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Origin of Modern Humans

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But, according to evolutionary theory, you and a monkey have common ancestors (way, way back) ... Sidebar: Anti-Evolutionary Creationists. Can be both lumpers ... – PowerPoint PPT presentation

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Title: Origin of Modern Humans


1
Origin of Modern Humans
  • Cavemen, Hobbits, Us

2
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.

3
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

4
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5
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6
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?

7
Main categories of Evidence
  • Fossils
  • Similarities and differences to modern apes and
    humans
  • Anatomy
  • Similarities among modern apes and humans
  • Embryos

8
Main categories of Evidence
  • Vestigial structures and design imperfections
  • Wrist bones
  • Spine
  • Tailbone
  • Wisdom teeth

9
Genetics
  • Same language for humans as for all other life
  • Francis Collins The Language of God
  • Closeness to Chimps

10
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

11
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!

12
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?

13
Hmm…
14
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!

15
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16
Hmm…
17
Why Dont Cats Eat Oranges?
Hmmm…?
  • Answer
  • They have a gene that allows them to make their
    own Vitamin C

18
So do all mammals except
  • Primates Monkeys, Apes… and Humans
  • …and Guinea Pigs for some reason!
  • Convergent evolution

19
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?

20
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

21
Overall, evolution is more like a fixer-upper
than a dream house very good or
perfect
22
Of course, it could all be an illusion! But,
Scientific Method assumes that nature is real -
that no tricky demons are making stuff
up Epistemology models Ontology
23
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…

24
Australopithecus
25
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26
Movie Theme for this Lecture
  • Out of Africa
  • and its sequel…
  • Out of Africa II

27
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

28
Fossil Evidence
  • Discovery of an early (1.6 - 1.8 Ma) Homo fossil
    outside of Africa

29
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

30
TIME PERSPECTIVE of this lecture...
31
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

32
CULTURE!
  • Is this what it means to be human?
  • Were now getting into Cultural Evolution, the
    third part of the course

33
Culture
  • The patterned behavior and mental constructs that
    individuals learn, are taught, and share within
    the context of the groups to which they belong

34
Early Culture
  • Involved tools, and later, art both of which
    need to be passed on from generation to
    generation by teaching, not genetics

35
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

36
THE ARCHEOLOGICAL AGES
  • Classified by types of tools

37
THE STONE AGES
38
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

39
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

40
Chauvet Cave, France 32 Ka
41
NEOLITHIC
  • 10 Ka gt ?
  • Also know as the Agricultural Revolution
  • A Neolithic product BEER!

42
Beyond the NEOLITHIC
  • Copper, Bronze Age, Iron Age,…
  • Industrial Age
  • 1700s in England
  • Now Information Age?

43
How Scientists and other folks interpret evidence
  • Lumpers vs. Splitters

44
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

45
Two Examples of Lumping vs. Splitting
  • The Hobbits Flores Man
  • Neandertals

46
A Strange New Species(?) -- Homo Floresiensis
  • Discovered Summer 2004 on the Indonesian island
    of Flores

47
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

48
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 ?

49
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) ?

50
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

51
Neandertal MEN
52
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 ?

53
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54
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55
Distinguishing anatomical features include
  • Short and stocky
  • High brow ridges
  • Weak chin
  • Protruding face
  • Modern-size brain with Brocas Area

56
Distinguishing anatomical features include
  • Short and stocky
  • High brow ridges
  • Weak chin
  • Protruding face
  • Modern-size brain with Brocas Area

57
How to Classify Neandertals? Are they human?
  • That is, are they Homo sapiens? (Lumping)
  • or Homo neanderthalensis? (Splitting)
  • or Homo sapiens neanderthalensis? (in between)

58
Or were they Homer sapiens ???
59
Well get back to the Neandertal controversy in a
moment…
60
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.

61
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)

62
Three lines of Evidence to establish Origin of
Modern Humans
  • Anatomy --gt fossils
  • Genetics --gt mostly on present-day humans
  • Archeology --gt Tools and Art

63
Genetic Diversity
  • Modern humans are genetically
  • less diverse than most other species
  • .08 F vs. gt.20 F

64
Mitochondrial DNA Study
lt Rebecca Cann
65
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

66
MtDNA Study conclusions...
  • Genetic distance is greatest between African
    populations and other groups

67
MtDNA Study conclusions...
  • Supports the Out of Africa II (monogenesis)
    rather than the multiregional hypothesis

Multiregional
Recent (Out of Africa)
68
How do Neandertals fit in?
  • Anatomy
  • Genetics
  • Culture

69
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

70
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

71
Specialized Tools
  • Levallois technique (flaking)
  • 20 different types discovered gt

72
Ritual Burial? Shanidar Cave, Iraq
73
Altruism ?
  • Some evidence of altruism
  • This specimen was old and crippled
  • Chimpanzees, e.g., abandon their sick

74
ART ?
  • No evidence of genuine art
  • Certainly no cave art
  • Were they too dumb or
  • Just too busy?

Reindeer phalanges gt
75
Most Recent N-tal Fossils
  • Found are 29 - 32 Ka
  • In Gibraltar (Portugal)

76
Out of Africa II Migrations
77
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?

78
Ntal replacement by modern H. sapiens … or
absorption?
79
Paleogeography of Modern Humans
  • Very simplified here…
  • When were each of the continents settled by
    modern humans?

80
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

81
Native Americans - Florida 14 Ka
82
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.

83
Midterm Exam
  • Wednesday February 28
  • Here in the Shen
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