Final answer:
The pattern seen over evolutionary time in the alternation of generations is that the sporophyte phase has become more dominant, transforming from a minor to a major stage in the life cycle of plants.
Step-by-step explanation:
Over evolutionary time in the alternation of generations, it is observed that the sporophyte phase has become more dominant. During early plant evolution, the gametophyte was the main stage of the plant life cycle, especially in non-vascular plants like mosses. However, through time, the sporophyte stage became increasingly prominent, evolving from being barely noticeable to forming the large multicellular structures, such as towering trees in seed plants like sequoias and pines.
The transition from a gametophyte-dominant to a sporophyte-dominant lifecycle is particularly evident in the transition from seedless vascular plants to seeded plants. Seedless vascular plants, like ferns, display a more dominant diploid sporophyte stage, but still maintain an independent and viable gametophyte stage. With the advent of seed plants, the sporophyte further asserted its dominance, effectively relegating the gametophyte to a much reduced, often microscopic role in the life cycle.