What does a phylogenetic tree illustrate?

A phylogenetic tree illustrates the evolutionary relationships among biological species. It is a diagram that represents the evolutionary history of a group of organisms, showing how species are related through common ancestors. Each branch of the tree represents a lineage, and the points where branches split indicate when two lineages diverged from a common ancestor.

This representation helps scientists and researchers understand how species have evolved over time, including the genetic distances between them. It visually conveys the concept of descent with modification, highlighting the connections among diverse forms of life. Phylogenetic trees are constructed based on various data, including genetic, morphological, and molecular characteristics, which provide evidence of the evolutionary pathways that have shaped the diversity of life on Earth.

The other options, while related to biological concepts, do not accurately describe the function of a phylogenetic tree. Hierarchical structures of living organisms or anatomical structures pertain to classification or morphology and do not directly depict evolutionary relationships. Feeding relationships are typically represented in food webs or ecological diagrams rather than in a phylogenetic context. Hence, recognizing the specific purpose of phylogenetic trees as a tool for illustrating evolutionary connections highlights why the correct answer is based on evolutionary relationships.