Laboratory components of introductory biology college-level courses are becoming increasingly rare. Due to the absence of laboratory funding and time, instructors at all levels are faced with the problem of implementing inquiry-based projects. In this article, the authors present an activity that they developed for the 50-minute discussion period attached to an undergraduate introductory ecology and evolution lecture course. This activity focuses on the inquiry skill, "recognize and analyze alternative explanations and models," using plant phylogenies that students generate from morphological data. Phylogenies and phylogenetic reconstruction are fundamental aspects of evolutionary study, and together present a conceptual framework through which students can examine other components of evolution such as speciation, adaptation, and natural selection. (Contains 1 table and 5 figures.)