This activity is to be used as an assessment after students have been exposed to the use of a dichotomous key, and therefore know what the term dichotomous refers to, and how it is used. There are 13 species of Triangulum pictured. It is suggested that each student identifies any three of the species.

• 1 point is awarded for each correct name identification of each species.
• 1 point is awarded for each correct choice or step along the way.

The example given on the student answer sheet (#101) would be awarded 3 points for a perfect answer. But if the student had only been able to reach choice 1B before making a mistake, only 1 point would be awarded.

Since a different number of choices is necessary to identify the different species, the students may end up with different total points. Therefore a percent grade may be given.

Total number of points are given for each species below, including the correct choice for each of the steps.

Choose any of the three species of Triangulum from the species sheet and key them to their scientific names. Be sure to write in the numbers of the species that you are trying to identify. In the proper spaces below write in the number and letter (example #101) for each of the choices you made as you identified the species. When you are sure of the species identification, write in the scientific name in the space provided.

Scientific name of Example #101 = Samplest correctus

Scientific name of species #105 = Triangulum pointiatus

Actual points = 6 Possible points = 6

Scientific name of species #112 = Trianulum oddcilius

Actual points = 2 Possible points = 6

Scientific name of species #107 = Trianulum waveus

Actual points = 1 Possible points = 4

• Award 1 point for each correct step in the determination and correct naming of the organism Triangulum oddcilius. (steps; 1A, 2A, 3B, 7A)

• Allow 4 points if each of the following traits are shown in the student drawing:
  • Sides are straight lines
  • Has no eyes
  • Has cilia for movement
  • Total number of cilia for movement are odd
  • (Note: The number must be odd and other than three.)
• 3 points if any three of the above traits are shown correctly
• 2 points if any two of the above traits are shown correctly
• 1 point if any one of the above traits is shown correctly
• 0 points if responses are incorrect, or no response is provided

  Note: Deduct 1 point from the total points of this question for each trait shown that should not be present (e.g. a nose).

1. • Allow 1 point if the student correctly identifies steps ten and eleven.
   • Allow 0 points for incorrect responses, or no responses provided.

2. • Allow 2 points if the student correctly describes two different conditions for the new trait.
     (Example:
     1. Half of the body has a dot pattern.
     2. The whole body has a dot pattern.)
   • Allow 1 point if the student correctly describes one condition for the new trait.
   • Allow 0 points for incorrect responses, or no response provided.
3. • Allow 4 points if the student properly writes the scientific name of the new species using each of the following conventions:
     • name consists of genus and species
     • the genus name is Triangulum
     • underlining entire name
     • first letter of the genus name capitalized, first letter of the species name lower case
   • Allow 3 points if any three of the above conventions are used correctly.
   • Allow 2 points if any two of the above conventions are used correctly.
   • Allow 1 point if any one of the above conventions are used correctly.
   • Allow 0 points for incorrect responses, or no response provided.