Directional, stabilizing and disruptive selection Knowledge-Based Practice

Questions

1. 1.

   Following a prolonged drought on Daphne Major, small seeds became scarce, and medium ground finches with deeper beaks survived at higher rates by feeding on large, tough seeds. Over successive generations, the average beak depth of the population significantly increased as a result of which mode of natural selection?

   • A) Stabilizing selection
   • B) Directional selection
   • C) Disruptive selection
   • D) Balancing selection
2. 2.

   Human birth weight is maintained within a relatively narrow range because infants of intermediate weight have significantly higher survival rates than those who are born exceptionally light or heavy. Which mode of natural selection is demonstrated by this survival pattern?

   • A) Stabilizing selection
   • B) Directional selection
   • C) Disruptive selection
   • D) Artificial selection
3. 3.

   Which mode of natural selection favors individuals with a phenotype at one extreme of a trait distribution, causing the population mean for that trait to shift over generations?

   • A) Stabilizing selection
   • B) Directional selection
   • C) Disruptive selection
   • D) Balancing selection
4. 4.

   Which mode of natural selection simultaneously favors individuals at both phenotypic extremes over those with intermediate phenotypes, potentially leading to a bimodal distribution in the population?

   • A) Directional selection
   • B) Stabilizing selection
   • C) Frequency-dependent selection
   • D) Disruptive selection
5. 5.

   Which mode of natural selection acts against both phenotypic extremes and favors intermediate phenotypes, thereby decreasing the phenotypic variance of a population over generations?

   • A) Directional selection
   • B) Stabilizing selection
   • C) Disruptive selection
   • D) Sexual selection

Answers and step-by-step solutions appear after you finish the test.