Final answer:
The pattern of contrasting trends within groups versus a population, where cooperation may increase in frequency in the population at large even if it decreases in frequency within groups, is called the paradox of cooperation.
Step-by-step explanation:
The pattern of contrasting trends within groups versus a population, where cooperation may increase in frequency in the population at large even if it decreases in frequency within groups, is called the paradox of cooperation.
For example, within a group, competition between individuals may lead to a decrease in cooperation. However, at a population level, cooperation may increase because individuals who cooperate are more successful in interacting with individuals from different groups, leading to higher overall fitness.
This paradox of cooperation highlights the complex dynamics of social interactions and the role of individual and group selection in shaping cooperative behaviors.