Final answer:
The 'changing environment' hypothesis posits that sexual reproduction provides an advantage due to the diversity it creates, which is beneficial in changing environments. The Red Queen Hypothesis underlines this by asserting the necessity for ongoing variation to keep pace with co-evolving species, an advantage seen in sexually reproducing organisms over those reproducing asexually.
Step-by-step explanation:
Within the context of evolutionary biology, the 'changing environment' hypothesis suggests that sexual reproduction is advantageous because the genetic diversity it produces among offspring can enhance the survival of a population facing environmental fluctuation. An important supporting concept for this view is the Red Queen Hypothesis, which posits that ongoing variation is a necessity due to the constant coevolution of species. This includes the evolutionary arms race between predators and prey, or parasites and their hosts, where any genetic advantage can be crucial for survival. Sexual reproduction allows for a rapid generation of diverse genetic combinations, thus better equipping a species to adapt and maintain a foothold in the ever-changing landscape of ecological niches and to keep pace with co-evolving species.
An illustrative scenario supporting the Red Queen Hypothesis would be the case of b. Individuals of a snail population that reproduce asexually dying out after a parasite invades its territory. This example highlights how a lack of genetic diversity, typical of asexual reproduction, renders a species vulnerable to novel threats such as invasive parasites. Conversely, sexually reproducing species have a higher chance of containing individuals with genetic variations that might provide resistance against new parasites, thus demonstrating the advantage of maintaining a high level of genetic variation within a population.