Final answer:
High-crowned teeth in various animals such as rodents, ungulates, and elephants likely represent a case of convergent evolution, as these groups are from different lineages and have adapted to similar environmental pressures independently.
Step-by-step explanation:
In evolutionary biology, the term synapomorphy refers to a characteristic that is shared by two or more groups due to inheritance from a common ancestor. Convergent evolution, on the other hand, refers to similar traits that have evolved independently in different lineages because of similar selective pressures, rather than from a shared ancestor. When it comes to high-crowned teeth found in some rodents, rabbits and hares, most even-toed hoofed animals, horses, and elephants, without the specific evolutionary tree (Figure 4.37) mentioned in the question, providing a conclusive answer is difficult. However, given that these animals belong to different lineages and have diverse evolutionary histories, it is plausible that the development of high-crowned teeth in these various groups is due more to convergent evolution rather than being a synapomorphy.