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Modern humans are not (quite) isometric
Adam D Sylvester1, Patricia A Kramer, William L Jungers
1Department of Mechanical, Aerospace and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996, USA. asylves4@jhmi.edu
American Journal of Physical Anthropology
|July 10, 2008
Summary
Modern humans exhibit minor deviations from geometric similarity, meaning shape slightly changes with body size. This study analyzed long bone lengths to formally test this principle in human populations.
Area of Science:
- Anthropology
- Human Biology
- Biomechanics
Background:
- Allometric relationships are crucial in biological and anthropological research.
- Isometry, or geometric similarity, assumes shape remains constant regardless of size.
- Understanding human morphological variation requires testing deviations from isometry.
Purpose of the Study:
- To formally assess geometric similarity in modern humans.
- To investigate allometric relationships in human long bone lengths.
- To determine if human shape scales isometrically with size.
Main Methods:
- Analysis of maximum lengths of four long bones: humerus, radius, femur, and tibia.
- Application of Jolicoeur's multivariate allometry method.
- Examination of globally distributed human population samples.
Main Results:
- Modern humans do not exhibit perfect geometric similarity.
- Morphological deviations from isometry were found to be small.
- Analysis considered both collective and individual population data.
Conclusions:
- Human skeletal proportions show slight, but measurable, variations with size.
- The findings contribute to a nuanced understanding of human biological diversity.
- Further research can explore the implications of these minor deviations in various contexts.
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