For instance, when an animal such as a cow or sheep eats a certain type of grass or plant they will exhibit an isotopic value in their bones or teeth that is representative of that particular type of grass or plant.
In addition, as humans consume animal protein, from resources such as terrestrial animals (e.g., cows, sheep, or goats) and aquatic resources (e.g., fish and shellfish) they will exhibit isotopic values that situate them within a particular "trophic level." A trophic level is most simply explained as where an organism (human or animal in these cases) is situated within a particular food chain.
In addition, these types of changes can influence where and/or when people may move throughout the landscape.
For instance, a shift in climate from a hotter or more arid environment to one that is wetter and milder, may have allowed people to move into a new area to make use of land resources that were previously unsuitable for farming or herding animals.
These isotopes have been used most commonly to study diets of marine versus terrestrial (land based) animals and the intake of particular types of plant resources (for example maize and millet).
Isotopes can be used to assess diet because a direct relationship exists between the type of food being consumed and the corresponding isotopic "signature" found in the bone collagen of both humans and animals.
Isotopic analysis is used in a variety of fields across the sciences, such as Geology, Biology, Organic Chemistry, and Ecology.
Archaeology, which is situated between the hard natural sciences and social sciences, has adapted the techniques developed in these fields to answer both archaeological and anthropological questions that span the globe over both time and space.
Isotopes and the Study of Mobility The study of mobility and migration in the past can be approached through a number of different archaeological methods, such as provenance studies of glass, ceramics and metal artefacts and in some cases even through the study of ancient DNA (a DNA). They may move in search of more optimal resources, for marriage, warfare, trade, and a host of other reasons.
Isotopic indicators of environment are most often investigated through the study of oxygen isotopes.
Different oxygen isotope values are representative of hotter and drier climates, versus those that were colder and wetter.
Isotopes and the Study of Environment Many scientific fields utilize isotopic analysis to study past climate and environment. It is important to determine the environmental setting of a particular time and place in order to gain a better understanding of the factors that could have influenced the way a community developed.
Long and short term changes in climate can have a dramatic impact on the ways in which people may procure or produce their food.