Final answer:
The discussion involving male peacocks and their gaudy tails illustrates natural selection and evolution in biology.
Step-by-step explanation:
The discussion involving male peacocks and their gaudy tails was used to illustrate natural selection and evolution. The peacock's tail, which serves as an honest signal of quality to the females, is an example of the handicap principle. Despite being a disadvantage to survival, the males with the longest and most extravagant tails are more likely to win the female and pass on their genes, causing the average tail length to decrease over time due to natural selection. This demonstrates how traits that may seem detrimental can actually be advantageous in the context of sexual selection.