This case study focuses on the characteristic of tusklessness in the African elephant population of Gorongosa National Park, Mozambique, to examine molecular and macroscopic aspects of evolution. Students are introduced to the plight of African elephants and the importance of tusks (modified incisor teeth) for elephant fitness and for their role as a keystone species. They learn that intense poaching of African elephants has caused an increase in tuskless females, despite the fitness benefit that tusks otherwise provide. To understand the gene-to-protein-to-phenotype connection at the molecular level, students explore the effect of an X-chromosome deletion on protein production of a key gene in tooth formation. Using Punnett squares, students examine the X-chromosome deletion to develop an understanding for why tusklessness is found only in female and not male elephants. Lastly, students connect phenotype (tusked or tuskless) to fitness in the presence and absence of heavy poaching. This case is ideally suited for upper-level biology students to thoroughly connect gene mutation to fitness during evolution.