Of course. Here is a complete AP Biology Unit 7 practice test, designed to be comprehensive, challenging, and deeply educational Easy to understand, harder to ignore..
AP Biology Unit 7 Practice Test: Evolution and Natural Selection
Unit 7 of the AP Biology curriculum, "Evolution and Natural Selection," is the cornerstone of the entire course. This unit tests your understanding of the mechanisms of evolution, the evidence that supports it, and its profound implications for life on Earth. It moves beyond the "what" of biology (how cells work, how DNA is copied) to the "why"—why organisms are the way they are. This practice test is designed to simulate the rigor of the actual AP exam, with multiple-choice questions that require nuanced analysis and free-response questions that demand synthesis of complex ideas And that's really what it comes down to. No workaround needed..
No fluff here — just what actually works Worth keeping that in mind..
Part I: Multiple Choice Questions
1. Which of the following is the best example of evolution occurring within a population? (A) A population of lizards experiences a harsh winter, and only the individuals with the thickest scales survive. (B) A single giraffe stretches its neck to reach high leaves, and its offspring inherit the longer neck. (C) A population of bacteria is treated with an antibiotic, and a few resistant cells survive and reproduce. (D) Over several generations, the average beak size in a population of finches increases That's the part that actually makes a difference..
Correct Answer: (D) Explanation: Evolution is defined as a change in the genetic composition of a population over generations. While (A) and (C) describe natural selection acting on individuals, they do not explicitly state a subsequent generational change. Option (B) is a classic example of Lamarckian inheritance, which is incorrect; acquired characteristics are not passed on genetically. Option (D) directly describes a change in a population's average trait (beak size) over time, which is the definition of evolution.
2. The peppered moth (Biston betularia) in England is a classic example of: (A) Genetic drift. (B) Directional selection. (C) Stabilizing selection. (D) Disruptive selection Worth keeping that in mind..
Correct Answer: (B) Explanation: The peppered moth case study demonstrates directional selection. Before the Industrial Revolution, most moths were light-colored (peppered) to blend with lichen-covered trees. Pollution killed the lichens, darkening the tree bark. Dark-colored moths, once rare, became more common because they were better camouflaged from predators. This selection pressure favored one extreme phenotype (dark coloration) over the other, shifting the population's trait distribution in one direction Less friction, more output..
3. In a population of 1000 mice, 400 have a homozygous recessive genotype (aa) for a coat color gene. The frequency of the recessive allele (a) is 0.6. What is the frequency of the heterozygous genotype (Aa)? (A) 0.12 (B) 0.24 (C) 0.48 (D) 0.36
Correct Answer: (C)
Explanation: This question tests your understanding of the Hardy-Weinberg principle. Let p be the frequency of the dominant allele (A) and q be the frequency of the recessive allele (a). We are given q = 0.6. Which means, p = 1 - q = 0.4.
The frequency of the heterozygous genotype (Aa) is given by 2pq.
Calculation: 2pq = 2 * (0.4) * (0.6) = 2 * 0.24 = 0.48.
Thus, 48% of the population, or 480 mice, are expected to be heterozygous Worth keeping that in mind. Took long enough..
4. Which of the following conditions is NOT required for Hardy-Weinberg equilibrium to be maintained in a population? (A) No mutation. (B) Random mating. (C) A very large population size. (D) Differential reproductive success Simple, but easy to overlook..
Correct Answer: (D) Explanation: The Hardy-Weinberg principle describes a theoretical population that is not evolving. The five required conditions are: 1) No mutations, 2) Random mating, 3) No migration (gene flow), 4) A very large population size (to prevent genetic drift), and 5) No natural selection. "Differential reproductive success" is the definition of natural selection, which is an evolutionary force that disrupts Hardy-Weinberg equilibrium. Because of this, it is NOT a condition for equilibrium And that's really what it comes down to..
5. A new species of plant evolves in the same geographic area as its parent species, but it can only interbreed with the parent species during a brief period in the early spring, while the parent species reproduces in the late spring. This is an example of: (A) Geographic isolation. (B) Temporal isolation. (C) Behavioral isolation. (D) Gametic isolation.
Correct Answer: (B) Explanation: This scenario describes a difference in the timing of reproduction. Since the two species are isolated in time (one in early spring, one in late spring), they cannot mate with each other. This is a classic case of temporal isolation, a prezygotic barrier that prevents speciation from being reversed Not complicated — just consistent..
Part II: Free-Response Questions
Question 1: Analyzing Evolutionary Mechanisms
A population of field crickets (Gryllus pennsylvanicus) has a gene that controls the pitch of their mating call. Even so, in environments with loud, low-frequency background noise (e.The allele for a high-pitched call (H) is dominant over the allele for a low-pitched call (h). In real terms, the environment is typically quiet, and females prefer high-pitched calls. g., from machinery), females can hear high-pitched calls less effectively and prefer low-pitched calls.
(a) Describe how natural selection would act on this cricket population if the environment became noisy with low-frequency background noise. Use specific terms from evolutionary biology in your answer Not complicated — just consistent..
(b) Predict what would happen to the frequency of the H and h alleles over several generations in this noisy environment. Explain your reasoning.
(c) If the noisy environment persists, what might you expect to see in the population after many generations? What evolutionary concept does this scenario illustrate?
Sample Student Response:
(a) In the noisy environment, the selective pressure changes. Females can no longer effectively hear high-pitched calls (the
