Time Estimate – 7 weeks, including a 10-day growing period
Essential Question: How can the phenotypes of offspring be used to determine the genotypes of the parents?
Purpose: In the lab you will grow Wisconsin fast plants and record data on phenotypes, generate a hypothesis regarding the genotypes of the parents and use a chi square analysis to support or reject your hypothesis.
This lab is fairly easy to conduct, though organizing the time frame can be challenging. My version was modified because the AP lab was just too long to be manageable in the time frame that I had. In this version, students gain some experience with growing plants, which some of my students have never done. They also gain an understanding of how hydroponics work to ensure that moisture in the quads stays constant. You don’t need to order the whole kit, the Wisconsin Fast Plant site has instructions for building chambers from small plastic water bottles. My grow chamber was created from a box lined with aluminum foil and CFL bulbs.
I order a dihybrid crossed plant AaBb x AaBb so that the first experiment will display a 9:3:3:1 ratio. Students count their plants and perform a chi square analysis.
Part 2 is more of an inquiry lab where students are asked to take the plants they grew in part 1 and design an experiment to answer a question about those plants. Sample questions are included. I also grow other types of seeds in a different area so that students can experiment with different crosses.
Finally, students write a lab report or create an infographic that summarizes what they have learned in this investigation.
The investigation was designed for AP Biology students but can work for other age groups.