The Missing Link

Student Handout

Nailing Cladistics

Cladistics is one way scientists classify organisms. A cladogram shows the nature of evolutionary relationships that may have occurred, similar to a family tree. You will make a cladogram in this activity.

Procedure
Part I

1. Display your set of hardware organisms and match each one to the organisms listed on your "Hardware Organism Key" student handout. Make sure you have all the organisms listed.

2. Classify your hardware organisms into groups. On a separate sheet of paper, make a record of your classifications, listing the letter for each organism you have classified. Then list the common characteristics of each of your groups.

Part II

1. You will now use a different method to classify your organisms. Follow the instructions on the "Cladogram Basics" student handout to create your cladogram.

2. After you have created and revised a rough draft of your cladogram, create a final version to share with the class.

3. When you have completed your cladogram, answer the questions.

Questions
Write your answers on a separate sheet of paper.

1. Compare your cladogram with others in the class. Will all correct cladograms be the same? Why or why not?

2. Compare cladistics with the more traditional taxonomy that you did in the Part I of the lesson. How do they differ? What are the advantages and disadvantages of each method?