Biology Reference
In-Depth Information
BOX 6.5
REVISED FULLY EQUATIONS AFTER
RAXTER ET AL. (2006)
Revised Fully equation including age:
living stature
Revised Fully equation excluding age:
living stature
¼
1.009
skeletal height
e
¼
0.996
skeletal height
þ
0.0426
age
þ
12.1 (for soft tissue)
11.7 (for soft tissue)
(r
(r
¼
0.956, SEE
¼
2.22)
¼
0.952, SEE
¼
2.31)
Secular Change
Secular (or temporal) changes in stature from one generation to the next are caused by
a combination of the environment, genetics, and evolutionary forces (
Trotter and Gleser,
1951b
). Secular trends are relevant for a number of biological traits in addition to stature,
such as growth/maturity rates and morphology. For example, an increase/decrease in nutri-
tion, exposure to infectious diseases, and access to medical care can all cause secular change
from one generation to the next. See McKeown and Schmidt (Chapter 12), this volume, for
further discussion of secular change.
Trotter and Gleser (1951b)
were the first to recognize
secular changes in stature from the Terry and military collections using both bone lengths
and reported stature (
Trotter and Gleser, 1951b
). The goal of their study was to detect irreg-
ular and cyclical patterns in stature across generations. They observed no secular trend from
1840 to 1895. A slight increase in stature occurred in African Americans between 1895 and
1905 and then a significant positive trend overall in the twentieth century. The results sug-
gested that stature increase was not constant, but fluctuated from one decade to the next.
Not all of the changes are positive; there can be small jumps with plateaus and small reduc-
tions (
Trotter and Gleser, 1951b
).
A comparable study by
Meadows and Jantz (1995)
used the Huntington Collection,
11
Terry Collection, and data from WWII casualties along with the Forensic Databank. They
regressed long bone length on year-of-birth to show
allometric secular change
. This study
found that secular change was greater in males, that the lower limb showed greater change
than the upper limb, and that the distal elements are affected more than the proximal
(
Meadows and Jantz, 1995
). All of the groups sampled exhibited an increase in femur length
over time. These allometric secular changes are strongly dependent on environmental forces,
showing that different bones respond more strongly to the environmental factors to reach
genetic potential.
Meadows and Jantz (1995)
suggested that females were more resistant to
environmental changes than were males (
Meadows and Jantz, 1995
). Other studies have
shown that females are thought to be buffered in some way against environmental stressors
due to their biological need to support pregnancy and lactation (
Stini 1975
, 1982;
Ross et al.
2003; Bogin, 1988
).
11
The George Huntington Collection is curated by the National Museum of Natural History at the
Smithsonian Institution, Washington, D.C.
