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Course, Subject

Biology/Living Environment, Math, Science & Technology, Science (NYS P-12)

Assessment

• Students will construct a graph using Microsoft Excel to illustrate the data collected in the activity (See student work for example).
• Students will follow the instructions on the provided worksheet and complete all answers on a separate sheet of paper to be handed in.
• Hide and Survive_Natural Selection Activity.doc

Duration

• Approximately 40 minutes

Essential Questions

What determines whether an individual is fit to survive?

How can a change in the environment initiate a change in a population?

Instructional/Environment Modifications

• Activity can be done in the classroom. It is suggested that the desks are grouped together so that students can work in pairs.
• Students can work individually if the teacher desires.
• Students can produce a graph on paper if they are not familiar with Microsoft Excel, or if no computers are available.
• Instructions and questions can be simplified to tailor this activity for the desired grade level.

Procedure

1. Prior to class the teacher will obtain the candy (the red and green holiday M & M's usually work well), and separate them according to color.
2. The teacher will first give a brief introduction pertaining to natural selection, and probe the students for their understanding of the essential questions listed above.
3. The students will work in pairs, and each pair will obtain 20 red and 20 green candies, a white sheet of paper and a green sheet of paper.
4. The teacher will introduce the activity to the student describing how the students will act as predators and the candy will be their prey. The different colored candies will be placed on the white construction paper which represents the environment. The students will close their eyes briefly, open them and choose the first piece of candy they see. This action will represent the predator located and killing its prey. The candy that is chosen is now 'dead' and will be removed from the environment (placed aside). The partner will mix the candies around on the sheet of paper while the student's eyes are closed and then will repeat the procedure again. The students will repeat for twenty trials, and record how many green and red candies are left after the twenty trials. (The numbers should be close to equal as the probability of choosing either a red or green is the same).
5. Next, the teacher will describe how over time the white environment, which represented a cold snowy climate, became a much warmer climate resulting in far less snow, and the presence of more green grass. The students will repeat these procedures again, using the 20 green and 20 red candies, but this time will do so on green colored construction paper. The students will repeat for twenty trials and record how many green and red candies are left. (There should be significantly more green candies left as they blend in to the construction paper and would generally not be the first candy seen by the student.)
6. After completion of the activity the students will create a graph showing the results.
7. Students will complete the attached worksheet found above in the assessment section.

Reflections and Feedback

This lesson is developed to give the students a hands-on, concrete example of the theory of natural selection, which can be difficult for students to understand. In addition this lesson integrates a diverse group of skill sets including working with technology, graphing, analyzing, and forming conclusions.

This lesson was also developed as part of an integrated curriculum unit which focused on the main theme of Change. The activity is a good example of how a population can be altered as changes in the surrounding environment occur. It also emphasizes the idea that traits that are now considered favorable (traits of the fit) can become unfavorable traits (traits of the weak) throughout time.

Student Work

Depending on the desires of the teacher, the students can produce a bar graph, line graph, or both illustrating the final results. See examples of student work below.

Note: To produce a line graph students must be instructed to make a chart outlining the number of surviving colors for each trial rather than simply counting the number of survivors at the end of the twenty trials as you would to produce a bar graph.

bar graph data.xls

line graph data.xls

Materials/Resources Needed

1. 40 pieces of candy per pair of students (red and green holiday M & M's are good)
2. One white sheet of paper per pair of students
3. One green sheet of paper per pair of students
4. Worksheet
5. Computer with Microsoft Excel

Similar Resources:

• Evolution and Gene Frequencies
• The Chips are Down: A Natural Selection Simulation

Description



Purpose:

Through this activity, students will explore and understand the concept of natural selection by playing the role of a predator searching for prey. Using colored construction paper to represent a simulated environment and different colored candies to represent the prey, students will discover that based on the environmental settings (color of the background) some individuals will blend in to their environment, decreasing their chances of being preyed upon and as a result will be better fit for survival, reproduction, and the passing of their genetic traits on to their offspring. Additionally, they will explore how a change in the environment can result in the favoring of a new set of traits, which over time can lead to a change in the genetic variation of a population.

In this lesson students will understand that:

• Genetic variations exist among populations.
• Some variations will lead to certain individuals within a population expressing favorable characteristics that allow them to be better suited for survival.
• Those individuals that survive pass on their favorable variations to their offspring and thus the frequency of these variations increases over time with each new generation.
• A change in the environment can lead to a change in the variations to be selected for, resulting in a shift in frequency of a variation among a population.

Related Academic Standards

New York State

S.MS.LS.4.4 Students who demonstrate understanding can construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals’ probability of surviving and reproducing in a specific environment.

S.MS.LS.4.6 Students who demonstrate understanding can use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

S.HS.LS.4.2 Students who demonstrate understanding can construct an explanation based on evidence that the process of evolution primarily results from four factors: (1) the potential for a species to increase in number, (2) the heritable genetic variation of individ

S.HS.LS.4.5 Students who demonstrate understanding can evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3)

MST4.I.LE.3.1 Students describe sources of variation in organisms and their structures and relate the variations to survival.

MST4.C.LE.LE.3.1 Students explain the mechanisms and patterns of evolution.

MST4.C.LE.LE.6.3 Students explain how the living and nonliving environments change over time and respond to disturbances.