In this lesson, students are introduced to a participatory computer simulation where each student takes the role of an individual consumer (a bug) in an ecosystem. Students make predictions about various model runs and compare their predictions to the outcomes they observe. In one exploration they control the direction of movement of a bug, trying to gather as much food (grass) as possible in a variety of conditions. In another exploration they observe the outcome when many bugs move randomly and blindly around an ecosystem consuming food without any intentional control. Students recreate a physical representation of a histogram graph (of energy levels of bugs) from NetLogo and analyze characteristics of the population in the graph to draw comparisons between populations and individuals. Through discussion, the teacher helps build consensus about what they discovered: Competition is an emergent outcome that results from 1) limited resources necessary for survival, 2) and unequal distribution of those resources throughout the ecosystem, 3) and from interactions (intentional or unintentional) that always are occurring between each individual and their environment. In their homework students address the difference between intentional and unintentional competition further. They critique the modeling assumptions used in the computer simulation. They describe the variation in local resource availability for individuals in the computer model. They calculate how changes in the amount of grass or amount of bugs in would change the average amount of grass per bug in the ecosystem and they identify that ecosystems with lower average grass per bug would have higher levels of competition than those with higher average amounts of grass per bug.