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Blame Colombus? New skeletal evidence and the paleodemography of the Americas over the millennia. Fertility : regulator of demographic dynamics in the Ancient Americas paper posted at: www.hist.umn.edu/ ~rmccaa/paleodem.doc .

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Blame colombus new skeletal evidence and the paleodemography of the americas over the millennia l.jpg
Blame Colombus? New skeletal evidence and the paleodemography of the Americas over the millennia.

Fertility: regulator of demographic dynamics in the Ancient Americaspaper posted at: www.hist.umn.edu/

~rmccaa/paleodem.doc

Fertility: the regulator of demographic dynamics in the Ancient Americas


Slide2 l.jpg

Richard Steckel and Jerome Rose (eds.), paleodemography of the Americas over the millennia.The Backbone of History: Health and Nutrition in the Western Hemisphere (7000 BP – 1900 AD), Cambridge University Press, 2002

  • Largest collection of skeletal microdata ever assembled: 12,500 skeletons, 65 sites, 7 millennia

  • Uniform methodology: 24 bio-archaeologists, 6 historians

Fertility: the regulator of demographic dynamics in the Ancient Americas


Subject the human skeleton microdata source for studying health nutrition and demographic dynamics l.jpg
Subject: paleodemography of the Americas over the millennia.The human skeleton.Microdata:source for studying health, nutrition and demographic dynamics

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Outline, 45 slides: paleodemography of the Americas over the millennia.

  • 1. (10) Bioarcheological evidence on paleopathologies and height: Ancient America was no paradise

  • 2. (15) Paleodemography: new method

  • 3. (20) New findings: demographic dynamics for 3 periods:Ancient (7000 – 1500 BP)Classic (1500 – 500 BP)Historical (500 – 100 BP)

Fertility: the regulator of demographic dynamics in the Ancient Americas


Blame columbus title of a new york times review of book but not a concern of the book itself l.jpg
Blame Columbus? paleodemography of the Americas over the millennia.(Title of a New York Times review of book, but not a concern of the book itself)

  • 1. Bioarcheological evidence on paleopathologies and height: Ancient America was no paradise

  • 2. Paleodemography: new method

  • 3. Demographic dynamics for 3 periods:Ancient (7000 – 1500 BP)Classic (1500 – 500 BP)Historical (500 – 100 BP)

Fertility: the regulator of demographic dynamics in the Ancient Americas


4 measures of health and nutrition l.jpg
4 measures of health and nutrition paleodemography of the Americas over the millennia.

  • Porotic hyperostosis

  • Degenerative joint disease (limbs, spine)

  • Dental disease

  • Stature

Fertility: the regulator of demographic dynamics in the Ancient Americas


Hard times in ancient americas l.jpg
Hard Times in Ancient Americas paleodemography of the Americas over the millennia.

  • Skeletal archaeology shows porotic hyperostosis as nearly universal —perhaps due to extreme dependence on corn.

Fertility: the regulator of demographic dynamics in the Ancient Americas


Porotic hyperostosis a physiological adaptation to inadequate absorption of oxygen l.jpg
Porotic Hyperostosis: paleodemography of the Americas over the millennia.a physiological adaptation to inadequate absorption of oxygen

  • High frequency: 1/3 – 1/12 of adults in these communities show signs of extraordinary bone remodeling.

  • Worsened over time: as the transition to sedentary agriculture proceeded (1-3,000 BP), physiological conditions deteriorated.

  • No gendered difference: “A near complete absence of sex differentials in pathologies is surprising.”

Fertility: the regulator of demographic dynamics in the Ancient Americas


Degenerative joint disease djd l.jpg
Degenerative joint disease (DJD) paleodemography of the Americas over the millennia.

  • DJD: 10-20% of adults of both sexes.

  • From age 20, hard, repetitive work exacted severe wear on both sexes, particularly of joints required for mobility, manipulation of objects, and carrying loads.

  • Genderdifferences:statisticallysignificantin DJD andcranialfractures.

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Degenerative joint disease, paleodemography of the Americas over the millennia.spine:picture worsens

  • Generally high levels ranging from 25 to 83% for adults from the Mesoamerican sites—a ubiquitous affliction, principally due to hard labor.

  • “Where the means of carrying heavy burdens is almost solely the human body, an enormous biological cost is exacted from the organism.”

Fertility: the regulator of demographic dynamics in the Ancient Americas


Shovel shaped incisors genetic trait of native americans l.jpg
Shovel shaped incisors: paleodemography of the Americas over the millennia.genetictrait of Native Americans

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Severe dental disease was common in societies based on corn paleodemography of the Americas over the millennia.

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Stature, 3 features stand out: paleodemography of the Americas over the millennia.

  • 1. Males decline over time in mean height: 1 cm. per thousand years--due to worsening nutrition?

  • 2. Female stature constant over time even from pre-historic period.

  • 3. Males show decreasing stature from north (164 cm) to south (161 cm).

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Male stature declines over time: confirmed in Center and South

North =165 cm “no” decline

South =161 cm much decline

Center=162 cm some decline

All =162 cm accelerating decline

Fertility: the regulator of demographic dynamics in the Ancient Americas


Male stature gradient s 15 to n 30 greatest in modern times 1900 1960 l.jpg
Male stature gradient S. (15°) to N. (30°): Southgreatest in modern times (1900-1960)

3200-1800 BP =164 cm b=-.25, r2=.12

1800-1200 BP =162 cm b=.50, r2=.36

1200-500 BP=163 cm b=.36, r2=.47

100-40 BP =159 cm b=.78, r2=.74

Females (<150 cm) little variation in space or time.

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Blame…? South

  • 1. Bioarcheological evidence on paleopathologies and height: Ancient America was no paradise

  • 2. Paleodemography: new method

  • 3. Demographic dynamics for 3 periods:Ancient (7000 – 1500 BP)Classic (1500 – 500 BP)Historical (500 – 100 BP)

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Paleodemography SouthMaterials:skeletons by estimated age at deathMethods:fit estimated age distributionto stable models

Fertility: the regulator of demographic dynamics in the Ancient Americas


A quick lesson in model life tables of stable populations l.jpg
A quick lesson in model life tables (of stable populations) South

  • Stable populations:

    • regardless of initial conditions

    • populations subjected to constant birth and death rates

    • will evolve to stable age and death structures, that is:

  • % population aged 0, 1, 2, … will be the same year-after-year as long as birth & death rates are stable

  • % of deaths aged 0, 1, 2, … will be the same year-after-year …

Fertility: the regulator of demographic dynamics in the Ancient Americas


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So, for the paleodemographer… South

  • If ancient populations were stable

  • If the recovered skeletons are representative of the dying population

  • And if the age at death of the skeletons can be estimated…

  • Then, we match observed skeletal age distribution with those of stable populations to derive:

    • Birth and death rates

    • Life expectancy, …even age structure

Fertility: the regulator of demographic dynamics in the Ancient Americas


How exactly do we do this 2 steps 1 materials age distribution of skeletons l.jpg
How exactly do we do this? South2 steps: 1. Materials: Age distribution of skeletons

Age

0

5

10

15

20

25

30

35

40

45+

Deaths (n)

239

31

12

4

22

11

21

36

31

116

%

45.7

5.9

2.3

0.8

4.2

2.1

4.0

6.9

5.9

22.1

Cum %

45.7

51.6

53.9

54.7

58.9

61.0

65.0

71.9

77.8

100.0

  • Example, Belleville, Ontario. 19th century white population—well preserved

Fertility: the regulator of demographic dynamics in the Ancient Americas


How exactly do we do this 2 steps 2 models life tables l.jpg
How exactly do we do this? South2 steps: 2. Models: life tables

  • Coale & Demeny 1983

  • 25 e0s: 20-80 years, at 2.5 year intervals

  • 13 GRRs: 1 – 6 girls, at various intervals

  • 4 Regions: North, South, East, West

  • Total: 25x13x4=1300

Fertility: the regulator of demographic dynamics in the Ancient Americas


Model west females level 2 grrs 0 8 6 e 0 22 5 years l.jpg

% Population at age South

Model West Females level 2,GRRs 0.8 – 6e0 = 22.5 years

Cummulative %

  • Statistics:

    • Population at/to age

% deaths at age

  • Deaths at/to age

  • 18 stats for each GRR (see separate pages for other e0s and regions)

Cummulative %

Other stats

Fertility: the regulator of demographic dynamics in the Ancient Americas


Slide23 l.jpg

e South0=22.5

e0=52.5

or mortality (between sheets)?

Question: Are age structures of dying determined by fertility (within a sheet) or mortality (between sheets)?

Between (mortality)?

Fertility: the regulator of demographic dynamics in the Ancient Americas

Answer: contrary to common sense, fertility!!!


Slide24 l.jpg

Fertility effects are big South

GRR =2, 3, 4, 5, 6; e0 = 20

Fertility: the regulator of demographic dynamics in the Ancient Americas


Fig 2 mortality offers a small target l.jpg

Mortality effects are small Southexcept at young (< 15) and old ages (60+)

Fig. 2. Mortality offers a small target

GRR = 3; e0 = 20, 30, 40, 50

Fertility: the regulator of demographic dynamics in the Ancient Americas


Slide26 l.jpg

GRR = 2, 3, 4, 5, 6 Southe0=20

GRR = 3e0=20, 30, 40, 50

GRR = 2, 3, 4, 5, 6e0=50

GRR = 4e0=20, 30, 40, 50

Fertility: the regulator of demographic dynamics in the Ancient Americas


Three recent advances in paleodemography l.jpg
Three recent advances in paleodemography: South

  • Fertility has stronger effects on age distributions than mortality.

  • Proportional hazard models are more robust than simple percentages.

  • Fitting observed skeletal distributions to stable populations yield valuable demographic insights.

Fertility: the regulator of demographic dynamics in the Ancient Americas


Four innovations here l.jpg
Four innovations here South

  • Use only “best” age data: ages 5-45

  • Fit all possible models:GRR (gross reproduction ratio) = 2-6 daughterse0(life expectancy at birth) = 20-50 years

  • Consider range of good fits, instead of only “best fit”—all “pretty good” fits

  • Calibrate paleodemographic results against historical demography—see next figure

Fertility: the regulator of demographic dynamics in the Ancient Americas


Calibrating method skeletal data for 19 th century belleville ontario l.jpg

Calibrating method: skeletal data for 19 Southth century Belleville, Ontario

Fertility: the regulator of demographic dynamics in the Ancient Americas



Calibration of life expectancy e 0 belleville l.jpg
Calibration of life expectancy, e Ancient Americas0 (Belleville)*

  • Conventional paleodemography: 20.8 years (MAD, “mean age at death”)

  • PH models, using best age data, pretty good fits, GRR = 3.16, growth rate = 2%:36 years (see table 4.1)

  • Historical data (parish books, census)36.5 years

*thanks to an anonymous reviewer for the idea of calibrating the method using Belleville.

Fertility: the regulator of demographic dynamics in the Ancient Americas


Blame32 l.jpg
Blame…? Ancient Americas

  • 1. Bioarcheological evidence on paleopathologies and height: Ancient America was no paradise

  • 2. Paleodemography: new method

  • 3. Demographic dynamics for 3 periods:Ancient (7000 – 1500 BP)Classic (1500 – 500 BP)Historical (1500 AD – 1900)

Fertility: the regulator of demographic dynamics in the Ancient Americas


Slide33 l.jpg

Paleodemography: new methods, surprising results: Fertility, the key

  • Fertility: an important regulator of American demographic dynamics

  • Lowest fertility: ancient times (1500+ BP), GRR=~2.2

  • Higher fertility: middle period (1500BP –1500AD), GRR=~2.9

  • Highest fertility: domesticated animals (horse, Plains Indians, 1500 AD-1900), GRR=3.2

    • Last five hundred years: large ethnic differentials, GRRNative Americans: 2.8-2.9African Americans: 3.1-3.3European Americans: 2.4-2.6

Fertility: the regulator of demographic dynamics in the Ancient Americas





Slide37 l.jpg

Paleodemography: new methods, surprising results: Mortality (pooled)

  • Life expectancy estimates, e0: contingent upon a good estimate of growth rate

  • Highest e0: ancient times (1500+ BP), ~34 years

  • Lowest e0: middle period (1500-500), ~23 years

  • Modern: large ethnic differentials in e0Native Americans: e0=~ 22-23 yearsAfrican Americans: e0=~ 21-29 yearsEuropean Americans: e0=~ 30-36 years

Fertility: the regulator of demographic dynamics in the Ancient Americas


Three conclusions l.jpg
Three conclusions Mortality (pooled)

  • Great variations in fertility

    • Ancient times,

      • low pressure demographic regime:

      • fertility was a brake on population growth

    • Classic times,

      • high pressure demographic system:

      • higher fertility, low life expectancy

      • mortality was the brake on pop. growth

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Three conclusions Mortality (pooled)

2. Agriculture was the “caboose” of demographic change, not the “engine”

  • Agriculture seems to have evolved as a response to demographic pressure

  • Rather than propelling demographic transformations.

  • Why? Because in classic times demographic transformations occurred in all settlement types.

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Three conclusions Mortality (pooled)

3. Modern period: fundamental demography of native peoples did not change with the clash of biospheres

  • Paleodemographic method is insensitive to demographic catastrophe—unless a mass grave is found

  • Underlying fundamentals persisted for almost a thousand years (til 1800)

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Postscript: Blame Colombus? Mortality (pooled)

  • Demographic catastrophe was real—the debate is about magnitude and cause(s)

  • Magnitude: extinction for many smaller populations (e.g, Tainos); 1/3-3/4 loss for larger populations (Aztecs).

  • Cause(s): the great debate—disease? War/pacification/exploitation? Both?

  • Varied place-to-place: Hispaniola: exploitation, not disease…

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Blame Colombus? Mortality (pooled)Hispaniola, certainly!!

Case of Hispaniola, see:

Bartolome de Las Casas, Brief Account of the Destruction of the Indies (1596), or

Massimo Livi-Bacci, “Return to Hispaniola”, February 2003, Hispanic American Historical Review

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Blame Colombus? Mortality (pooled)Hispaniola, certainly!!

Disease?:

  • First smallpox epidemic, 1518 (25 years after contact, colonization).

  • Evidence of other introduced diseases in first decades is scant (non-existent?).

  • Malaria and Yellow fever (cited by Wilford, NYT): 17th- 18th centuries

Fertility: the regulator of demographic dynamics in the Ancient Americas


Blame colombus hispaniola certainly44 l.jpg
Blame Colombus? Mortality (pooled)Hispaniola, certainly!!

Exploitation?:

ML-B: “tribute imposed by Colon at the end of 1495 to the caciques of the ‘pacified’ Tainos: every native of 14 years or more was required to pay every three months one Flanders hawk’s bell full of gold…”

Fertility: the regulator of demographic dynamics in the Ancient Americas


Blame colombus hispaniola certainly45 l.jpg
Blame Colombus? Mortality (pooled)Hispaniola, certainly!!

Exploitation?:

  • Fragile communities—”congregated”

  • Little agricultural surplus

  • All “work” devoted to food production

  • Unaccustomed to forced labor for building, gold mining.

  • Insatiable demand by Christians for gold, slaves, servants, … sex

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Demographic catastrophe and its causes: viruses, Black Legend and the social context of epidemics (Mexico)

Alonso de Zorita (~1565): “...and it is certain that from the day that D. Hernando Cortes, the Marquis del Valle, entered this land...the natives suffered many deaths, and many terrible dealings, robberies and oppressions were inflicted on them, taking advantage of their persons and their lands, without order, weight nor measure; ...the people diminished in great number, as much due to excessive taxes and mistreatment, as to illness and smallpox, such that now a very great and notable fraction of the people are gone, and especially in the hot country.”

Fertility: the regulator of demographic dynamics in the Ancient Americas


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Blame Colombus…?? Legend and the social context of epidemics (Mexico)The debate continues…

see next issues of Revista de Indias and Hispanic American Historical Review

Fertility: the regulator of demographic dynamics in the Ancient Americas


Thank you paper posted www hist umn edu rmccaa paleodem doc l.jpg
Thank you Legend and the social context of epidemics (Mexico)* * * * * *paper posted:www.hist.umn.edu/~rmccaa/paleodem.doc

others:Health & nutrition: /mxbioarc.docAztec household & family: /nacolhist.htmSmallpox & catastrophe: /vircatas/vir6.htm

Fertility: the regulator of demographic dynamics in the Ancient Americas


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