Ecological and Sexual Selection in African Rift Lake Cichlids
Are the following statements about ecological and sexual selection in African rift lake cichlids true or false?
1. Making a bower underwater serves as an honest signal of genetic quality in fish.
2. Sexual selection can occur in cichlid fishes due to the mouthbreeding system.
3. Traits under ecological selection may be subject to constraints.
4. Ecological factors influence the types of traits that are adaptive for survival.
5. A particular trait in a species can be under both ecological and sexual selection simultaneously.
Answers:
1. A. True
2. A. True
3. B. False
4. A. True
5. B. False
Explanation:
In the context of African rift lake cichlids, ecological and sexual selection play important roles in shaping the evolution of traits. Here is a detailed explanation for each statement:
1. Making a bower underwater serves as an honest signal of genetic quality in fish.
This statement is true. The ability to construct a bower underwater can be a challenging task that requires genetic fitness. Traits like this, which are difficult to fake, can serve as honest signals in the context of sexual selection.
2. Sexual selection can occur in cichlid fishes due to the mouthbreeding system.
This statement is true. The mouthbrooding system in cichlid fishes, where one sex carries and protects eggs or young in their mouths, leads to asymmetry in parental investment. This can create opportunities for sexual selection to occur.
3. Traits under ecological selection may be subject to constraints.
This statement is false. Traits under ecological selection are shaped by environmental conditions and the need to adapt, while traits under sexual selection can also have constraints and trade-offs.
4. Ecological factors influence the types of traits that are adaptive for survival.
This statement is true. Ecological factors like physical environment and available resources set boundaries for trait evolution, while sexual selection can further refine traits based on mate choice.
5. A particular trait in a species can be under both ecological and sexual selection simultaneously.
This statement is false. Traits in a species can be shaped by both ecological and sexual selection, as they are not mutually exclusive. A trait may enhance survival due to ecological factors and also be favored in mate choice.