Origin of Modern Humans

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Origin of Modern Humans

• Cavemen, Hobbits, Us

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The Genesis Account(s)

• Ge 127 So God created man in His own image in
  the image of God He created him male and female
  He created them.
• Ge 27 - And the LORD God formed man of the dust
  of the ground, and breathed into his nostrils the
  breath of life and man became a living being.

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I didnt come from no monkey!

• True!
• But, according to evolutionary theory, you and a
  monkey have common ancestors (way, way back)
• Just like you and your cousin have a pair of Most
  Recent Common Ancestors - MRCAs

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The previous two pictures are of Apes, not
Monkeys!

• And you didnt come from them either!
• But your Most Recent Common Ancestor (MRCA) with
  chimps is more recent
• 6-7 million years?

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Main categories of Evidence

• Fossils
• Similarities and differences to modern apes and
  humans
• Anatomy
• Similarities among modern apes and humans
• Embryos

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Main categories of Evidence

• Vestigial structures and design imperfections
• Wrist bones
• Spine
• Tailbone
• Wisdom teeth

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Genetics

• Same language for humans as for all other life
• Francis Collins The Language of God
• Closeness to Chimps

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Human and Chimp DNA

• Both have about 25,000 coding genes
• About 600 genes are different 97.7 identical
• 3 billion base pairs (rungs on the DNA
  ladder) with 35 million differences 98.8
  identical

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Human and Chimp DNA

• You differ from your parents in about 100 base
  pairs
• Lets say theres 18 years in a generation
• 35 million/100 350,000 generations x 18 years
  6.3 million years since human/chimp MRCA
• You and a chimp are 350,000th cousins!

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Human and Chimp DNA

• How many pairs of chromosomes do humans have?
  _____
• Chimps have 24 pairs of chromosomes (so do all
  other Great Apes)
• So then, chimps and humans must be totally
  different kinds end of story, right?

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Hmm
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Human Chromosome 2 and Chimp 2p and 2q (ref)

• The chimp chromosomes (2p and 2q) can be shown,
  when laid end to end, to create an identical
  banding structure to the human chromosome 2.
• Murder suspects have been sentenced to death on
  the basis of less evidence than this!

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Hmm
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Why Dont Cats Eat Oranges?
Hmmm?

• Answer
• They have a gene that allows them to make their
  own Vitamin C

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So do all mammals except

• Primates Monkeys, Apes and Humans
• and Guinea Pigs for some reason!
• Convergent evolution

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The Vitamin C gene

• Exists in us humans, but its broken
• FYI, this broken gene codes for the protein
  L-gulono-?-lactone oxidase
• Discussion question Why would we be specially
  created with a gene the doesnt work in us and
  our closest relatives but works in more distant
  relatives?

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Other broken genes

• There are other examples of these pseudogenes
  for example,
• decreased sense of smell in humans
• FOXP2, which is related to the development of
  speech
• FOXP2 works in humans, but is broken in chimps
• Molecular vestigial characters

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Overall, evolution is more like a fixer-upper
than a dream housevery good or
perfect
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Of course, it could all be an illusion! But,
Scientific Method assumes that nature is real -
that no tricky demons are making stuff
upEpistemology models Ontology
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Ok, back to Hominine Evolution

• Recall that Fr. Stang talked about some critters
  that have characteristics between modern chimps
  and modern humans theyre a Genus called

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Australopithecus
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Movie Theme for this Lecture

• Out of Africa
• and its sequel
• Out of Africa II

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Out of Africa I

• 1.8 million years ago (1.8 Ma)
• Some groups of the Homo genus populate the Old
  World from Africa
• Fairly well established Consensus Science

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Fossil Evidence

• Discovery of an early (1.6 - 1.8 Ma) Homo fossil
  outside of Africa

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Out of Africa II

• 100,000 years ago (100 Ka)
• Homo sapiens populates the Old World from Africa,
  replacing existing hominines
• This is controversial Frontier Science

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TIME PERSPECTIVE of this lecture...
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In This Lecture...

• Were concerned with the last 2,000,000 years (2
  Ma) or so of Earths 4.5 billion year (Ga)
  history
• 2,000,000 4,500,000,000 .044
• If all Earths history were one day...
• .044 X 24 X 60 X 60 38 seconds

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CULTURE!

• Is this what it means to be human?
• Were now getting into Cultural Evolution, the
  third part of the course

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Culture

• The patterned behavior and mental constructs that
  individuals learn, are taught, and share within
  the context of the groups to which they belong

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Early Culture

• Involved tools, and later, art both of which
  need to be passed on from generation to
  generation by teaching, not genetics

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Culture

• Very likely requires language abilities either
  spoken or symbolic
• Two complementary events in the Hominine lineage
• Bipedalism ? frees up hands
• Brocas Area in frontal lobe of brain to
  coordinate fine muscle movements, including
  whats needed for speech

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THE ARCHEOLOGICAL AGES

• Classified by types of tools

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THE STONE AGES
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PALEOLITHIC

• Old Stone Age
• 2.5 Ma gt about 10 Ka
• Started with Archaic Homo
• Recall last lecture Brain size Tools - keys to
  classification of the Homo genus
• Tool styles changed over time and can be used to
  classify cultures kind of like index fossils

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CAVE ART

• Earliest is around 50Ka
• The Upper Paleolithic
• Behaviorally modern humans
• In addition to being Anatomically Modern Humans
  (AmHs)
• Whats the meaning of this art?
• Dawn of Human Creativity

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Chauvet Cave, France 32 Ka
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NEOLITHIC

• 10 Ka gt ?
• Also know as the Agricultural Revolution
• A Neolithic product BEER!

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Beyond the NEOLITHIC

• Copper, Bronze Age, Iron Age,
• Industrial Age
• 1700s in England
• Now Information Age?

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How Scientists and other folks interpret evidence

• Lumpers vs. Splitters

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Lumpers vs. Splitters

• Lumpers gt Fewer species from the same data. In
  the extreme, favor a ladder pattern to
  evolution
• Splitters gt Many different species gt favor a
  bushier tree pattern
• Im more of a lumper in this lecture

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Two ExamplesofLumping vs. Splitting

• The Hobbits Flores Man
• Neandertals

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A Strange New Species(?) -- Homo Floresiensis

• Discovered Summer 2004 on the Indonesian island
  of Flores

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Flores Man The Hobbit

• Parts of seven individuals found
• Lived as recently as 13 Ka
• Just over three feet tall
• Brain size in Australopithecus range
• Body and facial features more like Homo genus
• Evidence of advanced tool use and hunting

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Flores Man The Hobbit

• One hypothesis is they are descendents of Homo
  groups from Out of Africa I This would be an
  example of splitting
• Comparison of skulls of Flores Man with modern
  human ?

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Flores Man The Hobbit

• Another hypothesis is they are mutant H. sapiens
  This would be an example of lumping
• Comparison of mutant (above) with Flores Man
  (below) ?

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Latest research shows that that Flores Man is

• Not a tiny-brained mutant,
• But is a side branch H. floresiensis
• Here the Splitters are more likely correct

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Neandertal MEN
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Neandertal

• remains were first discovered in 1856 in the
  valley (tal) of the Neander River near Düsseldorf
• Existed from probably at least 230 Ka to 29 Ka
• Fossils of at least 500 individuals have been
  found throughout Middle East and Europe (none in
  Africa or East Asia). Map ?

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Distinguishing anatomical features include

• Short and stocky
• High brow ridges
• Weak chin
• Protruding face
• Modern-size brain with Brocas Area

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Distinguishing anatomical features include

• Short and stocky
• High brow ridges
• Weak chin
• Protruding face
• Modern-size brain with Brocas Area

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How to Classify Neandertals?Are they human?

• That is, are they Homo sapiens? (Lumping)
• or Homo neanderthalensis? (Splitting)
• or Homo sapiens neanderthalensis? (in between)

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Or were they Homer sapiens ???
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Well get back to the Neandertal controversy in a
moment
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Sidebar Anti-Evolutionary Creationists

• Can be both lumpers and splitters at the same
  time!
• Lumpers All Australopithecines are apes, and
  all Homo are humans
• Splitters They continually complain about
  absence of missing links (transitional fossils)
• Recall Fr. Stang showed many examples of
  transitional fossils
• E.g., Brain size (1 ? 2), thumbs and feet,
  angle of spine, pelvis, knees, activities tools
  and fire, etc.

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Out of Africa II

• H. sapiens evolves in Africa and some populations
  of these migrate to the Old World replacing
  Neandertals and Later Homo
• Controversy! (Scientists arent afraid of
  controversy the essence of Scientific Method is
  to address controversy)

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Three lines of Evidenceto establish Origin of
Modern Humans

• Anatomy --gt fossils
• Genetics --gt mostly on present-day humans
• Archeology --gt Tools and Art

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Genetic Diversity

• Modern humans are genetically
• less diverse than most other species
• .08 F vs. gt.20 F

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Mitochondrial DNA Study
lt Rebecca Cann
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MtDNA Study conclusions...

• Genetic variability shows the greatest amount of
  diversity in sub-Saharan African populations
• High variability suggests that the African
  populations have been accumulating genetic
  mutations for the longest time -- i.e., they are
  the oldest living populations

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MtDNA Study conclusions...

• Genetic distance is greatest between African
  populations and other groups

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MtDNA Study conclusions...

• Supports the Out of Africa II (monogenesis)
  rather than the multiregional hypothesis

Multiregional
Recent (Out of Africa)
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How do Neandertals fit in?

• Anatomy
• Genetics
• Culture

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Ntal Genetics

• DNA recovered from several individuals
• October 2006 Nature article
• Within-group variation much less than between
  Ntals and moderns
• MRCA of them and moderns was 500 Ka
• Supports different species view
• Supports Out of Africa II as well

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Neandertal Culture

• Brocas Area ? Possible language ability, but
  phonemes dont fossilize!
• Specialized tools (Levallois technique)
• No cave art found
• Possible ritual burial pollen in one grave
• Possible altruism fossil of an old crippled
  individual found

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Specialized Tools

• Levallois technique (flaking)
• 20 different types discovered gt

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Ritual Burial? Shanidar Cave, Iraq
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Altruism ?

• Some evidence of altruism
• This specimen was old and crippled
• Chimpanzees, e.g., abandon their sick

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ART ?

• No evidence of genuine art
• Certainly no cave art
• Were they too dumb or
• Just too busy?

Reindeer phalanges gt
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Most Recent N-tal Fossils

• Found are 29 - 32 Ka
• In Gibraltar (Portugal)

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Out of Africa II Migrations
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An Open Question What happened to the Ntals?

• Did H. sapiens from Africa outcompete or outfight
  Neandertals ?
• Only 1 competitive edge in niche could lead to
  extinction in 5,000 years!
• Or were some Ntal genes absorbed into the modern
  population?

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Ntal replacement by modern H. sapiens or
absorption?
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Paleogeography of Modern Humans

• Very simplified here
• When were each of the continents settled by
  modern humans?

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Continents were populated in this order

• Africa (130 Ka)
• Asia
• Middle East (100 Ka)
• Remainder (60 Ka)
• Australia (60 Ka)
• Europe (35 Ka)
• Americas (20 - 30 Ka) Dec. 2000 Natl Geographic

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Native Americans - Florida 14 Ka
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Science doesnt claim to know everything about
everything

• But, it does claim to know something and to be
  fair about what it does know
• FYI the alternative is epistemological nihilism
• If we dont everything, then we know nothing.

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Midterm Exam

• Wednesday February 28
• Here in the Shen