Problem Set 10 Flashcards
Why did John M. Thoday, 1973 state that “No characteristic is inherited, and none is acquired. All are developed”?
John M. Thoday’s statement emphasizes the idea that characteristics of organisms are not simply passed down unchanged from parents to offspring (inherited) or solely the result of environmental influences (acquired). Instead, they are developed through the interaction of genetic and environmental factors over time. This perspective aligns with the understanding of phenotypic plasticity, where traits can change in response to environmental conditions, and highlights the complexity of development as a process shaped by both genetic and environmental influences.
How can plasticity evolve?
Plasticity can evolve through natural selection when the ability to change in response to environmental conditions provides a fitness advantage. If individuals with greater plasticity are more successful in varying environments, they may produce more offspring, leading to the propagation of plastic traits. Additionally, genetic variation in plasticity can arise through mutations, and if these variations confer benefits in specific contexts, they can become more prevalent in a population over generations.
What are the differences between phenotypes resulting from “unavoidable costs,” “the costs of prenatal adaptations,” and “PAR”?
Unavoidable costs refer to the inherent trade-offs that occur during development, where certain traits may come at a cost to other traits or functions (e.g., energy allocation).
The costs of prenatal adaptations involve changes in developmental trajectories that are necessary to survive prenatal challenges, which may lead to lower quality post-natal phenotypes (e.g., prioritizing certain developmental pathways at the expense of others).
Predictive Adaptive Responses (PAR) are phenotypic changes that occur in response to environmental cues during development, allowing the organism to anticipate and adapt to future conditions, potentially enhancing survival and reproductive success.
How is it possible for genes within a genome to be in conflict with each other?
Genes within a genome can be in conflict due to differing evolutionary interests. For example, some genes may promote traits that benefit the individual organism, while others may favor traits that enhance reproductive success at the expense of the organism’s health. This conflict can arise from the interactions between genes inherited from both parents, where alleles may have different effects on fitness depending on the context, leading to a tug-of-war between competing genetic interests.
Why would selection favor, on one hand, alleles that increase offspring’s demands on mothers and, on the other hand, alleles that suppress them?
Selection may favor alleles that increase offspring demands on mothers because higher demands can lead to greater resource allocation, potentially enhancing offspring survival and reproductive success. Conversely, alleles that suppress these demands may be favored to ensure maternal health and future reproductive opportunities. This balance reflects the conflict between maternal investment and offspring needs, where both strategies can be advantageous under different circumstances.
Why would the mating system of a species affect maternal-fetal conflict?
The mating system of a species can affect maternal-fetal conflict by influencing the degree of investment a mother is willing to make in her offspring. In monogamous systems, where paternal investment is likely, mothers may be more inclined to allocate resources to offspring. In contrast, in polygamous systems, where males may not provide support, mothers may face greater conflict over resource allocation, leading to different dynamics in maternal-fetal interactions.
In which circumstances should we expect there to be conflict between mothers and offspring during the times discussed in lecture?
We should expect conflict between mothers and offspring during critical periods such as pregnancy and lactation, where the demands of the developing offspring may exceed the mother’s capacity to provide resources. Additionally, conflicts may arise when offspring have high resource demands that could jeopardize the mother’s health or future reproductive success, leading to trade-offs in resource allocation.
Why don’t selective processes eliminate alleles that lead to outcomes in which both mothers and children can die such as, for example, eclampsia?
Selective processes may not eliminate such alleles because the conditions leading to severe outcomes like eclampsia may be rare or context-dependent. Additionally, the alleles may confer advantages in other contexts or stages of reproduction that outweigh the risks. Furthermore, the complex interactions between genetics, environment, and maternal health can make it difficult for selection to act effectively against these alleles.
Should we expect mothers, fathers, and children to always be in “biological conflict”?
In other words, should we expect them to collaborate on some tasks or always compete? While there are instances of biological conflict due to differing interests, we should not expect mothers, fathers, and children to always be in conflict. Collaboration is also a significant aspect of family dynamics, as cooperative behaviors can enhance the survival and reproductive success of all parties involved. For example, parents may work together to provide resources and care for their offspring, and offspring may engage in behaviors that promote parental investment. The balance between conflict and cooperation is influenced by ecological and social contexts.
