Demic diffusion, as opposed to
trans-cultural diffusion, is a
demographic
Demography () is the statistics, statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the interplay of fertility (births), mortality (deaths), and migration.
Demographic analy ...
term referring to a migratory model, developed by
Luigi Luca Cavalli-Sforza, of population
diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...
into and across an area that had been previously uninhabited by that group and possibly but not necessarily displacing, replacing, or intermixing with an existing
population
Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and pl ...
(such as has been suggested for the spread of
agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
across
Neolithic
The Neolithic or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revo ...
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
and several other
''Landnahme'' events).
In its original formulation, the demic diffusion model includes three phases: (1) population growth, prompted by new available resources as in the case of early farmers, and/or other technological developments; (2) a dispersal into regions with lower population density; (3) a limited initial admixture with the people encountered in the process.
Evidence
Theoretical work by Cavalli-Sforza showed that if admixture between expanding farmers and previously-resident groups of hunters and gatherers was not immediate, the process would result in the establishment of broad genetic gradients. Because broad gradients, spanning much of Europe from southeast to northwest, were identified in empirical genetic studies by Cavalli-Sforza,
Robert R. Sokal,
Guido Barbujani,
Lounès Chikhi and others, it seemed likely that the spread of agriculture into Europe occurred by the expansion and the spread of agriculturists, who possibly originated in the
Fertile Crescent
The Fertile Crescent () is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Israel, Jordan, Lebanon, Palestine, and Syria, together with northern Kuwait, south-eastern Turkey, and western Iran. Some authors also include ...
of the
Near East
The Near East () is a transcontinental region around the Eastern Mediterranean encompassing the historical Fertile Crescent, the Levant, Anatolia, Egypt, Mesopotamia, and coastal areas of the Arabian Peninsula. The term was invented in the 20th ...
. That is referred to as the Neolithic demic diffusion model.
Craniometric and
archaeological
Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...
[M. Zvelebil, ''Antiquity 63'' (1989) pp. 379–383.] studies have also arrived at the same conclusion.
References
{{Reflist
External links
Estimating the Impact of Prehistoric Admixture on the Genome of Europeans, Dupanloup et al., 2004Origin, Diffusion, and Differentiation of Y-Chromosome Haplogroups E and J: Inferences on the Neolithization of Europe and Later Migratory Events in the Mediterranean Area, 2004Y genetic data support the Neolithic demic diffusion model, Chikhi 2002.
Paleolithic and Neolithic lineages in the European mitochondrial gene pool, Cavalli-Sforza 1997.Clines of nuclear DNA markers suggest a largely Neolithic ancestry of the European gene, Chikhi 1997.
Demographics