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Title: HUMAN EVOLUTION: GENUS HOMO


1
HUMAN EVOLUTION GENUS HOMO
2
The following are misconceptions about evolution
3
Evolution 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.

4
Evolution 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

5
Evolution 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

6
FUN 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!

7
Individuals 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

8
Gaps 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

9
FUN 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

10
Humans 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

11
Humans 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

12
Mas 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

13
FUN 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

14
If 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

15
FUN 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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How 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.

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Previous 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.

20
Is 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

21
Follow 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?).

22
Feet 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.

23
Mas Pies
  • Lets watch this video
  • Feet Found 800,000 years ago

24
Stone 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.

25
Stone
  • 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.

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Early 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

27
The 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

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Hammerstone
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Oldowan Tools from Lokalalei, Kenya
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Stone Tools from Majuangou, China
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Things 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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Cranial capacity for Genus Homo
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How we Get food (evidence 4)
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Experiments 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
40
Stone 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
41
Humans 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
42
Hunting 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)
43
Stone 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.
44
The 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)
45
Technologies 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)
46
Early 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.
47
The 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!
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At 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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Burial
  • 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.

51
We 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.

52
More 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

53
More
  • 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

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Making 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.

55
Cosmopolitan
  • 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.

56
Art 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.

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Our 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.

58
Brains 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.

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  • 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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Time-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

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6 SPECIES OF GENUS HOMO
  1. Homo habilis
  2. Homo ergaster
  3. Homo erectus
  4. Homo antecessor (archaic Homo sapiens)
  5. Homo heidelbergensis (archaic Homo sapiens)
  6. Homo neanderthalensis

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Rise 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

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Homo habilis
http//www.archaeologyinfo.com/homohabilis.htm
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1. Homo habilis
  • 2.3-1.5 mya
  • East Africa (Kenya, Tanzania, Ethiopia)
    southern Africa
  • Increased brain size (680-800ml)
  • Stone tools

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Homo habilis
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Homo 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
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Homo ergaster
http//www.archaeologyinfo.com/homoergaster.htm
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2. 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)

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Turkana 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

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Homo erectus
http//www.archaeologyinfo.com/homoerectus.htm
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3. 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

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Homo erectus Facial Morphology
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EXAMPLE Peking Man Reconstruction
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Archaic 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
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4. 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 (?)

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Homo 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

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5. 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

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The Steinheim Cranium
The Steinheim specimen excavated in the 1930s
from Germany 1st archaic cranium discovered in
Europe
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Homo neanderthalensis
http//www.archaeologyinfo.com/homoneaderthalensis
.htm
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6. 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

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Original Neanderthal Skullcap
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Neanderthal Features
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Neanderthal Adaptations
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Modern Human Regional Variation
African
European-SW Asian
East Asian
Australian
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Out 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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Multiregional 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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Compromise (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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Recent 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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