HOMINID SKULL COMPARISON

Introduction

You are an Anthropologist in a team (ie 2 or 3) who are investigating the evolutionary relationships among living and extinct human relatives. You will work as a group to collect data for this project. It is your responsibility to keep all the data together. (This will be submitted as your rough draft.) You will use this data to write individual practical reports.

Materials per team : 1 skull copy of each of the following: • Homo sapiens (modern human) • Pan troglodytes (modern chimpanzee) • Homo neanderthalensis (Neanderthal), Homo erectus (Peking Man), , Homo habilis (Handy Man) , Australopithecus afarensis (Lucy)

Materials per team: 1 metric ruler 1 protractor Photographs, and other visuals of humans, chimpanzees, and gorillas

Procedure: – Comparing Modern and Extinct Hominid Skulls

In this part of the activity you will make detailed observations and measurements of skull casts of one modern and two extinct hominids. You will then use your data to determine if the extinct hominids are more ape-like or more human-like in appearance. Your data will also provide a basis for drawing some conclusions about patterns of hominid evolution.

1. Your team will examine the skull sheets chosen. For each skull you will need a metric ruler and a protractor. A few “rules” should be followed: • Do not make pencil or pen marks on the skulls. • Be sure to take turns in making the measurements. • Measure in millimeters (mm). Round off to whole numbers.

2. Complete the “Chart 2 - Hominid Skull Comparison Data Table” as you examine your chosen skulls. Refer to the “Hominid Skull Comparison Checklist” for a description of each hominid characteristic you observe.

Analysis Using observations and measurements from your completed Chart 2- Hominid Skull Comparison Data Table , answer the following question.

Question 1. Which traits distinguish modern humans from other modern apes?

Question 2. Briefly describe how the following characteristics have changed in hominid evolution from ape-like ancestors to modern humans. • Size of cranium/brain. • Type of brow ridge. • Presence of sagittal crest. • Facial prognathism (protrusion of snout). • Zygomatic arch. • Facial slope. • Size of canines. • Forehead shape.

Question 3. In terms of natural selection, describe how modern humans evolved a large brain from ape-like ancestors that had a smaller brain.

Question 4. Draw a phylogenetic tree that shows the position of the various hominids studied in this practical activity.

HOMINID SKULL COMPARISON CHECKLIST

1. FOREHEAD : Does the forehead (frontal bone) look more vertical or does it slope backward?

2. CHIN : Does the chin stick out or does it recede back?

3. SAGITTAL CREST : A sagittal crest is a bony ridge that runs from front to rear on top of the cranium. Is it small, medium, large, or absent?

4. FACIAL PROGNATHISM : How much does the snout protrude when looking at the skull from the side? Is the protrusion large, medium, small or absent?

5. BROWRIDGE : The brow ridge is a heavy mass of bone directly over the eye orbits. Rate it large, small, medium. 6. FORAMEN MAGNUM : The foramen magnum is a large opening in the back or bottom of the skull through which the spinal cord enters the cranium. Determine if it is more to the rear or towards the bottom of the skull. 7. FACIAL SLOPE : Use the protractor to measure the angle make by the face and the upper jaw when viewed from the side.

HOMINID SKULL COMPARISON DATA TABLE A B C D FEATURES H. sapiens Australopithecus H. erectus H. neanderthalensis

1.Forehead : more vertical or slopes back

2.Chin : sticks out or recedes back

3.Sagittal Crest : large, small, medium or absent

4.Facial Prognathism : (snout protrusion) large, small, medium, absent

5.Browridge : large, small, medium

7.Canine Tooth : length of exposed upper canine tooth in mm

6.Length of Cranium : maximum length of brain case in mm

7. Facial Slope: the angle made by the face and the upper jaw viewed from side