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CREATIVE WAYS TO TEACH
EVOLUTIONARY CONCEPTS

Myrtle A. Brijbasi
1993 Woodrow Wilson Biology Institute

INTRODUCTION

DNA, the genetic blueprint of living organisms, plays an essential role in the continuity of life. Therefore, the structure and function of DNA must be explained to students as simply as possible, using the most appealing methodologies.

DNA is often described by scientists as "the chemical language of life" (Monsanto, 1990). If the language were "edited"/changed, then the message it delivers to the cell would also be changed. The result is a natural event in evolution. Evolution is the genetic change in a population of organisms over time , produced by the integrating agencies of natural selection and variation. (Beck, Liems, Simpson, 1991)

Changes (mutations) in the gene pool of a population result in genotypic variation. These influence the destiny of the population from one generation to the next.

Rationale:

  • Identify the students' talents and interests, for planning suitable activities.
  • Elicit humor to make science less threatening and more stimulating.
  • Capitalize on students' manipulative skills - learning by doing - making models.
  • Apply concepts to real life experiences.
  • Promote interactive learning, group dynamics, and critical thinking.

    • BACKGROUND INFORMATION

  • DNA Structure,
  • RNA and Protein Synthesis,
  • Mutation,
  • Gene Expression,
  • Molecular Biology

    • Evolutionary Concepts

  • evolution
  • genetic variation
  • unicellular
  • Geologic Time Scale
  • multicellular
  • biochemistry (DNA)
  • prokaryote
  • common ancestry
  • eukaryote
  • gene pool
  • adaptation
  • allele frequency
  • natural selection
  • Hardy-Weinberg Principle
  • vestigial organ

    • TARGET AGE: Grade 9-12

    CLASS SIZE: 20-24

    TEACHER PREP TIME: 30 mins - 1 hour depending on the activity

    ACTIVITY TIME: 45 mins

    ACTIVITY 1: LAUGH A LITTLE, LEARN A LOT

    OBJECTIVE:

    Students will describe and explain evolutionary concepts featured in cartoon.

    MATERIALS:

    Overhead transparencies of cartoons Prescribed Biology text book, Reference Biology text, notebook, pen, pencil

    PROCEDURE:

  • Students read assigned chapter and define the given terms.Concepts are explained in lectures.

  • Teacher uses overhead transparencies of cartoons to explain selected concepts.

  • Students are encouraged to ask questions and make comments to promote interactive learning, critical thinking, and application of knowledge.

    • WRITING ACTIVITY:

  • Students write on the following:
    (a) concepts illustrated
    (b) brief explanation of each concept.

    • CHOICE OF CARTOON GRAPHICS:

    The Far Side (Gary Larson), Science Digest, local newspapers, Calvin and Hobbes (Bill Watterson) (COPYRIGHT LAWS APPLY), Student/teacher designs.

    ACTIVITY 3: NOT JUST A BAG OF BEANS

    TIME:

    2 - 45-min periods or 1- double period

    OBJECTIVE:

    Students will determine the types of natural selection in a given population,

    MATERIALS:

  • 2 pounds of kidney beans
  • 1 - 1000 mL beaker or a large container
  • ruler
  • lab notebook, pen, pencil, colored pencils, graph paper
  • 5 - 50 mL beakers or bathroom Dixie cups

    • PROCEDURE:

  • Pour all of the 2 pounds of beans into the 1000 mL beaker or large container.

  • One student from each group will take a 50-mL beaker or a Dixie cup and fill it with beans from the 1000 mL beaker or large container, and take back to the group.

  • Count out any 50 beans and measure the length of each one in mm, and record the data.

  • Complete a summary chart of the data.

    • DATA TABLE 1: BEAN SIZE

    1.*    6.*   11.*   *   *   *   *   *   *   
2.*    7.*   12.*   *   *   *   *   *   *   
3.*    8.*   13.*   *   *   *   *   *   *   
4.*    9.*   14.*   *   *   *   *   *   *   
5.*   10.*   15.*   *   *   *   *   *   *

    SUMMARY DATA TABLE

    Bean size*   *  *   *   *   *   *   *   *   *   
bean numbers*   *   *   *   *   *   *   *   *

    ANALYSIS OF DATA

  • Graph and analyze the data. Determine mean, median, mode, and range.

  • Determine/identify the type of natural selection that is occurring in the population - stabilizing, directional, or disruptive.

  • Compare your graph with that of another group and put that information on your graph also.

    • ANSWER THE FOLLOWING QUESTIONS.

  • Explain your results in terms of gene/allele frequency in a population.

  • From your population of beans explain the terms selection and fitness.

  • Translate this information in terms of a farmer who plants kidney beans in large quantities for commercial purposes.

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