Final answer:
Scientists use phylogenetic trees to infer taxonomic relationships by analyzing homologous characteristics derived from morphologic and molecular data, organizing these findings with cladistics, and applying maximum parsimony to hypothesize the evolutionary history of the plants.
Step-by-step explanation:
Scientists can use phylogenetic trees to determine the taxonomic groups to which plants belong by analyzing genetic similarities and differences, studying physical characteristics, observing ecological interactions, and conducting experiments on the plants. However, phylogenetic trees are primarily based on evolutionary connections, which means that to build these trees, scientists use homologous characteristics that are identified through morphologic and molecular data. These similarities may come from shared evolutionary history, known as homologies, which are favored over similarities from separate evolutionary paths, known as analogies.
After identifying homologous characteristics and genes, scientists employ cladistics to arrange and understand evolutionary events, and use the principle of maximum parsimony to deduce the most straightforward evolutionary pathway with the least number of major divergences. Phylogenetic trees are considered hypotheses of evolutionary history and can continuously be tested and refined as new information emerges. Consequently, they provide a powerful tool for scientists to classify organisms according to their evolutionary relationships, which is more informative than traditional taxonomic classification that solely relies on observable characteristics.