Question

1. based on the data, why do you think that frequency-dependent selection does or does not exist for male guppies?

Explanation:

To answer this, we first recall what frequency - dependent selection is. Frequency - dependent selection occurs when the fitness of a phenotype (or genotype) depends on its frequency in the population. There are two main types: positive (where fitness increases with frequency, like in some mimicry systems) and negative (where fitness decreases with frequency, also called "rare - phenotype advantage", such as in predator - prey interactions where predators focus on the most common prey type).

Step 1: Recall the context of guppy coloration and predation

Male guppies have different color patterns. In environments with predators, the survival and reproductive success (fitness) of male guppies with a particular color pattern can be related to how common that pattern is.

Step 2: Consider the data (even though not provided here, we can use general knowledge)

• If the data shows that the reproductive success (e.g., number of matings, survival to reproduce) of a male guppy color phenotype is higher when it is rare in the population, this would suggest negative frequency - dependent selection. For example, if predators are more likely to target the most common color pattern (because they can form a search image for it), then rare - colored males are less likely to be preyed upon and thus have higher fitness. As the rare phenotype becomes more common (due to higher fitness), its fitness would start to decrease because it becomes the new "common" target of predators.
• If the data shows that the fitness of a phenotype increases as it becomes more common, this could be positive frequency - dependent selection. For example, if females prefer a common color pattern (maybe because it is a signal of a "normal" or "high - quality" male in the population), then as the frequency of that pattern increases, more females will choose males with that pattern, increasing their fitness.

Step 3: Synthesize the answer based on typical guppy studies

In many studies on guppies, frequency - dependent selection (often negative) is observed for male coloration. For example, when a particular male color pattern is common, predators have a well - developed search image for it and prey more on males with that pattern. So, the rare color patterns have higher survival and reproductive success. As the rare pattern becomes more common (because the males with that pattern are surviving and reproducing more), it then becomes the target of predation, and its fitness decreases. This cycle of fitness depending on the frequency of the phenotype is characteristic of frequency - dependent selection.

If we assume the data shows this kind of pattern (rare phenotype advantage that changes with frequency), we can conclude that frequency - dependent selection exists for male guppies. If the data showed that fitness was independent of the frequency of the male's phenotype (e.g., all color patterns had the same fitness regardless of how common they were in the population), then we would conclude it does not exist.

Answer:

To determine if frequency - dependent selection exists for male guppies, we analyze the relationship between the frequency of male guppy phenotypes (e.g., color patterns) and their fitness (survival, reproduction). If the data shows that the fitness of a phenotype depends on its frequency (e.g., rare color patterns have higher fitness when common patterns are preyed upon more, and vice versa as frequencies shift), frequency - dependent selection exists. In typical guppy studies, frequency - dependent (often negative, with rare phenotypes having higher fitness) selection is observed for male coloration due to predator - prey dynamics (predators target common phenotypes) and/or mate choice. So, based on such data, frequency - dependent selection does exist for male guppies as the fitness of male guppy color phenotypes depends on their frequency in the population (e.g., rare phenotypes avoid predation more and have higher reproductive success, with this advantage reversing as their frequency increases).