Sexual Selection: Definition, Types, and Examples in AP Biology

🧬 Quick Study Guide

• 🌍 Sexual selection is a mode of natural selection where members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection).
• 🧮 It leads to the evolution of traits that increase mating success, even if those traits decrease survival.
• 🤔 Types of Sexual Selection:
  • 🏆 Intrasexual Selection: Competition within the same sex (e.g., male deer fighting for access to females).
  • 🌸 Intersexual Selection: Mate choice, where one sex (usually females) chooses mates based on certain traits (e.g., bright plumage in peacocks).
• 🌱 Examples in AP Biology:
  • 🦚 Peacock's tail (intersexual selection).
  • 🦌 Male deer antlers (intrasexual selection).
  • 🐸 Frog calls (intersexual selection).
• 💡 Sexual dimorphism (distinct differences in size or appearance between the sexes) often results from sexual selection.

🧪 Practice Quiz

1. Which of the following is the best definition of sexual selection?

   1. A) Natural selection based on differential survival rates.
   2. B) Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.
   3. C) Artificial selection performed by humans on animals.
   4. D) Random selection of mates based on chance.

2. Intrasexual selection typically involves which of the following?

   1. A) Competition between members of the opposite sex.
   2. B) Cooperation between members of the same sex.
   3. C) Competition between members of the same sex.
   4. D) Mate choice based on physical appearance.

3. Which of the following is an example of intersexual selection?

   1. A) Male lions fighting for control of a pride.
   2. B) Female birds choosing mates based on their song quality.
   3. C) Male deer using antlers to compete for mates.
   4. D) Male spiders offering nuptial gifts to females.

4. What is sexual dimorphism?

   1. A) The process of asexual reproduction.
   2. B) The distinct difference in appearance between males and females of a species.
   3. C) The similarity in appearance between males and females of a species.
   4. D) The process of genetic drift.

5. A peacock's tail is an example of:

   1. A) Intrasexual selection.
   2. B) Intersexual selection.
   3. C) Natural selection for camouflage.
   4. D) Artificial selection.

6. Which of the following is NOT a likely outcome of sexual selection?

   1. A) Increased mating success.
   2. B) Decreased survival rates.
   3. C) Enhanced camouflage.
   4. D) Sexual dimorphism.

7. Male deer using antlers in fights to win access to mates is an example of:

   1. A) Intersexual selection.
   2. B) Intrasexual selection.
   3. C) Artificial selection.
   4. D) Natural selection for survival.