overpopulation pull factors selective immigration pandemic push factors sex periodic movement rate of natural increase standard of living personal space refugee stationary population level physiological population refugee (SPL) density regional scale step migration population composition remittances total fertility rate (TFR) population density repatriation underpopulation population distribution restrictive population policies voluntary migration population explosion reverse remittances zero population growth population projection rural-urban migration population pyramids S-curve
overpopulation pandemic periodic movement personal space physiological population density population composition population density population distribution population explosion population projection population pyramids pull factors push factors rate of natural increase refugee refugee regional scale remittances repatriation restrictive population policies reverse remittances rural-urban migration S-curve selective immigration sex standard of living stationary population level (SPL) step migration total fertility rate (TFR) underpopulation voluntary migration zero population growth
APHuG%20unit%20syllabus%20populationmigration%2016.docx