Final answer:
Anatomical features with structural similarities due to common ancestry are called homologous structures, which can differ in function but indicate phylogenetic relationships.
Step-by-step explanation:
Anatomical features that show an underlying structural similarity even though their superficial structure is different are termed homologous structures. Homologous structures arise from the same embryonic origin and may or may not have the same function in their descendants. For example, the bones in the front flipper of a whale are homologous to the bones in the human arm, although they have different functions. This is different from analogous structures, which have a similar function but do not share common embryonic origins, such as the wings of butterflies and birds. A complex feature that is homologous in different species suggests a common evolutionary past, indicative of a shared ancestor, which is valuable information for scientists studying phylogeny. Phylogenetic relationships are often built on these kinds of structural morphologies.