Final answer:
Spring ephemerals grow rapidly early in the season to complete their lifecycle before the forest canopy fills in, which is an adaptation to avoid competition for sunlight with larger trees.
Step-by-step explanation:
Spring ephemerals are plant species that have a specific growing period which serves as an adaptation to a particular problem they face in their environment. This problem is the competition for sunlight with larger forest trees that fully leaf out in late spring and create a dense canopy. To solve this, spring ephemerals like the spring beauty (Claytonia virginica) have evolved to complete their lifecycle quickly. They grow, flower, and reproduce early in the season before the canopy trees develop their leaves, avoiding the intense competition for sunlight that occurs later in the growing season.
By responding to cues such as temperature and the length of day and night to time their life cycle events, these plants are employing strategies like photoperiodism--a biological response to seasonal changes which is crucial for plant survival. This rapid lifecycle is closely tied to the seasonal availability of light and the growing seasons, making the most of the conditions before they become unfavorable for growth.