SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
C
Chhaapptteerr 1199:: H
Huum
maann B
Beeggiinnnniinnggss &
&E
Evvoolluuttiioonn

According to fossil evidence and more and more accumulating data from the molecular
biological field of modern biology (see:  DNA sequencing projects), the evolutionary
short history of our own species Homo sapiens sapiens had very humble beginnings

our own species evolved from tree-dwelling (= arboreal) mammalian ancestors, socalled primates, during a time when reptiles and dinosaurs still dominated on Earth (for an
overview see Figure below)
P
Prriim
maatteess ((O
Orrddeerr:: P
Prriim
maatteess))

primates have unique body features, which were shaped through natural selection as an
adaptation to arboreal life
1. limber shoulder and hip joints
 enabling climbing and graceful movement in trees
2. 5 digits of hands and feet; thumbs and big toes are opposite to other digits
 enables efficient grasping and holding of branches
3. have a short snout and eyes are sitting close together
 leads to an overlapping of the field vision and improved
depth perception

2 major groups of primates are known:
1. Prosimian
 35 species are known, of which most live in the tropical rainforests
- many are threatened by extinction due to habitat destruction by humans
(deforestation!)
- in 2003, Miss Waldron’s red colobus monkey (Ghana, Africa) has been
announced to have become extinct





e.g. loris, bushbabies, lemurs, tarsiers
they are the oldest known primates
65 million year old fossils have been found
they expanded after the mass extinction of the dinosaurs about 70 million years ago (
primate radiation)
they have a good sense of smell and great eye sight; most are nocturnal animals
2.




Anthropoids
e.g. monkeys, apes and hhuum
maannss
evolved about 40 million years ago in Africa and Asia from prosimian ancestors
they have a larger brain in relation to body size
they rely more on eyesight than on smell
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Overview: Primate and human evolution
Homo sapiens sapiens
Million years ago
today
PLEISTOCENE
3
PLIOCENE
6
Chimpanzees
Chimp-Hominid Split
MIOCENE
Gibbons
C
E
N
O
Z
O
I
C
27
OLIGOCENE
New world
monkeys
(Lion tamarin)
late hominids
early hominids
Ape-like ancestor
A
Gorillas
N
T
H
Orangutan
R
O
early apes P
O
Old world
monkeys
I
(Baboons, Langurs)
D
early monkeys S
38
EOCENE
Lemurs
56
PALEOCENE
66
Graphic©ESchmid/2001
P
R
O
Lorises
S
early primates I
M
I
A
N
S
very early primates
Tarsiers
Extinction of dinosaurs
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
2.1. Monkeys
 2 types of monkeys are known
2.1.1. Old world monkeys
 inhabit Africa and Eurasia
 e.g. Baboons, Langur
 are ground-dwelling animals
 they have narrow and close together nostrils
 have seat pads
2.1.2. New world monkeys
 are native to the Americas
 e.g. Golden lion tamarin, Geoffrey spider
monkey
 have wide open nostrils
 have no seat pads but some have long tail
2.2. Apes
 e.g. gibbons, orangutans, gorillas, chimpanzees
 are genetically closely related to humans
 about 97% of chimp and gorilla DNA is identical with human genetic material
 most apes live in the equatorial tropical rainforests of Africa or Asia
 apes, especially the African mountain gorillas, are heavily threatened from extinction
due to man-made deforestation and human expansion into their habitats
 all apes lack a tail
 apes are chiefly vegetarians, but chimpanzees eat insect and occasionally larger
vertebrates
 chimpanzees, the genetically closest relatives of humans. make and use simple tools and
show complex social behavior and group activities
 chimpanzees have been reported to use wooden sticks as primitive tools to collect
termites from their nests
 all apes have very pronounced canines and a very protruding skull (see Image below)
 domesticated chimps also show behavior of self-awareness, e.g. in front of a mirror
2.3. Hominids
 about 6-8 million years ago, an ape-like ancestor separated from a primate population in
Central Africa to evolve into the first hominids
- the reasons for the splitting of the hominid-ancestral ape group/population from the
“main population” are not known
- but many scholars and scientists consider climate changes and over population as
possible natural forces which may have triggered that important evolutionary
“separation event” ( see: Chimp-Hominoid split”)
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Pan troglodytes
(Ape:
Skull (female)
Profile:
Height:
Cranial Volume:
Skull:
ridges
Teeth:
Tools:
< 1m
average 400cc
- small, pronounced brow
- flat forehead
pronounced canines,
incisory gap, large molars
occasional use, no making
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Human Evolution: Fossil findings & Early ancestors
Sahelanthropus
tschadensis
(5 Mio. years ago)
Africa
Chad
Australopithecus
afarensis / bosei
Chimpanzees
Gorillas

Australopithecus
africanus
the African origin hypothesis of early humans is supported by several findings and
evidences contributed by two different biological sub-disciplines:
1. Fossil evidence
- the oldest remains of early hominids (= hominid fossils), different in skull and other
skeletal features to today existing apes, link the hominid evolution to several regions
in East-/ North-East Africa (see Map below)
- the so far oldest remains of a hominid creature have been found in form of the skull of
Sahelanthropus thadensis the desert of todays’ Chad
- the skull has been dated with the help of the radio-isotope method to be about 5 million
years old
2. Molecular biological evidence
- today, the results of DNA sequencing projects of human and chimpanzee
chromosomal DNA enable the accurate comparison of genes of apes and humans
( see: Human Genome Project) with the help of computer programs (
Bioinformatics)
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
-
accumulated differences in nucleotide sequences (= mutations) in apes and humans
arose due to separation events and the subsequent prevention of inter-breeding
assuming a constant mutation rate of DNA in biological organisms over time,
evolutionary separation events can be traced and a phylogenetic tree can be
established
e.g. comparison of the nucleotide sequence of the MYH gene (a gene responsible for
the production of the important muscle protein myosin) of apes and humans indicates
that a mutation of the MYH gene must have happened in humans about 2.4 million
years ago
 this mutation, which leads to less MYH16 protein in human jaw muscles, is not
found in the MYH gene of chimp DNA
some scientists hypothesize that this mutation of the human MYH gene may have
triggered the evolution of the stronger masticatory (= jaw) muscle in early humans
 due to different food (re) sources and nutrition of the split hominid group?
-
-
-

about 4-5 million years ago, the human evolution started from that early hominoid branch
and 7 different hominoid species appeared in our lineage (see Graphic I below)
Graphic I: Fossil evidence and timeline of hominid species
Homo sapiens sapiens
0
Cro Magnon
0.5
H. neanderthalensis
1.0
1.5
T
I
M
E
2.0
2.5
3.0
(mya)
3.5
Homo erectus
A. robustus
A.boisei
Homo habilis
Australopithecus
africanus
4.0
4.5
5.0
Australopithecus
afarensis
Ardipithecus
ramidus
Sahelanthropus tschadensis
Africa
Eurasia
Graphic©E.Schmid/2001
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
1. Sahelanthropus tchadensis
 Lived about 6 to 7 million years ago (see Figure below)
 Size not known since only a skull fragment has been unearthed
 brain size between 320 and 380 ccm
 The earliest known hominid which appeared after the hypothesized
separation of a (small?) chimpanzee population from the major arboreal
group
= evolutionary important “chimp-human split”
Sahelanthropus tschadensis
(Fossil age: 6 – 7 million years)
 almost complete cranium (skull) of “Toumai”
- Discovered in 2001 in today’s Chad (S. Sahara, Africa)
- Small brain case (320 – 380 ccm)
- the oldest known hominid after the evolutionary important
split from chimpanzees (= Chimp- hominid split)
- erect stance ?, bipedal ? (probably not)
2.




Australopithecus afarensis
lived about 4.0 – 3.0 million years ago (see Image below)
they were only about 3 feet tall
fossilized bones and foot prints were found in East Africa in the so-called
Afar depression in todays Ethiopia and Tanzania
they were already upright walking (bipedals!) species
3. Australopithecus africanus
 lived about 3.0 – 2.2 million years ago (see Image below)
4. Australopithecus boisei
 lived about 2.5 – 1.4 million years ago
 first evidence of the enlargement of the hominoid brain appears
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Australopithecus afarensis
(Fossil age: 4 – 2.5 million years, East Africa)
1. Reconstruction of the skull
2. Reconstruction of the
5. Australopithecus robustus
 lived 2.2 – 1.4 million years ago
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Australopithecus africanus
(Fossil age: 3 – 2.0 million years, South Africa)
1. Skull (lacking lower jaw)
Profile:
Height:
Cranial Volume:
Weight:
Skull:
Teeth:
Tools/Artifacts:
1.1 – 1.4m
400 – 500cc
30 – 60kg
- higher forehead
- shorter face
- less pronounced brow ridges
small canines; no inc. gap
none
6. Homo habilis (‘handy man’)
 lived about 2.5 –1.6 million years ago (see Image below)
 coexisted on the African savanna with the Australopithecines for nearly 1
million years
 fossilized skulls suggest a larger brain than the Australopithecines
 first evidence of use of primitive tools
7.

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
Homo erectus
lived between 1. 8 million and 250,000 years ago
was taller than H. habilis and possessed a larger brain
was the first hominid that migrated out of Africa and settled at different
location outside of the African continent, e.g. in Europe (= Homo
heidelbergensis, Homo ergaster)
 see Migration map below)
used already fire, lived in huts and wear clothes
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Homo habilis
(Fossil age: 2.4 – 1.6 million years ago)
 East Africa, Lake Turkana
 first definite human ancestor, tool maker
1. Skull (lacking lower jaw)
Profile:
Height:
Cranial Volume:
Weight:
Skull:
Teeth:
Tools/Artifacts:
1.0 m
630 – 640cc
?
- less prognath
- large, flattened face
- barely brow ridges
robust jaw; small incisors
reduced molars and pre-molars
stone tools
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Fossil finding places of Homo erectus outside of Africa & Dates
Age
(millions
of years)
Europe
0.4
U.S.A.
H. sapiens sapiens
0.0
0.2
Asia
Africa
(Cro Magnon)
H. sapiens
neanderthalensi
Contact?
Gene transfer?
Meadow Croft (U.S.)
Qafzeh/Skhul
3. Migration out
of Africa ?
Schoeningen (Germany)
Boxgrove (U.K.)
Mauer (Germany)
H. heidelbergensis
(H. rhodesiensis)
0.6
2. Migration
of Africa ?
Ceprano (Italy)
0.8
1.0
Atapuerca (Spain)
Homo erectus
(H. ergaster)
1.2
Orce Basin (Spain)
Zagros (Turkey)
Ubeidya (Israel)
1.4
1.6
Dmanisi (Georgia)
1.8
1. Migration out
of Africa
Java
Sichuan (China)?
Graphic©ESchmid/2001
2.0
Birth of human lineage
Olduvai? Chad?
2.5
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
8.



Homo sapiens
is the only remaining member of the hominid family tree
the archaic H. sapiens appeared about 300,000 years ago in Africa
130,000 – 30,000 years ago, several archaic groups of H. sapiens,
e.g. H. sapiens neandertalensis, Cro Magnon appeared
throughout Europe, the Middle East and parts of Asia

Based on their robust skeletal features, physiognomy and their area of
distribution (see Figure below), H. sapiens neanderthalensis was a
successful H. sapiens species very well adapted to the harsh, cold Eurasian
climate existing during the ice-ages
Homo sapiens neanderthalensis
(Fossil ages: 230,000 – 30,000 years ago; Eurasia, Middle East)
 archaic homo sapiens, extinct homo sapiens species
Europ
Africa
Cranium
Maximum distribution of Neanderthals as
supported by fossil findings
Profile:
Height:
Cranial Volume:
Weight:
Skull:
Teeth:
Tools/Artifacts:

1.5 – 1.7m
1200 - 1750cc
?
- Reduced brow ridge
- large nose
- mid face projection
robust jaw; smaller teeth
than H. habilis
stone/bone tools & burial sites
about 30,000 years ago these archaic groups died out and the modern H.
sapiens sapiens appeared on the scene
Homo sapiens neanderthalensis is the only extinct Homo sapiens species found
so far
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.

the oldest known fossils of the modern H. sapiens (= H. sapiens sapiens) found in Africa
date back to about 100,000 years
The term “Homo sapiens sapiens” means: the very rational talented human

the modern humans must have co-existed with the archaic types until about 30,000 years
ago; then the archaic humans suddenly disappeared due to currently unknown reasons

there is still a heated debate about the question of when and where the modern species of
H. sapiens arose

some anthropologists favor the so-called multiregional hypothesis; this hypothesis
states, that the modern type H. sapiens evolved from archaic populations which existed at
different places around the globe and which interbred with each other

another group of scientists, however, favors the so-called monogenesis hypothesis,
which is based on DNA homology studies amongst different races of humankind and fossil
DNA analysis
 since all living ethnic groups of H. sapiens are genetically very similar, this hypothesis
proposes that modern H. sapiens arose from a single archaic group in North-East
Africa
 this group spread out of Africa and replaced the Neanderthals and other archaic groups
outside of Africa without mixing with them
 the archaic species H. sapiens simply got extinct and became dead-ends of evolution

recently molecular biologists hardened this view and concluded from mitochondrial DNA
(mtDNA) and Y-chromosomal analysis from Neanderthal fossils, that the Neanderthal DNA
is not closer to European sapiens mtDNA than to mtDNA from any other human
population ( no genetic evidence of inter-breeding)

currently there is therefore no reason to believe, that archaic groups of H. sapiens mixed
with individuals of the modern type of H. sapiens
- according to a favored hypothesis, H. sapiens neanderthalensis was slowly pushed
into extinction after the ending of the last ice-age
-

the modern type H. sapiens evolved several features which gained it important
advantages over other species and explain it’s tremendous evolutionary success
1. evolution of an erect stance
2. growth of the skull and enlargement of the brain
3. prolonged period of parental care
 the offspring have an extended time to learn from the
experience of parents and earlier generations
4. development of language and complex social behaviours
5. development and social transmission of technological, scientific
and cultural innovations
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
 e.g. Scavenging-gathering-hunting, tool making,
agriculture, industrialization and global communication
 e.g. establishment of educational institution like the
one you are just decided to attend
Homo sapiens sapiens
(150,000 – today; “global player”
 Cro Magnon = early modern H. sapiens
Skull
Profile:
Height:
Cranial Volume:
Weight:
Skull:
Teeth:
Tools:
1.6 – 1.85m
1200 - 1700cc
(you know yours!)
- small, no brow ridge
- high skull
shorter jaws than H. neandertalensis
smaller teeth
Ornaments, Arts, Technology
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SAN DIEGO MESA COLLEGE
SCHOOL OF NATURAL SCIENCES
General Biology Lectures (BIO 107); Instructor: Schmid, Elmar, Ph.D.
Skull comparison of the two Homo sapiens
H. sapiens neandertalensis vs. H. sapiens sapiens
H. sapiens neandertalensis
(skull reconstruction)
 extinct H. sapiens species !
H. sapiens sapiens
(authentic skull)
 keep smiling ;-)
Further Literature & Websites:
1. http://www.talkorigins.org/faqs/homs/
2.
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