the shady-side population?

28. Environments are not static; they change over time. How do changing environments drive evolution?

29. In a population at Hardy-Weinberg equilibrium, the frequency of the recessive allele 'b' is 0.2. What is the frequency of individuals with the genotype Bb?

30. The fossil record shows a clear sequence of life forms, from simpler organisms in older rock layers to more complex organisms in younger layers. Which claim does this evidence most directly support?

31. A fungal disease spreads through a forest, killing most of the pine trees. Scientists observe that a small number of trees have a rare allele that provides resistance to the disease and they survive. What is the most likely long-term consequence for this pine population?

32. Which of the following scenarios is most likely to result in evolution by genetic drift?

33. The genetic code, which translates nucleotide sequences into amino acid sequences, is nearly universal among all living organisms. What does this observation strongly suggest?

34. Phenotypic variation is the raw material for natural selection. Which of the following is the best example of phenotypic variation?

35. Which of the following statements is a correct interpretation of the data?

36. Based on this molecular data, which of the following organisms would be placed closest to humans on a phylogenetic tree?

37. Why is this type of molecular data a powerful tool for inferring evolutionary relationships?

38. According to Darwin's theory of natural selection, competition for limited resources results in:

39. In a forest ecosystem, the color of a beetle's exoskeleton provides camouflage. If the forest floor becomes significantly darker over many generations due to industrial pollution, what is the most likely relationship between the environmental change and the beetle population?

40. Pathogens, such as viruses and bacteria, often evolve much more rapidly than their hosts. Which of the following is the primary reason for this?

41. On a phylogenetic tree, what does a node (branch point) represent?

42. A researcher finds that the genotype frequencies in a population are $AA=0.30$, $Aa=0.20$, and $aa=0.50$. The calculated Hardy-Weinberg expected frequencies are $AA=0.16$, $Aa=0.48$, and $aa=0.36$. What can be concluded about this population?

43. Evolutionary fitness is best defined as:

44. A large, genetically diverse population of snails is separated into two isolated populations by the formation of a new mountain range. If the two populations experience different environmental conditions over a long period, which of the following is the most likely outcome?

45. Whales have tiny, non-functional pelvic and femur bones embedded in their bodies. These structures are best described as:

46. A scientist claims that a population of plants with high genetic diversity is more likely to survive an outbreak of a novel plant pathogen than a population with low genetic diversity. Which of the following statements best supports this claim?

47. A cladogram is constructed based on morphological characteristics. Later, DNA sequencing reveals that one of the organisms was placed incorrectly. This revision of the cladogram demonstrates that:

48. Which of the following is a key difference between the proposed conditions of early Earth and the conditions on Earth today that is relevant to the origin of life?