Periodic Reporting for period 1 - TRAUMOBITA (The role of traumatic mortality in late human evolution from an integrated non-invasive bioarchaeological and taphonomic perspective)
Période du rapport: 2021-03-01 au 2023-02-28
How the way we die affects our evolution?
Mortality is a major influence in evolution and ecology, and the timing and causes of death can drive many aspects of adaptation. In prehistoric hunter-gather societies the relation between resource availability and disease has been a major mortality parameter. However, there is increasing evidence that traumatic causes of death such as predation, accidents, and inter- and intra-specific violence, play a significant role in demography and adaptive response during our evolution. Did the way we died influenced our evolution? Answering to this question would represent a major advance in the understanding of how we are the way we are.
The project The role of traumatic mortality in late human evolution from an integrated non-invasive bioarchaeological and taphonomic perspective has been focused on the study of how different types of mortality have affected human evolution. In this sense, TRAUMOBITA aimed to answer why and how humans died in the past, and if the way we died influenced our behaviour. To do so, the project analysed more than 4,000 human bones from Turkana (Kenya) in East Africa, a place known as the cradle of humanity. By conducting non-destructive techniques the project searched microscopically and microscopically for modifications among the skeletal remains dated as far as 50,000 years ago and aimed to build a useful methodology for the analysis of human bones.
Mortality is a major influence in evolution and ecology, and the timing and causes of death can drive many aspects of adaptation. In prehistoric hunter-gather societies the relation between resource availability and disease has been a major mortality parameter. However, there is increasing evidence that traumatic causes of death such as predation, accidents, and inter- and intra-specific violence, play a significant role in demography and adaptive response during our evolution. Did the way we died influenced our evolution? Answering to this question would represent a major advance in the understanding of how we are the way we are.
The project The role of traumatic mortality in late human evolution from an integrated non-invasive bioarchaeological and taphonomic perspective has been focused on the study of how different types of mortality have affected human evolution. In this sense, TRAUMOBITA aimed to answer why and how humans died in the past, and if the way we died influenced our behaviour. To do so, the project analysed more than 4,000 human bones from Turkana (Kenya) in East Africa, a place known as the cradle of humanity. By conducting non-destructive techniques the project searched microscopically and microscopically for modifications among the skeletal remains dated as far as 50,000 years ago and aimed to build a useful methodology for the analysis of human bones.
New methods: Combining Archaeology and forensic science
Innovative techniques such as digital 3D microscopes or experimentations with synthetic bones aided in the recovery of key information to reconstruct our past by combining the archaeology and forensic sciences. Bones where analysed microscopically using digital devices than can create virtual models of the most tiny modification present on the skeletal surface, from a cutmark to a bite mark. Then, to diagnose such marks we conducted experiments with polyurethane replicas with the aim of comparing past and present modifications. This aided for example in the understanding of the biomechanics of any fracture present on the bones. Fore instance, we found a human skull 5,000 years old with fractures that may have been the result of a fight, an interpersonal violent event. To secure our diagnose we recreated traumatic lesions on a plastic sphere that is used by the scientific police with many different weapons available during prehistory. Now the case is clear: A righthanded individual this 20-30 years man on the left side of his head with a blunt object and died in the place were we found it thousand years later. Case by case, we reconstructed how people died in the past.
The results obtained showed that both experimentation and a close look to the bone surfaces can tell details of the life history of the people that lived during prehistory; arrow lesions, smashed skulls, old healed fractures and many other conditions that revealed aspects related to past behaviour and health conditions. Actually, the project discovered thank to the methodology applied that in addition to accidents, predation and violence many pathologies where present, including cancer. But a microscopic perspective also revealed that time, through postdepositional processes, also erase many proofs written on the bones that would have been very useful for archaeologist. All this puzzle is called taphonomy, and TRAUMOBITA has been dealing with it.
Innovative techniques such as digital 3D microscopes or experimentations with synthetic bones aided in the recovery of key information to reconstruct our past by combining the archaeology and forensic sciences. Bones where analysed microscopically using digital devices than can create virtual models of the most tiny modification present on the skeletal surface, from a cutmark to a bite mark. Then, to diagnose such marks we conducted experiments with polyurethane replicas with the aim of comparing past and present modifications. This aided for example in the understanding of the biomechanics of any fracture present on the bones. Fore instance, we found a human skull 5,000 years old with fractures that may have been the result of a fight, an interpersonal violent event. To secure our diagnose we recreated traumatic lesions on a plastic sphere that is used by the scientific police with many different weapons available during prehistory. Now the case is clear: A righthanded individual this 20-30 years man on the left side of his head with a blunt object and died in the place were we found it thousand years later. Case by case, we reconstructed how people died in the past.
The results obtained showed that both experimentation and a close look to the bone surfaces can tell details of the life history of the people that lived during prehistory; arrow lesions, smashed skulls, old healed fractures and many other conditions that revealed aspects related to past behaviour and health conditions. Actually, the project discovered thank to the methodology applied that in addition to accidents, predation and violence many pathologies where present, including cancer. But a microscopic perspective also revealed that time, through postdepositional processes, also erase many proofs written on the bones that would have been very useful for archaeologist. All this puzzle is called taphonomy, and TRAUMOBITA has been dealing with it.
Is traumatic mortality a major force in evolution?
The project hypothesised at the start of the research that traumatic mortality has been a major force in late human evolution. After TRAUMOBITA, we have a more detailed image of how this type of mortality affected late human evolution. The lack of resources due to climatic changes and social competition, may have influenced an increase of inter- and intra-personal violence, for instance. However, the project also obtained unpredicted results. Beyond traumatic lesions, skeletal remains display a wide range of pathological conditions including neoplastic and infectious diseases. In a higher rate than previously thought.
The methodological advancement that the project conducted, by combining taphonomic analysis, forensic sciences, experimentation and virtual microscopic techniques, has been essential to reach such conclusions. Conclusions that can help also understand how the gender role has changed through time. It seems that in late evolutionary stages of human history (ie Holocene, 12,000 years ago) there is no difference among traumatic mortality between males and females in Turkana region, which is interesting in terms of comparison with later historic periods and other geographic areas.
In sum, the project results have contributed to the advancement in the state of the art concerning the study of human evolution, and provided a methodological innovations for the analysis of skeletal remains. Interestingly, the project found that specific diseases were not recognised before, and might have been also a major evolutionary force among others. In this sense, TRAUMOBITA contributed opening generating new questions. How pathologies in a broad sense influence our late human evolution in Eastern Africa? We still have more questions than answer, however all the project’s outputs are key to the theoretical and methodological advancement of human evolution.
The project hypothesised at the start of the research that traumatic mortality has been a major force in late human evolution. After TRAUMOBITA, we have a more detailed image of how this type of mortality affected late human evolution. The lack of resources due to climatic changes and social competition, may have influenced an increase of inter- and intra-personal violence, for instance. However, the project also obtained unpredicted results. Beyond traumatic lesions, skeletal remains display a wide range of pathological conditions including neoplastic and infectious diseases. In a higher rate than previously thought.
The methodological advancement that the project conducted, by combining taphonomic analysis, forensic sciences, experimentation and virtual microscopic techniques, has been essential to reach such conclusions. Conclusions that can help also understand how the gender role has changed through time. It seems that in late evolutionary stages of human history (ie Holocene, 12,000 years ago) there is no difference among traumatic mortality between males and females in Turkana region, which is interesting in terms of comparison with later historic periods and other geographic areas.
In sum, the project results have contributed to the advancement in the state of the art concerning the study of human evolution, and provided a methodological innovations for the analysis of skeletal remains. Interestingly, the project found that specific diseases were not recognised before, and might have been also a major evolutionary force among others. In this sense, TRAUMOBITA contributed opening generating new questions. How pathologies in a broad sense influence our late human evolution in Eastern Africa? We still have more questions than answer, however all the project’s outputs are key to the theoretical and methodological advancement of human evolution.