Ecology Behavioral Ecology Concepts 3 — Questions and Answers
Question 1: Hamilton's rule states that altruism evolves when rB > C. What does 'r' represent in this inequality?
- Rate of reproductive success
- Relatedness between actor and recipient (Correct answer)
- Risk of predation to the actor
- Resource value of the territory
Correct answer: Relatedness between actor and recipient
In Hamilton's rule, r is the coefficient of relatedness, quantifying the probability that actor and recipient share a given allele by common descent.
Question 2: When a vervet monkey gives an alarm call that attracts a predator's attention toward the caller, this behavior is paradoxically maintained by:
- Individual selection favoring alarm callers directly
- Kin selection because group members are typically relatives (Correct answer)
- Group selection acting on populations
- Sexual selection favoring conspicuous display
Correct answer: Kin selection because group members are typically relatives
Alarm calling in vervets is best explained by kin selection: callers warn closely related group members, thereby passing copies of alarm-call alleles into the next generation.
Question 3: What is the primary distinction between proximate and ultimate explanations for behavior?
- Proximate explains evolutionary history; ultimate explains mechanisms
- Proximate explains immediate mechanisms; ultimate explains adaptive significance (Correct answer)
- They are interchangeable terms for the same level of analysis
- Proximate focuses on ecology; ultimate focuses on genetics
Correct answer: Proximate explains immediate mechanisms; ultimate explains adaptive significance
Proximate causes address the immediate physiological and developmental mechanisms triggering behavior, while ultimate causes address why the behavior evolved and its fitness consequences.
Question 4: A bird that joins a communal roost during winter gains warmth but also competes for food. This trade-off is best analyzed using:
- The ideal free distribution model
- Cost-benefit analysis within behavioral ecology (Correct answer)
- The marginal value theorem
- Optimal territory size theory
Correct answer: Cost-benefit analysis within behavioral ecology
Behavioral ecologists use cost-benefit analysis to evaluate whether the thermoregulatory benefits of roosting outweigh the increased food competition.
Question 5: Which parental investment pattern most commonly leads to sex-role reversal, where females compete for males?
- Females invest less than males in offspring (Correct answer)
- Males and females invest equally
- Females invest more than males in offspring
- Neither sex provides post-hatching care
Correct answer: Females invest less than males in offspring
Sex-role reversal arises when males provide greater parental investment than females, making males the limiting resource and causing females to compete for access to them.
Question 6: A honeybee worker that stings an intruder dies shortly afterward. This sacrifice is explained evolutionarily because:
- Workers reproduce independently and benefit directly
- Workers and the queen share 75% of their genes under haplodiploidy (Correct answer)
- Group selection favors altruistic colonies
- Workers are misidentifying the intruder as a competitor
Correct answer: Workers and the queen share 75% of their genes under haplodiploidy
Haplodiploidy in Hymenoptera means sisters share 75% of genes, so helping a sister reproduce can yield higher inclusive fitness than direct reproduction.
Question 7: The concept of 'honest signaling' in animal communication requires that signals:
- Be identical across all individuals in a population
- Carry a cost that prevents low-quality individuals from faking them (Correct answer)
- Be produced only during reproductive seasons
- Encode precise numerical information
Correct answer: Carry a cost that prevents low-quality individuals from faking them
Honest signals are maintained by costs (handicap principle) or constraints that make it too expensive for low-quality individuals to produce the same signal as high-quality ones.
Ecology Behavioral Ecology Concepts 3
Hamilton's rule states that altruism evolves when rB > C.
What does 'r' represent in this inequality?