20.1: Organizing Life on Earth Last updated Save as PDF Page ID 12580 Boundless Boundless 20.1A: Phylogenetic Trees Phylogenetic trees illustrate the hypothetical evolution of organisms and their relationship to other species. 20.1B: Limitations of Phylogenetic Trees Limitations of phylogenetic trees include the inability to distinguish evolutionary time and relatedness between distinct species. 20.1C: The Levels of Classification Taxanomic classification divides species in a hierarchical system beginning with a domain and ending with a single species.