The concept of population growth patterns is a key component of understanding evolution by natural selection and population dynamics in ecosystems. The National Science Education Standards (NSES) include standards related to population growth in sections on biological evolution, interdependence of organisms, and science in personal and social perspectives. Organisms have the potential to achieve exponential growth under ideal conditions, yet sustained exponential growth is not found in nature. This observation is a cornerstone of the theory of evolution through natural selection. To promote understanding of the concept of exponential growth, a set of activities was developed to engage students by integrating mathematical principles with the science concepts. This article presents an activity that helps students understand the key concept of exponential growth. This activity has been used successfully in undergraduate biology courses for majors and non-majors, and graduate courses in science teacher preparation. In this activity, students explore the concepts of population growth by predicting the growth potential of a plant population. Understanding exponential growth in a population includes knowledge of population dynamics, the mathematical principles used to calculate growth over time, and the ability to interpret the graphical representations of population growth. To facilitate the calculation and representation of growth patterns, students use a graphing calculator. Graphing calculators allow the students to predict population growth trends when conditions change and to answer questions about the future growth potential of a population. Students then apply the concepts they have learned by predicting how human population will grow in the future if current population trends continue. Finally, students discuss limits to population growth in nature and consequences of these limits to population phenotypic structure. (Contains 4 tables.)