Plant remains form part of the archaeological record. Water flotation and fine sieving have improved recovery of plant macroremains, and enhanced our ability to study plant domestication and agriculture. Identifying charred, dried, or waterlogged fragments as the remains of domesticated plants can require specialized methods, such as statistical analysis of size or microscopic examination of anatomical features. During the process of domestication, plants undergo selection for traits that make them more desirable to humans, and better able to compete under cultivation. These traits distinguish domesticates from their wild ancestors and include loss of natural dispersal mechanisms, increased size of edible parts, and more uniform appearance (see Macroremains Analysis; Paleoethnobotany).
Major domesticates are part of complexes of related wild and weedy species, and the analyst must determine whether the preserved plant remains match the wild, weedy, or domesticated forms. If remains come from an archaeological site far from the homeland of the domesticate, it may be possible to eliminate related wild species from consideration. In some cases, domesticated plants become so changed from wild species that identification is straightforward.
Analysis of pollen, phytoliths, and starch microfossils from sites, artifacts, agricultural fields, and coprolites (preserved feces) also form part of the archaeological record of domestication (see Pollen Analysis; Phytolith Analysis; Starch Grain Analysis; Agricultural Fields, Identification and Study; Coprolite Analysis). Naturally accumulating sediments in lakes, swamps, and alluvial settings are also excellent sources of plant microfossils that document human modification of environments, including clearance for slash and burn agriculture (see Paleoenvironmental Reconstruction, Methods). Approaches for identifying microfossils are the same as described for macroremains.
It is essential to understand the archaeological context of domesticates, especially their age. Macroremains and microfossil extractions may be directly radiocarbon dated, wood charcoal associated with domesticates may be dated, or domesticates may be associated stratigraphically with artifacts of known age (see Dating Methods, Overview). Dating by association is impacted by postdepositional disturbance, for example, movement of dried macroremains by rodents. Microfossil residues recovered directly from surfaces of artifacts used for crop processing, cooking, or consumption provide clear associations.
Agriculture is also identified through its consequences. Plants were domesticated by forgers in the Early Holocene. It took 1000-6000 years, depending on the region, for farming to become a mainstay of life, and for Neolithic or Formative cultures to appear. Successful, expanding Neolithic populations sometimes carried agriculture from primary centers into areas occupied by foragers, incorporating those people or pushing them into environments not suited for agriculture. In other cases individual crops spread and were accepted by foragers, sometimes followed by local domestications.
World History
