Final answer:
Conflicting selection pressure in males and females arises from differential sexual selection, where males evolve traits to maximize reproductive success, which can also increase survival risks, while females select mates based on these traits, leading to sexually dimorphic species. Diversifying selection favors multiple phenotypes that have their own advantages.
Step-by-step explanation:
Differential investment in males and females can lead to conflicting selection pressure due to sexual selection. Males often compete for reproductive success, leading to the evolution of elaborate traits, like a peacock's tail, which may attract mates but also pose survival risks, demonstrating the handicap principle. However, females typically select for favorable traits in males, such as strength or decorations, and therefore exert a different type of selection pressure on males.
Diversifying selection is when multiple phenotypes are favored, as seen in cases where large alpha males dominate through force and small males use stealth, while medium-sized males may have no advantage. This kind of selection can also occur in response to varied environmental conditions, leading to increased genetic variance within a population.