|Target age or|
|High school biology or life science classes.|
|Materials and equipment:||Text book for reference, pencil and paper. Pictures of various automobiles and trucks might be useful.|
|Summary of activity:||Students will construct a phylogenetic tree for the various automobiles and trucks listed after considering important characteristics of these "organisms." For many students it may be easier to construct a phylogenetic tree using vehicles rather than organisms with characteristics that may not be obvious or familiar This activity can lead into other similar exercises using real plants or animals.|
|Prior knowledge, concepts or vocabulary necessary to complete activity:||Be sure students understand the basics of biological classification, evolutionary processes and phylogenetic tree construction.|
Explain that a phylogenetic tree is a hypothesis regarding the evolutionary history of a group of organisms. Assume all of these vehicles evolved from a primitive ancestor having four wheels Have students work in small groups and devise a way that each group can present their work to the class. It may be necessary to draw a simple version of a phylogenetic tree to get students off to a good start. Students will probably interpret relationships in a variety of ways. Emphasize that this work is very speculative. The important point is to carefully consider all evidence. There is no single "right" interpretation.
Instructions: Using a pencil, draw a branched phylogenetic tree starting at the bottom of a sheet of paper. Start with what you think is the most primitive vehicle. Be sure you have a reason, based on a careful consideration of characteristics, for each branch. At the appropriate location on each branch place the name of the vehicle. Work with a small group and be prepared to present your work to the class. Keep in mind that there may not be a single ÒrightÓ way to draw a phylogenetic tree for these vehicles. Remember that scientific knowledge grows by trial and error. All theories or interpretations are open to revision.
1. What characteristics are you going to consider? List below.
2. Explain several of the branching points on your tree.
3. Which vehicle seems to be the most primitive? Justify your answer.
4. Which vehicles seem to be the most advanced? Justify your answer.
5. What is the value of a phylogenetic tree to biologists?
On to The Endosymbiotic Theory,
OR Eukaryotic and Prokaryotic Feast
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