Final answer:
Positive selection enhances reproductive success, increases genetic variance, and selects for rare phenotypes, while negative selection reduces reproductive success, decreases genetic variance, and selects for common phenotypes. The effects of positive and negative selection in scenarios like limited resources or predation depend on the circumstances. Exploring the interdependence of individual fates within the context of positive and negative selection involves understanding how different forces shape populations and lead to variations.
Step-by-step explanation:
Positive and negative selection are concepts in the context of natural selection. Positive selection occurs when organisms with certain traits have enhanced reproductive success, while negative selection occurs when organisms with certain traits have reduced reproductive success. In terms of mathematical/statistical effects, positive selection tends to increase genetic variance by selecting for rare phenotypes, while negative selection tends to decrease genetic variance by selecting for common phenotypes. For example, negative frequency-dependent selection selects for rare phenotypes, while positive frequency-dependent selection selects for common phenotypes.
In scenarios such as limited resources or predation, the effects of positive and negative selection can vary depending on the specific circumstances. For instance, predation is generally considered negative selection as it reduces the prey population. However, in some cases, predators can benefit prey populations by preventing overpopulation. Another example is seed predation, where the act of a bird eating pine seeds is harmful to the individual pine organism but benefits the pine population by allowing for seed dispersal.
Exploring the interdependence of individual fates within the context of positive and negative selection involves examining how selective pressures can shape populations. Different forces like limited resources or predation can lead to different outcomes in terms of population variation. For instance, if a selective pressure is a shortage of food, individuals who are better at obtaining resources are more likely to survive and reproduce, leading to an increase in the frequency of traits associated with resource acquisition in the population.