AP Biology Questions on Social Behavior: Altruism and Kin Selection

📚 Quick Study Guide

• 🤝 Altruism: Behavior that benefits another individual at a cost to oneself.
• 👨‍👩‍👧‍👦 Kin Selection: Natural selection that favors altruistic behavior by enhancing the reproductive success of relatives.
• 🧬 Hamilton's Rule: An inequality that predicts when altruistic behavior is favored: $rB > C$, where:
  • $r$ = coefficient of relatedness (the fraction of genes shared between individuals)
  • $B$ = benefit to the recipient
  • $C$ = cost to the altruist
• 🐜 Haplodiploidy in Hymenoptera: Females are diploid, males are haploid. Sisters share, on average, 75% of their genes, making altruism towards sisters highly beneficial.
• 💡 Inclusive Fitness: The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables other close relatives to increase the production of their offspring.
• 🌍 Examples of Altruism: Alarm calls in prairie dogs, cooperative breeding in birds, and sterile worker castes in social insects.

🧪 Practice Quiz

1. Which of the following best describes altruistic behavior?
   1. A) Behavior that benefits the individual performing the action.
   2. B) Behavior that benefits another individual at a cost to the individual performing the action.
   3. C) Behavior that benefits both individuals involved equally.
   4. D) Behavior that has no effect on either individual involved.
2. According to Hamilton's rule, when is altruistic behavior most likely to occur?
   1. A) When the cost to the altruist is high and the benefit to the recipient is low.
   2. B) When the cost to the altruist is low and the benefit to the recipient is high, and they are closely related.
   3. C) When the cost to the altruist is equal to the benefit to the recipient.
   4. D) When the individuals are unrelated.
3. What does the variable 'r' represent in Hamilton's rule?
   1. A) Reproductive rate of the altruist.
   2. B) Benefit to the recipient.
   3. C) Cost to the altruist.
   4. D) Coefficient of relatedness between the altruist and the recipient.
4. In haplodiploid insect societies, such as those of bees and ants, which of the following is true?
   1. A) Sisters are less related to each other than they are to their own offspring.
   2. B) Sisters are equally related to each other as they are to their own offspring.
   3. C) Sisters are more related to each other than they are to their own offspring.
   4. D) Males are diploid and females are haploid.
5. What is inclusive fitness?
   1. A) The ability of an individual to survive in a given environment.
   2. B) The total number of offspring an individual produces.
   3. C) The total effect an individual has on proliferating its genes by producing its own offspring and helping relatives.
   4. D) The direct fitness of an organism.
6. Which of the following is an example of altruistic behavior in nature?
   1. A) A lion hunting a zebra.
   2. B) A bird building a nest for its young.
   3. C) A prairie dog giving an alarm call when a predator is spotted, alerting others but increasing its own risk.
   4. D) A flower producing nectar to attract pollinators.
7. If the benefit to a recipient of an altruistic act is 5, the cost to the altruist is 1, and the coefficient of relatedness is 0.2, will altruism be favored based on Hamilton's rule?
   1. A) Yes, because (0.2)(5) > 1
   2. B) No, because (0.2)(5) < 1
   3. C) Yes, because (0.2)(1) > 5
   4. D) No, because (0.2)(1) < 5