modern variation and evolutionary change in the hominin eye orbit

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Indices & Size Estimates Label LandmarksCranial Index cri xcb * 100 / golOrbital Index obi obb * 100 / obhUpper Facial Index ufi nph * 100 / zybCranial SizeGM crg (gol * xcb * bbh)·³³³³³Orbital SizeGM obg (obb * obh * obd)·³³³³³Table 2.3: Indexes and size variables derived from linear measurementsSize of the orbit is investigated using measurements of orbital volume (obv),orbital depth (obd), distance from basion to the superior and inferior orbital margins (bso,bio), orbital breadth (obb), orbital height (obh) as well as bi-orbital and interorbitalbreadth (ekb, dkb). A ratio of orbital width/height was created to test for differences inshape of the exterior margins (obi), and vertical orientation of the orbit relative to theFrankfurt Horizontal Plane facilitates an examination of population differences, andevolutionary change in orbital frontation (obf).Orbital frontation was determined by measuring the angle formed between a straitvertical line across the upper and lower orbit and the Frankfurt Horizontal Plane (porionto orbitale).This was determined in 1877 by the International Congress ofAnthropologists to be a standard plane for normal skull orientation (Byrnes, 2007), andrepresents a flat line that runs parallel to the floor in most individuals. However, thebiological rational of the Frankfurt Horizontal Plane (FH) as a way of orienting skulls inreference to normal head position has recently come into question (Barash, Marom, 2008;Strait & Ross, 1999).31
In this investigation the FH is not used to determine “normal” skull position, butrather as a basic standard reference point for determining orbital frontation due to itspassage through orbitale on the inferior orbital margins. Orbitale is used as the vertexbetween the FH and a ray running across the upper and lower margins of the orbit, andthe angle formed between them is measured to determine the degree of vertical rotationof the orbits relative to this standard plane.An important element of understanding orbital variation and change involves anestimation of orbital volume, however because the posterior orbit is composed of thinfragile bone, it is often impossible to obtain accurate volumetric measurements in pasthuman groups dating to before the Neolithic. In modern humans and non-humanprimates the orbit is typically in good condition and rigid enough to allow a directmeasure of its capacity. In these samples, careful volumetric measurements are recordedby lining the orbit with a thin piece of plastic wrap, filling it to the orbital margins withmustard seed, and then transferring the seed to a graduated cylinder to determine theactual metric volume in milliliters.A similar technique was used in a recent study of modern humans from TohokuJapan (Brown & Maeda, 2004), and along with 64 other craniofacial variables from thisJapanese sample, were made available to researchers on the author’s website (Brown P.,1998–2003). Sex differences in orbital capacity across different samples of modernhumans are investigated in chapter 6 of this thesis using orbital volume data collected byBrown and Maeda, (2004).A comparison of the technique described by these authors and that used as part ofthis research indicates that both yield nearly identical results. This ensures that minor32
Page 1: MODERN VARIATION AND EVOLUTIONARY C
Page 7 and 8: VITAJanuary 2, 1978……………
Page 9 and 10: TABLE OF CONTENTSPageAbstract .….
Page 11 and 12: 7. Summary and Conclusion………
Page 13 and 14: Table 3.13: Wilks' lambda and Chi-s
Page 15 and 16: Figure 5.4: Change in orbital bread
Page 17 and 18: Although there is a great deal of c
Page 19 and 20: extent that in modern humans it sit
Page 21 and 22: in the face and cranium” (Enlow &
Page 23 and 24: etween the neurocranium and face, u
Page 25 and 26: Schultz (1940) observes a negative
Page 27 and 28: sphenoid, and between 5 and 6 in th
Page 29 and 30: its relative position during forwar
Page 31 and 32: fact more variation exist between r
Page 33 and 34: plane is highly related to factors
Page 35 and 36: cranial and facial height occurs in
Page 37 and 38: assessed in relation to patterns of
Page 39 and 40: or throughout hominin evolution cou
Page 41 and 42: in roughly the same proportions (An
Page 43 and 44: association with juvenile-onset myo
Page 45: Craniofacial Variables Label Landma
Page 49 and 50: this study most research questions
Page 51 and 52: Craniofacial Variables Label ErrorC
Page 53 and 54: CHAPTER 3MODERN HUMAN VARIATION IN
Page 55 and 56: Sample Sample Size RepositoryAfrica
Page 57 and 58: change in orbital anatomy and will
Page 59 and 60: 3.3.1 Interorbital breadth and bior
Page 61 and 62: 3.3.2 Orbital height and orbital br
Page 63 and 64: Basion-Superior Orbit, Basion-Infer
Page 65 and 66: 98Vertical Angle of Orbital Margins
Page 67 and 68: statistical tools. In the next sect
Page 69 and 70: Correlation obbobhobdobvobfekbdkbbs
Page 71 and 72: obbobhobdobvobfekbdkbbsobioFunction
Page 73 and 74: variables in the first discriminant
Page 75 and 76: distance matrix, which shows the Af
Page 77 and 78: golxcbzybbbhbplufbnphnlhobbobhobdob
Page 79 and 80: non-orbital cranial and facial trai
Page 81 and 82: Function 242012AncestryAfricanAsian
Page 83 and 84: eadth (ekb), and basion-orbitale (b
Page 85 and 86: CHAPTER 4EVOLUTIONARY CHANGE IN THE
Page 87 and 88: This sample represents the most mor
Page 89 and 90: analysis. This was done to remove a
Page 91 and 92: 190Boxplot of Cranial Size vs Time1
Page 93 and 94: flexed in association with neurocra
Page 95 and 96: Variables N Coefficient t p R²1) B
Page 97 and 98:
Ross (1995) also finds a relationsh
Page 99 and 100:
Figure 4.4: Image of Shandingdong (
Page 101 and 102:
CHAPTER 5EVOLUTIONARY CHANGE IN THE
Page 103 and 104:
ecause of a general reduction in cr
Page 105 and 106:
adequate space within the orbits fo
Page 107 and 108:
Western European temporal groups sa
Page 109 and 110:
Upper Paleolithic (Figure 5.4). The
Page 111 and 112:
Regardless of the relative contribu
Page 113 and 114:
of facial projection vs. time indic
Page 115 and 116:
Boxplot of Cranial Index vs Time908
Page 117 and 118:
5.6 Results of regression analyses:
Page 119 and 120:
Although the direction and magnitud
Page 121 and 122:
Additionally, because the eyeball s
Page 123 and 124:
corroborates the findings of other
Page 125 and 126:
Sample Sample Sizes Method DataFema
Page 127 and 128:
approximately 3.5 show little to no
Page 129 and 130:
In females there is a clear differe
Page 131 and 132:
Boxplot of Orbital Vol vs Sex25.022
Page 133 and 134:
Ancestral Group N mean s.d. t pAfri
Page 135 and 136:
5.5Boxplot of Relative Eye Size vs
Page 137 and 138:
away from emmetropia in individuals
Page 139 and 140:
ceases. Additionally, different pat
Page 141 and 142:
of the orbit that the eyeball fills
Page 143 and 144:
CHAPTER 7SUMMARY AND CONCLUSION7.1
Page 145 and 146:
margins in this group. The slightly
Page 147 and 148:
classification of dry skulls and as
Page 149 and 150:
Six orbital variables were used to
Page 151 and 152:
A final prediction relating to how
Page 153 and 154:
Nevertheless, orbital traits that c
Page 155 and 156:
etraction could not be evaluated. H
Page 157 and 158:
A statistically significant negativ
Page 159 and 160:
to engage in non-subsistence activi
Page 161 and 162:
comes at a cost to visual acuity ho
Page 163 and 164:
trajectories between the eye and or
Page 165 and 166:
BIBLIOGRAPHYAiello, L., Dean, C. (1
Page 167 and 168:
Bruner, E., Saracino, B., Passarell
Page 169 and 170:
Goldschmidt, E., Lam, C., Opper, S.
Page 171 and 172:
Lam, C., Edwards, M., Millodot, M.,
Page 173 and 174:
Quant, J., Woo, G. (1992) Normal va
Page 175:
Weiss, K. (2002) How the Eye Got it
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