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Biology 10 Evolution Lab Activity
Materials List & Instructions
This lab is generally preceded by an explanation of evolution by natural selection, including the concepts of predator/prey interactions. Students work in groups of 3 or 4, and each group uses one “environment.” The environments can either be a 3 ft. x 3 ft. piece of patterned cloth (used indoors), or 9 ft X 9 ft. quadrant outdoors. The different colored beans represent different types of prey, and the students will alternate as predators that capture the prey. Variables affecting natural selection that will be examined include: 1)camouflage, 2)reproductive fitness, 3) prey density, and 4) predator competition
Note that the overhead lights in class should be turned off during the activity to simulate twilight conditions during which many predators forage (there should still be plenty of light from the overhead windows). Also, predators should be advised that they can only pick up ONE bean “prey” at a time and place it in their zip lock bag “nest” before picking up another “prey.” After completion of the exercises, all beans should be picked up and returned to their proper bags.
Materials required per group:
1 – 3 ft. x 3 ft. patterned cloth (for indoor activity) OR
4 – 9 ft. sections of rope OR 4 traffic cones (for outdoor activity)
100 - dry pinto beans in quart sized, clear plastic zip-lock bag
100 – dry black beans in zip-lock bag
100 – dry green peas in zip-lock bag
100 – dry white beans in zip-lock bag
100 – dry black-eyed peas in zip-lock bag
1 – quart sized clear plastic zip-lock bag for a “nest”
A. Effects of Camouflage on Natural Selection
1) Each group will select one patterned cloth “environment” and lay it flat, pattern side up, on the table top in front of them (if outside, lay out ropes in a 9 ft. square OR place traffic cones at the corners of a 9 ft. square).
2) One group member from each group is selected as the first predator and will turn his/her back so that they cannot see the environment as it is set up.
3) The remaining group members will take 20 of each type of bean “prey” and scatter them over the “environment.”
4) The predator is given an empty zip-lock bag “nest” and instructed gather as many prey as possible (one at a time) in the 30 second time limit. The predator then turns toward the environment and begins gathering “prey” and placing them in the “nest” until the timer states the time is up.
5) The group counts the number of each type of prey the predator gathered, records their numbers on the camouflage table, and calculates how many of each type of prey remain in the environment.
6) The predator turns away again while the group adds one prey of the same type for each prey that remains in the environment (representing reproduction of the prey that survived).
7) Steps 4 and 5 are then repeated two times, for a total of 3 trials (1st, 2nd, and 3rd generations of prey), then use your data to answer the following questions.
Effects of Camouflage on Natural Selection Data TablePinto beans / Black beans / Green peas / White beans / Black-eyed peas
Trial 1
A. Initial number of bean prey / 20 / 20 / 20 / 20 / 20
B. Number of prey gathered
C. Number of surviving prey (A – B = C)
D. Reproduction of surviving prey
(C x 2 = D)
Trial 2
A. Number of prey from 1-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
Trial 3
A. Number of prey from 2-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
a. What were the predominant colors of your “environment”? ______
b. Which prey variant (bean color) was selected for (the ones that survived and reproduced) in the environment? ______
c. Which prey variant (bean color) was selected against(the ones that were gathered by the predator) in the environment? ______
d. Compare your results with those of other groups with other environments. From the overall results, what can you deduce about the effects of camouflage on natural selection?
______
B. Effects of Reproductive Fitness on Natural Selection
1) Select a new predator from your group.
2) Follow the directions from the “Effects of Camouflage on Natural Selection,” except add TWO of each prey for each surviving prey type at the end of each trial.
3) Record your results in the table below and answer the questions.
Effects of Reproductive Fitness on Natural Selection Data TablePinto beans / Black beans / Green peas / White beans / Black-eyed peas
Trial 1
A. Initial number of bean prey / 20 / 20 / 20 / 20 / 20
B. Number of prey gathered
C. Number of surviving prey (A – B = C)
D. Reproduction of surviving prey
(C x 3 = D)
Trial 2
A. Number of prey from 1-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
Trial 3
A. Number of prey from 2-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
a. How did increasing the reproductive fitness of the prey compare with the effects of camouflage results? ______
b. Compare your group’s results with those of the other groups with different environments. From the overall results, what can you deduce about the effects of reproductive fitness on natural selection? ______
C. Effects of Prey Density on Natural Selection
1) Select a new predator from your group.
2) Follow the directions in the “Effects of Camouflage on Natural Selection,” except, instead of beginning with 20 of each prey, use 10 of each prey type initally.
3) Perform 3 trials, and record your data in the table below.
4) If all of the prey are gathered by the predator before the end of the 3rd trial, the predator dies.
Effects of Prey Density on Natural Selection Data TablePinto beans / Black beans / Green peas / White beans / Black-eyed peas
Trial 1
A. Initial number of bean prey / 10 / 10 / 10 / 10 / 10
B. Number of prey gathered
C. Number of surviving prey (A – B = C)
D. Reproduction of surviving prey
(C x 2 = D)
Trial 2
A. Number of prey from 1-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
Trial 3
A. Number of prey from 2-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
a. Compare the data from the “Effects of Reproductive Fitness” and the “Effects of Prey Density” and relate it to “Boom and Bust” cycles of predator/prey interactions and Natural Selection
______
______
D. Effects of Predator Competition on Natural Selection
1) Select TWO predators from your group.
2) Follow the directions from the “Effects of Camouflage on Natural Selection,” except the two predators will compete to gather prey at the same time. Touching another predator is prohibited, and will result in a loss of 5 prey penalty during foraging for the toucher.
3) If a predator cannot gather at least 30 prey during any trial, that predator is dead.
Effects of Predator Competition on Natural Selection Data TablePinto beans / Black beans / Green peas / White beans / Black-eyed peas
Trial 1
A. Initial number of bean prey / 20 / 20 / 20 / 20 / 20
B. Number of prey gathered
C. Number of surviving prey (A – B = C)
D. Reproduction of surviving prey
(C x 2 = D)
Trial 2
A. Number of prey from 1-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
Trial 3
A. Number of prey from 2-D
B. Number of prey gathered
C. Number of surviving prey
D. Reproduction of surviving prey
a. How did competition affect the number and type of surviving prey? ______
______
b. How did competition for the same prey in the same environment affect the predator’s chance of survival? ______