Population Mitchell McGovern Sarah Mason Jessie Fedyke
Importance of Population • Studying populations allows us to see where people are found across Earth’s surface. • It also allows us to see the areas where population is growing too fast/ too slow. • Demography: the study of the characteristics of human populations • Population is measured by a Census, a count of the number of people in a given area, usually every ten years. Very important to determine government funding.
Declining Rate of Natural Increase • NIR:-% a population grows each year -CDR-CBR=NIR • CDR: -Total # of deaths in a year for every 1,000 people • CBR:-Total # of live births in a year for every 1,000 people • Doubling Time-# of years needed to double a population • World NIR is decreasing (as of 1963) • Causes:-Sterilization, especially in India -Increase in Education-Family Planning-Lower birth rates improve economic conditions-propaganda now encourages small families (china) *Exception: LDC-Almost all the world population growth is from LDC’s (95% of World NIR)
Measures of population • Total Fertility Rate:-measures the # of births in society, average # of children a woman will have during childbearing years of 15-49. • World TFR is 2.6 children per woman-LDC’s TFR is high-MDC’s TFR is low • Infant Mortality Rate-# of deaths of infants under the age of 1, per year-LDC’s IMR is high-MDC’s IMR is low • Life Expectancy-Average # of years a newborn infant can expect to live at current mortality levels-High in MDC’s-Low in LDC’s • Dependency ratio-# of people too old or young to work compared to the # of their working years-High levels of YOUNG dependent people in LDc’s-High levels of OLD dependent people in MDC’s
World Population Distribution • 7 billion • Factors of distribution:-Climate and Weather, availability/quality of water, topography, arable land, along with political and economic factors • Culture/ethnicity • Areas of high political instability are undergoing changes in population • Population growth curves:-S curve; historical growth-J curve; exponential growth
Population distribution • Ecumene-Portion of the earth’s surface occupied by permanent settlement-today 3/4ths of the world population lives on only 5% of earth’s surface • 20% of earth’s surface is not arable due to dry lands and large deserts, low population in these areas • In areas of high rainfall with more than 50 inches per year the soil is depleted of nutrients therefore the population is low • Near the North and South poles with massive elevations and ice coverage very little humans or animals live.
Density • Population Density-numerical measure of the relationship between the number of people and some other unit expressed as a ratio- helps geographers describe distribution of people in comparison to available resources. • Arithmetic Density-Total # of objects in an area-To find it you take the total # of people divided by total land area-Does not always accurately portray population distribution because in some countries a large majority of the people live in a certain part, they are not spread out evenly. • Physiological Density-# of people per area of arable land in a region • Agricultural Density-ratio of farmers to the amount of arable land-measures economic differences • Why? -Comparing agricultural and physiological densities allows you to see the relationship between population and resources
World population threats • Epidemiologic transition: -Focuses on distinctive causes of death in each stage of the demographic transition • Epidemiology:-branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people
Epidemiologic transition • Stage 1, Pestilence and Famine ex. Black Plague-spread from urban areas to rural areas wiping out entire villages, thought to originate from the Tatar army. • Stage 2, Receding Pandemics occuring over a wide geographic area. ex. -Edwin Chadwick (1800-1890) said that residents in poorer neighborhoods had higher incidences of pandemic diseases -Dr. John Snow (1813-1858) said that the contaminated water was the cause of death, not sinful behavior. • Stage 3, Degenerative and human-created diseases. Ex. Cancer -End of deaths from infectious illnesses due to vaccines • Stage 4, delayed degenerative diseases ex. Stage 3 diseases still linger but there are new treatments to extend life expectancy. -Result of more research in medicine and reduced use of drugs. • Stage 5, Stage of reemergence of infectious diseases and parasitic disease ex. Malaria-Stage is more of a theory, thought to might happen due to evolution with microbes evolving and changing vaccines may stop working, like building up immunity to certain medicine from so much use.
Malthus Theory • Thomas Malthus predicted that population was growing too fast that eventually we would run out of food.-With an increase in population resources would deplete and disease, famine, and war would ensue. -population grows geometrically while population growths arithmetically • Reasons he was wrong • Malthus failed to anticipate that poor countries would have rapid population growth • Theory based on his idea that food and resources were at a fixed amount. • Malthus’s arithmetic theory didn’t take into account that too few people could also slow the economy just as overpopulation might • Food production increased with green revolution -fertilizer-Genetically enhanced food-technology
Demorgaphic Transition Model • Stage 1: Low Growth, high birth AND death rates-Hunting and Gathering, no modern medicine, no country is still in stage one today • Stage 2: Death rate drops, but birth rate stays high-Occurred in MDC’s during the 18th with most LDC’s during mid 19th century due to the industrial revolution, improved sanitation/medicine/technology • Stage 3:Birth rate drops, death rate low-CBR is still higher than CDR, most MDC’s went through stage 3 during the early 1900’s with a sudden drop of birth rates with rural families moving to cities no longer needing several kids to work farms • Stage 4: Low growth overall-Countries enter stage 4 when there is zero population growth, or negative growth (communist rule)-BR = DR or zero population growth-most of Europe and the U.S. have zero NIR • Stage 5: When the crude death rate is higher than the birth rate-no countries have undergone stage 5 yet
Population Pyramids • Population Pyramid: bar graph that displays age and gender of a population with males on the left and females on right, determined by CBR -broken down into 5 year age groups -Sex ratio: # of males per hundred females
Helpful review links • http://www.superteachertools.com/jeopardyx/jeopardy-review-game.php?gamefile=1304099801 • http://quizlet.com/18089567/population-and-migration-eghs-human-geography-flash-cards/ • http://www.youtube.com/watch?v=sc4HxPxNrZ0