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Joel E. Greengiant Learns About Peas

From Nucleotides to Selection

Merle K. Heidemann (rr)
College of Natural Science, Emeritus
Michigan State University
Peter J.T. White
Lyman Briggs College
Michigan State University
James J. Smith
Lyman Briggs College
Michigan State University


This case study follows purveyors of peas, Joel E. and Jolene Greengiant, as they learn about the origin, biochemistry, genetics and eventual artificial selection of sweet (wrinkled) peas, all in the context of evolutionary biology. This integrative approach employs both problem-based learning techniques and directed questions as students engage in a series of modules. These modules include a natural history of domestic peas, cell biology of round and wrinkled peas, the Mendelian and molecular genetics of wrinkled peas and the population genetics of round and wrinkled peas. These can be used in any order as dictated by instructional needs. The case study is appropriate for an introductory biology course, an AP or Honor's high school biology course or an upper level course in evolution. Each module would have instructional value in related upper division courses. A key feature of the case study is weaving evolutionary thinking into the biology curriculum.   The research phase of problem-based learning is supported by a series of slides and simulations that can be downloaded, edited and used according to instructors' needs.


  • Explain the differences in cell biology and biochemistry of wrinkled (sweet) and round (starchy) peas and the advantage of sweet peas to ancient farmers.
  • Explain Mendel's rules of patterns of inheritance in terms of meiosis.
  • Explain how insertion of nucleotide sequences leads to a difference in gene expression and cell function, as they connect to evolutionary theory (i.e., the connection between genotype and phenotype and the role of mutation in producing new phenotypes).
  • Engage in a population genetics simulation in light of artificial selection to answer key questions regarding selection.
  • Explain that the study of evolution requires learning across the biological sciences curriculum and provide relevant examples.
  • Engage in independent research.


Evolution; population genetics; Mendel’s peas; pea plant; Pisum sativum; Mendel’s Laws; genetics; molecular genetics; meiosis; mutation; nucleotide insertion; artificial selection; starch synthesis; starch branching enzyme; plant domestication; legumes

Educational Level

High school, Undergraduate lower division, Undergraduate upper division



Type Methods

Discussion, Interrupted, Problem-Based Learning



Subject Headings

Biology (General) Genetics / Heredity Cell Biology Molecular Biology Evolutionary Biology Ecology Biochemistry Agriculture Botany / Plant Science

Date Posted


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