Developing a Dichotomous Key

from Hominoid Skulls

A WebQuest for grades 7-12 (Human Biology or Anatomy)

Designed by Gene Gregory - South Hagerstown High School

Gregoeug@wcboe.k12.md.us
taungchild Taungchild

Introduction

Suppose you were on an archeological dig. You uncover what appears to be a hominoid skull. ("Hominoid" is the collective term for apes and humans.) It is your job to figure out what kind of skull it is. But how? Each hominoid can be identified by specific characteristics. As hominoids split off from hominids which then evolved into modern man, certain trends in  skull features have been documented that will allow for a  proper identification. In this activity you will go through a series of assignments that will lead you to understand how to identify those characteristics and trends hominid evolution.

Task

You have multiple tasks. Students will describe, measure and compare 3-D cranial replicas from chimpanzees, modern humans and fossil "hominids" (erect and bipedal forms evolutionarily separated from apes).  The purpose of the activity is for students to discover for themselves what some of the similarities and differences are that exist between these forms, and to see the pattern of the gradual accumulation of traits over time, leading to modern humans. The goal of this assignment is to identify those patterns and create a dichotomous key that others may use to identify the hominoid skulls that you have researched.

The Process

In order to accomplish the task, there are a number of steps that you must go through. You will need to use to a computer with Interent access and a printer.
 (Your teacher may decide to download the materials for you.) You will still need Internet access to complete the project.
  1. You will be grouped into teams of 2 students. Take turns being the researcher and the recorder.
  2. Please print this page
  3. Please download the following materials:

* In order to fill out the Human Evolution Data Chart you will need to use the Hominoid Skull Comparison Checklist as a guide.
  1. Fill in the far left hand column of the chart with the following hominoid names:
  1. Go to http://www.anth.ucsb.edu/projects/human/ and Enter the Gallery
  2. You will see a timeline with an evolutionary tree containing various hominoid creatures. Click on the picture marked Human Origins.
  3. At the top of the page you will see, in a viewing box, a 3-Dimensional replica of a chimpanzee skull. To rotate the skull, click on it and drag your mouse horizontally. You can turn the skull 360 degrees.
  4. There is way to make measurements of the skull. Point to any area of the skull with your mouse. Hold down the “shift” key and drag your mouse along the skull. At the bottom of the viewing box you can see the measurement in millimeters. Release the shift button to stop measuring. 
  5. Using the Hominoid Skull Comparison Checklist as a guide fill out the Human Evolution Data Chart for the chimpanzee
  6. Now click on the blue arrow pointing toward the Human figure in the evolutionary tree.
  7. Finish completing the chart by clicking on the members of the tree one by one. If a lower jaw is missing use "N/A" on the chart instead of none to avoid confusion.
  8. The purpose of the activity was for you to discover what some of the similarities and differences are that exist between hominoids, and to see the pattern of the gradual accumulation of traits over time, leading to modern humans. You will now create a dichotomous key based on the traits that you have observed using the information from the Human Evolution Data Chart.
  9. Check your dichotomous key by exchanging it with another group to try. Have them go to http://www.indiana.edu/~ensiweb/lessons/hom.draw.html and print out any of the hominoids named above to see if your key works.

Evaluation

Everyone will receive a group project grade using the rubric below. Notice that there will be an individual  participiation grade for each person in your group.

Beginning
1

Developing
2

Accomplished
3

Exemplary
4

Score

 

Students will accurately record  information  for the Skull Comparison Chart

 
Students made measurements most may be innacurate but the chart is at least  25% complete.
Students made measurements some may be innacurate but the chart is at least  50% complete.

Students made measurements - some may be innacurate
 but  the chart is complete.

Students made accurate measurements and completed the entire chart.

12 points possible

 


 Dichotomous Key

 

Other students are able to accurately identify at least 1 skull  by using the  dichotomous key.
The team cannot explain the mistakes in the key.

Other students are able to accurately identify at least 3 of the skulls  by using the  dichotomous key.
The team cannot explain the mistakes in the key.
Other students are able to accurately identify all but 1  skull by using the  dichotomous key.
The team can explain the mistakes in the key.

Other students are able to accurately identify all of the skulls by using the  dichotomous key.

12 points possible

 


Participation grade

 

Student participated but contriubuted very little to the project, did not remain on task and needed more than 1 "reminder for behavior."
Student contriubuted to the project and remained on task but needed more than 1 "reminder for behavior."

Student contriubuted to the project and remained on task but needed a "reminder for behavior."

Student contriubuted to the project and remained on task without "reminders for behavior."

6 points possible

 

Conclusion
Congratulations you have just completed my Hominoid dichotomous key webquest. I hope that you enjoyed the assignment. If are interested in reading more about hominid evolution click on one of the links below.
http://www.accessexcellence.org/AE/AEPC/WWC/1995/fossilshominids.html
http://www.mc.maricopa.edu/dept/d10/asb/anthro2003/origins/manbegan.html
http://Becominghuman.org

Credits
Thanks to:

The Webquest page at http://webquest.sdsu.edu/ for their webquest template.

Phillip L. Walker and Edward Hagen at University of California, Santa Barbara for creating the 3D gallery of modern primate relatives and fossil ancestors of humans.
http://www.anth.ucsb.edu/projects/human/

Martin Nickels for creating the Hominid Cranium Comparison Lab. It was his HOMINOID SKULL COMPARISON CHECKLIST and HUMAN EVOLUTION DATA CHART that made this Webquest possible.
http://www.indiana.edu/~ensiweb/lessons/hom.cran.html

Buddy Phillips at McDaniel college for helping me remove the "junk" from my source code.