Using “Chromosomal Socks” To Demonstrate Ploidy in Mitosis & Meiosis

Today, many biology instructors use visual models to help students understand abstract concepts like cell division. For all biology instructors, dealing with student misconceptions of cell division may seem hopeless at times--even after using visual models. Although student errors in cell division are built around the three key events of cell division (i.e., chromosome doubling, pairing, and separating) (Smith, 1991), no panacea exists to relieve biology instructors of the recurrent learning patterns that seem to afflict students year after year. Therefore, each type of misconception must be treated separately to effectively resolve student misunderstanding. Taking advantage of models carefully designed to address specific misconceptions is an excellent means to achieve this goal. To help students gain a meaningful understanding of ploidy, these authors developed a quick, straightforward activity using colorful pairs of socks to represent chromosomes during cell division. Expanding on Oakley's (1994) sweat sock chromosome model, this activity focuses on karyotype formation from scattered arrays of "chromosomal socks" and on ploidy differences in body cells and gametes (diploid vs. haploid) rather than on the various individual stages of mitosis or meiosis. (Contains 8 figures.)