The document traces human evolution from primates to modern humans based on fossil and genetic evidence. Key events include: - Primates diverged from other mammals around 55 million years ago, with the earliest primate fossil dated to 65 million years ago. - The earliest hominins, like Sahelanthropus tchadensis from 6-7 million years ago, displayed both ape-like and human-like traits. - Species like Australopithecus afarensis from 3-2.9 million years ago were the first to walk fully upright. - Homo habilis and Homo erectus, dating back to 2.3 million and 1.8 million years ago respectively

1. TRACING THE HUMAN
EVOLUTION
- PRIMATES TO RACES..
M. JAGATHEESWARI
I M.Sc. SPECIAL ZOOLOGY
UNIVERSITY OF MADRAS

2. OBJECTIVE
 Tracing and understanding the
human origin and evolution,with
reference to fossil and genetic
evidences.

3. PRIMATE EVOLUTION
EUARCHONTA
 Euarchonta are the grand order of mammals
containing the orders of extinct Pleisiadapiformes,
Scadentia or tree shrews and Primates.
 Arose around 88mya. However earliest fossils
recorded is around 65mya (Purgatorious coracis).
 Small ,nocturnal, arboreal, insect eating mammals
 Includes Primates and Stem primates.

4. Purgatorious coracis

5. STEM PRIMATES- Pleisiadapis
 Includes Pleisiadapis from the
order Pleisiadapiformes.
 Considered to be the ancestor
of all the primates.
 Lived about 55mya.
 First to develop finger nails,
and front facing eyes.
 Dentition showed functional
shift towards omnivority.
 Placed as a sister group to
Primates.

6. PRIMATES
 First or most completely developed members of
the animal world. ( J.Z. Young)
 Primate = Prime, first rank (Latin)
 Characterized by large brains compared to
mammals, increased reliance towards steroscopic
vision at the expense of olfactory senses.
 Includes the suborders :
Strepsirrhini
Haplorrhini

7. STREPSIRRHINI
 Includes
Prosomians,Lemurs,
and Lorises.
 Characterised by their
wet nose or Rhinarium
 Rhinarium is connected
to the upper lip

8. HAPLORRHINI
 Defined by their dry nose
where rhinarium is
replaced by more mobile
and continuous upper lip.
 Includes Tarsiers , Simian
monkeys, and Apes.
 Further dived into
suborders
Platyrrhini
Catarrhini

9. PLATYRRHINI
 Includes new world
monkeys.
 Examples: Spider
monkeys, howler
monkeys.
 Characteristics includes
Prehensile tail, Flat nose
(with nostrils flaring out),
adaptation for arborel life
with long limbs, delicate
hands and tails for
balancing and seizing.

10. CATARRHINI
 Includes Cercopithecoidea
–the old world monkeys.
 Larger than new world
monkeys.
 Characteristics includes
small tail, naked, highly
coloured rear which
becomes enlarged in
females before ovulation.
 Eg: Rhesus monkey
(Macaque), Sacred Baboon
(Papio), Mandrill(
Mandrillus).

11. PROCONSUL
 Split from
Cercopithecoidea about
20mya.
 Best known african genus
is Proconsul africanus.
 Branched off before the
split of greater and lesser
apes.
 Had both
Cercopithecoidea and
Ape characterstics.

12. Proconsul africanus
CERCOPITHECOIDEA APE
 Thin toothed enamel
 Light build and
Narrow chest
 Short forelimbs
 Arboreal
Quadrupedal
lifestyle.
 No tail
 Ape like elbows
 Larger brain than the
body size

13. HOMINIDAE
 Includes greater apes like Pongo (Orangutans), Pan
(Chimpanzee), Gorilla (Gorrila), and lesser apes like
Hylobates (Gibbons)

14. DIVERGENCE OFHUMANS FROM
OTHERAPES
Hylobates (Gibbons)
• First to diverge
• About 15 mya.
Pongo ( Orangutans)
• About 13 mya
Gorrila (Gorrila)
• Speciated from Pan and human lineage.
• About 10 mya
Pan ( chimpanzees)
Speciated from human lineage
About 7 mya

15. EARLIEST HOMININS
Sahenlanthropus tchadensis
 Last common ancestor for
human and chimpanzees
 Lived about 7-6 mya.
 Discovered in 2001, near
Chad,Western Africa.
 had both ape like and human
like characteristics.

16. Sahenlanthropus tchadensis
APE HUMAN
 Small brain
 Sloping face
 Very prominent
brow ridges
 Elongated skull
 Small canine teeth
 Short middle part of
the face.
 Spinal cord opening
underneath the skull
instead of the back.

17. Orrorin tugenesis
 Lived about 6.2 – 5.8 mya.
 Discovered in Kenya.
 Position of Foramen magnum
suggests bipedalism.
 Post cranium suggests they climbed
trees.
 Had smaller teeth than the
Australopithecines.
 Some consider it as the human
ancestor rather than the
Australopithecines.
 If proven then Australopithecines will
be the side branch of the human
family tree.

18. Sahenlanthropus Orrorin
tchadensis tugenesis

19. Ardipithecus kadabba
 Lived about 5.8-5.2 mya in
eastern Africa.
 Discovered in 1997,Kenya.
 Bipedal, canine resembled later
hominins
 Toe has robust appearance
suggesting bipedal push off.
 Diet included fibrous foods.

20. Ardipithecus ramidus
 Lived about 4.4 mya in Eastern
Africa.
 Discovered in 1994.
 Pelvis- both arboreal and bipedal .
 Brain was small ( 300-350cc)
 Feet – adaptation for grasping
more than walking.
 Pelvis, angle of Foramen magnum,
thin wrists suggests Bipedalism.
 Diet – omnivorous, non preference
to hard nuts and tubers.

21. AUSTRALOPITHECINES-
Australopithecus afarensis
 Lived about 3.8-2.9mya in
eastern Africa.
 Discovered in 1974.
Nicknamed ‘Lucy’.
 Foot prints of a couple in
volcanic ash ( Lateoli foot
prints) – Bipedalism.
 Had both ape and human
characteristics.

22. Australopithecus afarensis
APE HUMAN
 Flat nose.
 Protruding jaw
 Small brain
 Curved fingers
 Small canine and molars
 Bipedal gait
 Lower vertebrae modified
to support to bipedalism
even during pregnancy.

23. MISSING LINK??
 In 2015, jaw bone had been
found in Ethiopia.
 Argued to be earliest Homo
(2.8mya) that links
Austraopithecines to Homo.
 Bipedal, enlarged brain,
hands suitable for tool
making.
 Not assigned to specific
species yet.

24. EARLY HOMO
Homo habilis
 Lived in Eastern Africa about
2.3mya.
 Earliest member of the genus
Homo
 Larger brain, smaller face,
teeth than Australopithecines
 Ape like long arms and
moderately prognathic face.
 First to make tools – ‘Handy
man’.

25.  Chief predator of
habilis and
Australopithecines –
Dinofelis
 Led to the development
of stone making
abilities and living in
group for protection.

26. PARANTHROPUS
 Includes P. robustus, P.
aethiopicus, P. boisei
 Lived about 2.3- 1.2 mya in
Eastern Africa.
 Branched off from H.habilis.
 Strong Jaw for eating nuts- thus
named ‘nut cracker man’.
 Extinct due to lack of diet
adaptations
 Side branch of human lineage-
did not lead to human evolution.

27. Homo erectus (1.8 mya)
 Lived in Africa and Asia.
Homo who lived the longest.
 Large brain, smaller teeth, less
sloping forehead, elongated
legs and, shorter arms than
torso.
 Completely erect gait.
 First to migrate outside Africa.
 Used fire.
 Height 4.9-6feet weight 40-
68kgs.

28. Homo ergaster Homo pekinensis
 Lived about 1.5 mya
 Evolution of dark skin
happened during its
time indicating that the
loss of body hair is
complete.
 Nick named ‘peking
man’.
 Lived in Asia.
 Considered not to be
the direct ancestors of
humans but cousins that
emerged from H.erectus

29. Homo antecessor
 Lived about 1.2 mya
 Considered to be the common
ancestor for humans and
Neanderthals.
 Cut marks on the skulls and
bones discovered suggests
that they practiced
cannibalism.

30. LATER HOMO
Homo heidelbergensis
 Lived about 700k-200k
years ago in eastern and
southern Africa, Europe
and Asia.
 Discovered in 1908.
 Large brow ridge, larger
braincase, flatter face than
early Homo.
 First to hunt large animals,
create simple dwellings
( Terra amata,France).
 Larger and more muscular
than modern humans.

31. Homo neanderthalensis (400k-40kya)
 Discovered in 1829.
 Our closest extinct human
relative.
 Shorter , stockier, had large
brain and body.
 Used Tools,clothes, painted
on caves,lived in groups,
buried the dead.
 Diet was omnivorous.

32.  Extinction- causes not known-perhaps lack of
better adaptation or pathogen infection from
migrated H.sapiens might have caused the
extinction.
 No violent interactions with H.sapiens found
(infact they coexisted and inter bred).
 H.neanderthals disappeared all of a sudden
despite having bigger brain capacity (1400cc)
and burlier body , and the H.sapiens (1300cc
and gracile ) survived.
 Perhaps it is the Survival of the weakest in
our case.

33. Homo sapien idaltu (160kya)
 Extinct sub species of Homo
sapiens sapiens.
 Discovered in 1997, Ethiopia.
 Globular braincase and face like
humans,though huge and robust.
 Fossils-Non neanderthal.
 Shows modern humans evolved in
Africa long before neanderthals in
Europe.
 Thus there is no Neanderthal
stage in human evolution.

34. DENISOVANS (30k- 50kya)
 Discovered in 2010 in
Denisova cave, Siberia
 Cave also had Neanderthal
fossils(dated 45kya) and
human fossils.
 Gene sequencing- non
neanderthal
 Also some of the DNA in
Australian aborigines is from
them.
 Indicates interbreeding b/w
archaic H.sapiens,
H.neanderthals and
denisovans

35. Homo floresiensis (18kya)
 Until recently it was thought that we were
the only hominin existed after the
neanderthal extinction about 40kya.
 But H.floresiensis was discovered in 2003
from Flores, Indonesia, which is supposed
to have lived along with Homo sapiens
 Showed Rapid reduction in body size.
 Considered as human hobbit.
 But argued that the cranium used to
describe the species could have been
example of Microcephaly.
 Still unresolved.

36. Homo sapien sapien(200kya)
 Only living Homo.
 Originated from eastern africa and spread
to all corners of the world.
 Also caleed Cro-magnon man or Omo.
 Characterised by
 Skull- thin walled & high vaulted to
accommodate large brain.
 Distinct chin.
 Near vertical fore head.
 Much less(if any) eyebrow ridges.
 Much less prognathism.
 Jaws with small teeth.
 Lighter build.
 Large brain capacity-1300cc.

37. HYPOTHESIS FOR HUMAN
ORIGINS
RECENT AFRICAN
ORIGIN

38. MULTI -REGIONALORIGIN
 Proposed by Milford Wolpoff in 1984.
 Modern humans arose about 2mya and
subsequent human evolution has been
within a single species.
 This species encompasses all archaic
humans such as the H.erectus,
H.neanderthal as well as the modern forms
and evolved world wide to diverse
population of Homo sapien sapiens.
 Genes exchanged between continental
populations via cross migration enabling
various groups to reach the same Homo
sapien sapien status.
 Major blow- Mitochondrial eve , Y
chromosomal adam, anatomically modern
human fossils( idaltu).

39. THE RECENTAFRICAN ORIGIN
(OUT OFAFRICA)
 Homo sapiens evolved from Homo erectus
only in Africa.
 Migrated from Africa about 100kya.
 Widely accepted.
 Genetic evidence(mt eve, Y chromosomal
adam) and fossil evidence(idatu) suggests
anatomically modern humans evolved
solely in Africa b/w 200k-60kya.
 H.sapiens left africa and replaced other
homos such as H.neanderthal and H.
erectus.
 Also archaic humans may have interbred
with other homo to give rise to modern
humans

41. MITOCHONDRIALEVE
(140k-200kya)
 Alan Wilson et al proposed it in
1979. Published on ‘nature’ in 1987.
 Matrilineal most recent common
ancestor(MRCA) of all the
currently living humans.
 We descend in an unbroken line , on
our mother’s side & mothers of our
mothers and so on untill all lines
converge on one woman.
 mtDNA is passed from mother
without recombination.
 Lived after H.heidelbergiensis and
after the emergence of H.
neanderthal in Africa.
 Boost to ‘out of Africa’ hypothesis.

42. Y-CHROMOSOMAL ADAM
 Patrilineal most recent
common ancestor.
 Male who was the last one
from whom all males
inherit their Y
chromosome.
 A phylogenetic analysis of
more than 1500 individuals
from all continents traced
the Y chromosome to a
common African ancestor.
 Confirms ‘out of Africa’
hypothesis.

43. EVOLUTION OF RACES
 All contemporary humans are members of the same
polytypic specie, Homo sapien sapiens.
 People are clumped together in a particular race by
characteristics such as the skin colour, face shape,hair
colour and form, skin around the eyes, eye colour etc.
 CAUSES: Global cooling trend, about 1,30,000 years
ago caused average drop in temperature.
 Homo sapiens moved to different regions and were
isolated long enough and inherited some traits.
 Darkness of the skin decreased with increasing
latitude.
 Major races of today are
Caucasians,Blacks,Mongoloids, and Australoids

45.  CAUCASIANS : White skinned people
majorly seen in europe. They have
orthognathic face with vertically straight fore
head.Have 4% Neanderthal genes.
 BLACKS: Negroes include the native African
and Afro-americans. They have prognathic
face, bigger teeth, lips, concave forehead).

46.  MONGOLOIDS: Yellow skinned people of the
Asian continent with characteristic facial features
( flat face, epicanthic folds)
 AUSTRALOIDS: Includes the native Australians
( Australian aborigines) and the Dravidians(
Tamils) of south India.
 It is believed that the Australoids and negroes
have the most primitive features( proganthic face,
concave forehead).

47. RECENT EVOLUTION OF MAN
 It’s a most common misconception that the humans
had stopped evolving.
 But The Natural selection still affects the humans.
 Current evolution seen in man are
 Delay of the menopause and early puberty in females
resulting in the lengthening of the reproductive
period.
 Reduction in blood glucose levels, cholesterol levels
and blood pressure in some populations.(Human diet
is high in fats and calories, there is currently a
selective pressure going on to make the humans more
adapted to these diets and thus more resistant to
diseases.)

48.  Lactase persistence ( lactose intolerance has been
greatly reduced).
 Loss of wisdom tooth owing to the smaller jaw(
about 35% of the population today does not
develop wisdom tooth, as evolution tends to
favour the elimination of the unwanted traits to
save the unnecessary energy expenditure it takes
to develop it).
 Blending of races- due to globalization there are
very few populations that remains isolated. Thus
the racial differences are gradually disappearing.
 Decrease in robust muscular strength ( studies
show we’re weaker than our ancestors).

49.  Loss of Palmaris longus in 10% of the world
population.

50. CONCLUSION
 Homo sapiens are the apex beings of our
world today.
 But on seeing the grand scheme, we’re the
youngest beings on earth.
 Our existence of about 200k years is nothing
compared to the other organisms or even our
hominin ancestors who lived longer than us.
 Adaptation, natural selection,and genetical
evolution shaped our species to what we’re
today and is still shaping us toward our future.

51. REFERENCES FOR FURTHER READING
BIBLIOGRAPHY
•Concepts of biology – Sylvia S.Mader
•Evolution- Nicholas H.Barton et al
•Evolution(4th edition ) – Strickberger
•Evolutionary Analysis(4th edition)- Scott freeman & Jon C.Herron
•Human and primate evolution- Susan cachel
•Human evolution- Birdsell
•Human genetics- Russ Hodge
•Humankind emerging (9th edition) - Bernard G.Campbell et al
•Introduction to physical Anthropology(2009-2010 edition)- Robert Jurmain et al
•Neanderthals and modern humans-Clive Finlayson
•Primates of the world- Rod & Ken preston
•Principles of organic evolution-E.k .Iyer
•Smithsonian intimate guide to human origin- Carl Zimmer
•The Descent of man- Charles Darwin
•The life of Vertebrates- J.Z.Young
•The Rise of Homo sapiens- Fredrick L. Coolidge & Thomas wynn
•What on the Earth evolved – Christopher llyod

52. Websites and e-journals
•Bradshawfoundation.com
•Forbes.com – missing link fossil found (2015)
•Humanorigins.si.edu
•Leakeyfoundation.org
•Mhrc.net – Mitochondrial Eve
•Mnn.com – Projecting Human Evolution( 2012)
•Modern humans came out of Africa-Owen James,
National geographic news(2007)
•Nature.com
•Sciencemag.org – molecular genomic data identify the
closest living relative of primates , Jan E. Janeka et al
•Scientificamerican.com
•Usnews.com (2012)