Learning Goals
 Students will:
1) Understand how scientists are able to reconstruct
the evolution of humans from other primates.
2) Understand the various intermediate species that
preceded humans.
3) Understand the evolutionary forces involved in
human evolution.
Success Criteria
 Students will show their understanding of learning
goals by:
1) Stating the methods used by scientists to
reconstruct evolution.
2) Listing the species that preceded humans.
3) Understanding the physical changes that occurred
during human evolution and what forces drove
that evolution.
Prerequisite Learning
 To be able to understand these concepts, students
should have a basic understanding of the following
information:
1) Process of evolution (Grade 12 Univ Biology helps)
2) Fossils and fossilization
Evolution
 Evolution IS the change in inherited
characteristics of biological
populations over successive
generations.
 Mutations in our genes (DNA) give
rise to these changes - while many are
harmful and decrease the survival
chances of the host, some improve
the chances of survival of the host
giving it more chance to breed and
pass on its genes to successive
generations. Eventually the mutation
becomes common in the biological
population.
 Changes in physiology (body form)
occur due to mutations.
 Many generations are required for
these changes to become common in
a biological population.
Evolution
 The theory was first proposed in 1859 by Charles Darwin,




based heavily on the scientific work he collected from a
voyage he undertook in the 1830’s.
One species gives rise to another
Often geographical isolation of two groups within a species
leads to change if the two groups are separated for a long
period of time. After thousands of generations or more, the
two groups become so distinct (due to mutations) that they
can no longer breed and thus become distinct species.
Changes in environment (ex. Climate change) often put
“evolutionary pressure” on a species . Only those individuals
that adapt through mutations survive and pass their genes
onto a new (and distinct) generation.
Basically evolution favours those genetic changes that help a
population to survive.
Evolution - common
micsonceptions
 Evolution will not produce a
“Flying Pig” even though this
mutation would help them to
survive (I wouldn’t want to stand
below a flock of flying Pigs)
 Evolution must use the “toolkit”
that it already has - animals with
wings developed them from parts
that their ancestors had - for
example bird wings come from
arms/forelimbs and have the same
bones but they are just modified to
suit another purpose. Bats have
wings evolved from hand bones
A bird’s wing compared to a
human’s arm - same bones,
but modified for different
functions
Evolution
 Notice the
similarities in bone
structure - humans,
birds, bats,
dolphins and horses
all evolved from a
common ancestor.
 Evolutionary
changes over
millions of years
and countless
species brought
these organisms to
their present states
The Crocoduck
 Former child TV star and born
again Christian, Kirk Cameron
suggested that if evolution exists,
“Why aren’t there Crocoducks?”
 This is a simple misconception of
straight-line evolution. Crocodiles
don’t evolve into ducks with the
Crocoduck as an intermediate or
missing link. The crocodile and
duck, both being vertebrates, share
a common ancestor (that probably
existed hundreds of millions of
years ago.)
 If not, we might see Fronkeys and
Hippoturtles.
The Crocoduck
 Another common misconception (presented by
Creationists) is that there is a straight line evolution
between organisms. For example, chimpanzees evolved
into gorillas that evolved into Neanderthals who turned
into humans.
 This is not true, all of these organisms shared a common
ancestor (which likely looked more like a chimp than a
human).
 Evolution is not a straight line path but more like a tree.
 It also does not suggest that one species is more
“advanced” than another. Rats are a very successful
species and cockroach may well survive on this planet
longer than we do.
Cladistics
 Note that evolution does
not follow a straight line.
 The correct method of
representing evolution is
called a cladogram.
 The diagram at right
shows homologies - the
advent of a specific
characteristic passed on
to all successive species.
Using Genetic Mutations to
make Cladograms
 ERV is an inactive gene
found in all apes.
 By looking at the mutations
of this gene, scientists can
create a cladogram to show
the evolutionary
relationships between apes
 The cladogram suggests
which species evolved
from which.
 Scientists can also use this
method to approximate
when one species diverged
from another (as seen in the
cladogram for the
evolution of horses)
Proof of Evolution
 Proof comes along 4 lines:
1) Fossils (and geological dating techniques) - though
fossils show a “snapshot in time”, the continuing
abundance of fossil information clarifies evolution.
2) Genetics - mtDNA, Y-chromosomes, protein
mutations
3) Comparative Anatomy - similarities in skeletal and
body structure
4) Embryology - development of the embryo and
fetus
Questioning Evolution
1)
2)
Many doubters state “Evolution” is
just a theory. This a misinterpretation
of the term theory. Many suggest that
because evolution is just a theory, it is
an educated guess or conjecture and
that we do not really know if
evolution occurs for certain!
A theory is a coherent group of tested
propositions, commonly regarded as
correct, that can be used as principles
of explanation and prediction for a
class of phenomena. In simpler terms
it is a model used to explain the
observable facts and that the model
can stand up to new information
A common misunderstanding
being added.
of the term “Theory”
Theories
 In common English usage, “theory” means something like
“guess” or “hunch”. It means something speculative,
uncertain.
 In science, however, the meaning is almost exactly the
opposite. In science, a theory is an idea that has stood the test
of time.
 This difference between the common usage and the scientific
usage of the word is a frequent source of confusion for
nonscientists.
 In science, a theory is a well-tested idea – an explanatory
framework that makes sense of the current facts available, and
continues to make accurate predictions about the natural
world
- Dennis Venema
Questioning Evolution
1)
2)
3)
4)

Remember, Gravity is also a Theory
We can observe Gravity easily - we can
watch objects fall, observe planets
orbiting the Sun, and astronomers can
even observe light being “bent” by
massive stars.
Despite the fact that we can measure
the force of gravity and state that all
objects containing mass have gravity,
we still cannot explain how gravity is
created at a sub-atomic particle level.
Does this lack of knowledge refute the
whole “Theory” of Gravity?
Remember the lessons learned when
Science and the Church battled over
the issue of Heliocentrism and
Geocentrism.
Evolution
Introductory Video
 Becoming Human Documentary - 3 episodes - 2:34:33 -
https://www.youtube.com/watch?v=YBp3SHp_Mwo
 Homo Sapiens - The Birth of Humanity (NOVA Full
Documentary) - 52:22
https://www.youtube.com/watch?v=pzmZjO1RDOQ
 Ape To Man: Evolution Documentary History Channel
- 89:54
(https://www.youtube.com/watch?v=5sMqFivWTmk)
 The Human Journey - In Search Of Human Origins 46:58 https://www.youtube.com/watch?v=4vOwUtywxI8
Sources of Evidence Used to
Deduce Human Evolution
1) Paleoanthropologists (Paleontologists/Geologists)
a) collect and study fossil remains of hominoids over
b)
c)
d)
2)
a)
100,000 years old.
use these remains to reconstruct skeletons
use rocks, fossilized pollen, etc. to determine the
environmental conditions
collect and study fossil tools
Archaeologists
collect and study fossil remains of hominoids
younger than 100,000 years old.
Sources of Evidence Used to
Deduce Human Evolution
3)
a)
b)
c)
d)
e)
Population Geneticists
Track the migrations of humans using
DNA
Mitochondrial (mtDNA) evidence is
used.
Mitochondria within the cell have
their own DNA - only 16000 base
pairs (vs. 3 billion in the nucleus)
When then ovum (egg) is fertilized,
the sperm cell does not pass its
mitochondria to the fertilized egg only the head of the sperm enters the
egg.
As a result all of the DNA in the
mitochondria comes from your
mother. Technically we all inherited
our mtDNA from a single woman the “mitochondrial Eve”
Sources of Evidence Used to
Deduce Human Evolution
Population Geneticists can track
mutations back in populations they have used this to track
migrations of humans back to
their original source (in the case of
Homo Sapiens - eastern Africa)
g) A similar technique can be used
with the Y-chromosome (only
malse pass this chromosome
forward to their sons) - we can
trace back to the “original Adam”
h) Population Geneticists can track
mutations back in populations
using any protein in our Genome
- red hair, lactose tolerance, etc.
f)
Once a mutation occurs in
mtDNA it is passed on to all that
woman’s progeny. Since the rate
of mutations can be timed (with
some accuracy), the date of the
mutation can be determined.
Sources of Evidence Used to
Deduce Human Evolution
4)
a)
b)
c)
5)
a)
Historical Linguists
Linguists study Languages and are able to group them
based on similarities (ex. Romance Languages - Italian,
French, Portugeuse, Spanish, Romanian - all derive from
Latin (the Roman’s Language)
It is likely that all languages sprung from a single language
developed by behaviourally modern Homo Sapiens)
Historical linguists track languages back to their root
languages and can thus trace the migration of peoples.
Primatologists
Study the behaviour and social organization of primate
societies (chimpanzee behaviour gives us insight into our
own behaviour)
Sources of Evidence Used to
Deduce Human Evolution
6) Social Anthropologists
a) Study hunter-gatherer (stone age) and other
primitive societies that still exist on Earth to
construct the evolution of human societies.
7) Evolutionary Psychologists
a) Determine how evolution shaped the behaviour of
our ancestors.
Chimpanzees
 Emergence: 6.2 million
years ago
 Physical Characteristics:
very muscular, very long
arm: body ratio (for
climbing in trees).
Relatively long digestive
tract
 Walking: Knuckle
walking. Can maintain
bipedal walking for short
periods at a relatively
slow rate.
 Brain Size: 400 cm3
Chimpanzees
 Chimpanzees (Pan Troglodytes)
and the closely related Bonobo
(also called the pygmy
chimpanzee) are our closest
primate relatives.
 We evolved from apes Chimpanzees, gorillas, gibbons
and orangutans are considered
apes due to their lack of a tail.
 We share over 99% of our DNA
with Chimpanzees.
 DNA studies show that
Chimpanzees are our closest
relatives on the primate family
tree. As a result, we carefully
study Chimpanzee and Bonobo
social structure
 Diet: mostly vegetarian (mostly
fruit), uses tools to catch insects,
will eat some meat
 Male:Female Size Ratio: 1.5:1 indicative of male dominated
hierarchies. Males need size as they
fight for females and for status
among males.
 Social Structure: stay in family
groups of 15 - 120; male dominated
- very aggressive; separate male
and female hierarchies. Bonobos
live in female dominated societies
that are far less aggressive.
 Use of tools: studies by Jane
Goodall first showed chimpanzees
using tools - mostly to feed
Chimpanzees
A chimpanzee using a stick
to catch termites.
This hairless chimpanzee
shows its musculature - far
more dense than humans.
A comparison of the skeletons of the 5 types
of Apes.
Human Evolution Timeline
Human Evolution Timeline
 An excellent
cladogram for human
evolution
 Exploratorium
provides a good
timeline with pictures
of fossils:
http://www.explorat
orium.edu/evidence/l
owbandwidth/INT_h
ominid_timeline.html
Human
Evolution
Timeline
 This is the best timeline, but
it does not project well using
the BrightLinks board.
 This graphic shows timelines
and the numbers of fossils
used to describe the species.
 The graphic also shows the
advent of different
assemblages of tools and the
location of fossils.
Ardipithecus
 Emergence: 5.6 (A. Kadabba) to 4.4
million (A. Ramidus) years ago
 Physical Characteristics: 4 feet tall
and 110 lbs. Still very ape-like - its
long arms and feet with an opposing
thumb suggest that “Ardi” lived in
trees.
 Walking: Flat feet and changes in
the pelvis and spine suggest that
Ardipithecus spent more time
walking than its ancestors.
Geological evidence suggests that
the region had swamp and
grasslands, which differs from the
Jungle environment of Chimpanzees.
 Brain Size: 300- 350 cm3. Similar
brain to body weight ratio as a
chimpanzee.
Ardipithecus
 This genus is a more ape-like




intermediate between apes
(chimps) and humans (genus
Homo)
There are two species of
Australopithicenes
Discovered in 1994 - this very
recent discovery means that there
is still much research and debate
on this genus. 9 more fossils have
since been excavated.
The famous Ardi skeleton is
about 45% complete
Ardi means “root” or “ground” in
the Afar language used in the
region of Ethiopia where the
fossils were found.
 Diet: mostly vegetarian but
with a significant larger
increase in the amount of tough
fibrous foods - as suggested by
its teeth.
 Male:Female Size Ratio:
Smaller canine teeth indicate
less sexual dimorphism
 Social Structure: not much
known but the teeth hint at a
less aggressive social structure
than chimpanzees.
 Use of tools: No evidence of
tool use - but use of tools by
chimpanzees suggests use of
rocks and sticks as tools.
Ardipithecus
 Ardipithecus lived in
forests, woodlands,
grasslands and swamp.
 Since Ardi was not
restricted to the jungle it
evolved bipedal walking as
a more efficient method or
travelling through
grasslands and swamps.
Australopithecus
 Emergence: 4.5 million years ago -
extending to 2.0 mya. They lived
along side early Homo species.
 Physical Characteristics: The skeleton
contain both human and ape-like
features. The first group to walk
upright almost exclusively. Still had
long arms to aid in tree climbing.
 Walking: Bones indicate an upright
bipedal walking motion. This
evoltionary change allowed
Australopithecus to move through
grasslands and woodlands to feed.
 Brain Size: 4-500 cm3. Similar brain to
body weight ratio as a chimpanzee.
 Diet: mostly vegetarian but
with a significant larger
increase in the amount of tough
fibrous foods - leaves, tubers.
The saggital crest on the skull is
proof of massive chewing
muscles.
 Male:Female Size Ratio: Males
and females varied
significantly in body size, with
males standing approximately
4 feet 11 inches tall and
weighing 100 pounds and
females standing about 3 feet 5
inches tall and weighing about
62 pounds. Males also typically
had large crests on top of their
skulls; females did not.
 Social Structure: stay in family
groups of 15 - 120; male
dominated as indicated by the
distinct sexual dimorphism.
 Use of tools: No evidence of
tool use - but use of tools by
chimpanzees suggests use of
rocks and sticks as tools.
Australopithecus
 This genus is an intermediate





between apes (chimps) and humans
(genus Homo)
They evolved from a more ape-like
ancestor called Ardepithecus Ramidus
(4.5 mya), but little fossil evidence is
available for this most distant
human ancestor.
There are several species of
Australopithicenes in the fossil
record - A. Anamensis (4.0 mya), A.
Afarensis (3.9 - 3.0 mya), A. Africanus,
A. Sediba (1.98) mya and others.
Note that A. is short for
Australopithecus
Another more ape-like genus arose
from Australopithecus called
Paranthropus. They lived until 1.0
mya but are not our direct ancestors.
The famous LUCY skeleton is an
example of A. Afarensis.
Australopithecus
Evolution
 The climate of Africa’s central forests turned much more arid
during this period (4.5 to 4 million years ago).
 Tropical Jungle gave way to savannah grasslands.
 Chimpanzees lost habitat, but a new species evolved to live in
the grassland and woodlands.
 Australopithecus would have had to change its diet to
ground-based plants - grasses (grains), roots and tubers.
Australopithecus
Australopithecus
Digestive Systems of
Herbivores and Carnivores
 Mammalian carnivores
have intestines that
are1.5 to 3 times their
body length.
Mammalian herbivores
have intestines that
are10 - 20 times their
body length.
 Herbivores have
multiple chambered
stomachs and often
have a large cecum
(appendix) for bacterial
digestion of food.
 Herbivores expend a lot
of energy digesting low
calorie foods with high
cellulose content.
Diet and Brain Size
 As hominids adapted to more




carnivorous diets, they had more
energy to feed a larger brain.
Brain cells require over 4 times as
much energy as other cells. Human
brains account for 3% of our weight
and 20% of our energy demands.
They also required less energy for
digestion.
Basically - the rapidly increasing
brain size in homonids is related to
a change to a carnivorous diet.
Cooking meat allows it be digested
more easily and allows for more to
be eaten for more calories.
2.33 to 1.44 mya
Homo Habilis  Emergence:
Physical Characteristics: 4-5
feet tall and 70 -100 lbs. (1.10 1.50 m, 35-45 kg.). Much larger
cranium and upright posture
but still has longer arms and
ape-like facial features.
 Walking: Definitely bipedal as
indicated by the pelvis and
feet bones. Arms attached at
the sides of shoulder blade vs.
top for chimps.
 Brain Size: expanded from
Australopithicenes to 600 - 800
cm3. The skull is more
human-like, with an enlarged
Broca’s Area (the part of the
brain used for speech
(suggesting rudimentary
speech) and smaller molars
(less fibrous food)
omnivorous, but less
Homo Habilis  Diet:
tough fibrous food and the
first major signs of meat
and marrow eating as
Homo.
determined by butchered
Homo Habilis means
animal bones at fossil sites.
“Handy Man” in latin - a
reference to the tool-making  Male:Female Size Ratio:
not much evidence but
abilities of this species.
sexual dimorphism is
The first fossil specimen of
inferred.
this species was unearthed
 Social Structure: likely
by the team of the famous
stayed in family groups
paleontologist Louis Leakey.
like Australopithecus.
Fossils sites are also
 Use of tools: The first
associated with an
evidence of tool making.
assemblage of simple tools
Sites show chipped rocks
Another early, but very
(flint) with jagged edges.
similar hominid was called
Homo Rudolfensis.
 First member of our genus 



Homo Habilis Evolution
 The climate of Africa’s central forests continues to be arid with more
jungle giving way to grasslands and woodlands (2.5 - 2.0 mya)
 Homo habilis begins to become more of a meat-eater. The increase
protein allows for increased brain size and better cognitive ability.
 Better cognitive skills allowed for tool making, better hunting, the
origins of vocal communication and eventually the use of fire by
later homonins (Homo Erectus).
Homo Habilis
Modern Homo Sapiens skeleton
compared to Homo Habilis
Homo Ergaster and Homo Erectus
 Three species H. Ergaster




(Africa), H. Erectus (Asia - Java
and Peking Man) and H.
Heidelbergensis (Europe) are
considered by many scientists
to be part of the same species Homo Erectus.
Other scientists believe that H.
Erectus evolved from H.
Ergaster.
Homo Ergaster means “Working
Man” in reference to its tool
making.
Homo Erectus means “Upright
Man” - H. Erectus was
discovered before H. Habilis
and the Australopithicenes.
According to archaeologists, H.
Ergaster is likely to be the
descendant of Homo Sapiens
(our species).
 H. Ergaster is also the oldest




and most “primitive” of the 3
species.
Homo Heidelbergensis seems
the likely candidate to be the
descendant of Homo Sapiens
Neanderthalensis (Neanderthal
Man) due to the fact that its
range is in Europe.
Homo Erectus skeletons are
much larger than Homo
Habilus (almost the same size
as modern humans)
Homo Erectus coexisted with
Homo Habilus for 100000 200000 years.
Homo Erectus survived until
about 35,000 years ago and
therefore coexisted with early
Homo Sapiens.
Homo Ergaster and Homo Erectus
 Emergence: Homo Ergaster (1.9 -
1.5 mya), Homo Heidelbergensis
(900000 - 180000 ya), Homo
Erectus (1.9 mya - 35,000ya)
 Physical Characteristics: shorter
arm: body ratio (suggests that
they no longer spend time
climbing trees). Robust
musculature, Increasing size H. Erectus was only slightly
smaller than us.
 Walking: Totally bipedal,
developing running skills
needed to hunt.
 Brain Size: Much more meat
eating leads to larger brains. H.
Ergaster (800 - 900 cm3) and
Homo Erectus (850 - 1250 cm3)
 Diet: omnivorous, but an
increasing meat component as
they hunt more.
 Male:Female Size Ratio: Males
only 20% larger, suggesting less
competition between males greater male-female pair bonds.
 Social Structure: significant
change suggested. Still have
small family groups, but a more
human (vs. ape-like) social
structure. Fathers stay with the
mothers of their offspring much
longer.
 Use of tools: More advanced
“stone age tool making”. Rocks
are chipped to make tools with
different uses - axes, scrapers,
picks, etc.
Homo Ergaster and Homo
Erectus Evolution
 The climate became even more
arid in northeast Africa, yet
Homo Ergaster was able to
survive these arid conditions.
 The ability to make tools and
fire, hunt and eat meat and
survive in various environments
allowed Homo Ergaster/Erectus
to become the first hominid to
leave Africa.
 This period was also a glacial
period - note that the range of
Homo Erectus remains south of
the glacial ice sheets.
 In fact, many of the first H.
Erectus fossils were found in
Asia - Java Man and Peking
Man.
Homo Ergaster and Homo
Erectus Evolution
 Homo Erectus survived long enough to co-exist with Neanderthals and
modern humans. But were slowly driven to extinction (likely by modern
humans) starting about 50,000 years ago.
 Homo Erectus probably worked in groups to hunt, cook food and take
care of offspring. They spread across Asia, likely in pursuit of hunting
grounds as they followed game animals for food.
 Common climate changes between glacial and interglacial periods
probably made Homo Erectus more adaptable and forced them to
develop more tools and skills.
Homo Ergaster and Homo
Erectus
H. Erectus vs H. Sapiens skulls
Homo Erectus
Homo Ergaster
The more advanced “tool kit”
used by H. Erectus
Male Female Size Ratio
Male-Female size ratio or sexual dimorphism is a
telling indicator of the social structure of primates.
 When males are much larger than females:
1) it suggests male dominated social structures in
which males are very aggressive and often have
fights for dominance and control over females for
mating.
2) males are much less involved with the feeding and
protection of their offspring and their mothers.
3) The male-female pair bond is limited.
Male Female Size Ratio
Male-Female size ratio or sexual dimorphism is a
telling indicator of the social structure of primates.
 When male/female ratios are lower:
1) The male-female bond is much greater (often due
to infants requiring longer gestations and longer
care) - as a result the father is needed for feeding
and protection of the infant and mother
2) Less aggressive societies - the male-female bond
requires fewer fights for dominance between
males.
3) Since there are fewer fights there is less
evolutionary need for males to be larger.
Homo
Floresiensis
 An unusual find in 2003 on the
island of Flores in Indonesia was
of an Erectus-like skeleton of an
adult female that was only 3 and a
half feet tall.
 These cave-dwelling homonids
were nicknamed “Hobbit Man”
due to the Lord of the Rings
movies which were playing at
that time.
 This pygmy species lived only
18000 years ago and survived
later than all other H. Erectus
groups, probably by existing in
isolation. They may have died
out due to a major volcanic
eruption 12000 years ago.
 The biological phenomenon of
“Island Dwarfing” may be
responsible for their size. Dwarf
elephants also lived on the island.
Homo Ergaster and Homo
Erectus and Gary Larson
Homo Ergaster and Homo
Erectus and Gary Larson
Homo Ergaster and Homo
Erectus and Gary Larson
Neanderthals
 Emergence: 200,000 - 28,000 years ago
 Physical Characteristics: similar
morphology to modern humans but
slightly shorter with very robust
skeletons, strong musculature, skulls
with sloping foreheads, reduced
chins, an occipital bun (see picture)
and wide noses and mouths. It is
likely that Neanderthal’s were
extraordinarily strong in comparison
to humans.
 Walking: Likely were not as quick
and agile as modern humans based
on foot bones and tibia.
 Brain Size: 1435 cm3 - actually larger
than modern humans, but this may
be due to increased body mass.
Neanderthals
 There is still debate about
putting Neanderthals in their
own group - Homo
Neanderthalensis or grouping
them as a subspecies with us Homo Sapiens
Neanderthalensis.
 The likely reason for the latter
is that DNA evidence shows
that most humans of
European descent have 2-4%
Neanderthal DNA.
 This explains some of the
behaviour of your teacher.
 Diet: omnivorous, but mostly
carnivorous. Hunter-gatherer society
 Male:Female Size Ratio: On average,
males were 165 cm and females 155
cm - ratio of modern humans
 Social Structure: Neanderthals made
and used sophisticated tools,
controlled fire, lived in shelters, made
and wore clothing, were skilled
hunters of large animals. They made
symbolic or ornamental objects,
deliberately buried their dead and
occasionally even marked their graves
with offerings, such as flowers. No
earlier human species, had ever
practiced this symbolic behavior.
 Use of tools: Used sophisticated tools
for hunting and removing meat from
carcasses.
Neanderthal Evolution
 Neanderthal - comes from the the
German Neander thal meaning
Neander Valley - the location
where one of the first skulls was
found in 1856.
 Neanderthals likely evolved from
H. Heidelbergensis (a form of H.
Erectus that lived in Europe).
 The Neanderthal ranged from
Europe to the Middle East.
 Just before they went extinct
about 30000 years ago they were
pushed to the edges of the range
in Spain(most likely by modern
humans)
The Gibraltor sites where the last
Neanderthals lived.
Neanderthal Evolution
 The climate in Europe was
glacial for much of
theNeanderthal’s existence.
 As a result, the Neanderthals
body was adapted to this
climate. Wide noses for
breathing cold air, thick
bodies like today’s Inuit.
 This period was also a glacial
period - note that the range of
Homo Erectus remains south
of the glacial ice sheets.
 In fact many of the first H.
Erectus fossils were found in
Asia - Java Man and Peking
Man.
Neanderthals
Skull and Brain Size
Comparative brain
volumes
1) Chimpanzee
2) Australopithicus
3) Homo Erectus
4) Neanderthal
5) Modern Homo
Sapiens
Skull and Brain Size
 Increase in
hominid
brain size
over time!
 Note the
sudden
increase
about 1.7
million
years ago
starting
with Homo
Habilis.
Homo
Sapiens
 Homo Sapiens is latin for “Wise
Man”
 Sometimes is referred to as Homo
Sapiens Sapiens, if we are
considered to be a subspecies
related to Neanderthals.
 Homo Sapiens left Africa about
100000 years ago - we are still
hunter/gatherers at this point.
 Human “races” develop as an
evolutionary response to climatic
conditions in just the past 20 to
50000 years - races are NOT
SUBSPECIES but adaptations of
geographically separated groups.
 All humans share 99.9% of their
DNA and are far less genetically
diverse than chimpanzees.
 Diet: omnivorous, hunterer-gatherers.
Farming and animal husbandry begin
approximately 10,000 years ago distinctly
changing our eating patterns.
 Male:Female Size Ratio: males are on
average 15% larger
 Social Structure: First hominoid species to
stop a nomadic hunter- gatherer society
with small family groups to settle and
form villages and towns, with a stratified
social structure (leaders, elites, peasants,
warriors).
 Use of tools: Sophistication of tools by
early Homo Sapiens allows them to hunt,
fish, build shelters, make clothing and
battle more effectively than the hominid
species living along side them.
Development of farming and
woodworking tools eventually leading to
the use of metals prior to developing our
modern technology
Homo Sapiens
 Emergence: 195,000 years ago
 Physical Characteristics: taller but far
more slender and gracile than other
homonids. Lighter bone structure thinner skulls, smaller rib cages,
longer limbs, smaller jaws and teeth.
 Walking: skeletal changes designed
to allow us to run and throw - these
evolutionary adaptations allowed us
to hunt better.
 Brain Size: 1400 cm3 - round cranium
than is better balanced than other
hominids. Increasing cognitive
ability and increasing ability for
abstract thought (art, religion, speech,
music). The ability for speech also
increases our ability to hunt (work
together far more effectively)
A sudden change
 From 195000 to 50000 years ago
anatomically modern human beings
existed, but behaviourally they were not
much different than the other homonid
species that shared the Earth - similar
tools and likely similar social
behaviours.
 Early Homo Sapiens known as Archaic
Homo Sapiens or even Anatomically
Modern (vs. Behaviourally Modern)
Homo Sapiens were much more “robust”
- thicker skeletons.
 Something changed about 50000 years
ago
 The Scientific American graphic shows
the changes that allowed a relatively
small “animal” (Behaviourally Modern
Human) to become the planet’s most
fearsome predator.
The Spread of Homo Sapiens
 But about 50000 years ago, Homo Sapiens

The skull of an Archaic 
Homo Sapiens. Note the
thick brow ridges and
robust features


rose to dominance and started pushing
Homo Erectus and Neanderthals towards
extinction. By about 30000 years ago, only
Homo Sapiens remained.
In 20000 years, Homo Sapiens had left Africa
and spread across Asia and Europe.
By 12000 years ago they had crossed from
Asia over the Bering Sea land mass (during a
glacial period when sea levels were low) and
expanded into North America and to the
very southern tip of South America.
The entry of humans into the Americas
caused a wave of extinctions among large
mammals (sabre-tooth cats, mammoths,
ground sloths, etc.)
Archeological and DNA evidence back up
this migration very well.
Behaviourally Modern Humans
 The second great development occurred





when we settled into permanent dwellings.
Oddly, Archaeologists believe that
settlement occurred before the advent of
farming.
Settlement changed human behaviour
drastically - allowing for the development of
specialization within a society - toolmaker,
farmer, warrior, fisher, etc.
For the first time, humans were able to
gather possessions and “social status” based
on values other than strength.
The egalitarian hunter-gatherer family-sized
societies gave way to a stratified society
with elites, warriors, “peasants”, etc.
Humans also developed religious rituals as
seen in burial rites, jewellery and cave art.
Behaviourally Modern Homo
Sapiens - What Changed?
 Scientist have been studying the reasons that Homo


Cro-Magnon Man development of the modern
human skull from 50000 years
ago.



Sapiens became dominant.
It appears that the development of language
coincides with this event.
Studies of the genes that control language (called the
FOXP2 genes) - showed sudden changes in the
genome about 50000 years ago.
It is suggested that our ability to communicate (and
therefore use strategy and teamwork at a much
higher level) gave Homo Sapiens a huge advantage
when hunting, fighting and even just surviving as
compared to other Homo species.
Anatomically, we see humans becoming more
“gracile” - finer boned - hunting required speed and
cunning vs. raw strength. Activities such as farming
could be done by all members of a group.
Humans actually become smaller with the advent of
farming. For evolutionary reasons, farmers do not
need as much strength as hunters and more
importantly, they had less protein in their diet.
Migration of Anatomically
Modern Humans
Migration of Anatomically
Modern Humans
Migration of Anatomically
 Much of the evidence of
migration has come
Modern Humans human
from studies of




mitochondrial DNA.
Since sperm cells don’t pass
mitochondria to the fertilized
egg, 100% of your mtDNA is
inherited from your mother.
Tracing mutations in mtDNA
has allowed us to trace the
flow of humans backwards in
time.
All humans can be traced
back to a “Mitochondrial
Eve”, a female from a small
human family group that
lived 200,000 years ago.
A similar method using Ychromosomes can track the
“ancestral Adam”. The data
closely corresponds to the
mtDNA data.
Nice review from Scientific American