The graph below shows a fitness curve based on body size for a fictional population of butterflies. Assuming all the necessary and sufficient conditions for selection to occur are met in this population, what pattern of selection does this fitness curve predict will occur?

Question

BlackTom AI · Accepted Answer

To begin, let's restate the core elements of the question: we have a graph of fitness (mortality) versus body size in butterflies, and we assume the standard conditions for selection hold. The key pattern to infer is how fitness changes with body size.
Option 1: Stabilizing selection. In stabilizing selection, individuals with intermediate trait values have higher fitness than those at the extremes. Looking at the graph, mortality is lowest at intermediate body sizes and higher at both very small and very large sizes. Since higher fitness corresponds to lower mortality, this pattern supports stabilizing selection, where the population mean is favored and variation around it is selected against.
Option 2: Directional selection in favor of smaller body size. This would require a fitness curve that increases consistently as body size decreases (or mortality decreases as size increases in one direction). The depicted U-shaped curve shows higher mortality at both extremes, not a consistent advantage to smaller sizes alone, so this option doesn’t fit.
Option 3: Directional selection in favor of larger body size. Similar reasoning as above: directional selection would show fitness increasing in one direction (e.g., larger size lead to higher fitness). The graph does not show a linear increase with size; instead, the extremes are both disfavored, which contradicts a unidirectional shift.
Option 4: Diversifying/disruptive selection. This occurs when extreme trait values have higher fitness than intermediate values, leading to a bimodal distribution. In the graph, the intermediate sizes have the lowest mortality (highest fitness), while extremes have higher mortality, which is the opposite of disruptive selection.
Across these interpretations, the pattern in the graph precisely matches stabilizing selection: intermediate body sizes are favored, and both very small and very large sizes are selected against, leading to reduced variation around the mean.

BIS 002B Sections A and B SQ 2025 Practice Midterm #2

The graph below shows a fitness curve based on body size for a fictional population of butterflies. Assuming all the necessary and sufficient conditions for selection to occur are met in this population, what pattern of selection does this fitness curve predict will occur?

查看解析

登录即可查看完整答案

类似问题

Male deer compete for mates by fighting with their antlers. The male deer with the largest antlers tend to secure the most mates. Why do we not see a large number of male deer with super large antlers?

Stabilizing selection tends to genetic diversity within a population.

The type of natural selection that favors individuals with intermediate phenotypes and selects against those with extreme phenotypes is called selection.

What type of selection on phenotypes is this?

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单