This is a lesson about phenotypical variation within populations and how these differences are essential for biological evolution. Students will use a model organism (in this case, kidney beans) to explore variation patterns and subsequently connect these differences to artificial & natural selection. The NGSS’ CrossCutting Concepts and Science & Engineering Practices are embedded throughout the lesson. The NGSS Performance Expectations covered are HS-LS4-2. & HS-LS4-4.

The main learning objectives are:

• Using a model (kidney beans) to explore the natural variations within a population.
• Measuring differences between individuals in a population (population of beans).
• Describing how genetic/phenotypic variation is a key part of biological evolution because it is a prerequisite for natural selection.
• Demonstrating in which ways genetic variation is advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.

There is no specific prerequisite knowledge required prior to completing this lesson as this can be an introductory lesson (and it is flexible enough that it can be completed during different times of the curriculum). This lesson will require more than one 50-minute class period to complete. However, if students are not familiar with writing lab abstracts, this could take additional time. Also, if you chose to have students complete the advanced math component (standard deviation), then more time will surely be required.The materials required for this lesson include a Bag of dried kidney* (or any other kind of beans) beans (split into smaller bags of 50 beans), the guide-sheet, metric rulers, and graphing paper.

During the five classroom activities in this lesson students will be:

1. Using patterns to identify different physical attributes that are measurable and that vary over the population
2. Measuring the length of fifty beans to the nearest millimeter, in order to see variation within the patterns.
3. Graphing and analyzing data of the beans grouped by length.
4. Exploring patterns of variation as possible important causes for the survival of species, and
5. Evaluating evidence about the causes and effects of variation.