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Biology LibreTexts

6.3: Optional Class Exercise

  • Page ID
    15987
  • Divide into two groups, each containing 8 students. Fill out the characteristics of the individuals in your group in the provided table. You can start with the characteristics listed in the table, but you may have to use different or additional characteristics for a complete identification (e.g., if all of the members of your group have brown hair, then hair color cannot be used as an identifier).

    Using the information in your table, design (draw) a dichotomous key (a branch diagram) that can be used to identify the members of your group. Each person in the group should have a copy of the key. Design the key so that each choice has only 2 alternatives. For example, if members of your group range in height from 5’4” to 6’ 2”, your key could include two branch points: < 6’ tall and > 6’tall.

    Once each of you have completed a dichotomous key for your group, exchange keys with an individual from the other group. Using the key, try to determine their name without speaking to them (unless you need to ask their height or their shoe size). Ask that individual if your identification is correct. If not, review the key to see if you made a mistake, or if there was a point where the key was misleading.

    Student Characteristics
    Student Name Gender Height Eye color Hair color Shoe size Additional characteristics

    Construct Classmate Dichotomous Key Below

    SAMPLE DICHOTOMOUS KEY DATA FOR CLASSMATE IDENTIFICATION
    Name Gender Hair color Eye color Age Shoe Size
    Jim M Blonde Grey 19 10
    Tom M Brown Green 55 9
    George M Blonde Brown 23 11
    Fred M Black Blue 35 12
    Dan M Brown Brown 22 10
    Martha F Black Brown 43 7
    Amy F Brown Brown 32 7
    Connie F Brown Brown 21 6
    Carol F Blonde Brown 23 8
    Fran F Red Blue 23 6

    Construct Sample Dichotomous Key Below