Final answer:
The Red Queen hypothesis suggests that sex is beneficial because it promotes genetic variation, essential for the adaptation and evolution of species in response to ecological pressures.
Step-by-step explanation:
The Red Queen hypothesis proposes that sex is beneficial because it enables continuous genetic variation, which is critical for the survival and evolution of species. This concept is compared to the Red Queen's race in Lewis Carroll's Through the Looking-Glass, illustrating the idea that species must evolve rapidly just to maintain their current position in the ecosystem.
In essence, sexual reproduction fosters diversity within a population, thereby enhancing the ability of the population to adapt to changing environmental conditions, prey, predators, and parasites. Sexual reproduction's generation of variation provides the essential 'raw material' upon which natural selection acts, allowing favorable traits to be spread within a population.
Therefore, while sexual reproduction may be more costly and produce fewer offspring for individual organisms, the resulting genetic variation provides significant evolutionary advantages at the population level.