Studying Living Organisms

An Automobile Phylogenetic Tree

Al Vogel

1995 Woodrow Wilson Biology Institute

Target age or
ability group: High school biology or life science classes.

Class time
required: One period.

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.

Teacher Instructions

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.

An Automobile Phylogenetic Tree

Purpose of this activity: Carefully look at the list of cars and trucks below. In this activity we are going to consider these vehicles to be organisms that are all related in an evolutionary way. Actually, there has been an evolutionary process in automotive design that is a lot like biological evolution. As you study this list of vehicles think about the characteristics that can be used to show relationships. The number of wheels and the number of doors are two that come immediately to mind, but there are others as well. Using the characteristics you identify, you can construct a phylogenetic tree to show how this group evolved over time. We can never really know what happened in the past, but we can make reasonable speculations.

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.

Vehicles:

car with three wheels and one seat (nearly extinct in the U.S.)
car with four wheels, four doors , front and back seat
car with four wheels, two doors, front seat only
car with four wheels, two doors, front and back seat, no top
truck with four wheels, two doors, one seat and a short bed
truck with four wheels, two doors, one seat and a long bed
truck with six wheels, two doors and only one seat
truck with six wheels, four doors, front and back seat

Questions:

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
Back to Index

The Woodrow Wilson National Fellowship Foundation

webmaster@woodrow.org
CN 5281, Princeton NJ 08543-5281

Tel:(609)452-7007

Fax:(609)452-0066

Target age or ability group:	High school biology or life science classes.
Class time required:	One period.
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.