Helen Kurki

Helen Kurki
Position
Associate Professor
Anthropology
Credentials

PhD Toronto

Contact
Office: COR B211A

Accepting both MA and PhD students for Fall 2020.

My research interests centre on morphological variation in recent humans and the mechanisms that have produced it, as a means of understanding the processes of hominin evolution in general. I am particularly interested in the biological adaptations of hunter-gatherers to their environment from a biocultural perspective.

My main approach to this research is through analysis of functional anatomy and skeletal biology in humans. A major focus of my current research is the examination of adaptation to small body size among human populations. This research explores several aspects of the morphology of small-bodied human populations through analysis of skeletal remains of past populations, including ecogeographic patterning of body proportions, body size reconstruction, and pelvic obstetric capacity in relation to body size and shape.

In particular, this research seeks to understand what selective pressures may act to create small-body size as an adaptation in human populations, versus the common assumption that small body size in humans reflects nutritional or health deficiencies. While the small-bodied Later Stone Age foragers from southern Africa have been the major focus of this research to date, ongoing research activities are expanding the populations represented.

Interests

  • Biological anthropology
  • Skeletal biology
  • Hominin functional anatomy

Courses

Fall 2019

  • ANTH 150 HOW TO MAKE A HUMAN New Course
  • ANTH 317 QUANTITATIVE METHODS IN ANTHROPOLOGICAL RESEARCH

Spring 2020

  • ANTH 552A METHOD AND THEORY IN BIOARCHAEOLOGY
  • ANTH 651/551 ADVANCE RESEARCH SEMINAR IN ECOLOGY AND EVOLUTION

Summer 2020

  • Not teaching

 

Current projects

Examining plastic adaptive responses in the generation of human skeletal variation

Evolutionary models for skeletal morphology often apply “form follows function” explanations, focusing on the selective context of adult morphology. But, adult skeletal form is the product of the processes of growth and development, which are themselves subject to selection, and to environmental influences. Due to biological plasticity, human skeletal variation reflects, in part, differences in environmental (climate, terrain), ecological (resource availability, disease load), and lifestyle (diet, activity, technology) contexts. Challenging environments, with nutritional or dietary limitation, high activity budgets, or high parasitic or infectious disease loads lead to restricted skeletal growth, often leaving signatures in bone and dental tissues preserving evidence of these developmental stressors. Habitual activities load bones through body weight and muscle action and alter bone tissue distribution in the shafts of limb bones. As such, skeletal morphology can offer insights on evolutionary processes shaping our species, and factors affecting populations and individuals. But given the plasticity of skeletal tissue, these may not be the only ways in which these processes influence skeletal morphology during development. Joint regions of bones are thought to be tightly controlled during development by genetic factors and less responsive to the environment, suggesting their form should be more stable. Yet, ankle orientation varies in relation to substrate use, and the vertebral canal varies with stress. Plasticity exists in these regions. This research uses 3D geometric morphometric approaches to examine the size and shape characteristics of bones of the limbs and vertebrae in archaeologically derived human skeletal samples in relation to traditional skeletal indicators of developmental stress and habitual activity, to elucidate whether and how stress and activity during ontogeny can influence morphology. Anthropologists assume the morphology of extinct hominins largely reflects their evolutionary history as a product of normal growth, rather than plastic responses to environmental stressors. But in order to decipher the meaning of morphological variation in the fossil record we must understanding how plastic adaptive responses generate skeletal morphology. This is also important for bioarchaeologists, who employ outcomes of growth processes as indicators of population health through time in response to demographic and ecological changes. This research represents a novel approach to examining the influence of environment and activity in producing skeletal variation in humans. Understanding the interplay between plasticity and constraint (evolutionary, functional, developmental) in the generation of morphological variation in a species aids in identifying factors (environmental, ecological, lifestyle) that influence adaptation, which are of particular importance to evolutionary anthropologists, paleoanthropologists, and evolutionary anatomists.

 

This NSERC-funded project continues my collaboration with Dr. Lesley Harrington (University of Alberta).

 

Human skeletal variation: Adaptive responses during growth of the bony pelvis

Evolutionary explanations of the difficulty and risk to the mother and newborn associated with human childbirth have focused on the close fit between the size of the maternal pelvis and the size of the newborn as resulting from our distinctive method of walking on two legs and our large brains. This “obstetric dilemma” views female pelvic form as a compromise between the mechanical requirements of bipedalism for a narrow pelvis and the obstetric requirements for a roomy pelvic canal for our large-brained babies, resulting in strong selective pressures acting on the female pelvis among humans and over our evolutionary history. Physical variation within a population or species can be limited by such competing selective processes (as predicted by the obstetric dilemma hypothesis), yet morphology is also influenced by environmental stimuli acting during growth and development, through biological plasticity. For the pelvis these stimuli may include gait, activity levels and technological means of mitigating activity, diet, and health. Plastic responses generate variation among individuals and populations in anatomy and physiology. Hence, the cultural production of the human skeleton provides bioarchaeologists a window on the activities and adaptations of past populations. However, my research on adult skeletons has shown significant variation among and within human populations in pelvic canal shape and capacity. Further, historical preconceptions of an “obstetric dilemma” may actually be the result of differential plasticity between the maternal pelvis and newborn size in changing cultural environments. Under this model, human ecological and cultural changes may play a particular role in determining pelvic form.

I am collaborating on this NSERC-funded research project with Dr. Lesley Harrington (University of Alberta) examining the potential role of biological plasticity in shaping the bones of the human pelvis during growth. Human skeletal remains of juveniles from varied and well-documented archaeological contexts provide an opportunity to study factors influencing growth and development in specific ecological (e.g., subsistence, technologies, and geographical location) contexts. In order to understand the potential role of biological plasticity in shaping the maternal pelvis, we ask: when and why does variation in pelvic forms arise, and what role does biological plasticity play in generating variation in relation to environmental stimuli? This study utilizes three-dimensional (3D) approaches to studying the form of juvenile and adult human pelvic bones from diverse skeletal samples to investigate the relationships among ecological and cultural attributes of populations and pelvic growth and development.

The influence of body size and climate on the size and shape of the human bony pelvis

This research, funded by the Social Sciences and Humanities Research Council of Canada (standard research grant 410-2008-2344) examines the variation in human pelvic capacity and the factors that contribute to the determination of size and shape of the pelvis, particularly as they relate to body size and obstetric capacity in women.

It applies current methodological and theoretical approaches to the analysis of skeletal remains of adults from populations derived from different climatic regions, body sizes and body proportions. The purpose is to test the hypothesis that just as overall body size and body proportions (e.g. stature, body mass, body breadth, and limb proportions) vary among human populations, so too do the relative size and shape of the bony pelvis vary among populations.

This variation in pelvic geometry reflects adaptation to the competing requirements of bipedal locomotion for a narrow pelvis and of obstetrics for a roomier pelvis. Further, it is known that a relationship exists between body size and pelvic size in human populations such that larger/taller women in a given population have absolutely larger pelves in certain key dimensions relating to obstetric capacity than do smaller women.

The question is whether these relationships between body size and pelvic capacity are similar in populations of differing body sizes and body proportions. This research seeks to understand how selection for obstetric adequacy, via natural selection, acts to diminish the risk to women in childbirth and contributes to morphological variation and sexual dimorphism in humans.

In a broader context, this research questions the traditional view in clinical obstetrics whereby women of short stature are preemptively deemed to be at risk for problem childbirth regardless of their ancestral (i.e. population) affinity.

Selected publications

Books

  • Forthcoming – C. Wall-Scheffler, H. Kurki & B. Auerbach. The Evolutionary Biology of the Human Pelvis: An Integrative Approach. Cambridge Studies in Biological and Evolutionary Biology. Cambridge University Press. Link

Articles and chapters

  • 2020 – A. Nowell & H. Kurki. Moving Beyond the Obstetrical Dilemma Hypothesis: Birth, Weaning an Infant Care in the Plio-Pleistocene. In, R. Gowland & S. Halcrow (editors): The Mother-Infant Nexus in Anthropology: Small Beginnings, Significant Outcomes. Springer. Link
  • 2017 – H. Kurki. Bilateral asymmetry in the human pelvis. Anatomical Record 300: 653-665. DOI: 10.1002/ar23546
  • 2016 – H. Kurki & S-L. Decrausaz. Shape variation in the human pelvis and limb skeleton: Implications for obstetric adaptation. American Journal of Physical Anthropology 159:630-638. DOI: 10.1002/ajpa.22922
  • 2015 - M. Elliott, H. Kurki, D.A. Weston, & M. Collard. Estimating body mass from skeletal material: new predictive equations and methodological insights from analyses of a known-mass sample of humans. Archaeological and Anthropological Sciences. doi: 10.​1007/​s12520-015-0252-5
  • 2015 - M. Elliott, H. Kurki, D.A. Weston, & M. Collard. Estimating body mass from postcranial variables: an evaluation of current equations using a large known-mass sample of modern humans. Archaeological and Anthropological Sciences. doi: 10.​1007/​s12520-015-0251-6
  • 2014 – (M. Elliott, H. Kurki, D.A. Weston, & M. Collard) Estimating fossil hominin body mass from cranial variables: An assessment using CT data from modern humans of known body mass. American Journal of Physical Anthropology 154:201-214. DOI: 10.1002/ajpa.22493
  • 2014 – (S. Pfeiffer, L.E. Doyle, H. Kurki, L. Harrington, J.K. Ginter, & C.E. Merritt) Discernment of mortality risk associated with childbirth in archaeologically derived forager skeletons. International Journal of Paleopathology. 7:15-24. DOI: 10.1016/j.ijpp.2014.05.005
  • 2013 - Skeletal variability in the pelvis and limb skeleton of humans: Does stabilizing selection limit female pelvic variation? American Journal of Human Biology. 25: 795-802. DOI: 10.1002/ajhb.22455
  • 2013 - Bony pelvic canal size and shape in relation to body proportionality in humans. American Journal of Physical Anthropology 151:88-101 DOI: 10.1002/ajpa.22243
  • 2012 – (H. Kurki, S. Pfeiffer, & D. Stynder) Allometry of Head and Body Size in Holocene Foragers of the South African Cape. American Journal of Physical Anthropology 147:462-471 DOI 10.1002/ajpa22024.
  • 2011 – Pelvic Dimorphism in Relation to Body Size Dimorphism in Humans. Journal of Human Evolution 61:631-643 DOI 10.1016/j.jhevol.2011.07.006
  • 2011 – Compromised Skeletal Growth? Small Body Size and Clinical Contraction Thresholds for the Female Pelvic Canal. International Journal of Paleopathology DOI 10.1016/j/ijpp.2011.10.004.
  • 2010 - (H. Kurki, J. Ginter, J. Stock & S. Pfeiffer S. Body Size Estimation of Small-Bodied Humans: Applicability of Current Methods. American Journal of Physical Anthropology 141:169-180 DOI 10.1002/ajpa.21127
  • 2008 - (H. Kurki, J Ginter, J. Stock & S. Pfeiffer). Adult Proportionality in Small-Bodied Foragers: A test of Ecogeographic Expectations. American Journal of Physical Anthropology 136:28-38 DOI 10.1002/ajpa.20774
  • 2007 - Protection of Obstetric Dimensions in a Small-Bodied Human Sample. American Journal of Physical Anthropology. 133:1152-1165 DOI 10.1002/ajpa.20636
  • 2005 - Use of the First Rib for Adult Age Estimation: A Test of One Method. International Journal of Osteoarchaeology 15:342-350 DOI 10.1002/oa.788