Natural Selection Hands on Lesson Plan

Students tend to understand concepts better after performing hands-on activities that reinforce the ideas they are studying. This lesson plan on natural selection can be used in many different ways and can be changed to meet the needs of all types of learners.

Materials

1. A variety of at least five different kinds of dried beans, split peas, and other legume seeds of various sizes and colors (can be purchased at the grocery store relatively inexpensively).

2. At least three pieces of carpet or cloth (about a square yard) of different colors and texture types.

3. Plastic knives, forks, spoons, and cups.

4. Stopwatch or clock with a second hand.

Natural Selection Hands-On Activity

Each group of four students should:

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1. Count out 50 of each kind of seed and scatter them on the piece of carpet. The seeds represent individuals of a prey population. The different kinds of seeds represent genetic variations or adaptations among the members of the population or different species of prey.

2. Equip three students with a knife, spoon, or fork to represent a population of predators. The knife, spoon, and fork represent variations in the predator population. The fourth student will act as a timekeeper.

3. At the signal of "GO" given by the timekeeper, the predators proceed to catch prey. They must pick prey off the carpet using their respective tool only and transfer the prey into their cup (no fair putting the cup on the carpet and pushing seeds into it). Predators should only grab one prey at a time rather than "scooping" the prey up in large numbers.

4. At the end of 45 seconds, the timekeeper should signal "STOP." This is the end of the first generation. Each predator should count their number of seeds and record the results. Any predator with fewer than 20 seeds has starved and is out of the game. Any predator with more than 40 seeds successfully reproduced an offspring of the same type. One more player of this type will be added to the next generation. Any predator that has between 20 and 40 seeds is still alive but has not reproduced.

5. Collect the surviving prey off the carpet and count the number for each type of seed. Record the results. Reproduction of the prey population is now represented by adding one more prey of that type the number for every 2 seeds that survived, simulating sexual reproduction. The prey is then scattered on the carpet for the second generation round.

6. Repeat steps 3-6 for two more generations.

7. Repeat steps 1-6 using a different environment (carpet) or compare results with other groups who used different environments.

Suggested Discussion Questions

1. The prey population started with an equal number of individuals of each variation. Which variations became more common in the population over time? Explain why.

2. Which variations became less common in the total population or were eliminated entirely? Explain why.

3. Which variations (if any) remained about the same in the population over time? Explain why.

4. Compare the data between the different environments (types of carpet). Were the results the same in the prey populations in all environments? Explain.

5. Relate your data to a natural prey population. Can natural populations be expected to change under pressure of changing biotic or abiotic factors? Explain.

6. The predator population started with an equal number of individuals of each variation (knife, fork, and spoon). Which variation became more common in the total population over time? Explain why.

7. Which variations were eliminated from the population? Explain why.

8. Relate this exercise to a natural predator population.

9. Explain how natural selection works in changing the prey and predator populations over time.