Helen Kurki

Helen Kurki
Position
Associate Professor
Anthropology
Credentials

PhD Toronto

Contact
Office: COR B211A

Accepting both MA and PhD students for Fall 2020.

I am a biological anthropologist whose research centers on morphological variation in recent humans and the evolutionary, cultural, and developmental mechanisms that have produced it, as a means of understanding the processes of hominin evolution and adaptability in general. My main approach to this research is through analysis of functional anatomy and skeletal biology in humans, using both traditional osteological methods and 3D modeling of the skeleton.

Interests

  • Biological anthropology
  • Skeletal biology
  • Hominin functional anatomy

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.

Selected publications

Books

  • 2020 – 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

  • 2018 - S.E. Calce, H. Kurki, D.A. Weston & L. Gould. The relationship of age, activity, and body size on osteoarthritis in weight-bearing skeletal regions. International Journal of Paleopathology. 22: 45-53. DOI: 10.1016/j.ijpp.2018.04.001 

  • 2018 - S.E. Calce, H. Kurki, D.A. Weston & L. Gould. Effects of osteoarthritis on age-at-death estimates from the human pelvis. American Journal of Physical Anthropology. 167: 3-19. DOI: 10.1002/ajpa.23595