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Physical Anthropology
Comparing Hominids
Introduction:
It is widely believed that Australopithecus africanus was closely related to the ancestors of modern
humans, including ourselves. Some members of A. africanus eventually evolved into Homo habilis, the first
human species. In turn, Homo habilis was the ancestor of Homo erectus, the direct ancestor to two lines of
humans, Homo sapiens neandertalensis and Homo sapiens sapiens
In this investigation you will be examining skull casts of A. africanus, H. erectus, and H. sapiens
sapiens, modern man.
Objectives:
1. Compare major similarities and differences between the skulls of Australopithecus africanus, Homo
erectus, and Homo sapiens.
2. Measure some anatomical features of the skulls.
3. Use indices to compare the features of the skulls.
Materials:
Cast of A. africanus skull
Cast of H. erectus skull
Cast of H. sapiens skull
Calipers
Metric rulers
Procedure:
A. Examine the skull, face and forehead of the casts of A. africanus, H. erectus, and modern H. sapiens.
Record your results in the table below.
Relative to one another:
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1. Describe the forehead as more vertical or more sloping.
2. Describe the face as larger and more projecting or smaller and straighter.
3 Describe the brow ridges as larger or smaller.
4 Describe the maximum skull width, as seen from the back, as closer to the base, closer to the
top, or in between.
COMPARATIVE SKULL
FEATURES
FEATURE
A. africanus.
Homo erectus
Homo sapiens e
Forehead
Face
Brow Ridges
Maximum Skull Width
B. Now let's take a closer look at the skulls and see if we can get some sort of measurements to backup
our general observations. Scientists use three basic sets of measurements to compare skulls. Two of this
measurements use an area called the Frankfurt plane. The Frankfurt plane is a line that passes from the
bottom of the eye socket through the top of the ear opening. This is the plane in which the head is
normally carried during life. As you make the measurement, record the results in the table on the next
page.
Upper facial height/cranial length index -- used to tell if skulls are of the same basic shape.
Condylar index -- used to tell how far forward or backward the occipital condyles (the part that rests on
the backbone) are.
This gives an indication of how upright the organism stood.
Supraorbital height index -- used to measure the height of the eyes above the skull.
a Draw a line that passes through the bottom of the orbit (eye socket) and. through the top of the
auditory aperture (ear opening). This line defines the Frankfurt Plane, the plane in which the head is
normally carried during life.
b. Draw a perpendicular line from the highqst point of the cranium ("B") to the Frankfurt Plane. Label
the point where these lines meet "A."
c. Draw a line parallel to the Frankfurt Plane, between the top of the orbit and the vertical line AB. Label
the point where these lines meet "F."
d Measure and record (in,mm) the distance AB and the distance FB. Compute and record the
supraorbital height index, which equals (FB/AB) X 100.
1. Upper facial height/crania length ratio
a. Measure the upper facial height and cranial length of the Choukoutien skull.
b Compute the ratio (upper facial height/cranial length.) X 100..
2. Condylar index
a. Measure the distances CD and CE on the Choukoutien skull.
b. Compute the condylar index: (CD/CE) X 100
3. Supraorbita height index
i
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This index is used to measure the height of the skull above the eyes. It indicates how
much the skull arches from front to back.
e
j,r ; rv
rkx n~
~ S E,1
,r a .'~~.~
Frankfurt Plane
B
Frankfur t °~`~ ~'~ ` _ ~ . "~" ~~- ~_ Plane
- :n7
a Draw a line that passes through the bottom of the orbit (eye socket) and. through the top of the auditory
aperture (ear opening). This line defines the Frankfurt Plane, the plane in which the head is normally carried
during life.
b. Draw a perpendicular line from the highqst point of the cranium ("B") to the Frankfurt Plane. Label the point
where these lines meet "A."
c. Draw a line parallel to the Frankfurt Plane, between the top of the orbit and the vertical line AB. Label the
point where these lines meet "F."
d Measure and record (in,mm) the distance AB and the distance FB. Compute and record the supraorbital height
index, which equals (FB/AB) X 100.
1. Upper facial height/crania length ratio
a. Measure the upper facial height and cranial length of the Choukoutien skull.
b Compute the ratio (upper facial height/cranial length.) X 100..
2. Condylar index
a. Measure the distances CD and CE on the Choukoutien skull.
b. Compute the condylar index: (CD/CE) X 100
3. Supraorbital height index
This index is used to measure the-height of the skull above the eyes. It indicates how much the skull arches
from front to back.
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Frankfurt
2. Condylar index
a. Measure the distances CD and CE on the Choukoutien skull.
b. Compute the condylar index: (CD/CE) X 100
3, Supraorbita height index
This.index is used to measure the. height of the skull above the eyes. It indicates how much the skull.arches
from front to back.
Frankfur
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a Draw a line that passes through the bottom of the orbit (eye socket) and. through the top of the auditory
aperture (ear opening). This line defines the Frankfurt Plane, the plane in which the head is normally carried
during life.
b. Draw a perpendicular line from the highest point of the cranium ("B") to the Frankfurt Plane. Label the point
where these lines meet "A."
c. Draw a line parallel to the Frankfurt Plane, between the top of the orbit and the vertical line AB. Label the
point where these lines meet "F."
d Measure and record (in.mm) the distance AB and the distance FB. Compute and record the supraorbital height
index, which equals (FB/AB) X 100.
COMPARATIVE SKULL INDICES
FEATURE A. africanus, _H. erectus H. sapiens
1
(Sts 5) I(Choukoutien) (modern)
Upper facial height
Cranial length
Ratio, facial J cranial lengths
CD
CE
Condylar index - _
3.
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AB
FB
-r
Ij Supraorbital height index
I Cranial capacity (range) 400 -500 cc 775 -1225 cc 1000 -2000 cc
Evaluation:
As humans have evolved, try to describe three patterns of change illustrated by the skulls you have examined.
Evaluation:
By using the information you have recorded in your table and the display of skulls, answer the following
questions.
1 Arrange the five skulls in order, from the largest index to the smallest index. List them in that order.
a. 

d.
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b. 

c.
e.

2 Arrange the skulls in order, from most projecting face to flattest face. List them in that order.
a. 

b. 

c.
d.
e.

3. As humans developed through time, what are two changes that have taken place in the head?


4. Does the facial/cranial index get larger or smaller over time? What does this mean?


5. From Australopithecus to modern humans, what has happened to the cranial capacity? What does this mean?

