Final answer:
The major transitions hypothesis explains the origin of complete metamorphosis, which provides survival advantages such as occupying different ecological niches, protecting juvenile stages, and promoting genetic diversity and adaptability.
Step-by-step explanation:
The hypothesis that helps explain the origin of complete metamorphosis is the “major transitions hypothesis.” This hypothesis suggests that complete metamorphosis evolved through a series of major evolutionary transitions. It proposes that the development of complete metamorphosis allowed insects to exploit new ecological niches and avoid competition with their juvenile stages. This hypothesis is supported by evidence from the fossil record and comparative studies of insect development. Complete metamorphosis provides several survival advantages. First, it allows insects to occupy different ecological niches at different life stages. For example, the larval stage can be specialized for feeding and growth, while the adult stage can be specialized for reproduction and dispersal. This division of labor increases the efficiency and effectiveness of resource use. Second, complete metamorphosis protects the developing juvenile stages from predation and competition with adult individuals. The pupal stage, in particular, provides a protective period of inactivity during which the insect undergoes internal reorganization and development. Third, complete metamorphosis promotes genetic diversity and adaptability by separating the reproductive stage (adult) from the growth and development stage (larva). This allows for independent evolution and adaptation of the two stages, which can lead to increased survival and reproductive success in changing environments.