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Q: How did speech arise in humans?
A: We don’t know.
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How did speech arise in humans?
• scholars: interminable, acrimonious debates • limited scientific data
• 1860: Paris Linguistic Society banned discussion of the topic (not worthy of consideration)
How did speech arise in humans?
Speculative Accounts:
Proposed Origin of Speech based on onomatopoeia: animal and environmental sounds arose from human sounds indicating pleasure, discomfort (laughs, groans) arose from music arose from sign arose from primate vocalizations (like vervet calls) did not arise from anything else (no basis in human or other animal behaviour)
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Are we (homo sapiens) the only creatures ever to have used speech?
We don’t know.
No other extant primates use speech.
However, it is possible that some close but now- extinct relatives, such as Neanderthals, did speak.
How do we explain the use of speech by humans but not by other extant primates?
1. Vocal anatomy itself: position of the larynx (hyoid bone in particular) in humans vs. other primates
2. Brain development: vocal mimetic abilities in humans vs. other primates
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NON-HUMAN ANIMALS
Other animals make sounds for
Defense
Mating
Other social purposes (bonding, sharing)
However, the mechanisms they use are not necessarily the same as ours...
Bird vocal structures
illustrate parallel evolution
• avian sound-producing mechanism evolved separately from that of humans.
• little connection with our speech production mechanism
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Avian Vocal Anatomy syrinx – syringeal consists of membranes that vibrate
Source: birdwatching-bliss.com
Avian Vocal Anatomy
sits at the junction of the bronchi
some birds can produce sound on one side only
OR
two distinct sounds simultaneously
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Photograph of the ventral surface of the syrinx of a male wild-type domestic fowl. Krakauer A H et al. J Exp Biol 2009;212:3719-3727
a: tracheal rings; b: tracheal narrowing; c: syrinx
©2009 by The Company of Biologists Ltd
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Dolphins: don’t have vocal folds produce vocalizations through vibrating tissues in nasal passageways (“phonic lips”) Produce sound at audible frequencies for social purposes
and
at much higher frequencies for echolocation
Dolphin Sound
Source: www.seaworld.org
Dolphin Larynx: no true vocal folds 2015
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Dolphin Larynx: no true vocal folds (
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Evolutionary advantages of sound production
• defense, food sharing, mating
Not surprising that sound-producing capabilities are seen more than once in evolutionary history.
tolweb.org
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Placental Mammals
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Primates
Source: Tree of Life web project
Catarrhini
Source: Tree of Life web project
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Hominids (Hominidae)
Source: Tree of Life web project
Hominid Group all modern and extinct Great Apes (modern humans, chimpanzees, gorillas and orangutans) PLUS all their immediate ancestors).
Subgroup:
Hominin Group – modern humans, extinct human species and all our immediate ancestors (including members of the genera Homo, Australopithecus, Paranthropus and Ardipithecus).
source: Australian Museum
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Hominids (Hominidae) Genome sequencing shows 98.8% similarity between modern humans and chimps/bonobos.
This branch-off occurred about 5 – 7 million years ago
Smithsonian: http://humanorigins.si.edu/evidence/human-fossils/species
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ARDI
Hypothetical reconstruction of ardipithecus ramidus (ca. 4.4 million years ago)
Source: bbc.co.uk
Lucy
Hypothetical reconstruction of Lucy ca. 3 million yrs ago
(Australopithecus)
Source: bbc.co.uk
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Homo
sapiens “wise” erectus “upright” ergaster “working” rudolfensis “found near L. Rudolf” habilis “able”
Source: Tree of Life web project
Also
homo neanderthalensis (disc. 1829) homo floresiensis (disc. 2003) homo naledi (first reported 2015)
Source: Tree of Life web project
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How homo neanderthalensis might have looked.
Source: BBC
Homo Neanderthanesis
our closest extinct relatives
lived 200,000 to 40,000 years ago and therefore coexisted with homo sapiens
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Homo Neanderthanesis
Physical
Large nose, angled cheek bones Bodies: short and stocky compared to us Brains: same size as ours or larger
Behavioral/social
used tools for hunting, sewing; used fire built shelters, wore clothing probably buried their dead, sometimes in marked graves
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Homo Neanderthanesis
ALSO:
Genome sequencing (2010) shows 99.7% similarity between neanderthals and homo sapiens
è Neanderthals interbred with homo sapiens after migration from Africa.
All people of non-African origin are “part neanderthal.”
Depiction of homo floresiensis (Hobbit)
Source: discovermagazine.com
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How homo neanderthalensis might have looked.
How homo floresiensis might have looked Source: Wikimedia Commons
Source: janesoceania.com
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Two critical areas of change as we diverged from our evolutionary relatives:
1. Changes to peripheral mechanisms
2. Changes to central neural mechanisms
There are no specialized “organs of speech.”
Tongue, lips, nose, teeth evolved to serve other functions: e.g., mastication, deglutition, gustation.
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There are no specialized “organs of speech.”
Tongue, lips, nose, teeth evolved to serve other functions
Many other animals have these structures + larynx, vocal folds, but don’t speak
èThese structures can be used to produce speech
Exaptation: using something for a purpose other than its original function
Two critical areas of change as we diverged from our evolutionary relatives:
1. Changes to peripheral mechanisms
2. Changes to central neural mechanisms
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