Problem 9 - AP Psychology Premium Prep 2021

Question

Peacock males have evolved to have huge, beautiful tails with numerous large eye spots. Long, colorful tails are difficult to carry when you are running from a predator. However, peahens (female peacocks) have been shown by researchers to mate preferably with males with more eye spots and longer tails, despite these traits making the males more susceptible to predation. Over time, this preference has resulted in peacocks with huge tails due to (A) sexual selection (B) disrupted selection (C) divergent evolution (D) sympatric speciation

Step-by-Step Solution

Answer

The evolutionary process responsible for peacocks having huge, beautiful tails with numerous eye spots is (A) sexual selection, as peahens prefer to mate with males having more eye spots and longer tails, leading to increased reproductive success for males with these traits.

Step 1: Define Each Evolutionary Process

Let's first briefly define each of the evolutionary processes mentioned in the options: 1. (A) Sexual selection: A type of natural selection resulting from individuals with certain traits being more likely to find mates and reproduce. This can lead to traits that might not be beneficial for survival but increase reproductive success. 2. (B) Disrupted selection: A type of balancing selection that maintains the diversity of traits within a population. It occurs when extreme trait values are favored over intermediate trait values. 3. (C) Divergent evolution: The process by which different species evolve distinct traits from a common ancestor due to adaptation to different environments or ecological niches. 4. (D) Sympatric speciation: The formation of new species within the same geographical area, occurring due to genetic changes that reduce the likelihood of interbreeding between populations.

Step 2: Identify the Relevant Process

We are given that peahens (female peacocks) prefer to mate with males with more eye spots and longer tails, leading to the evolution of males with these traits. This description aligns with the definition of sexual selection, where certain traits make individuals more attractive to potential mates and lead to increased reproductive success. Therefore, the correct answer is: (A) sexual selection