Title: HUMAN EVOLUTION: GENUS HOMO
1HUMAN EVOLUTION GENUS HOMO
2The following are misconceptions about evolution
3Evolution involves only random changesthings
happening by chance.
- Random mutation is the ultimate source of genetic
variation - But natural selection (the process by which only
some variants survive) is not random
- For example, streamlined body shapes evolved
among some aquatic animals like sharks and
dolphins. They could swim faster and therefore
better capture prey and escape danger. - They were more likely to survive, reproduce, and
pass on their traits to the next generation.
4Evolution is about progress. Organisms are always
changing and getting better, with humans as the
culmination.
- Evolution is not about organisms marching up a
ladder of progress - Many organismsincluding some mosses, fungi,
opossums, and crayfishhave changed little over
long periods of time - They are fit enough to survive and reproduce in
their environment
- Beetles and finches changed and diversified
greatly as they adapted to changing climates or
new competitors. But that doesnt mean they got
better - Humans were definitely not the last organism to
evolve. Numerous other species have evolved since
the onset of human evolution
5Evolution is directed toward an intentional goal
or need
- The process of biological evolution is not
intentional - There is no evidence that evolution responds to
what a species needs - Evolution does shape adaptations that enable
organisms to survive and thrive in their
environments
- If an individual has a particular genetic
variation, What occurs? - It will have more offspring and the population
will evolve - Without this process of adaptation, or natural
selection, a population may die out
6FUN FACT!!!!!!!!!!!!! 1
- Compared to other primates, humans have huge
whites of the eyes, or sclera. This means that
humans can easily read each others gaze. In
experiments, great ape infants usually follow a
gaze only when the experimenter also turns his
head. But human infants follow the gaze when the
experimenter moves only his eyes. The whites of
our eyes may help a lot in communicating with one
another
- Why do we have so much white in our eyes?
- Our eyes say it!
- Get it!
- No really do you get it?
- Think here/now!
7Individuals can evolve during their lifetimes
- Evolution happens to populations and species,
not to individuals - An individual giraffes neck will not grow longer
during its lifetime due to selection pressure to
eat from taller trees (LaMarck)
- If pressure for long necks exists, then
individual giraffes with longer necks will
survive and reproduce more often than those with
shorter necks - They will produce offspring with longer necks,
resulting in a population or species shift to
giraffes with longer necks
8Gaps in the fossil record disprove evolution
- Science actually predicts gaps in the fossil
record - Many species leave no fossils at all, and the
environmental conditions for forming good fossils
are not common - The chance of any individual organism becoming
fossilized is incredibly small
- New fossils are constantly being discovered.
These include many transitional fossilse.g.,
intermediary fossils between birds and dinosaurs,
and between humans and our primate ancestors - Our lack of knowledge about certain parts of the
fossil record does not disprove evolution
9FUN FACT!!!!!!!!!!!!!!!!!!!! 2
- Your BRAIN sucks!
- Literally.
- Did you know that your brain makes up about 2 of
your body weight - but uses about 20-25 of your bodys total
energy, just for its basic activity?
- No wonder its good to eat nutritious foods that
offer a lot of energy - The brain of a newborn baby is even more amazing,
as it takes up about 60 of the babys energy as
the brain grows at an astonishing pace
10Humans are no longer evolving, and we cant
actually observe evolution in action
- Human evolution usually occurs over so many
generations that we cant observe it - sometimes it happens over a relatively short span
- Thoughts on what?
- Ability to digest milk
- Humans, are lactose-intolerant and cannot digest
milk
- Nearly 80 of adults of European ancestry have a
gene that enables them to digest milk - Researchers think that this genetic change
evolved in response to the spread of dairy
farming 5,00010,000 years ago
11Humans are too complex to have evolved
- Humans are the product of evolutionary processes
that go back more than 3.5 billion years - We evolved new physical traits and behaviors on
top of those inherited from earlier primates,
mammals, vertebrates, and the very oldest living
organisms
- Human eye-Scientists think that 550 million years
ago or more, a lightsensitive spot on the skin of
an ancestral creature provided a survival
advantage - Random changes over millions of years led to the
evolution of a pit with a narrow opening, a
retina, and eventually a lens
12Mas Ojo
- Eyes corresponding to these stages exist in
living species. According to one calculation,
only 364,000 years would have been needed for a
complex eye like ours to evolve from a
light-sensitive patch
13FUN FACT!!!!!!!!!!!!!!!!!!!!!!!!! 3
- Why do we get goose bumps?
- The body hair of all mammals automatically stands
up when cold - Creating a fluffy layer of warmth. When were
cold, the muscles around the hair follicles
contract
- a reflex left over from when our ancestors had
long body hair. But since we dont have much body
hair, all we see are the goose bumps on our skin
14If humans evolved from apes, there wouldnt still
be apes.
- Humans and chimpanzees both evolved from a common
ape ancestor that is now extinct - Based on genetic differences between humans and
chimpanzees, scientists estimate that this common
ancestor lived between 8 and 6 million years ago
- Humans evolved a series of differences from this
common ancestor chimpanzees evolved their own
unique series of differences - Like many other species that evolved from the
same common ancestor, modern humans and modern
chimpanzees continue to exist at the same time
15FUN FACT!!!!!!!!!!!!!!!!!! 4
- Why do we have wisdom teeth?
- When our back molars are impacted in our jaw,
they dont seem very wise! Thats funny (yes,
Summer it is funny) - Theyre the last teeth to come into place, and
having them was helpful to our early ancestors
who ate tough, uncooked foods that wore away
their teeth.
- But with cooking and making food softer, the
size of our jaws has diminished, often with room
for the last molars to form in the jawbut
ouch! not enough room to erupt. BOOM! Thats
funny
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18How Did We Evolve?
- 1) Before 5 mya In Africa, our ancestral lineage
and the chimpanzee lineage split. - 2) Before 4 mya The hominid Australopithecus
anamensis walked around what is now Kenya on its
hind legs. - 3) gt3 mya Australopithecus afarensis (Lucy)
lived in Africa. - 4) 2.5 mya Some hominids made tools by chipping
stones to form a cutting edge. There were perhaps
four or more species of hominid living in Africa. - 5) 2 mya The first members of the Homo clade,
with their relatively large brains, lived in
Africa.
19Previous slide Cont.
- 6) 1.5 mya Hand axes were used. Also, hominids
had spread out of Africa and into much of Asia
and Europe. These hominids included the ancestors
of Neanderthals (Homo neanderthalensis) in Europe
andHomo erectus in Asia. - 7) 100,000 years ago Human brains reached more
or less the current range of sizes. Early Homo
sapiens lived in Africa. At the same time, Homo
neanderthalensis and Homo erectus lived in other
parts of the Old World. - 8) 50,000 years ago Human cultures produced cave
paintings and body adornment, and constructed
elaborate burials. Also, some groups of modern
humans extended their range beyond Africa. - 9) 25,000 years ago Other Homo species had gone
extinct, leaving only modern humans, Homo
sapiens, spread throughout the Old World.
20Is this real, How do we know?
- Primate Behavior (evidence 1)
- Primates include lemurs, lorises, tarsiers,
monkeys, and apes a group of species that is
well known for being social, smart, and very
adept at using their hands.
- They are also very vocal and communicative with
the members of their social group. And they move
around in a wide variety of ways, including
sometimes on two legs. - Video 1
- Video 2
- Video 3
- Video 4
21Follow the footsteps (evidence 2)
- Footprints are a kind of evidence of behavior
often called a 'trace fossil' - geological
evidence of biological activity. This is in
contrast to 'body fossils', fossilized remains
from organisms' bodies. - Scientists can learn a lot from sites where human
footprints have been found
- Estimates of height, weight, and gait of the
humans who made the footprints - which also tells
us how many people made the footprints. - Features of the substrate that the footprints
were formed in (was it soft? hard? wet? dry?).
22Feet Continued
- Aspects of the environment that the humans who
made the footprints were living in, especially if
there are footprints left by other animals. - Several human footprints sites have been
discovered.
23Mas Pies
- Lets watch this video
- Feet Found 800,000 years ago
24Stone Tools (evidence 3)
- Stone tools and other artifacts offer evidence
about how early humans made things, how they
lived, interacted with their surroundings, and
evolved over time.
- Spanning the past 2.6 million years, many
thousands of archeological sites have been
excavated, studied, and dated. These sites often
consist of the accumulated debris from making and
using stone tools.
25Stone
- But since multiple hominin species often existed
at the same time, it can be difficult to
determine which species made the tools at any
given site. - Most important is that stone tools provide
evidence about the technologies, dexterity,
particular kinds of mental skills, and
innovations that were within the grasp of early
human toolmakers.
- Because stone tools are less susceptible to
destruction than bones, stone artifacts typically
offer the best evidence of where and when early
humans lived, their geographic dispersal, and
their ability to survive in a variety of habitats.
26Early Stone Tools
- The oldest stone tools, known as the Oldowan
toolkit, consist of at least - Hammerstones that show battering on their
surfaces - Stone cores that show a series of flake scars
along one or more edges - Sharp stone flakes that were struck from the
cores and offer useful cutting edges, along with
lots of debris from the process of percussion
flaking - This began 2.6 million years ago
27The Birth of the hand axe
- By about 1.76 million years ago, early humans
began to strike really large flakes and then
continue to shape them by striking smaller flakes
from around the edges.
- The resulting implements included a new kind of
tool called a handaxe. These tools and other
kinds of large cutting tools characterize the
Acheulean toolkit. - Homo Habilis made these
28Hammerstone
29Oldowan Tools from Lokalalei, Kenya
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31Stone Tools from Majuangou, China
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34Things start to change
- These toolkits were established by at least
285,000 years in some parts of Africa, and by
250,000-200,000 years in Europe and parts of
western Asia.
- We start to make points and attach them to spears
and are able to expand quickly what our food
sources are and what we can eat. We start to take
off as a species. The beginning of us! - Homo Erectus made these
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37Cranial capacity for Genus Homo
38How we Get food (evidence 4)
39Experiments and microscopic studies show that
early humans used the ends of these bone tools to
dig in termite mounds. Through repeated use, the
ends became rounded and polished. Termites are
rich in protein and would have been a nutritious
source of food for Paranthropus robustus (above).
1.5mya
40Stone tool marks on this extinct zebra ankle
bone fossil look like those made during butchery
experiments. Scientists have made experimental
stone tools and used them to butcher modern
animals. There is a strong similarity between the
marks their tools made and the marks on fossil
animal bones, indicating that early humans used
stone tools to butcher animals by this time. 2.6
MYA
41Humans in Central Africa used some of the
earliest barbed points, like this harpoon point,
to spear huge prehistoric catfish weighing as
much as 68 kg (150 lb)enough to feed 80 people
for two days. Later, humans used harpoons to hunt
large, fast marine mammals. 90,000 years old
42Hunting large animals was a risky business. Long
spears were thrust into an animal, enabling our
ancestors to hunt from a somewhat safer distance
than was possible with earlier weapons. Three
wooden spears like this one were found at
Schöningen, Germany, along with stone tools and
the butchered remains of more than 10 horses.
These spears are currently the oldest known
wooden artifacts in the world. (400,000 years)
43Stone or bone projectile points, like the one
seen here, attached to spears or darts and
enabled humans to exploit fast-moving prey like
birds and large, dangerous prey like mammoths.
104,000 years.
44The semicircular wound on this fragment of a
horse shoulder blade was made by a weapon such as
a spear, indicating it was killed by early
humans. Other horse bones from the same site have
butchery marks from stone tools. 500,000 years
old (England)
45Technologies enabling plant and animal
domestication, as seen in by these stone sickle
blades from Dynastic Egypt and Ali Kosh, southern
Iran, represent a turning point of human
interaction with the environment.
4,650 - 4,150 years old (Egypt) and about 8,600
- 8,000 years old (Iran)
46Early humans may have made bags from skin long
ago. By around 26,000 years ago, they were
weaving plant fibers to make cords and perhaps
baskets. Some of the oldest known pottery from
Japans Jomon culture, seen here, is about 18,000
years old. On the right 6,000 years old.
47The earliest hearths are at least 790,000 years
old, and some researchers think cooking may reach
back more than 1.5 million years. Control of fire
provided a new tool with several usesincluding
cooking, which led to a fundamental change in the
early human diet. Cooking released nutrients in
foods and made them easier to digest. It also rid
some plants of poisons. Building shelters 400,000
years ago. Scientists found post holes and other
evidence of multiple shelters at this site. 49
feet long in some areas!
48At Qafzeh, Israel, the remains of as many as 15
individuals were found in a cave, along with 71
pieces of red ocher and ocher-stained stone
tools. The ocher was found near the bones,
suggesting it was used in a ritual. 101,000 years
old.
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50Burial
- Our ancestors often buried the dead together with
beads and other symbolic objects. Burial rituals
heightened the groups memory of the deceased
person. These rituals may imply a belief that a
persons identity extends beyond death.
51We start recording ourselves
- By around 8,000 years ago, humans were using
symbols to represent words and concepts. As seen
in this Assyrian lapis lazuli cylinder seal from
Bablyon, Iraq, cylinder seals were rolled across
wet clay tablet to produce raised designs. True
forms of writing developed over the next few
thousand years.
52More Documents
- This ocher plaque has marks that may have been
used to count or store information. A close-up
look at the object shows that the markings are
clearly organized. This systematic pattern
suggests to some researchers that the markings
represent information rather than decoration.
77,000 years old
53More
- This fossil mammal bone has three rows of tally
marks along its length. They may have been used
to add or multiply. 25,000 years old
54Making Clothes
- Awls and perforators were probably invented in
Africa and carried to colder climates, where they
were used to pierce holes in clothing. Later,
humans used bone and ivory needles to sew warm,
closely fitted garmentsperhaps like those carved
on some human figurines. 30,000-22,000 years.
55Cosmopolitan
- Awls and perforators were probably invented in
Africa and carried to colder climates, where they
were used to pierce holes in clothing. 77,000
years.
56Art and Music
- By 40,000 years ago, humans were creating musical
instruments and two- and three-dimensional images
of the world around them. By 17,000 years ago,
they had developed all the major representational
techniques including painting, drawing,
engraving, sculpture, ceramics, and stenciling.
Working on stone, ivory, antler, and occasionally
clay, they created imaginative and highly complex
works of art.
57Our Brains Evolve-SLOWLY
- From 62 million years ago
- During this time period, early humans began to
walk upright and make simple tools. Brain size
increased, but only slightly. - From 2 million800,000 years ago
- During this time period early humans spread
around the globe, encountering many new
environments on different continents. These
challenges, along with an increase in body size,
led to an increase in brain size.
58Brains Continued
- From 800,000200,000 years ago
- Human brain size evolved most rapidly during a
time of dramatic climate change. Larger, more
complex brains enabled early humans of this time
period to interact with each other and with their
surroundings in new and different ways. As the
environment became more unpredictable, bigger
brains helped our ancestors survive.
59- The top graph shows how Earths climate has
fluctuated over the past 3 million years. Notice
how much the fluctuations increased between
800,000 and 200,000 years ago. To construct this
graph, scientists studied fossils of tiny
organisms found in ocean sediment cores. - The bottom graph shows how brain size increased
over the past 3 million yearsespecially between
800,000 and 200,000 years ago. A large brain
capable of processing new information was a big
advantage during times of dramatic climate
change. To construct this graph, scientists
measured the brain cavities of more than 160
early human skulls.
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62Time-Line of Hominid Evolution5 Adaptive
Radiations
- First Adaptive Radiation 6-7 mya in the late
Miocene, potential last common ancestors - Second Adaptive Radiation 4-5 mya in early
Pliocene, first true hominids - Third Adaptive Radiation 3-4 mya in middle
Pliocene, more hominids - Fourth Adaptive Radiation 2-3 mya in late
Pliocene, more robust hominids - Fifth Adaptive Radiation 2-1.8 mya in late
Pliocene early ice age, genus Homo
636 SPECIES OF GENUS HOMO
- Homo habilis
- Homo ergaster
- Homo erectus
- Homo antecessor (archaic Homo sapiens)
- Homo heidelbergensis (archaic Homo sapiens)
- Homo neanderthalensis
64Rise of the genus Homo
- Earliest fossils from same African sites as
Australopithecines - Most date between 2.4 and 1.8 mya
- Homo habilis means handy man
- Growing consensus that there may have been 2 or
more species of Homo living at the same time by
about 2 mya
65Homo habilis
http//www.archaeologyinfo.com/homohabilis.htm
661. Homo habilis
- 2.3-1.5 mya
- East Africa (Kenya, Tanzania, Ethiopia)
southern Africa - Increased brain size (680-800ml)
- Stone tools
67Homo habilis
68Homo habilis at Olduvai Gorge, Tanzania
Skeletal remains discovered at Olduvai Gorge in
1986 by Don Johanson revealed limb sizes and
proportions nearly identical to australopithecines
Brain size face showed advances towards more
human-like form
69Homo ergaster
http//www.archaeologyinfo.com/homoergaster.htm
702. Homo ergaster
- 1.8-1.6 mya
- Lake Turkana, Kenya
- Increased Brain Size (800-880 ml)
- Thinner Skull with smaller facial bones (than
Homo erectus)
71Turkana Boy Skeleton
- 90 of skeleton of adolescent male found west of
Lake Turkana in the mid 1980s - 1.6 mya, very modern skeleton, similar to that of
fully modern human
72Homo erectus
http//www.archaeologyinfo.com/homoerectus.htm
733. Homo erectus
- 1.8 mya 33,000 ya
- First hominid to migrate out of Africa! Africa,
then Russia, China, Java, Italy, etc. (p. 270-71) - 50 increased brain size (900-1600 ml)
- Fire, clothing, shelters, cooking
74Homo erectus Facial Morphology
75EXAMPLE Peking Man Reconstruction
76Archaic Homo sapiens
- Hominids with larger brains more modern cranial
features than classic H. erectus - Recently divided into Homo antecessor
heidelbergensis - Taxonomy is problematic some fossils could be H.
erectus, others could be direct ancestors of
later Neanderthals or pre-modern forms of H.
sapiens
AFRICAN ARCHAICS
Kabwe, Zambia
Bodo, Ethiopia
EUROPEAN ARCHAICS
Arago, France
Petroloma, Greece
774. Homo antecessor
- 780,000 ya
- Gran Dolina, Spain (oldest fossil humans in EU!)
- Increased Brain Size (1000 ml)
- Direct ancestor of H. heidelbergensis H.
neanderthalensis (?)
78Homo antecessor
- Mixture of "archaic" and "modern" traits, with
especially modern-looking mid-face - Other features are not unique could be
considered a form of European H. erectus
795. Homo heidelbergensis
- 130,000 ya 700,000 ya
- Germany, China, Ethiopia, Greece, Hungary,
Zambia, etc. (p.289) - Increased Brain Size (1000-1400 ml)
- Prepared Core tools, wooden spears, dealt with
changing environments
80The Steinheim Cranium
The Steinheim specimen excavated in the 1930s
from Germany 1st archaic cranium discovered in
Europe
81Homo neanderthalensis
http//www.archaeologyinfo.com/homoneaderthalensis
.htm
826. Homo neanderthalensis
- 28,000 ya 225,000 ya
- Belgium, Croatia, Germany, France, Iraq, Israel,
Italy (p.297) - Increased Brain Size (1200-1700 ml)
- Retouched flakes (tool use), big game hunters,
buried dead, cave art, early language?, compassion
83Original Neanderthal Skullcap
84Neanderthal Features
85Neanderthal Adaptations
86Modern Human Regional Variation
African
European-SW Asian
East Asian
Australian
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89Out of Africa (Single Region)
- About 130,000 years ago, the first anatomically
modern Homo sapiens evolved in East Africa
(probably from H. erectus) - then migrated out of Africa to Europe, Asia, and
the rest of the world. - At this point, H. sapiens may have interbred with
or out-competed other existing species, such as
H. erectus and H. neanderthalensis.
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91Multiregional Hypothesis
- 1.8 mya, Homo erectus evolved in East Africa and
then began to migrate to Europe and Asia (due to
lack of water and shelter) - A very successful species, H. erectus survived
until 33,000 years ago! Sothe Multiregional
hypothesis argues that modern H. sapiens evolved
from the different H. erectus stocks in different
regions (continents) at the same time. - After H. sapiens evolved in these different
regions, may have been interbreeding, thus
sharing of genes.
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93Compromise (Mostly Out of Africa)
- About 130,000 years ago, the first anatomically
modern Homo sapiens evolved in East Africa
(probably from H. erectus) and then migrated out
of Africa to Europe, Asia, rest of world. - At this point, H. sapiens did interbreed with
members of other species (H. erectus H.
Neanderthalensis)
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101Recent Research Mungo Man
- Part of mDNA extracted recently from bones of a
60,000 year old modern Homo sapiens skeleton
found in 1974 on the shores of Lake Mungo in
Australia - Oldest DNA extracted from a human so far!
- Comparison of this DNA with that of 9 other
ancient Australian skeletons, 2 Neanderthals, and
3,453 contemporary people from around the world
indicates "Mungo Man" had a unique genetic
marker - Indicates that a now lost genetic line of modern
Homo sapiens existed in Australia BEFORE arrival
of later Australian Aborigines - This evidence provides significant support for
rejecting the "out of Africa" complete
replacement model of modern Homo sapiens evolution
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