AP Biology Free-Response Questions Notes

AP Biology Free-Response Questions Overview
  • The provided materials contain examples of past free-response questions (FRQs) from AP Biology.
  • Students should refer to these as examples and not anticipate their inclusion in upcoming exams.
  • Responses should be written in paragraph form, avoiding mere bullet points.
2013 AP® Biology FRQs
  • Topic: Transitional species between lobe-finned fishes and amphibians
    • Question (a):
    • Select the most appropriate rock sample to search for transitional fossils:
      • Available rock samples:
      • 350 million years old
      • 370 million years old
      • 390 million years old
    • Selection Justification:
      • Choose the 370 million years old rock sample, as it is the closest to the time frame where amphibian-like vertebrate fossils are found (363 million years old).
    • Question (b):
    • Evidence supporting amphibian evolution from lobe-finned fishes:
      1. Presence of true legs in fossils that indicate adaptation for terrestrial life.
      2. Evidence of lungs in transitional species indicating adaptation to an air-breathing lifestyle.
2009 AP® Biology FRQs
  • Topic: Phylogeny and genetic changes
    • Question (a):
    • Two mechanisms of genetic change:
      1. Mutation:
      • Changes in the DNA sequence that create new alleles, enhancing variation.
      1. Recombination:
      • Rearrangement of genetic material, especially during meiosis, leading to varied genotypes in offspring.
    • Question (b):
    • Draw a phylogenetic tree based on cytochrome c sequences.
      • Identify the organism most closely related to chickens based on amino-acid differences.
    • Question (c):
    • Evidence types for phylogeny determination:
      1. Morphological Comparisons:
      • Strength: Easy to observe and quantify.
      1. Molecular Data (DNA Sequencing):
      • Strength: Provides detailed insights into evolutionary relationships based on genetic similarities.
2011 AP® Biology FRQs (Form B)
  • Topic: Speciation and phylogeny investigation methods
    • Question (a):
    • Two mechanisms of speciation:
      1. Allopatric speciation:
      • Species diverge due to physical barriers.
      1. Sympatric speciation:
      • Species diverge while inhabiting the same area, often due to behavioral differences or polyploidy in plants.
    • Question (b):
    • Methods for investigating phylogeny:
      1. Comparative Genomics:
      • Strength: High resolution of genetic relationships.
      1. Fossil Studies:
      • Weakness: Incomplete fossil records may lead to gaps in data.
    • Question (c):
    • Analyze relationships in two phylogenetic trees of whales and mammals, focusing on the pulley-shaped astragalus bone.
      • Use the principle of parsimony to determine the best tree representation.
Phylogenetic Trees and Genetic Research on Bears
  • Phylogenetic tree (Figure 1):
    • Shows evolutionary relatedness among bear populations.
    • Question (a):
    • Estimate age of common ancestor of brown bears based on the phylogenetic tree.
    • Question (b):
    • Construct a cladogram based on LYST protein sequences and identify the outgroup.
    • Question (c):
    • Argue why mitochondrial DNA comparisons could be more accurate than LYST protein comparisons.
    • Question (d):
    • Predict phenotypic differences in a genetically engineered mouse with polar bear LYST gene compared to wild-type.
    • Question (e):
    • Discuss how LYST mutations spread through polar bear populations and predict offspring color in a cross between a polar bear and a brown bear.