CRANIAL CAPERS
INTRODUCTION:
If you place apes and humans on an evolutionary time line, you would find
the genus Australopithecus closest to humans. They are the immediate
ancestors of humans because both australopithecines and humans are
biologically similar enough to be in the same family of Hominidae. All people,
including australopithecines are hominids. Not only do humans share common
ape ancestry in Africa with australopithecines, but we also share the fact that we
are bipedal, or two-footed, upright walkers. In contrast, chimpanzees and gorillas
are quadrupedal, or four-footed.
In biological evolution, the potential of individuals to survive and reproduce
requires species change over time. The environment provides the impetus for
species to play out their evolutionary roles. Hominids are defined by being
bipedal. This mode of locomotion did not appear suddenly, but more probably
emerged in two phases. In phase one, they came to the ground as knucklewalkers, like chimpanzees and gorillas today. In phase two, they moved into the
savanna mosaic and became habitually bipedal.
Raymond Dart, an Australian anatomy professor in Johannesburg, South
Africa, identified a fossil skull of a child as a human ancestor. He became
convinced that the fossil confirmed Africa as the place of human origins as
Darwin had argued fifty years earlier. In 1925 he named it Australopithecus
africanus, although most paleoanthropologists rejected his view that the fossil
was an intermediate between apes and humans. They thought it was just another
ape. Eventually he was vindicated when Mary and Louis Leakey uncovered
fossils at Olduvai Gorge, Africa, in the 1960’s.
Rarely do paleoanthropologists find complete fossils of hominids, so one
can imagine how ecstatic they are to find a skull in tact. Like the pages of a book
may be read to reveal the life of a person, so may a skull be “read” to reveal the
lifestyle of a hominid.
The following lessons will focus on “reading” skull replicas to see how they are
used to support the theory of evolution, and to learn how global tectonic
movements changed Africa to support the evolution of hominids.
Title of Unit: Hominid Evolution
Courses or Grade: Life Sciences/7th Grade
Prior Knowledge:
Students should be able to list attributes of living and nonliving material.
Students should be able to conceptualize and categorize.
Students should be able to write a summary report.
Students should be able to measure in metric.
Big Idea/Unit Theme/Essential Questions: Evolution: Change Over Time
How do anthropologists learn about evolution? How have humans evolved?
What environmental changes occurred to provide a stage for human evolution?
Science Content Standards of Lesson:
3.
Biological evolution accounts for the diversity of species developed
through processes over many generations. As a basis for
understanding this concept:
a.
Students know both genetic variation and environmental factors
are causes of evolution and diversity of organisms.
b.
Students know how independent lines of evidence from
geology, fossils, and comparative anatomy provide the bases
for the theory of evolution.
Social Sciences Standards of Lesson:
Chronological and Spatial Thinking
2.
Students construct various time lines of key events, people, and
Periods of the historical era they are studying.
Lesson Objectives: Students will:
1.
Create a concept map and summary report about evolution of
hominids.
2.
Compare and contrast similarities and differences of primate and
hominid skulls
3.
Students create an organism for the year 1,002,004 that has
undergone evolutionary changes.
4.
Complete a data chart of hominid measurements.
5.
Create a time line of hominid evolution.
6.
Develop a map of Africa indicating results of global tectonic movement
and environmental changes.
Length of Lesson: Seven 90-minute periods
Materials:
K-W-L chart per student skull photos chart paper
Transparency of K-W-L chart
Opening Activity: Constructing Prior Knowledge
1. Distribute copies of the 11 x 14 K-W-L charts to the students. Allow them a few
minutes to write what they know about skulls.
2. Display the skull photos with chart paper at various stations around the room.
Instruct a group (4 students) to go to station 1 and make observations about the
photo at that station. They should write 1 observation agreed upon by the group
on the chart paper and then move on to the other stations in order. When they
have completed the tour of the stations they should return to their seats and add,
delete or modify what they have written on their charts. The students waiting in
their seats should look at the resource materials on their tables. Guide students in
generating questions and writing them in the second column (Want To Learn).
2. Questions may be developed from the discussion about the photos, from the
resource material, or the news article.
3. When group 1 has moved on to station 2, another group should visit station 1.
Each group should have about 3 minutes at each station.
4. Distribute copies of the article, “Skulls Found in Africa and in Europe
Challenge Theories of Human Origins” written by John Noble Wilford, for the
New York Times, August 7, 2002.http://www.nytimes.com/learning.
5. Assign a paragraph to each group to read and discuss among themselves.
They should select a spokesperson from the group to report to the whole class.
6. When the article has been read and discussed, instruct students to add information
to their K-W-L charts. They may have more questions or they may have found
answers to questions they have already written. The three columns of the chart
should be complete at this time.
7. Homework Assignment:
1. Students are to read each of the statements they have written in columns 1
and 3 of the K-W-L charts and label them with categories that they
brainstorm. Examples: structure, function, paleontologists, location,
geologic time period, theory, etc.
2. Students are given a Frayer Model vocabulary foursquare activity sheet
and a list of vocabulary words. (See attachment)
They are to enter each word in the center circle and complete the
instructions in each square for defining the word. Square One: Textbook
sentence with the
Vocabulary word underlined; Square Two: Student’s own definition;
Square 3: Dictionary/glossary definition; Square Four: Student generated
sentence encompassing the vocabulary word. (See attachment)
1.
2.
3.
Activity 2:
Concept Mapping Student Activity
Displaying the K-W-L chart on the projector screen, the instructor will model
how each of the statements is to be labeled with a category. Remind students that
no two charts are alike so they will need to label their own statements with the
categories they have written under the heading “Categories We Expect to Use”, at
the bottom of their charts. Allow time for students to label their statements if they
have not already done so. They should use the first letter of each category to label
the statements.
Students are to create a concept map by placing the topic “skulls” in a circle in the
middle of a sheet of paper. The categories they used to organize their statements
will become the major concept headings radiating from the center circle.
Connecting lines show the relationship of the main topic to the categories and
explanatory details that are written on circles connected to the lines.
Students will use the software program Inspirations to make a computergenerated concept map and outline.
Culminating Activity/Assessment:
Students will write a summary report from the outline generated by the software
program. They will submit their K-W-L charts, concept maps and summaries for
assessment.
Rubric:
See attachment for the concept map and summary rubrics.
Activity 3:
Now That’s Using Your Head! From Sample AIMS Investigations
Brochure AIMS Education Foundation P.O. Box 8120 Fresno, California
93747
Materials:
one tape measure (per pair of students) 1 yardstick (per pair of students)
worksheet (per student) one calculator (per pair of students)
Introduction:
Very rarely are complete fossil remains of human organisms found. Fortunately, skulls
of hominids have been discovered on many continents and have been used to further the
evolution theory. One may think that very little can be determined with so little to work
with, but thanks to anthropometry, anthropologists are able to learn a great deal from a
skull.
This activity will allow students to explore the relationship between their heights and the
circumference of their heads.
Procedure:
1. Students make predictions of how much greater their height is than the
circumference of their heads. They should record their prediction on their
worksheet.
2. Next students will estimate his or her height and the circumference of his or her
head and record it on the worksheet.
3. Working in pairs, students measure each other for height and circumference of
their heads. They should record the information on their worksheets and find the
difference between their estimate and actual measurements.
4. The students will then compute how many times greater their heights are by
dividing their heights by the circumferences of their heads and rounding the
numbers to the nearest tenth.
5. Compute the group average ratio and record as a decimal.
6. The class height to circumference of the head can then be calculated using a
calculator and recorded.
7. To apply what they have learned, students are given the circumference or the
height of the instructor and ask students to predict the instructor’s height or head
8. circumference. (See attachment for worksheet).
Discussion Questions:
1.
Were you close in your prediction of how many times greater your height was
than the circumference of your head? Why or why not?
2.
Is there a close relationship between height and circumference of the head?
What is that relationship? How can this relationship help anthropologists?
Extension:
Students can explore “The Golden Proportion” that anatomists use to determine the
height of an individual using a formula based on the length of the thigh bone. For males:
Height = length of femur x 1.88 + 813.06 millimeters. For females: Height = length of
femur x 1.945 + 728. 44 millimeters.
NOW THAT’S USING YOUR HEAD!
Prediction:
My height is _____________ times greater than the circumference of my head at
its widest point.
Measurements:
Estimate
Actual
Difference
Height
_______cm
______cm
________cm
Circumference of head
_______cm
______cm
________cm
Ratio of height to head
Circumference
________cm _______cm
Height divided by circumference
Of head
________cm ________cm ________cm
Group average ratio
(decimal)
________
Class average ratio
(decimal)
________
VOCABULARY
________cm
1.
anthropometry
11.
anthropology
2.
cranium
12.
canine diastema
3.
cranial module
13.
sagittal crest
4.
hominid
14.
dental arcade
5.
foramen magnum
15.
facial slope
6.
forehead
16.
prognathism
7.
incisors
17.
canine
8.
premolars
18.
molars
9.
postorbital constriction
19.
calipers
10.
supraorbital ridge
20.
braincase
Activity 4:
Cracking The Cranial Codes
Introduction:
This lab introduces students to anthropometric measurements as a means of studying
evolution. Students will observe, measure, compare and contrast anatomical variations
for each of the seven replica skulls of hominids placed in stations around the room.
The measurement guide and the data recording sheet were adapted from a lesson posted
at www.carolina.com/anthropology/index.asp
Objective:
1. Students will become familiar with anthropometric terms and techniques used by
paleoanthropologists.
2. Students will identify the homologous structures.
3. Students will collect and analyze data by measuring homologous features of skull
replicas.
Materials:
seven skulls calipers calculators
Science journals
data sheet
rulers
Procedure:
1.
Place a skull, a caliper, a ruler, a tape measure and a protractor at each station.
2.
Give each student a data sheet and each group of four students a skull
measurement guide.
3.
Instruct one group to go to the first station and begin measuring the skull
replica. Each student is to participate fully by undertaking a specific task at
the station. After 5 to 7 minutes, instruct the group to move to station two as
another group begins work at station one. Students are to continue to rotate
until they have visited each station. Students should make sketches of the
most pronounced features of the skulls in their journals and record the
measurement data on the worksheet.
4.
After all measurements have been taken, students are to return to their seats to
analyze and discuss the data within their group. Have students look for
patterns represented by their data:
a. List the features that all the skulls have in common
b. List the features that are most helpful for distinguishing among the
replicas.
5.
Hold a whole group discussion about the data:
a. Why do you think the canine tooth reduced in size so much from earlier to
later hominids? (Grasping function of long canines replaced by easy use
of
Hands, associated with bipedalism.)
b. Why do you think the face flattens over time in hominids? (Similar reason
as for item one.)
c. How does the position of the foramen magnum relate to the body posture
and locomotor pattern of the animal? (More forward and under the skull,
associated with erect posture of bipedalism; skull balances on top of spinal
column. With semi-erect posture of apes, foramen magnum is located
more to the rear of the skull.)
d. Have we really lost the browridge? (Not really; forehead rises directly
above the browridge, enclosing the much-enlarged frontal lobes.)
Extension:
Students are given a blank timeline and small photos of the seven skull replicas. Using
research, students are to find the period on the timeline that each of the skulls fit into.
They should cut the photos apart and glue them on the timeline in the correct location.
Social Sciences Connection: Our Ancestors
1.
Using information entitled Our Ancestors from Prehistoric Ages an Usborne
book, students will complete a chart that requires time period, weight, height,
skull location, and accomplishment of early ape to modern man.
2.
Secondly, students will create an Ancestor Map using information taken from
Famous Finds, in Prehistoric Ages. They are to label the continents and
oceans, draw a legend and place a marker where each of the ancestors was
found.
3.
The last activity requires students to create an ancestor timeline from the data
they have collected.
(See attachments for chart and information pages)
Australopithecus boisei: His age is about 1.75 million years;
Lower Pleistocene; discovered by Mary Leakey in 1959 in he
Olduvai Gorge, Tanzania.
The specimen is a nearly complete skull with teeth. It has a
large face and palate, molars and premolars much larger than
incisors and canines. The cranial vault is low and has a
marked post-orbital constriction with strong brow ridges.
The cranial capacity is 530 cc with a sagittal crest . This is a
very robust species of Australopithecus. He was bipedal and
erect. He has no simian shelf or chin.
Australopithecus africanus: Age is perhaps between 3 and 2
million years; Pliocene period. He was discovered in Taung,
Cape Province, South Africa, in 1924 by Raymond Dart. The
specimen has milk teeth and first permanent molars present.
Canines and premolars are small relative to molars. The
specimen has a “v” shaped dental arcade. This species has
small canine diastema. The postcranial skeleton is unknown.
It may be the first hominid species or a specialized small ape.
Homo sapiens sapiens:
This specimen is about 30,000 –
50,000 years old; Upper Pleistocene. He was located in La
Ferrassie, Dordogne, France by L. Capitan and D. Peyrony in
1909. The skeleton was of an adult male (several other
skeletons are known from this site) and it was a deliberate
burial. The skull is large with a high forehead and vault. The
face is large and he has rather large brow ridges. There is a
rounded occipital region and a definite chin is present. He
differs in no major way from modern humans. The cranial
capacity is 1520cc.
Gorilla gorilla: The earliest fossil apes are known from
Miocene sites about 17 to 20 mya. Dentally these early apes
are distinct from monkeys and represent several genera and a
number of species. By the middle Miocene, the distribution of
fossil apes extended beyond Africa to Europe and Asia, and the
number of species notably expanded. By the end of the
Miocene, fossil apes had virtually disappeared. Miocene ape
fossils cannot linked directly to any of the living apes.
Molecular studies now delineate two species of gorilla. The
mountain gorilla (Gorilla beringei beringei) of Uganda,
Rwanda, and Congo is the mot studied and endangered of the
gorillas. The Western lowland gorillas (Gorilla gorilla) inhabit
Congo, Central African Republic, Gabon and a small
population remains in Nigeria. They are the largest of the
great apes, and dangerously few of them remain. They are
intelligent peaceful and persistent problem solvers. Gorillas
weigh 300-400 pounds and stand 6’ tall.
Chimpanzee: (Pan troglodytes) They are native to the
African rain forests, and they are highly intelligent and social.
They are capable of insight and have the human ability to use
tools. Chimps closely resemble humans both behaviorally and
genetically.
Homo sapiens: Human Asian Male. Having evolved from
algae, this persistent species has managed to inhabit even the
most undesirable of environments. Although humans inhabit
many states, they are most often found in the state of
confusion.
Australopithicus boisei:
Female specimen.