When Wilma Met Fred:
A Human Evolution Case
By Bruno Borsari, Biology Department, Winona State University
CQ#1: Were Charles
Darwin and other scientists
in the 1700s and 1800s
interested in human
evolution?
A. Yes
B. No
C. I do not know
2
The Discovery
Dr. Heinen’s anthropology field class was camped in Tanzania at the Olduvai
Gorge on the edge of the Serengeti Plain. They had been searching for
Pleistocene hominin fossils for almost three months. Experiencing Africa through
this field course had been a lifetime opportunity for most of the students.
Then, just five days before their planned departure, a student suddenly called,
“Hey, we think we have hominid remains, Dr. Heinen! Please look!”
As he hurried over, Heinen replied, “Remember,
the word hominid refers to both the great apes and
humans. We don’t expect to find apes here, but we
do hope for human remains, so the proper word is
hominin; it refers to the human and chimp subfamily.
“So, let’s see what you have found!”
3
CQ#2: Why were they searching for hominin
fossils in Tanzania?
A. Because course costs were less expensive.
B. Because it’s a dry climate so fossils stay preserved.
C. Because hominins didn’t live outside Africa until
10,000 years ago.
D. Because East Africa is probably the origin of
ancient humans.
4
CQ#3: Dr. Heinen in his class was constantly
referring to the Pleistocene Epoch. What is the
Pleistocene?
A. The most ancient period in geology.
B. The age of dinosaurs.
C. A time when most species now living became
extinct.
D. The geological age just before the present age.
E. I do not know.
5
The Pleistocene
The Pleistocene Epoch began about 2.6 mya, and ended 12,000 BP
(before the present). It was a period dramatically affected by
continental glaciations. In North America and Europe, glaciers
advanced far to the south four times in the past 425,000 years. For
much of this time, the human species, Homo erectus, was colonizing
Europe and Asia, having migrated into this region from Africa one
million years ago.
The northern climate was more extreme than that found today, with
colder winters and cooler summers. Snow caps extended to lower
elevations. Most precipitation in the northern hemisphere occurred
during the winter, as it does today.
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The Pleistocene
Meanwhile, back in Africa 160,000 ya, a population of H.
erectus was evolving into Homo sapiens. Then perhaps
70,000 years ago, a group of H. sapiens left Africa and
migrated through the Middle East into Europe and then
beyond. Gradually, they replaced the populations of H.
erectus who had preceded them.
It was at the end of the Pleistocene that another extinction
occurred, this time of large mammals, most dramatically in
North America, where horses, camels, giant sloths, and
mammoths vanished.
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The Pleistocene
The Pleistocene extinction was less dramatic than the
mass extinction 65 mya at the end of the Cretaceous,
when the dinosaurs were wiped out. Even this was a
minor event compared to the Permian extinction 248 mya,
which wiped out 95% of all animal species. Still, the
Pleistocene extinction must have had a major impact on
the human populations, since the species that vanished
were a major food source.
Because of that fact, some anthropologists blame humans
for over-hunting and causing the Pleistocene extinction.
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ERAS
Mass extinction
Period
Epoch
MYA
Quaternary
Holocene
0.01
Pleistocene
Pliocene
1.8
5.3
Cenozoic
Miocene
24
Mass Extinctions
Tertiary
Oligocene
37
Eocene
Paleocene
Mass extinction
58
65
Cretaceous
Mesozoic
144
Jurassic
Triassic
Mass extinction
Permian
208
248
290
Carboniferous
Paleozoic
Devonian
Silurian
Ordovician
360
443
505
Cambrian
Precambrian
9
570
The Pleistocene
Cave paintings by H.
sapiens in France about
10,000-15,000 BC show
some of the animals.
Plant communities
supported large herds of
herbivores and their
predators.
But H. sapiens didn’t evolve in Europe; they evolved in
Africa, which is why Dr. Heinen took his class there.
10
The Out-of-Africa or Recent African Origin Model
First proposed by Darwin. H. sapiens evolved in Africa. Recent
evidence suggests East Africa, about 160,000 years ago. From
there, they spread across the world, starting 70,000ya and
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displacing H. erectus.
CQ#4: Paleontologists excavating an area that was once a
shallow lake find fossils of two extinct species that were
ancestors to modern humans. The more modern species was
found in a shallow pit and the older species was found in a
deeper pit. Why would scientists look for fossils in areas that
were once in shallow water?
A. Fossils form better in shallow water because there is
more sunlight.
B. Nothing in an aquatic environment would eat dead
animals.
C. Animal remains are often trapped and buried in
sediments in shallow bodies of water.
D. Animals would have been trapped and buried near the
water during catastrophic floods.
12
Dr. Heinen Examines the Specimens
After two days a right femur had been found, a well
preserved base of a skull, two ribs with a fragmented
sternum, and more fragments from upper limbs. Dr.
Heinen showed the class how to measure these
specimens and the class concluded that this hominin
must have been about 170 cm tall and weighed about 65
kg. His brain size was about 1000 cc, he probably had
large muscles, and he had strong teeth.
13
Now join your group and share information
about the species of Homo you have
studied independently
14
CQ#5: What species in the genus Homo is most
likely to be the one found by Dr. Heinen’s class?
Hint: look at your homework in your groups!
A. Homo erectus
B. Homo habilis
C. Homo neanderthalensis
D. Homo sapiens
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CQ#6: What feature of the remains identifies
this early hominid as H. erectus and excludes
the other species?
A.
B.
C.
D.
E.
The length of the femur
The size of the ribcage
The volume of the cranial vault
The strong teeth
All of the above
16
Meet: Homo erectus
Category
Range
H. erectus
China, Europe, Africa
Ht/wt
1.6-1.8 m. M: 65 Kg.
Build
Same as human.
Climate/habitat
Time Range
Diet
African savanna-cold
Europe.
1.5 mya-200,000 ya.
Small game, plants,
nuts, fruit, some large
game.
Use fire?
Tool making?
Yes; cooked food.
Hand axes, scrapers.
Brain size
Communication skills
750-1140 cc.
?
Distinguishing
characteristics
Heavy brows, strong
jaws and teeth.
17
Meet: Homo habilis
Category
Range
Ht/wt
Build
Climate/habitat
Time Range
Diet
Use fire?
Tool making?
Brain size
Communication
skills
Distinguishing
characteristics
H. habilis
First found in
Tanzania; some put
Kenyan material into
H. rudolfensis
Less than 1.6 m., very
light.
Lighter than humans
2.0-1.6 mya
Marrow, scavenging,
seasonal vegetation.
?
Simple stone tools.
560-700 cc.
?
First evidence of stone
tools.
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Meet: Homo sapiens
Category
Range
Ht/wt
Build
Climate/habitat
Time Range
Diet
H. sapiens (us)
All over
Modern – as in European
Modern
All over, especially
warmer regions
160,000 ya – to present
Hunting, fishing, wild
grains, plants, big game.
Cooked.
Use fire?
Yes; hearths.
Tool making?
Varied material, innovation.
Brain size
Communication skills
1040-1595 cc.
Art, language, ritual, music.
Distinguishing characteristics Innovation, math, complex
tools with regional
differences and dialects.
Agriculture, religion,
warfare.
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Meet: Homo neanderthalensis
Category
Range
Ht/wt
Build
Climate/habitat
Time Range
Diet
H. neanderthalensis
Europe, western Asia.
1.7m., 65-80 Kg.
Very muscular.
Cold N. Europe-warmer
Israel.
120,000-28,000 ya.
Plants, nuts, fruit, big game
animals.
Use fire?
Yes; cooked food on hearths.
Tool making?
Advanced, little variation
Brain size
Communication skills
1400 - 1800 cc.
Probably; used some rituals.
Distinguishing characteristics
Heavy brows, sloping
forehead, large nose and
lower jaw. Evidence of
clothes, burial ceremonies.
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Timeline of H. sapiens
and its Relatives
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CQ#7: Is there a positive or negative correlation
between cranial volume and time for different species?
2000
1800
A.
Positive
1200
B.
Negative
1000
Average cranial volume
1600
Cranial volume
1400
800
____ Linear (Cranial
600
volume)
400
200
0
2000 1600 1400 1000 800 600 400 200 100 50 10
Thousand of years before present
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CQ#8: Is there evidence for this evolutionary
trend leveling off since 400,000 ya?
A. Yes
B. No
In your groups,
develop a hypothesis
to explain the pattern
you see.
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Discussion
That evening the students were full of questions. Select one
of the questions below and discuss it with your neighbor (2-3
min).
A. Did early hominins co-exist with other species of the
genus Homo? Why? Why not?
B. What selective forces might have had an important effect
upon these early hominins, contributing to shape the traits
of present-day humans?
C. What will happen to this specimen?
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Meet the Relatives
Homo sapiens
appeared about
160,000 years ago.
The genus Homo
is about 2.3
million years old.
Did H.
neanderthalensis
exist at the same
time as H.
sapiens?
25
Play the Game
Hey, Wilma….Can you find your Fred?
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Epilogue
While all four species in the game never lived together, certainly
several different species of hominins did coexist in some geographic
areas during the Pleistocene.
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Epilogue
“We are all connected,
and descended from
African ancestors!”
emphasized Dr. Heinen.
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Common Descent Theory
“Fossils of our early human ancestors provide evidence
supporting the theory of common descent,” pointed out Dr.
Heinen. “We now have hundreds of hominin fossils
showing a beautiful graded series. However, an interesting
problem remains. The common ancestor of humans and
chimpanzees has not been found. Some critics of evolution
cite this when arguing that the relationship between apes
and humans remains unproven.
“It is true, we haven’t found the perfect link yet, but we
are getting really close!”
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“The newest evidence (Science, October 2, 2009) shows that the
human line split away from the chimps more than 4.4 mya. Here is
Ardipithecus ramidus. She really doesn’t look much like a chimp at
all, does she?”
30
Summary of the 11 papers published in Science on
October 2, 2009:
The skeleton nicknamed “Ardi” is from a female who lived in a
woodland, stood about 120 cm. tall and weighed about 50 kg.
She was thus about as big as a chimpanzee and had a brain size
to match.
She did not knuckle-walk or swing through the trees like living
apes. Instead, she walked upright, planting her feet flat on the
ground, perhaps eating nuts, insects, and small mammals in the
woods.
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Rather than humans evolving from an ancient chimp-like creature,
the new find provides evidence that chimps and humans evolved
from some long-ago common ancestor—but each evolved and
changed separately along the way.
“This (Ardi) is not that common ancestor, but it’s the closest we
have ever been able to come,” said Tim White, director of the
Human Evolution Research Center at the University of California,
Berkeley.
Chimps
Common
ancestor
Humans
Ardi
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Image Credits
Slide 1
Description: Photo of stone heart.
Author: : © Olikli
Source: Dreamstime
Link: http://www.dreamstime.com/stock-photography-heart-of-stone-image8344832
Clearance: Licensed image.
Slide 2
Description: Photograph of Charles Darwin circa1874.
Author: John G. Murdoch (publisher) (died 1902); possibly created by Elliott & Fry.
Source: Robert Ashby Collection; obtained from Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Darwin_-_John_G_Murdoch_Portrait_restored.jpg
Clearance: This image is in the public domain because its copyright has expired.
Slide 3
Description: Photo of student participating in an archaeological dig.
Author: © Brianna May
Source: iStockphoto
Link: http://www.istockphoto.com/stock-photo-9829512-graduate-archaeology-student-in-williamsburg-va.php
Clearance: Licensed image.
Slide 9
Description: Table of the geologic time scale.
Author: Bruno Borsari.
Source: Case author.
Clearance: Used with permission.
Slide 10
Description: Painting from the Chauvet cave, replica in the Brno museum Anthropos. 31,000 years old art, probably Aurignacien.
Author: HTO
Source: Wkipmedia
Link: http://commons.wikimedia.org/wiki/File:Chauvet_cave,_paintings.JPG
Clearance: Released into the public domain by its author.
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Image Credits cont.
Slide 11
Description: Map of Homo sapiens spreading over the world.
Author: Altaileopard
Source: Wkipmedia Commons
Link: http://commons.wikimedia.org/wiki/File:Spreading_homo_sapiens.jpg
Clearance: Released into the public domain by its author.
Slide 17
Description: Homo erectus, Museum of Natural History, Ann Arbor, Michigan, November 2007.
Author: Thomas Roche from San Francisco, USA
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Homo_erectus.jpg
Clearance: Licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.
Slide 18
Description: Homo habilis KNMR 1813 discovered at Koobi Fora (replica)
Author: José-Manuel Benito Álvarez (España) —> Locutus Borg
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Homo_habilis-KNM_ER_1813.jpg
Clearance: Released into the public domain by its author.
Slide 19
Description: Cro-Magnon man skull. Bichon cave (la Chaux de Fonds-Neuchâtel). ca. 11000 B. C. N° inv. CF-BI-1.
Author: Y. André / Laténium
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Lat%C3%A9nium-cr%C3%A2ne-bichon.jpg
Clearance: This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic
license.
Slide 20
Description: Homo neanderthalensis skull discovered in 1908 at la Chapelle aux saints (France).
Author: unspecified
Source: Wikimedia Commons.
Link: http://commons.wikimedia.org/wiki/File:Homo_sapiens_neanderthalensis.jpg
Clearance: This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
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Image Credits cont.
Slide 21, Side 25, and Slide 27
Description: Timeline of H. sapiensand relatives, based on Friedemann Schrenk, Die Frühzeit des Menschen. Der Weg zu Homo sapiens, Verlag C. H.
Beck, 1997 und 2003, p. 122.
Author: Bwd. Original uploader was Bwd at de.wikipedia (with slight modification by NCSTS).
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Stammbaum_der_Entwicklung_des_Menschen.png
Clearance: Released into the public domain by its author.
Slide 22 and 23
Description: Scatterplot of brain volume and time.
Author: Bruno Borsari.
Source: Case author.
Clearance: Used with permission.
Slide 26
Description: Cartoons.
Author: © Cory Thoman
Source: Fotolia
Clearance: Licensed images.
Slide 28
Description: Biology faculty and students in field excavation.
Author: Bruno Borsari.
Source: Case author.
Clearance: Used with permission.
Slide 30, left
Description: Photo of bust of Ardipithecus ramidus
Author: Jason Sannar
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Ardipithecus.jpg
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Image Credits cont.
Slide 30, right
Description: Drawing of Ardipithecus ramidus (“Ardi”), complete skeleton, after p.36, Science of October 2, 2009.
Author: Tobias Fluegel
Source: Wikimedia Commons
Link: http://commons.wikimedia.org/wiki/File:Ardipithecus_Gesamt.jpg
Clearance: This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Slide 32
Description: Arrow diagram.
Author: Clyde F. Herreid
Clearance: Used with permission.
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