4.human evolution

HISTORY PRESENTATION
1
CHAITANYA.P
I MDS
Dept of Public
Health
Dentistry

PREVIOUS QUESTIONS
1. Human evolution (OCT 13)
2. Human race (OCT 12)
2

CONTENTS
1. Introduction
2. History
3. Theories of human evolution
4. Stages of human evolution
5. Human characteristics
6. Conclusion
3

"Hominid" refers to members of the human family,
Hominidae, which consist of all species from the point
where the human line splits from apes towards present day
humans.
Habitual bipedal locomotion (movement on two legs), an
upright position, and a large brain that has lead to: tool
use, language, and culture characterize hominids.
Introduction
4

History
1856-Neander Valley
Discovery of a skull that was not quite human
5

1859 – Darwin
publishes ‘The
Origin of Species’
1871- Darwin
predicts that
ancestors of
humans would be
found in Africa
6

1970s – present
• more fossils
• molecular
techniques
• ‘tree model’ of
human evolution
7

The precursors of the modern human being1 Humans appeared late in Earth’s history
The earliest ancestors of
humans (hominids) diverged
from apes about 8 million years
ago.
First Europeans:
approx. 780,000
years ago
9

THEORIES OF HUMAN EVOLUTION
1. Theory Of Special Creation:- (Father Suarez 1548-1671)
• Living organisms on the earth were created by divine power
• He believed that universe was created in 6days
• Purely a mythological belief followed until middle of 19th
century.
Ref:-G.Sivaramakrishna intermediate 2nd year zoology, telugu akademi publishers, 2007,
pgno.171-189
10

2. Cosmozoic theory or Panspermia
• Life is distributed all over cosmos in the form of resistant
spores.
• Resistant spores living organisms called cosmozoa.
• Spores with cosmic dust might have reached the earth
accidentally from other planets of universe
pgno.171-189
11

3. Theory of spontaneous generation or Abiogenesis
• It explained that life originated from nonliving substances.
• Worms Manure
• Insects Dew, rotten slime, dry wood, sweat and meat.
• Frogs & salamanders slime.
• Toads, Snakes & Mice Mud of Nile
• Aristotle, Thales, Plato and Von Helmont believed abiogenesis
until 17th century.
• Franceo Redi, Spallanzani and Louis Pasteur experimentally
disproved abiogenesis theory.
12

4. Biogenesis theory (Louis Pasteur)
• Biogenesis theory states that living organisms originate from
the pre-existing organisms.
• Swan-neck flask experiment
pgno.171-189
13

Theory of Catastrophism (Cuvier)
• He advocated that the earth was subjected to periodic
catastrophes.
• These catastrophes destroyed the life from time to time and
created new and special form of life.
pgno.171-189
14

Theory of Organic Evolution
• The origin of primordial life on the earth was associated with the
origin of universe.
• Primitive organisms evolved spontaneously from the inorganic
matter as a result of formative action of physical forces like
electric charges, U.V radiations, and radiations of radio-active
elements.
• This theory was strongly supported by Darwin, Haldane,
A.I.Oparin, H.Urey and Stanley Miller.
15

• Darwin, Haldane & A.I.Oparin the first phase of the origin of life
was the spontaneous generation of early molecules.
• These molecules later transformed into protobionts.
• Protobionts evolved in to early living organisms
• Thus origin of life is a phenomenon of chemical evolution that
led to biological evolution
pgno.171-189
16

Paleolithic Age:
( Old Stone Age )
2,500,000 BCE
to 8,000 BCE
1. 4,000,000 BCE - 1,000,000 BCE
2. 1,500,000 BCE - 2,50,000 BCE
3. 2,50,000 BCE - 30,000 BCE
4. 30,000 BCE - 10,000 BCE
17

 2,500,000 BCE – 10,000 BCE
 hunting (men) & gathering (women)
 small bands of 20-30 humans
 NOMADIC
 Made tools
“PALEOLITHIC” – OLD STONE AGE
18

 Humans during this period found shelter in caves.
 Cave paintings left behind.
Purpose??
19

 “Neolithic”  “New Stone” Age
 10,000 BCE – 4,000 BCE
 Gradual shift from:
Nomadic lifestyle  settled, stationery lifestyle.
Hunting/Gathering  agricultural production and
domestication of animals.
20

 8,000 BCE – 5,000 BCE
 Agriculture developed independently in
different parts of the world.
 SLASH-AND-BURN Farming
Middle East India Central America China Southeast Asia
8,000 BCE 7,000 BCE 6,500 BCE 6,000 BCE 5,000 BCE
21

Humans have evolved form 2 species:
1) Australopithecine species
2) Homo species
22

4,000,000 BCE – 1,000,000 BCE
 Hominids --> any member
of the family of two-legged
primates that includes all
humans.
 Australopithecines
 An Apposable
Thumb
23

The Australopithecines
• Generally refers to any species in the related
genera Australopithecus and Paranthropus.
• Occurred in the Plio-Pleistocene era
• The genus Homo (humans, appear about 2.4
million years ago with Homo habilis) appear to be
descended from australopithecine ancestors, more
precisely from Kenyanthropus platyops branching
off Australopithecus some 3.5 million years ago.
24
C. E. OXNARD*The place of the australopithecines in human evolution: grounds
for doubt? Nature 258, 389 - 395 (04 December 1975); doi:10.1038/258389a0

Characteristics
i. Bipedal and dentally similar to humans
ii. Brain size not much larger than modern apes
iii. Lacking the encephalization characteristics of the genus
Homo.
25

Australopithecus afarensis
One of the earliest of modern man's
ancestors.
They lived between 3.2 to 4 million
years ago in eastern Africa.
Fossils are found in Tanzania and
Ethiopia .
26

Features
i. Long curved fingers, long arms relative to the length of their
legs.
ii. Small brain capacity (380-430 cc).
iii. Had a large face relative to the rest of the cranium. The
forehead is very small.
iv. The Zygomatic arches flair to the side and produce the
characteristically broad face.
27

v. Sagittal ridge where strong chewing muscles are attached.
vi. Marked prognathism of the face.
vii The cranium attaches to the backbone in a relatively
backward position when compared with humans.
28

Dentition status:
i. Large pointed dimorphic upper canines
ii. Presence of primate spaces
iii. The molars are larger in size than in modern humans
iv. The arcade is omega shaped, intermediate between the box
row in apes and the parabolic curve in humans.
29

Australopithecus africanus
Lived between 2.3 to 3.0 million years ago,
mostly in South Africa although remains
have been found else where.
First discovered by Raymond Dart in 1925.
Direct descendent of A. afarensis.
30

Characteristics
i. Cranial capacity - between 435cc and 530cc.
ii. Body consists of longer arms and shorter legs as compared to
A. afarensis .
iii. The zygomatic arch is less robust than other
australopithecines
iv. No sagittal ridge or crest.
v. Less prognathic than A. afarensis with a more rounded jaw
and larger back teeth and canines.
31

Dentition status:
i. Specialized than the dentition of A. afarensis.
ii. The size of A. africanus teeth are larger
iii. The molar teeth are relatively larger in size than the earlier
form, for powerful chewing.
iv. The rows of teeth in A. africanus are more parallel rather
than being parabolic.
v. The incisors are angled forward instead of being vertical in
position.
32
C. E. OXNARD*The place of the australopithecines in human evolution: grounds
for doubt? Nature 258, 389 - 395 (04 December 1975); doi:10.1038/258389a0

Paranthropus robustus
First appeared about 1.8 million years ago
and disappeared around 1 million
years ago.
This species was first discovered and
named by Dr. Robert Broom.
Mostly lived in eastern Africa.
33

Characteristics:
i. Dish-shaped face
ii. Forward migration of the cheekbones
iii. Prominent sagittal crest in males
34

Paranthropus boisei
Lived from around 1.3 million years to
about 2.2 million years ago.
The first specimen of this species was
discovered by Mary Leaky in 1959.
Found in East Africa, Ethiopia, Kenya and
Tanzania.
35

CHARACTERISTICS
i. Slightly larger cranial capacity (490-530cc) than early
hominids
ii. Huge chewing apparatus with enormous molar teeth
iii. Thick jaw and check bones
iv. More pronounced cranial crest
36

HOMO SPECIES
It is the genus that includes modern humans
and species closely related to them.
The genus is estimated to be about 2.3 to 2.4
million years old evolving from
australopithecine ancestors with the
appearance of Homo habilis.
All species of the genus except Homo sapiens
(modern humans) are extinct.
37

 HOMO HABILIS
( “Man of Skills” )
 found in East Africa.
 created stone tools.
38
Chris Stringer, Human evolution: Out of Ethiopia, Nature 423, 692-695
(12 June 2003) | doi:10.1038/423692a

Homo habilis
First appeared around 2.5 million years
ago at the beginning of the
Pleistocene period.
Fossils were first discovered in
Tanzania, East Africa between 1962
and 1964.
Named by Louis Leakey, Phillip Tobias,
and John Napier.
39

Tool making
Homo habilis onwards
• Tool-making was considered a ‘human trait’
H.heidelbergensis made Hand
axes, wooden spears etc. Oldowan Tools
40

CHARACTERISTICS
i. Handy man/ tool user hominid.
ii. Bipedal, larger cranial capacity (700 cc) than
australopithecines (500 cc).
iii. An “apelike” (long arms and a small body) body structure
was characteristic of the Homo habilis.
41

• Dentition status:
i. Flat face and large molars.
ii. Molar teeth present a more squared outline and are more
identifiably modern.
iii. Posterior teeth & canines have undergone a reduction as
compared to A. africanus.
iv. Crenulations are lost
v. Maxilla and mandible are decreased in size and bone
thickness because the teeth are decreased in size.
42

1,600,000 BCE – 30,000 BCE
 HOMO ERECTUS
( “Upright Human Being” )
 Larger and more varied
tools --> primitive technology
 First hominid to migrate and
leave Africa to Europe and
Asia.
 First to use fire ( 500,000 BCE )
 BIPEDALISM
43

Homo erectus
Extinct species of hominid that originated in
Africa and is the first species which move
out of Africa.
Lived about 1.6 million years ago to around
400,000 years ago.
It was first discovered in 1891 by Dr. Eugene
Dubois.
44

CHARACTERISTICS
i. Systematic hunting and ‘home base camps’ for living.
ii. Systematic tool-making
iii. Controlled fire for cooking food and other purposes
iv. Sexual dimorphism
v. Relatively greater cranial capacity (800 - 1300 cc)
45

vi. Orthognathy
vii. Dental size reduction
viii Greater body size
46

Dentition status
i. Jaws and teeth are still larger compared to those of modern
humans but smaller than those of earlier hominids.
ii. Sizes of the back teeth are decreased as compared to
Australopithecines.
iii. Anterior teeth are larger than those of modern humans.
iv. Upper central incisors are distinctively shovel-shaped.
47

200,000 BCE – 10,000 BCE
HOMO SAPIENS
( “Wise Human Being” )
Neanderthals
( 200,000 BCE – 30,000 BCE )
Cro-Magnons
( 40,000 BCE – 10,000 BCE )
48
Chris Stringer, Human evolution: Out of Ethiopia, Nature 423, 692-695 (12
June 2003) | doi:10.1038/423692a

Neander valley,
German(1856)
Made clothes
from animal
skins
Live in caves
and tents.
NEANDERTHALS
49

CHARACTERISTICS
i. Short build dominated by enormous noses
ii. Barrel-shaped chest
iii. Slightly bent thigh bones
iv. Stronger fingers and toes
v. Severe arthritis
50

vi Worn teeth
vii Fractures like rodeo riders
viii Large brain (average 1400 cc, up to
1750 cc)
ix. Low forehead
51

Dentition status
i. Jaw was massive and large and lacked a prominent chin
ii. Large wisdom tooth with ample retro-molar space
iii. Taurodontism
iv. Very large canines and incisors relative to their molars and
premolars.
52

Theories on prehistory and early man
constantly change as new evidence
comes to light.
- Louis Leakey, British
paleoanthropologist
53

CRO-MAGNONs:
 Homo sapiens sapiens
( “Wise, wise human” )
 By 30,000 BCE they
replaced Neanderthals.
54

Homo neanderthalensis
Extinct member of the genus Homo.
Lived around 50,000 years ago .
Found in Europe and parts of western
and Central Asia.
55

Homo sapiens
Only living species in the Homo genus.
Anatomically modern humans originated in Africa about 200,000
years ago, reaching full behavioural modernity around 50,000
years ago.
56

CHARACTERISTICS
i. Skulls were slightly rounder and larger.
ii. Forehead rises vertically above the eye orbits and does not
slope as in Neanderthal.
iii. Brow ridges are small.
iv. Orthognathic face with a strong chin
v. Teeth and jaws were noticeably smaller as compared to other
previous species.
57

vi. Brain capacity averaged an impressive 1,350 cc.
vii. Bipedal locomotion.
58

Dentition status
Larger back teeth with massive muscular structures to aid
chewing.
parabolic shape of the palate.
59

Modern humans arose about 200,000 years
ago.
Homo sapiens fossils date to 200,000 years ago.
Human evolution is influenced by a tool-based
culture.
There is a trend toward increased brain size in
hominids.
Australopithecus
afarensis
Homo habilis Homo
neanderthalensis
Homo sapiens
60

Human characteristics
1. Bipedal gait
2. Big brain
3. Tool making
4. Social relationships, Art & Culture
63

What differentiates Ape from Man?
Critical Characteristics:
Large brain
Foramen magnum
Dentition – Teeth
Bipedal skeletal structure & musculature
S-shaped spinal column [not C]
pelvic structure [shortening-bowl shaped]
muscular (gluteal & hamstring)
lengthening of lower limb [femur]
changes in feet to become weight-bearing
structures
64

Bipedalism
• Advantages:
• Freed hands to carry objects
• See predators better in grasslands
• Access to foods not previously available
• Carry children
• Protection from sun in grasslands
65

Human vs. Chimp
• chimps 280 - 400 cc
• modern man 1000 - 2000 cc
Brain Size
66

Foramen Magnum
Position of foramen magnum
strong indicator of the angle of
the spinal column to the head
Habitual bipedalism
68

Dentition / Teeth
Reduction in size of incisors &
canines
Ape canines  displays of
aggression and as defensive
weapons
Premolar & molar with flat
occlusal wear pattern Chimpanzee
Human
69

Skeletal Structure
Upper legs angled inward from hip joints position knees to better support
body during upright walking [apes away from side to side]
A = femur b = tibia c = weight-bearing axis
70

Comparison of Pelvis Structure
Human Pelvis
Chimpanzee Pelvis
• position of big toe
• Foot shorter – less
flexible toes  more
rigid lever for pushing
off with each step
• Arch  shock absorber
Human Ilium shorter and broader allows hip muscles to steady the body during
each bipedal step
71

Gorilla vs. Human Skeleton Comparisons
Shape and position of the
skull
Relative size of the neck
Relative length of the arm
Relative length and shape
of pelvis
Posture especially shape
of the spine
C-shaped vs. S-shaped
72

Comparison of some soft tissue involved in biomechanical differences between
chimps and humans [American Museum of Natural History webpage]
• Humans  2 of 3 semicircular
canals [balance] specialized
to stabilize head
• Less muscle between head and
shoulders in humans
• Chimps have to fight gravity to hold
heads up while walking.
• Our head just sits on our necks
• Humans  more gluteus maximus
muscle
• Stabilizes femur into pelvis and
helps keeps trunk and leg moving
together.
• Achilles tendon and tendon of arch
of the foot larger in humans
• In running act like springs,
absorbing and releasing energy 73

• Homo sapiens survived extinction in late
Pleistocene
• ‘bottlenecks’ (drastic reduction in population size )
• cultural explosion
• Societies became co-operative (‘troop-to-tribe
transition’)
Social relationships, art, and culture
74

Indian evolution
1. It is not definitely known when civilization has actually started
in India. Whether Vedic culture(1750–500 BCE) has pre-
existed Harappan (3300–1300 BCE) civilization.
2. They very unambiguously stated that “Gods” are inventions of
and created by, humans.
3. The evolution of Indian culture will be followed here by
observing the evolution of spiritual texts, religions, social
institutions, social and political philosophies, social justice
movements, which have influenced the origin, being and
advancement of various schools of thought and cultures.
75

Conclusion
There is no alleviation for the sufferings of man-kind except
veracity of thought and of action, and the resolute facing of the
world as it is when the garment of make-believe by which pious
hands have hidden its uglier features is stripped off
Thomas Henry Huxley, 1909
76
Are we still evolving?????

1. Richard D. alexander: How did Humans evolve? Special
publication No.1, 1990, pg.no. 1-38
2. G.Sivaramakrishna intermediate 2nd year zoology, telugu
akademi publishers, 2007, pgno.171-189 .
3. C. E. OXNARD*The place of the australopithecines in
human evolution: grounds for doubt? Nature 258, 389 - 395
(04 December 1975); doi:10.1038/258389a0.
4. Chris Stringer, Human evolution: Out of Ethiopia,
Nature 423, 692-695 (12 June 2003)
| doi:10.1038/423692a . 77

5. Human evolution Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Human_evolution. accessed
on 2/10/2015
78

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