2006j-264 20thcentury africancontinentalancestrygroup anthropology bangladesh blacks caribbeanarea centralamerican cross-culturalcomparison cross-culturalstudies demographictransition demography diseases economichistory families family familyplanningservices fertility generations genetics gn289m183h2006 history human humanbiology humanpopulationgenetics india indians jharkhand methods mortality physical physicalanthropology population santal(southasianpeople) scheduledtribes socialconditions socialecology socialhistory statistics tribes