Chapter 4 Becoming Human

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Chapter 4 Becoming Human
2
Todays Objectives

• How do humans differ from apes?
• Skeleton, organs, culture
• Why was Homo erectus so successful as an early
  hominid?
• What happened to Neandertals?
• Be able to briefly trace the cultural development
  of
• tools, fire, clothing, shelter, art
• What is so important about the Upper
  Palaeolithic?

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Theories of Human Origins

• Origin Myths/Cosmologies
• Greek Prometheus
• Genesis

Western examples
Left Prometheus giving fire to mankind Top God
and Adam
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Carl Sagans Universe Calendar

• 24 days 1 billion years
• 1 second 475 years
• Big Bang January 1
• Milky Way May 1
• Solar System September 9
• Life on Earth September 25
• Humanlike Primates December 31, 1030pm

Milky Way
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Carl Sagans Universe Calendar
http//www.youtube.com/watch?vg2qezQzfgIY
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Biological Evolution

• In biology, evolution is the process of change in
  the inherited traits of a population of organisms
  from one generation to the next.
• The genes that are passed on to an organism's
  offspring produce the inherited traits that are
  the basis of evolution.
• In species that reproduce sexually, new
  combinations of genes are produced by genetic
  recombination, which can increase the variation
  in traits between organisms. Evolution occurs
  when these heritable differences become more
  common or rare in a population.
• When a species is separated into populations that
  are prevented from interbreeding mutations,
  genetic drift, and natural selection cause the
  accumulation of differences over generations and
  the emergence of new species.

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Evolution

• By the mid-nineteenth century studies of the
  fossil record and the diversity of living
  organisms had convinced most scientists that
  species change over time.
• However, the mechanism driving these changes
  remained unclear until the 1859 publication of
  Charles Darwin's On the Origin of Species,
  detailing the theory of evolution by natural
  selection.

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Before Darwin

• Geologists and paleontologists had made a
  compelling case that
• Uniformitarianism the assumption that the
  natural processes operating in the past are the
  same as those that can be observed operating in
  the present.
• life had been on Earth for a long time.
• it had changed over that time
• and many species had become extinct.

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Theories of Evolution

• Darwin and Wallace, 1850s
• Natural selection is the process by which
  favorable heritable traits become more common in
  successive generations of a population of
  reproducing organisms, and unfavorable heritable
  traits become less common, due to differential
  reproduction of genotypes.
• On the origin of species, 1859

Charles Darwin
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Influences on the Theory

• Thomas Malthus published a book in 1797 called
  Essay on the Principle of Population in which he
  warned his fellow Englishmen that most policies
  designed to help the poor were doomed because of
  the relentless pressure of population growth. A
  nation could easily double its population in a
  few decades, leading to famine and misery for
  all.
• Species cannot reproduce to their full potential
  because there is struggle for existence. In this
  struggle for existence, survival and reproduction
  do not come down to pure chance. Some traits help
  produce more offspring.

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Natural Selection

• Natural selection is the process by which
  favorable heritable traits become more common in
  successive generations of a population of
  reproducing organisms, and unfavorable heritable
  traits become less common, due to differential
  reproduction of genotypes.
• For natural selection to work on a given
  population, there must be variety within that
  population and competition for strategic
  resources.
• The concept of natural selection argues that
  organisms which have a better fit within their
  environmental niche will reproduce more
  frequently than those organisms that fit less
  well.
• By the definition of fitness, individuals with
  greater fitness are more likely to contribute
  offspring to the next generation, while
  individuals with lesser fitness are more likely
  to die early or fail to reproduce.

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The Process of Natural Selection
There is variation in traits. For example, some
beetles are green and some are brown.
There is differential reproduction. -
Environments cannot support unlimited population
growth (Malthus) - Not all individuals get to
reproduce to their full potential.
There is heredity. Traits have genetic basis.
The more advantageous trait allows more offspring.
If you have variation, differential reproduction,
and heredity, you will have evolution by natural
selection.
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Sources of Variation - Genetic
Facial features get shuffled.

• Sex can introduce new gene combinations into a
  population.
• Gene Flow (migration) is any movement of genes
  from one population to another.
• Mutation random changes in the DNA of sex cells.
  Can be beneficial, neutral, or harmful.

Genes carried to a population where they did not
previously exist.
Single mutation caused the cats ears to curl
backwards.
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Evolution vs. Natural Selection

• In biology, evolution is the process of change in
  the inherited traits of a population of organisms
  from one generation to the next (processed at the
  level of the genes).
• Natural selection is the process by which
  favorable heritable traits become more common in
  successive generations of a population of
  reproducing organisms, and unfavorable heritable
  traits become less common, due to differential
  reproduction of genotypes.

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Genetic Drift

• Genetic drift is the process of change in gene
  frequencies that occurs entirely from chance.
• In each generation, some individuals may, just
  by chance, leave behind a few more descendents
  (and genes, of course!) than other individuals.
  The genes of the next generation will be the
  genes of the "lucky" individuals, not necessarily
  the healthier or "better" individuals.
• Genetic drift depends strongly on small
  population size since the law of large numbers
  predicts weak effects of random sampling with
  large populations.
• By definition, genetic drift has no preferred
  direction - it doesnt produce adaptations.

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Mutations

• In biology, mutations are changes to the
  nucleotide sequence of the genetic material of an
  organism.
• Mutations can be caused by copying errors in the
  genetic material during cell division.
• Mutations create variation within the gene pool.
  Less favorable (or deleterious) mutations can be
  reduced in frequency in the gene pool by natural
  selection, while more favorable (beneficial or
  advantageous) mutations may accumulate and result
  in adaptive evolutionary changes.

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Fossils

• Around 1800, William Smith in England, who was a
  canal surveyor, noticed that he could map out
  great tracts of rocks on the basis of their
  contained fossils. The sequences he saw in one
  part of the country could be correlated (matched)
  precisely with the sequences in another. He, and
  others at the time, had discovered the first
  principles of stratigraphy that older rocks lie
  below younger rocks and that fossils occur in a
  particular, predictable order.
• Then, geologists began to build up the
  stratigraphic column, the familiar listing of
  divisions of geological time Jurassic,
  Cretaceous, Tertiary, and so on. Each time unit
  was characterized by particular fossils. The
  scheme worked all round the world, without fail.
• From the 1830s onwards, geologists noted how
  fossils became more complex through time. The
  oldest rocks contained no fossils, then came
  simple sea creatures, then more complex ones like
  fishes, then came life on land, then reptiles,
  then mammals, and finally humans.

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Fossil Dating

• Relative dating is done by observing the
  stratigraphy of fossils, and recording which
  fossil is younger, which is older.
• Certain naturally occurring elements are
  radioactive, and they decay, or break down, at
  predictable rates.
• Chemists measure the half-life of such elements,
  i.e., the time it takes for half of the
  radioactive parent element to break down to the
  stable daughter element. Sometimes, one isotope,
  or naturally occurring form, of an element decays
  into another, more stable form of the same
  element.
• By comparing the proportions of parent to
  daughter element in a rock sample, and knowing
  the half-life, the age can be calculated.

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Early Primates

• Prosimians (65mya)
• Monkeys (35mya)
• Apes (23mya)
• Hominids (5mya)

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Primate Family Tree
Orangutan
Crown lemur
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Primates

• Prosimians are the most primitive extant
  primates they have characteristics similar to
  forms that were ancestral to monkeys, apes and
  humans. Prosimians are the only primates native
  to Madagascar, and are also found in Africa and
  Southeast Asia.

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Monkeys

• A monkey is any member of either the New World
  monkeys or Old World monkeys.

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Apes
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Early Primates - Traits

• Common physical primate traits
• Dense hair or fur covering
• Warm-blooded
• Live young
• Suckle
• Infant dependence
• Common social primate traits
• Social life
• Play
• Observation and imitation
• Pecking order

Common Primate Traits
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Why Bipedalism?

• Anatomical changes
• Neck (1), chest (2), lower back (3), hips and
  pelvis (4), thighs (5), knees (6), feet (7)

http//www.youtube.com/watch?vSPit_Mca8dM
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Hominid Evolution

• Ardipithecus ramidus 4.4 - ? mya
• A. anamensis 4.2 - 3.9
• A. afarensis 4.2 - 2.5
• A. bahrelghazali 3.5 - 3.0
• A. africanus 3.5 - 2.5
• P. aethiopicus 2.7 - 2.3
• A. garhi 2.5 - ?
• P. boisei 2.3 - 1.3
• P. robustus 2.0 - 1.0
• Bipedalism
• Tools
• Language

Reconstruction of Australopithecine
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Hominid Evolution

• Homo habilis (2.0 1.6mya)
• H. rudolfensis (2.4-1.6mya)
• H. erectus (1.9-27kyBP)
• H. heidelbergensis (800-100kyBP)
• H. neanderthalensis (300-30kyBP)
• H. sapiens (130kyBP present)

Scale Millions of Years BP
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Hominid Evolution
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Beginnings of Paleoanthropology
First discovered in 1856 in the Neandertal valley
near Dusseldorf, Germany. The original
Neanderthal discovery is now considered the
beginning of paleoanthropology.
Raymond Dart was the first to discover human
ancestor fossils in Africa in 1926.  The Taung
child skull he found had a braincase scarcely
bigger than that of a chimpanzee, but Dart
recognized this hominid had walked upright.
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Hominid Evolution

• Major Homo advances
• Brain size
• Better bipedalism
• Hunting
• Fire (H. erectus)
• Tools
• Oldowon (H. habilis)
• Acheulean (H. erectus)
• Mousterian (H. heidelbergensis)
• Solutrean (H. sapiens)
• Built shelters (H. heidelbergensis)
• Clothing (H. neandertalensis)
• Language (Neanderthals?)

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The Great Rift Valley
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Hominid fossil sites
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Robust Vs. Gracile Australopithecines
Robust Australopithecines
Gracile Australopithecines
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Robust Vs. Gracile Skulls
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Homo habilis

• 612 cc brain
• 2.3 - 1.6 mya
• first toolmaker
• prognathic face, brow ridge
• probable meat-eater
• possibly arboreal
• discovered in 1960 by Leakeys
• no speech

Artists representation of a Homo habilis band as
it might have existed two million years ago.
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Oldowan Tool Industry

• Chopper with simple edge
• Chopping tool
• Unretouched biface

The Oldowan is the first known industrial complex
in prehistory. It takes its name from Olduvai
Gorge, Tanzania Oldowan tool use is estimated to
have begun about 2.5 million years ago (mya),
lasting to as late as 0.5 mya. It is thought
that Oldowan tools were produced by several
species of hominids ranging from Australopithecus
to early Homo.
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Homo erectus

• 1891 - Eugene Dubois discovers H. erectus in Java
• Dubois calls it Pithecanthropus erectus
  initially, also dubbed Java Man
• finds in China called Sinanthropus Peking Man
• dates from 1.9 mya to 27,000 years B.P.
• 994 cc brain size (compare to 612 for H. habilis)
• Acheulean tool industry

Photograph of Nariokotome boy, an early Homo
erectus found near Lake Turkana, Kenya.
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Homo erectus 1.9mya to 27k yBP

• Why was H. erectus so successful?
• Less sexual dimorphism possible pair bonds,
  marriage
• Less hair on body wearing of furs, other
  clothing
• Wearing of furs ability to live further north

• Quick adaptation to environment without physical
  changes
• Culture is main reason H. erectus was so
  successful
• organization for hunting
• ability to protect against predators
• control of fire?
• possible campsites
• tools (Acheulean industry)

Distribution of H. erectus
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Acheulean Tools

• Acheulean tools are typically found with Homo
  erectus remains.
• It was the dominant technology for the vast
  majority of human history and more than one
  million years ago it was Acheulean tool users who
  left Africa to first successfully colonize
  Eurasia.

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Homo neanderthalensis

• discovered in the Neander Valley (Tal) near
  Dusseldorf, 1856
• massive brain--about 1,400cc on average
• large torso, short limbs, broad nasal passages
• later remains show decrease in robustness of the
  front teeth and face, suggesting use of tools
  replaced teeth
• retained occipital torus, some mid-facial
  prognathism

The skull of the classic Neandertal found in 1908
at La Chapelle-aux-Saints.
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Neanderthal Culture

• Homesites In caves, also in the open (near
  rivers, framed with wood and covered with skins)
• Burial Is there evidence of purposeful burial
  and ritual?
• Language Could Neandertals talk or not?
• Tools Mousterian tradition

Top Reconstruction of Neandertal burial from
Shanidar cave Bottom Mousterian tools
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What happened to Neandertals?

• H. neanderthalensis coexisted with H. sapiens for
  at least 20,000 years, perhaps as long as 60,000
  years
• What happened?
• Neandertals interbred with H. sapiens
• Neandertals were killed off by H. sapiens
• H. sapiens drove Neandertals into extinction by
  competition

http//www.youtube.com/watch?vrfBmFx-g13Q
http//www.pbs.org/wgbh/nova/hobbit/brains.html
http//www.pbs.org/wgbh/nova/hobbit/program.html
http//www.pbs.org/wgbh/nova/hobbit/tree.html
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Homo sapiens

• Archaic 150,000 to 35,000 years BP
• Earliest members of the species Homo sapiens with
  different subspecies such as H.s.
  neanderthalensis or H. s. idaltu
• Modern 50,000 years BP to present
• Fully modern behavior anatomy becomes prominent.
• Ritual burying reproduced tools of bone
  antlers fishing (costal sites show evidence of
  fishing after 50k ya).
• First hominids to reach Australia (language?).
• Cultural universals emerge art, music, religion.
• Sometimes called Homo sapiens sapiens

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Cro-Magnon Man

• Cro-Magnon humans (Homo sapiens) Found in
  southwest France in 1868.
• 35,000 years B.P. in western Europe to 17,000
  years B.P.
• 1,500 cc cranial capacity
• Name comes from a hotel in France
• Not a different species, just old Homo sapiens
  from Europe

Artists reconstruction of a Cro-Magnon man
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Early H. sapiens Culture

• Art
• Traces of art found in beads, carvings, and
  paintings
• Cave paintings in Spain and southern France
  showed a marked degree of skill
• Female figurines
• 27,000 to 22,000 years B.P. (Western Europe to
  Siberia)
• Called venuses, these figurines depicted women
  with large breasts and broad hips
• Perhaps it was an example of an ideal type, or
  perhaps an expression of a desire for fertility

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Archaic H. sapiens Culture
Cave paintings from 20,000 years ago at
Vallon-Pont-dArc in southern France (left) and
from Lascaux, in southwest France

• Cave paintings
• Mostly animals on bare walls
• Subjects were animals favored for their meat and
  skins
• Human figures were rarely drawn due to taboos and
  fears that it would somehow harm others

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Upper Palaeolithic

• 40 10k yBP
• Shelters
• 15,000 yBP Ukraine
• Some made with mammoth bones
• Wood, leather working carpentry
• Tools
• From cores to blades
• Specialization
• Composite tools
• Bow and arrow
• Domestication of dogs
• Gathering rather than hunting became the mainstay
  of human economies.

Top Straw Hut Left Mammoth bone hut Bottom
Tool progression
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Modern Homo Sapiens

• Regional-Continuity Model (Milford Wolpoff,
  UMich)
• Humans evolved more or less simultaneously across
  the entire Old World from several ancestral
  populations.
• Rapid-Replacement Model (Chris Stringer, NHM
  London)
• Humans evolved only once--in Africa from H.
  heidelbergensis ancestors--and then migrated
  throughout the Old World,

• replacing their archaic predecessors. Also
  called the Out of Africa and Killer Ape
  hypothesis.

http//www.youtube.com/watch?vdoF4sNrQtmg
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Social Organization

• Hunter-gatherer analogy
• Small group, low population density, nomadism,
  kinship groups
• Migration
• North America was the last colonized by hominids.
• Beringia (land bridge) between Russia and Alaska
• Asian origin of Native Americans
• 30,000 to 12,000 years B.P. was first migration

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Homo floresiensis - Quiz

• 1. The Island of Flores is found in or around
  __________________.
• Africa B. South East Asia C. Europe D. Canada
• 2. The skeleton found in Flores was a
  _______________________.
• A. Small human child B. Microcephalic
  C. Enigmatic hominin D. H. erectus
• 3. The skeleton found at Flores lived
  approximately ____________ y.a.
• A. 3,000 B. 30,000 C. 500,000 D. 1
  million
• The brain of H. foresiensis is the same size and
  shape as a chimpanzee.
• A. True B. False
• Most experts believe H. floresiensis was simply a
  shrunk down version of Homo erectus, such as Java
  Man, which was found on near by islands.
• A. True B. False