Final answer:
Predator-based selection favors traits that aid in survival against predators, while sexual selection favors traits that enhance mating success, often leading to sexual dimorphism such as colorful plumage in birds or elaborate mating dances.
Step-by-step explanation:
Predator-based selection, also known as natural selection, involves traits that increase an individual's chance of survival and reproduction in the presence of predators. For example, guppies with more drab coloration may survive better in environments with predators, as they are less visible. On the other hand, sexual selection is driven by an individual's ability to attract mates and results in traits that may not be advantageous for survival but increase mating success. This can manifest as male birds having more colorful plumage to attract females or the performance of intricate mating rituals. In the example of Endler's guppies, the females prefer more brightly colored males in the absence of predation, leading to sexual dimorphism in guppy populations.