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Feeding Facilitation: A lesson in Evolution and Sociobiology

By Vickie Bejda

Type of Activity:

  • Hands-on
  • Simulation
  • Inquiry lab
  • Group-cooperative learning

Target Audience:

  • Biology
  • Advanced/AP Biology
  • Life Science


Notes for teacher:

This exercise has been used to stress the importance of studying an organism's behavior as a manifestation of the integration of all of the biochemical and physiological processes set in motion by that organism's genes which is an indication of the ability of that individual to survive in its environment and play a part in the survival of the species as a whole. It therefore brings together all of the areas of biology that a student has been exposed to , e.g., evolution, biochemistry, genetics, reproduction, and ecology. (Refer to Sociobiology, The New Synthesis by E. O. Wilson, the Belknap Press of Harvard Univ. Press, Cambridge, Mass., 1982, pp. 51-57 and 135-138 for a discussion of foraging strategy.)

Each student will need a container with a hole drilled in the top just large enough for a toothpick to pass through. Small jars work well. Two paper or plastic cups can be taped together and a small hole punched into one end. Prior to the exercise, 100 red toothpicks need to be spread out in each of six random patches of about six to eight feet in diameter. The area must be large enough such that the students cannot see the toothpick patches by merely standing in one place and looking around. This procedure is repeated in two other locations for parts two and three of the exercise.

Required of students:

Students should have an understanding of the basic meaning of evolution, i.e., change within a population over time. They do not have to be familiar with the theory of Natural Selection as this exercise can be used for reinforcement or inquiry. For students who have already completed a course in biology, this activity can be used to initiate discussion of evolution.

Preparation: 1 hour

Class time needed: Two class periods



This is an outdoor activity designed to demonstrate evolution of feeding behavior in flocking, schooling or herding animals that maximizes allocation of food resources and enhances survival. Students simulate foraging by searching for and gathering toothpicks. While there are many exercises which utilize toothpicks and other materials to demonstrate food selection made by animals as an illustration of various aspects of Natural Selection, "Feeding Facilitation" is an attempt to show the relationship between energy costs of foraging and predator avoidance (optimum foraging theory) with flocking behavior and their relationship to evolution. Students with a wide range of abilities can complete this activity successfully because "energy expenditure" relates to the number of food items collected and can be easily seen.

Materials needed:

  • 600 toothpicks for each part of the exercise
  • 1 small plastic bag
  • 1 small container with a small hole drilled into the lid
  • 1 stop watch
  • Video camera and TV (optional)

This activity is conducted in three parts, each of which is video taped for 10 minutes, with the first demonstrating feeding success, and the second and third illustrating the energy cost of food handling and predator avoidance respectively. Upon arriving at the already prepared study area, students are given a small plastic bag and instructed to search for toothpicks, not to talk and that fighting animals will be declared dead and removed from the population? After 10 minutes, the collection activity is repeated in a new area only this time each student is given a jar with a hole drilled into the lid that is just large enough for one toothpick to slip through. this simulates the energy expenditure of an organism in handling the food source. Students repeat this last activity in a new area only this time with a "predator" walking around the study area. Touched animals are declared dead.

In the classroom, students record the number of toothpicks collected during each part of the exercise. While watching the video tape, students use a stop watch to record the amount of time during each of the activities that they were engaged in feeding. Class data is recorded and bar graphed with number of tooth picks collected vs. the amount of time spent feeding for each of the three trials. The energy cost of food handling and predator avoidance is then calculated.

In viewing the video tape, students immediately recognize themselves as behaving like a flock of birds. Discussion focuses around how students located a food source, how communication was involved in locating a food source, the energy cost of food handling, how flocking is related to predator avoidance and how this behavior relates to natural selection.

Method of Evaluation: Laboratory reports by individuals or cooperative groups.

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