A phylogenetics exercise is incorporated into the "Introduction to biocomputing" course, a junior-level course at Savannah State University. This exercise is designed to help students learn important concepts and practical skills in molecular phylogenetics through solving a real-world problem. In this application, students are required to identify orthologous protein sequences of the human ("Homo sapiens") cystic fibrosis transmembrane conductance regulator (CFTR) from other species and to reconstruct a phylogenetic tree of these species by comparing their CFTR amino acid sequences. Students are also asked to evaluate their trees critically by comparing them with published phylogenies in the literature. This exercise helps students understand the principles underlying molecular phylogenetics and gain practical skills in searching genetic databases and conducting phylogenetic analysis using computer programs. In addition, this inquiry-based exercise encourages students to develop their critical-thinking skills through evaluating conflicting phylogenies reconstructed from different data or approaches. Although this exercise is designed to teach molecular phylogenetics in the biocomputing course, it can be easily adapted and used to enhance instruction in other biology courses. The activities are well suited for college students at all academic levels. (Contains 1 figure and 2 tables.)