AP Biology Questions on Mechanisms of Evolution

🧬 Quick Study Guide

• 🌱 Natural Selection: Differential survival and reproduction of individuals due to differences in phenotype. Acts on heritable traits.
• 🐾 Genetic Drift: Random changes in allele frequencies within a population. Significant in small populations. Includes bottleneck effect and founder effect.
• 🌊 Gene Flow: The transfer of genetic material from one population to another. Reduces genetic differences between populations.
• mutation Mutation: A change in the DNA sequence. Introduces new alleles into a population. Can be beneficial, neutral, or harmful.
• 💑 Non-random Mating: Mating in which a pair of organisms are preferentially chosen based on their genotypes or phenotypes (e.g., sexual selection).
• 📊 Hardy-Weinberg Equilibrium: Describes a population that is not evolving. Conditions include: no mutations, random mating, no gene flow, no natural selection, and a large population size. The equations are: $p + q = 1$ and $p^2 + 2pq + q^2 = 1$, where $p$ and $q$ are allele frequencies.

🧪 Practice Quiz

1. Which of the following mechanisms of evolution is most likely to decrease the genetic variation between two populations?
   1. Gene flow
   2. Genetic drift
   3. Natural selection
   4. Mutation


2. A population of butterflies has two color forms: blue and orange. A sudden volcanic eruption kills most of the butterflies. Only a small number of orange butterflies survive. This is an example of:
   1. The founder effect
   2. The bottleneck effect
   3. Natural selection
   4. Gene flow


3. Which of the following conditions is NOT a requirement for Hardy-Weinberg equilibrium?
   1. No mutations
   2. Random mating
   3. Small population size
   4. No gene flow


4. The differential survival and reproduction of individuals with certain heritable traits is known as:
   1. Genetic drift
   2. Gene flow
   3. Natural selection
   4. Mutation


5. A new mutation arises in a population that provides resistance to a common disease. Over time, the frequency of this mutation increases. This is an example of:
   1. Genetic drift
   2. Gene flow
   3. Natural selection
   4. Non-random mating


6. In a population of birds, individuals with larger beaks are better able to crack open seeds and survive. This is an example of:
   1. Directional selection
   2. Disruptive selection
   3. Stabilizing selection
   4. Sexual selection


7. Which mechanism introduces new alleles into a population?
   1. Genetic drift
   2. Gene flow
   3. Mutation
   4. Natural selection