What do phylogenetic trees illustrate?

Phylogenetic trees illustrate evolutionary relationships among species by depicting how different organisms share common ancestors and diverge from one another over time. This visualization helps scientists understand the lineage and ancestry of different species, showing the connections and evolutionary pathways that have led to the current diversity of life.

The branching structure of a phylogenetic tree represents the hypothesis of who is more closely related to whom, based on various forms of evidence, including genetic, morphological, and fossil data. By analyzing these trees, researchers can infer the evolutionary history of species, identify patterns of speciation, and see how traits have evolved within lineages. This makes phylogenetic trees an essential tool in the field of evolutionary biology.

Other options, such as geographic distribution, population density, or life cycles, focus on different aspects of biology and do not provide insights into the evolutionary relationships among species, which is the primary focus of phylogenetic trees.