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Bioarchaeology (osteoarchaeology,
osteology Osteology () is the scientific study of bones, practiced by osteologists . A subdiscipline of anatomy, anthropology, archaeology and paleontology, osteology is the detailed study of the structure of bones, skeletal elements, teeth, microbone mo ...
or palaeo-osteology) in Europe describes the study of biological remains from archaeological sites. In the United States it is the scientific study of human remains from archaeological sites. The term was minted by British archaeologist Grahame Clark who, in 1972, defined it as the study of animal and human bones from archaeological sites. Jane Buikstra came up with the current US definition in 1977. Human remains can inform about health, lifestyle, diet, mortality and physique of the past. Although Clark used it to describe just human remains and animal remains, increasingly archaeologists include botanical remains. Bioarchaeology was largely born from the practices of
New Archaeology Processual archaeology (formerly, the New Archaeology) is a form of archaeological theory. It had its beginnings in 1958 with the work of Gordon Willey and Philip Phillips, ''Method and Theory in American Archaeology,'' in which the pair stated ...
, which developed in the United States in the 1970s as a reaction to a mainly cultural-historical approach to understanding the past. Proponents of New Archaeology advocate testing hypotheses about the interaction between culture and biology, or a biocultural approach. Some archaeologists advocate a more holistic approach that incorporates
critical theory Critical theory is a social, historical, and political school of thought and philosophical perspective which centers on analyzing and challenging systemic power relations in society, arguing that knowledge, truth, and social structures are ...
.


Paleodemography

Paleodemography studies demographic characteristics of past populations. Bioarchaeologists use paleodemography to create
life table In actuarial science and demography, a life table (also called a mortality table or actuarial table) is a table which shows, for each age, the probability that a person of that age will die before their next birthday ("probability of death"). In ...
s, a type of
cohort analysis Cohort analysis is a kind of behavioral analytics that breaks the data in a data set into related groups before analysis. These groups, or cohort (statistics), cohorts, usually share common characteristics or experiences within a defined time-span. ...
, to understand zdemographic characteristics (such as risk of death or
sex ratio A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. However, many species deviate from an even sex ratio, ei ...
) of a given age cohort within a population. It is often necessary to estimate the age and sex of individuals based on specific morphological characteristics of the skeleton.


Age

Age estimation attempts to determine the skeletal/biological age-at-death. The primary assumption is that an individual's skeletal age is closely associated with their chronological age. Age estimation can be based on patterns of growth and development or degenerative changes in the skeleton. A variety of skeletal series methods to assess these types of changes have been developed. For instance, in children age is typically estimated by assessing dental development, ossification and fusion of specific skeletal elements, or long bone length. For children, different teeth erupt from the gums serially are the most reliable for telling a child's age. However, fully developed teeth are less indicative. In adults, degenerative changes to the
pubic symphysis The pubic symphysis (: symphyses) is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attache ...
, the auricular surface of the ilium, the sternal end of the 4th rib, and dental attrition are commonly used to estimate skeletal age. Until the age of about 30, human bones keep growing. Different bones fuse at different points of growth. This development can vary acros individuals. Wear and tear on bones further complicates age estimates. Often, estimates are limited to 'young' (20–35 years), 'middle' (35–50 years), or 'old' (50+ years).


Sex

Differences in male and female skeletal anatomy are used by bioarchaeologists to determine the biological sex of human skeletons. Humans are
sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
, although overlap in body shape and sexual characteristics is possible. Not all skeletons can be assigned a sex, and some may be wrongly identified. Biological males and biological females differ most in the skull and pelvis; bioarchaeologists focus on these body parts, although other body parts can be used. The female pelvis is generally broader than the male pelvis, and the angle between the two inferior pubic rami (the sub-pubic angle) is wider and more U-shaped, while the sub-pubic angle of the male is more V-shaped and less than 90 degrees. In general, the male skeleton is more robust than the female skeleton because of male's greater muscles mass. Male skeletons generally have more pronounced
brow ridge The brow ridge, or supraorbital ridge known as superciliary arch in medicine, is a bony ridge located above the eye sockets of all primates and some other animals. In humans, the eyebrows are located on their lower margin. Structure The brow ri ...
s, nuchal crests, and mastoid processes. Skeletal size and robustness are influenced by nutrition and activity levels. Pelvic and cranial features are considered to be more reliable indicators of biological sex. Sexing skeletons of young people who have not completed puberty is more difficult and problematic, because the body has not fully developed. Bioarchaeological sexing of skeletons is not error-proof. Recording errors and re-arranging of human remains may play a part in such misidentification. Direct testing of bioarchaeological methods for sexing skeletons by comparing gendered names on coffin plates from the crypt at Christ Church, Spitalfields, London to the associated remains achieved a 98 percent success rate. Gendered work patterns may leave marks on bones and be identifiable in the archaeological record. One study found extremely arthritic big toes, a collapse of the last dorsal vertebrae, and muscular arms and legs among female skeletons at Abu Hureyra, interpreting this as indicative of gendered work patterns. Such skeletal changes could have resulted from women spending long periods kneeling while grinding grain with the toes curled forward. Investigation of gender from mortuary remains is of growing interest to archaeologists.


Modern sex determination methods

Recent developments in bioarchaeological methods have introduced more accurate and standardized techniques for sex estimation, especially when skeletal preservation is poor. Metric analyses of pelvic morphology using tools such as the Diagnose Sexuelle Probabiliste (DSP) method have achieved over 95% accuracy in adult individuals when analyzing the
os coxae The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the ilium, isch ...
, using discriminant functions based on population-specific reference data. Geometric morphometric analyses of
cranial Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Thi ...
and
pelvic The pelvis (: pelves or pelvises) is the lower part of an anatomical trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis or pelvic skeleton). ...
landmarks, particularly when paired with statistical classifiers or machine learning algorithms, have also shown high success rates in identifying sex across both
forensic Forensic science combines principles of law and science to investigate criminal activity. Through crime scene investigations and laboratory analysis, forensic scientists are able to link suspects to evidence. An example is determining the time and ...
and archaeological samples. Molecular techniques have also become integrated into bioarchaeological practice. Ancient DNA (aDNA)
shotgun sequencing In genetics, shotgun sequencing is a method used for sequencing random DNA strands. It is named by analogy with the rapidly expanding, quasi-random shot grouping of a shotgun. The Sanger sequencing#Method, chain-termination method of DNA sequencin ...
enables near-perfect sex determination by quantifying X- and Y-chromosome reads, proving especially valuable when osteological indicators are absent or ambiguous. Where DNA preservation is insufficient, dental proteomics as detecting
amelogenin Amelogenins are a group of protein isoforms produced by alternative splicing or proteolysis from the '' AMELX'' gene, on the X chromosome, and also the '' AMELY'' gene in males, on the Y chromosome. They are involved in amelogenesis, the develo ...
peptides Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Dalton (unit), Da or more are called proteins. Chains of fewer t ...
in
tooth enamel Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other ...
provides a minimally destructive and highly reliable alternative for sex estimation.


Non-specific stress indicators


Dental non-specific stress indicators


Enamel hypoplasia

Enamel hypoplasia refers to transverse furrows or pits that form in the enamel surface of teeth when the normal process of tooth growth stops, leaving a deficit. Enamel hypoplasias generally form due to disease and/or poor nutrition.Mays, Simon. The Archaeology of Human Bones. 1998. Second ed. New York: Routledge, 2010. 2010. Linear furrows are commonly referred to as linear enamel hypoplasias (LEHs); LEHs can range in size from microscopic to visible to the naked eye. By examining the spacing of perikymata grooves (horizontal growth lines), the duration of the stressor can be estimated, although Mays argued that the width of the hypoplasia bears only an indirect relationship to the duration of the stressor. Studies of dental enamel hypoplasia are used to study child health. Unlike bone, teeth are not remodeled, so intact enamel can provide a more reliable indicator of past health events. Dental hypoplasias provide an indicator of health status during the time in childhood when the enamel of the tooth crown is forming. Not all enamel layers are visible on the tooth surface because enamel layers that are formed early in crown development are buried by later layers. Hypoplasias on this part of the tooth do not show on the tooth surface. Because of this buried enamel, teeth record stressors form a few months after the start of the event. The proportion of enamel crown formation time represented by this buried enamel varies from up to 50 percent in molars to 15-20 percent in anterior teeth. Surface hypoplasias record stressors occur from about one to seven years, or up to 13 years if the third molar is included.


Skeletal non-specific stress indicators


Porotic hyperostosis/cribra orbitalia

It was long assumed that
iron deficiency anemia Iron-deficiency anemia is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague such as feeling tired, weak, sh ...
has marked effects on the flat bones of the cranium of infants and young children. That as the body attempts to compensate for low iron levels by increasing red blood cell production in the young, sieve-like lesions develop in the cranial vaults (termed porotic hyperostosis) and/or the
orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...
(termed cribra orbitalia). This bone is spongy and soft.Martin, Debra L., Ryan P. Harrod, and Ventura R. Pérez. Bioarchaeology: An Integrated Approach to Working with Human Remains. New York: Springer, 2013. It is however, unlikely that iron deficiency anemia is a cause of either porotic hyperostosis or cribra orbitalia. These are more likely the result of vascular activity in these areas and are unlikely to be pathological. The development of cribra orbitalia and porotic hyperostosis could also be attributed to other causes besides a dietary iron deficiency, such as nutrients lost to intestinal parasites. However, dietary deficiencies are the most probable cause.Schutkowski, Holger. "Thoughts for Food: Evidence and Meaning of Past Dietary Habits." Between Biology and Culture. Ed. Holger Schutkowski. Cambridge Studies in Biological and Evolutionary Anthropology: Cambridge University Press, 2008. 141–64. Anemia incidence may be a result of inequalities within society, and/or indicative of different work patterns and activities among different groups within society. A study of iron-deficiency among early Mongolian nomads showed that although overall rates of cribra orbitalia declined from 28.7 percent (27.8 percent of the total female population, 28.4 percent of the total male population, 75 percent of the total juvenile population) during the
Bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...
and
Iron Age The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progre ...
s, to 15.5 percent during the
Hunnu The Xiongnu (, ) were a tribal confederation of nomadic peoples who, according to ancient Chinese sources, inhabited the eastern Eurasian Steppe from the 3rd century BC to the late 1st century AD. Modu Chanyu, the supreme leader after 209& ...
(2209–1907 BP) period, the rate of females with cribra orbitalia remained roughly the same, while incidence among males and children declined (29.4 percent of the total female population, 5.3 percent of the total male population, and 25 percent of the juvenile population had cribra orbitalia). This study hypothesized that adults may have lower rates of cribra orbitalia than juveniles because lesions either heal with age or lead to death. Higher rates of cribia orbitalia among females may indicate lesser health status, or greater survival of young females with cribia orbitalia into adulthood.


Harris lines

Harris lines form before adulthood, when bone growth is temporarily halted or slowed down due to some sort of stress (typically disease or malnutrition). During this time, bone mineralization continues, but growth does not, or does so at reduced levels. If and when the stressor is overcome, bone growth resumes, resulting in a line of increased mineral density visible in a
radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeu ...
. Absent removal of the stressor, no line forms. Particularly, deficiencies in
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
and
vitamin Vitamins are Organic compound, organic molecules (or a set of closely related molecules called vitamer, vitamers) that are essential to an organism in small quantities for proper metabolism, metabolic function. Nutrient#Essential nutrients, ...
s, which lead to delayed longitudinal bone growth, can result in the formation of Harris lines. During the process of
endochondral Endochondral ossification is one of the two essential pathways by which bone tissue is produced during fetal development and bone repair of the mammalian skeletal system, the other pathway being intramembranous ossification. Both endochondral an ...
bone growth, the cessation of osteoblastic activity results in the deposition of a thin layer of bone beneath the
cartilage Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...
cap, potentially forming Harris lines. Subsequent recovery, necessary for the restoration of
osteoblast Osteoblasts (from the Greek combining forms for " bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts fu ...
ic activity, is also implicated in Harris line formation. When matured cartilage cells reactivate, bone growth resumes, thickening the bony stratum. Therefore, complete recovery from periods of chronic illness or
malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...
manifests as transverse lines on radiographs. Lines tend to be thicker with prolonged and severe malnutrition. Harris line formation typically peaks in long bones around 2–3 years after birth and becomes rare after the age of 5 until adulthood. Harris lines occur more frequently in boys than in girls.


Hair

The stress hormone
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
is deposited in hair as it grows. This has been used successfully to detect fluctuating levels of stress in the later lifespan of mummies.


Mechanical stress and activity indicators

Examining the effects that activities has upon the skeleton allows the archaeologist to examine who was doing what kinds of labor, and how activities were structured within society. Labor within the
household A household consists of one or more persons who live in the same dwelling. It may be of a single family or another type of person group. The household is the basic unit of analysis in many social, microeconomic and government models, and is im ...
may be divided according to
gender Gender is the range of social, psychological, cultural, and behavioral aspects of being a man (or boy), woman (or girl), or third gender. Although gender often corresponds to sex, a transgender person may identify with a gender other tha ...
and age, or be based on other social structures. Human remains can allow archaeologists to uncover these patterns. Living bones are subject to
Wolff's law Wolff's law, developed by the German anatomist and surgeon Julius Wolff (surgeon), Julius Wolff (1836–1902) in the 19th century, states that bone in a healthy animal will adapt to the loads under which it is placed. If loading on a particular ...
, which states that bones are physically affected and remodeled by physical activity or inactivity. Increases in mechanical stress tend to produce thicker and stronger bones. Disruptions in homeostasis caused by nutritional deficiency or disease or profound inactivity/disuse/disability can lead to bone loss. While the acquisition of bipedal locomotion and body mass appear to determine the size and shape of children's bones, activity during the adolescent growth period seems to exert a greater influence on the size and shape of adult bones than exercise later in life. Muscle attachment sites (
entheses The enthesis (plural entheses) is the connective tissue which attaches tendons or ligaments to a bone. There are two types of entheses: ''Fibrous tissue, fibrous entheses'' and ''fibrocartilaginous entheses''. In a fibrous enthesis, the collage ...
) have been thought to be impacted in the same way, causing entheseal changes. These changes were widely used to study activity-patterns, but research has shown that processes associated with aging have a greater impact than occupational stresses. It has also been shown that geometric changes to bone structure (described above) and entheseal changes differ in their underlying cause with the latter little affected by occupation. Joint changes, including
osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...
, have been used to infer occupations, but in general these are also manifestations of the aging process. Markers of occupational stress, which include morphological changes to the skeleton and dentition as well as joint changes at specific locations have been widely used to infer specific (rather than general) activities. Such markers are often based on single cases described in late nineteenth century clinical literature. One such marker has been found to be a reliable indicator of lifestyle: the external auditory exostosis also called surfer's ear, which is a small bony protuberance in the ear canal that occurs in those working in proximity to cold water. One example of how these changes have been used to study activities is the New York African Burial Ground in New York. This provides evidence of the brutal working conditions under which the enslaved labored;
osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...
of the vertebrae was common even among the young. The pattern of osteoarthritis combined with the early age of onset provides evidence of labor that resulted in mechanical strain to the neck. One male skeleton shows stress lesions at 37 percent of 33 muscle or ligament attachments, showing he experienced significant musculoskeletal stress. Overall, the interred show signs of significant musculoskeletal stress and heavy workloads, although workload and activities varied by individual. Some show high levels of stress, while others do not. This indicates the variety of types of labor (e.g., domestic vs. carrying heavy loads) labor.


Injury and workload

Fractures Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress (mechanics), stress. The fracture of a solid usually occurs due to the development of certain displacemen ...
to bones during or after excavation appear relatively fresh, with broken surfaces appearing white and unweathered. Distinguishing between fractures around the time of death and post-depositional fractures in bone is difficult, as both types of fractures show signs of weathering. Unless evidence of bone healing or other factors are present, researchers may choose to regard all weathered fractures as post-depositional. Evidence of perimortal fractures (or fractures inflicted on a fresh corpse) can be distinguished in unhealed metal blade injuries to the bones. Living or freshly dead bones are somewhat resilient, so metal blade injuries to bone generate a linear cut with relatively clean edges rather than irregular shattering. Archaeologists have attempted to use the microscopic parallel scratch marks on cut bones in order to estimate the trajectory of the blade that caused the injury.


Diet and dental health

Dental caries Tooth decay, also known as caries,The word 'caries' is a mass noun, and is not a plural of 'carie'.'' is the breakdown of teeth due to acids produced by bacteria. The resulting cavities may be a number of different colors, from yellow to black ...
are caused by localized destruction of tooth enamel, as a result of acids produced by bacteria feeding upon and fermenting carbohydrates in the mouth. Agriculture is strongly associated with a higher rate of caries than foraging, because of the associated higher levels of carbohydrates produced by agriculture. For example, bioarchaeologists have used caries in skeletons to correlate a diet of rice with disease. Women may be more vulnerable to caries compared to men due to having lower saliva flow, the positive correlation of
estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...
with increased caries rates, and because of pregnancy-associated physiological changes, such as suppression of the immune system and a possible concomitant decrease in antimicrobial activity in the oral cavity.


Stable isotope analysis

Stable isotope
biogeochemistry Biogeochemistry is the Branches of science, scientific discipline that involves the study of the chemistry, chemical, physics, physical, geology, geological, and biology, biological processes and reactions that govern the composition of the natu ...
uses variations in isotopic signatures and relates them to biogeochemical processes. The science is based on the preferential fractionation of lighter or heavier isotopes, which results in enriched and depleted isotopic signatures compared to a standard value. Essential elements for life such as carbon, nitrogen, oxygen, and sulfur are the primary stable isotope systems used to interrogate archeological discoveries. Isotopic signatures from multiple systems are typically used in tandem to create a comprehensive understanding of the analyzed material. These systems are most commonly used to trace the geographic origin of archaeological remains and investigate the diets, mobility, and cultural practices of ancient humans.


Applications


Carbon

Stable isotope analysis of
carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...
in human bone
collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...
allows bioarchaeologists to carry out dietary reconstruction and to make
nutrition Nutrition is the biochemistry, biochemical and physiology, physiological process by which an organism uses food and water to support its life. The intake of these substances provides organisms with nutrients (divided into Macronutrient, macro- ...
al inferences. These chemical signatures reflect long-term dietary patterns, rather than a single meal or
feast A banquet (; ) is a formal large meal where a number of people consume food together. Banquets are traditionally held to enhance the prestige of a host, or reinforce social bonds among joint contributors. Modern examples of these purposes inc ...
. Isotope ratios in food, especially plant food, are directly and predictably reflected in bone chemistry, allowing researchers to partially reconstruct recent diet using stable isotopes as tracers. Stable isotope analysis monitors the ratio of carbon 13 to carbon 12 (13C/12C), which is expressed as parts per thousand using delta notation ( δ13C). The 13C and 12C ratio is either depleted (more negative) or enriched (more positive) relative to a
standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object ...
. 12C and 13C occur in a ratio of approximately 98.9 to 1.1. The ratio of carbon isotopes in humans varies according to the types of plants digested with different
photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...
pathways. The three photosynthesis pathways are
C3 carbon fixation carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, the other two being and CAM. This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of ...
,
C4 carbon fixation carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960s discovery by Marshall Davidson Hatch and Charles Roger Slack. fixation is an addition ...
and
Crassulacean acid metabolism Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night. ...
. C4 plants are mainly grasses from tropical and subtropical regions, and are adapted to higher levels of radiation than C3 plants.
Corn Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout Poaceae, grass that produces cereal grain. It was domesticated by indigenous peoples of Mexico, indigenous peoples in southern Mexico about 9,000 years ago ...
,
millet Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most millets belong to the tribe Paniceae. Millets are important crops in the Semi-arid climate, ...
and
sugar cane Sugarcane or sugar cane is a species of tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fib ...
are some well-known C4 crops, while trees and shrubs use the C3 pathway. C4 carbon fixation is more efficient when temperatures are high and atmospheric CO2 concentrations are low. C3 plants are more common and numerous than C4 plants as C3 carbon fixation is more efficient in a wider range of temperatures and atmospheric CO2 concentrations. The different photosynthesis pathways used by C3 and C4 plants cause them to discriminate differently towards 13C leading to distinctly different ranges of δ13C. C4 plants range between -9 and -16‰, and C3 plants range between -22 and -34‰. The isotopic signature of consumer collagen is close the δ13C of dietary plants, while
apatite Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of Hydroxide, OH−, Fluoride, F− and Chloride, Cl− ion, respectively, in the crystal. The formula of the admixture of ...
, a mineral component of bones and teeth, has an ~14‰ offset from dietary plants due fractionation associated with mineral formation. Stable carbon isotopes have been used as tracers of C4 plants in paleodiets. For example, the rapid and dramatic increase in 13C in human collagen after the adoption of
maize Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native American ...
agriculture in North America documents the transition from a C3 to a C4 (native plants to corn) diet by 1300 CE. Skeletons excavated from the Coburn Street Burial Ground (1750 to 1827 CE) in
Cape Town Cape Town is the legislature, legislative capital city, capital of South Africa. It is the country's oldest city and the seat of the Parliament of South Africa. Cape Town is the country's List of municipalities in South Africa, second-largest ...
, South Africa, were analyzed using stable isotope data in order to determine geographical histories and life histories. The people buried in this cemetery were assumed to be slaves and members of the underclass based on the informal nature of the cemetery; biomechanical stress analysis and stable isotope analysis, combined with other archaeological data, seem to support this supposition. Based on stable isotope levels, one study reported that eight Cobern Street Burial Ground individuals consumed a diet based on C4 (tropical) plants in childhood, then consumed more C3 plants, which were more common there later in their lives. Six of these individuals had dental modifications similar to those carried out by peoples inhabiting tropical areas known to be targeted by slavers who brought enslaved individuals from other parts of Africa to the colony. Based on this evidence, it was argued that these individuals represent enslaved persons from areas of Africa where C4 plants were consumed and who were brought to the Cape as laborers. These individuals were not assigned to a specific ethnicity, but similar dental modifications are carried out by the Makua, Yao, and Marav peoples. Four individuals were buried with no
grave goods Grave goods, in archaeology and anthropology, are items buried along with a body. They are usually personal possessions, supplies to smooth the deceased's journey into an afterlife, or offerings to gods. Grave goods may be classed by researche ...
, in accordance with Muslim tradition, facing Signal Hill, which is a point of significance for local Muslims. Their isotopic signatures indicate that they grew up in a temperate environment consuming mostly C3 plants, but some C4 The study argued that these individuals were from the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
area. It also suggested that these individuals were
Muslims Muslims () are people who adhere to Islam, a Monotheism, monotheistic religion belonging to the Abrahamic religions, Abrahamic tradition. They consider the Quran, the foundational religious text of Islam, to be the verbatim word of the God ...
. It argued that stable isotopic analysis of burials, combined with historical and archaeological data were an effective way of investigating the migrations forced by the
African Slave Trade Slavery has historically been widespread in Africa. Systems of servitude and slavery were once commonplace in parts of Africa, as they were in much of the rest of the ancient and medieval world. When the trans-Saharan slave trade, Red Sea s ...
, as well as the emergence of the underclass and working class in the Old World.


Nitrogen

The nitrogen stable isotope system is based on the relative enrichment/depletion of 15N in comparison to 14N in
δ15N In geochemistry, hydrology, paleoclimatology and paleoceanography, ''δ''15N (pronounced "delta fifteen n") or delta-N-15 is a measure of the ratio of the two stable isotopes of nitrogen, 15N: 14N. Formulas Two very similar expressions for a ...
. Carbon and nitrogen stable isotope analyses are complementary in paleodiet studies. Nitrogen isotopes in bone collagen are ultimately derived from dietary protein, while carbon can be contributed by protein,
carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...
, or fat. δ13C values help distinguish between dietary protein and plant sources while systematic increases in δ15N values as you move up in
trophic Trophic, from Ancient Greek τροφικός (''trophikos'') "pertaining to food or nourishment", may refer to: * Trophic cascade * Trophic coherence * Trophic egg * Trophic function * Trophic hormone * Trophic level index * Trophic level * ...
level helps determine the position of protein sources in the food web. 15N increases 3-4% with each trophic step upward. It has been suggested that the relative difference between human δ15N values and animal protein values scales with the proportion of that animal protein in the diet, though this interpretation has been questioned due to contradictory views on the impact of nitrogen intake through protein consumption and nitrogen loss through waste release on 15N enrichment in the body. Variations in nitrogen values within the same trophic level are also considered. Nitrogen variations in plants, for example, can be caused by plant-specific reliance on nitrogen gas which causes the plant to mirror atmospheric values. Enriched or higher δ15N values can be achieved in plants that grew in soil fertilized by animal waste.
Nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
isotopes have been used to estimate the relative contributions of
legumes Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consu ...
verses nonlegumes, as well as terrestrial versus marine resources. While other plants have δ15N values that range from 2 to 6‰, legumes have lower 14N/15N ratios (close to 0‰, i.e. atmospheric N2) because they can fix molecular nitrogen, rather than having to rely on soil
nitrates Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insol ...
and
nitrites The nitrite polyatomic ion, ion has the chemical formula . Nitrite (mostly sodium nitrite) is widely used throughout chemical and pharmaceutical industries. The nitrite anion is a pervasive intermediate in the nitrogen cycle in nature. The name ...
. Therefore, one potential explanation for lower δ15N values in human remains is an increased consumption of legumes or animals that eat them. 15N values increase with meat consumption, and decrease with legume consumption. The 14N/15N ratio could be used to gauge the contribution of meat and legumes to the diet.


Oxygen

The oxygen stable isotope system is based on the 18O/16O ( δ18O) ratio in a given material, which is enriched/depleted relative to a standard. The field typically normalizes to both Vienna Standard Mean Ocean Water ( VSMOW) and Standard Light Antarctic Precipitation (SLAP). This system is famous for its use in paleoclimatic studies but it also a prominent source of information in bioarchaeology. Variations in δ18O values in skeletal remains are directly related to the isotopic composition of the consumer's body water. isotopic composition of mammalian body water is primarily controlled by consumed water. δ18O values of freshwater drinking sources vary due to mass fractionations related to mechanisms of the global water cycle. Evaporated water vapor is more enriched in 16O (isotopically lighter; more negative delta value) compared to the remaining water, which is depleted in 16O (isotopically heavier; more positive delta value). An accepted first-order approximation for the isotopic composition of animal drinking water is local precipitation, though this is complicated to varying degrees by confounding water sources like natural springs or lakes. The baseline δ18O used in archaeological studies is modified depending on the relevant environmental and historical context. δ18O values of bioapatite in human skeletal remains are assumed to have formed in equilibrium with body water, thus providing a species-specific relationship to oxygen isotopic composition of body water. The same cannot be said for human bone collagen, as δ18O values in collagen seem to be impacted by drinking water, food water, and a combination of metabolic and physiological processes. δ18O values from bone minerals are essentially an averaged isotopic signature throughout the entire life of the individual. While carbon and nitrogen are used primarily to investigate the diets of ancient humans, oxygen isotopes offer insight into body water at different life stages. δ18O values are used to understand drinking behaviors, animal husbandry, and track mobility. 97 burials from the ancient
Maya Maya may refer to: Ethnic groups * Maya peoples, of southern Mexico and northern Central America ** Maya civilization, the historical civilization of the Maya peoples ** Mayan languages, the languages of the Maya peoples * Maya (East Africa), a p ...
citadel of
Tikal Tikal (; ''Tik'al'' in modern Mayan orthography) is the ruin of an ancient city, which was likely to have been called Yax Mutal, found in a rainforest in Guatemala. It is one of the largest archaeological sites and urban centers of the Pre-Col ...
were studied using oxygen isotopes. Results from tooth enamel identified statistically different individuals, interpreted to be individuals from Maya lowlands,
Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...
, and potentially
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
. Historical context combined with isotopic data from burials were used to argue that migrant individuals were a part of lower and higher social classes within Tikal. Female migrants who arrived in Tikal during Early Classic period could have been the brides of Maya elite.


Sulfur

The sulfur stable isotope system is based on small, mass-dependent fractionations of sulfur isotopes. These fractionations are reported relative to Canyon Diablo Troilite (V-CDT), the agreed upon standard. The ratio of the most abundant sulfur isotope, 32S, compared to rarer isotopes such as, 33S, 34S, and 36S, is used to characterize biological signatures and geological reservoirs. The fractionation of 34S ( δ34S) is particularly useful since it is the most abundant of the rare isotopes. This system is less commonly used on its own and typically complements studies of carbon and nitrogen. In bioarchaeology, the sulfur system has been used to investigate paleodiets and spatial behaviors through the analysis of hair and bone collagen. Dietary proteins incorporated into living organisms tend to determine the stable isotope values of their organic tissues.
Methionine Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other non-essential amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine play ...
and
cysteine Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the chemical formula, formula . The thiol side chain in cysteine enables the formation of Disulfide, disulfide bonds, and often participates in enzymatic reactions as ...
are the canonical sulfur-containing amino acids. Of the two, δ34S values of methionine are considered to better reflect isotopic compositions of dietary sulfur, since cysteine values are impacted by diet and internal cycling. While other stable isotope systems have significant
trophic Trophic, from Ancient Greek τροφικός (''trophikos'') "pertaining to food or nourishment", may refer to: * Trophic cascade * Trophic coherence * Trophic egg * Trophic function * Trophic hormone * Trophic level index * Trophic level * ...
shifts, sulfur shows only a small shift (~0.5‰). Consumers yield isotopic signatures that reflect the sulfur reservoir(s) of the dietary protein source. Animal proteins sourced from marine ecosystems tend to have δ34S values between +16 and +17‰, terrestrial plants range from -7‰ to +8‰, while proteins from
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...
and terrestrial ecosystems are highly variable. The sulfate content of the modern ocean is well-mixed with a δ34S of approximately +21‰, while riverine water is heavily influenced by sulfur-bearing minerals in surrounding bedrock and terrestrial plants are influenced by the sulfur content of local soils. Estuarian ecosystems have increased complexity due to seawater and river inputs. The extreme range of δ34S values for freshwater ecosystems often interferes with terrestrial signals, making it difficult to use the sulfur system as the sole tool in paleodiet studies. Various studies have analyzed the isotopic ratios of sulfur in mummified hair. Hair is a good candidate for sulfur studies as it typically contains at least 5% elemental sulfur. One study incorporated sulfur isotope ratios into their paleodietary investigation of four mummified child victims of
Incan The Inca Empire, officially known as the Realm of the Four Parts (, ), was the largest empire in pre-Columbian America. The administrative, political, and military center of the empire was in the city of Cusco. The Inca civilisation rose fr ...
sacrificial practices. δ34S values helped them conclude that the children had not been eating marine protein before their death. Historical insight coupled with consistent sulfur signatures for three of the children suggests that they were living in the same location 6 months prior to the sacrifice. Studies have measured δ34S values of bone collagen, though the interpretation of these values was not reliable until quality criteria were published in 2009. Though bone collagen is abundant in skeletal remains, less than 1% of the tissue is made of sulfur, making it imperative that these studies carefully assess the meaning of bone collagen δ34S values.


DNA

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
analysis of past populations is used to genetically determine sex, determine genetic relatedness, understand marriage patterns, and investigate prehistoric migration. In 2012 archaeologists found skeletal remains of an adult male. He was buried under a car park in England. DNA evidence allowed the archaeologists to confirm that the remains belonged to
Richard III Richard III (2 October 1452 – 22 August 1485) was King of England from 26 June 1483 until his death in 1485. He was the last king of the Plantagenet dynasty and its cadet branch the House of York. His defeat and death at the Battle of Boswor ...
, the former king of England who died in the
Battle of Bosworth The Battle of Bosworth or Bosworth Field ( ) was the last significant battle of the Wars of the Roses, the civil war between the houses of Lancaster and York that extended across England in the latter half of the 15th century. Fought on 22 ...
. In 2021, Canadian researchers analyzed skeletal remains found on
King William Island King William Island (, ; previously: King William Land) is an island in the Kitikmeot Region of Nunavut, which is part of the Arctic Archipelago. In area it is between and making it the list of islands by area, 61st-largest island in the world ...
, identifying them as belonging to Warrant Officer John Gregory, an engineer serving aboard HMS ''Erebus'' in the ill-fated 1845 Franklin Expedition. He was the first expedition member to be identified by DNA analysis.


Biocultural bioarchaeology

The study of human remains can illuminate the relationship between physical bodies and socio-cultural conditions and practices, via a biocultural bioarchaeology model. Bioarchaeology is typically regarded as a positivist, science-based discipline, while the social sciences are regarded as constructivist. Bioarchaeology has been criticized for having little to no concern for culture or history. One scholar argued that scientific/forensic scholarship ignores cultural/historic factors. He proposed that a biocultural version of bioarchaeology offered a more meaningful, nuanced, and relevant picture, especially for descent populations. Biocultural bioarchaeology combines standard forensic techniques with investigations of demography and epidemiology in order to assess socioeconomic conditions experienced by human communities. For example, incorporation of analysis of
grave goods Grave goods, in archaeology and anthropology, are items buried along with a body. They are usually personal possessions, supplies to smooth the deceased's journey into an afterlife, or offerings to gods. Grave goods may be classed by researche ...
can further the understanding of daily activities. Some bioarchaeologists view the discipline as a crucial interface between the science and the humanities; as the human body is made and re-made by both biological and cultural factors. Another type of bioarchaeology focuses on quality of life, lifestyle, behavior, biological relatedness, and population history. It does not closely link skeletal remains to their archaeological context, and may best be viewed as a "skeletal biology of the past". Inequalities exist in all human societies. Bioarchaeology has helped to dispel the idea that life for foragers of the past was "nasty, brutish and short"; bioarchaeological studies reported that foragers of the past were often healthy, while agricultural societies tended to have increased incidence of malnutrition and disease. One study compared foragers from Oakhurst to agriculturalists from K2 and
Mapungubwe The Kingdom of Mapungubwe (pronounced ) was an ancient state located at the confluence of the Shashe River, Shashe and Limpopo River, Limpopo rivers in South Africa, south of Great Zimbabwe. The capital's population was 5,000 by 1250, and the s ...
and reported that agriculturalists from K2 and Mapungubwe were not subject to the lower nutritional levels expected. Danforth argues that more "complex" state-level societies display greater health differences between elites and the rest of society, with elites having the advantage, and that this disparity increases as societies become more unequal. Some status differences in society do not necessarily mean radically different nutritional levels; Powell did not find evidence of great nutritional differences between elites and commoners, but did find lower rates of anemia among elites in Moundville. An area of increasing interest interested in understanding inequality is the study of
violence Violence is characterized as the use of physical force by humans to cause harm to other living beings, or property, such as pain, injury, disablement, death, damage and destruction. The World Health Organization (WHO) defines violence a ...
. Researchers analyzing traumatic injuries on human remains have shown that social status and gender can have a significant impact on exposure to violence.Martin, Debra L., Ryan P. Harrod, and Misty Fields. "Beaten Down and Worked to the Bone: Bioarchaeological Investigations of Women and Violence in the Ancient Southwest." Landscapes of Violence 1.1 (2010): Article 3. http://scholarworks.umass.edu/lov/vol1/iss1/3/ Numerous researchers study violence in human remains, exploring violent behavior, including
intimate partner violence Intimate partner violence (IPV) is domestic violence by a current or former spouse or partner in an intimate relationship against the other spouse or partner. IPV can take a number of forms, including physical abuse, physical, verbal abuse, verb ...
,
child abuse Child abuse (also called child endangerment or child maltreatment) is physical abuse, physical, child sexual abuse, sexual, emotional and/or psychological abuse, psychological maltreatment or Child neglect, neglect of a child, especially by a p ...
,
institutional abuse Institutional abuse is the maltreatment of a person (often children or older adults) from a system of power. This can range from acts similar to home-based child abuse, such as neglect, physical and sexual abuse, and hunger, to the effects of as ...
,
torture Torture is the deliberate infliction of severe pain or suffering on a person for reasons including corporal punishment, punishment, forced confession, extracting a confession, interrogational torture, interrogation for information, or intimid ...
,
warfare War is an armed conflict between the armed forces of State (polity), states, or between governmental forces and armed groups that are organized under a certain command structure and have the capacity to sustain military operations, or betwe ...
,
human sacrifice Human sacrifice is the act of killing one or more humans as part of a ritual, which is usually intended to please or appease deity, gods, a human ruler, public or jurisdictional demands for justice by capital punishment, an authoritative/prie ...
, and
structural violence Structural violence is a form of violence wherein some social structure or social institution may harm people by preventing them from meeting their basic needs or rights. The term was coined by Norwegian sociologist Johan Galtung, who intr ...
.


Ethics

Ethical issues with bioarchaeology revolve around the treatment and respect for the dead. Large-scale skeletal collections were first amassed in the US in the 19th century, largely the remains of Native Americans. No permission was granted by surviving family for study and display. Federal laws such as 1990's NAGPRA (Native American Graves Protection and Repatriation Act) allowed Native Americans to regain control over their ancestors' remains and associated artifacts. Many archaeologists did not realize that many people perceive archaeologists as non-productive and/or grave robbers. Concerns about mistreatment of remains are not unfounded: in a 1971 Minnesota excavation, White and Native American remains were treated differently; Whites were reburied, while Native Americans were moved to a
natural history Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...
museum. African American bioarchaeology grew after NAGPRA and its effect of ending the study of Native American remains. Bioarchaeology in Europe was not as disrupted by repatriation issues. However, because much of European archaeology has been focused on classical roots, artifacts and art have been emphasized and Roman and post-Roman skeletal remains were nearly completely neglected until the 1980s. In prehistoric European archaeology, biological remains began to be analyzed earlier than in classical archaeology. While ethical approaches to the excavation and analysis of physical human remains have received considerable attention, professional and academic dialogue regarding how to appropriately record, share, and display human remains in the digital realm is less developed. While digital technologies for recording and analysing human remains are increasingly accessible, justification for such recording and analysis is essential e.g. 3D scanning performed simply because it is possible is inappropriate and disrespectful to the deceased.


See also

*
Ancient DNA Ancient DNA (aDNA) is DNA isolated from ancient sources (typically Biological specimen, specimens, but also environmental DNA). Due to degradation processes (including Crosslinking of DNA, cross-linking, deamination and DNA fragmentation, fragme ...
* Biocultural anthropology * Odontometrics *
Osteoarchaeology Bioarchaeology (osteoarchaeology, osteology or palaeo-osteology) in Europe describes the study of biological remains from archaeological sites. In the United States it is the scientific study of human remains from archaeological sites. The term ...
* Paleopathology *
Zooarchaeology Zooarchaeology or archaeozoology merges the disciplines of zoology and archaeology, focusing on the analysis of animal remains within archaeological sites. This field, managed by specialists known as zooarchaeologists or faunal analysts, examines ...


References


Further reading

* J. Buikstra, 1977. "Biocultural dimensions of archaeological study: a regional perspective". In:''Biocultural adaptation in prehistoric America,'' pp. 67–84. University of Georgia Press. * J. Buikstra and L. Beck, eds., 2006. "Bioarchaeology: the Contextual Study of Human Remains." Elsevier. * M. Katzenberg and S. Saunders, eds., 2000. ''Biological anthropology of the human skeleton.'' Wiley. * K. Killgrove, 2014.
Bioarchaeology
.'' In: Oxford Annotated Bibliographies Online. Oxford. * C.S. Larsen, 1997. ''Bioarchaeology: interpreting behavior from the human skeleton.'' Cambridge University Press. * * S. Mays, 1998. ''The archaeology of human bones.'' Routledge. * Samuel J. Redman, 2016. ''Bone Rooms: From Scientific Racism to Human Prehistory in Museums.'' Harvard University Press. * M. Parker Pearson, 2001. ''The archaeology of death and burial.'' Texas A&M University Press. * D. Ubelaker, 1989. ''Human skeletal remains: excavation, analysis, interpretation.'' Taraxacum. * T. White, 1991. ''Human osteology.'' Academic Press.


External links

Organizations
American Association of Physical Anthropologists


* ttp://www.babao.org.uk/ British Association of Biological Anthropologists and Osteoarchaeologists
Canadian Association for Physical Anthropology
Journals
American Journal of Physical Anthropology

International Journal of Osteoarchaeology

HOMO: Journal of Comparative Human Biology

International Journal of Paleopathology

Bioarchaeology of the Near East
Other




Bioarchaeology and the Center for Bioarchaeological Research



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{{Authority control 1970s neologisms Collections care Conservation and restoration of cultural heritage Museology Cultural heritage Archaeological science Art and cultural repatriation Zooarchaeology *