Until the 1800s, population growth was incredibly slow on a global level. The global population was estimated to have been around 188 million people in the year 1CE, and did not reach one billion until around 1803. However, since the 1800s, a phenomenon known as the demographic transition has seen population growth skyrocket, reaching eight billion people in 2023, and this is expected to peak at over 10 billion in the 2080s.

The world's population first reached one billion people in 1805, and reached eight billion in 2022, and will peak at almost 10.2 billion by the end of the century. Although it took thousands of years to reach one billion people, it did so at the beginning of a phenomenon known as the demographic transition; from this point onwards, population growth has skyrocketed, and since the 1960s the population has increased by one billion people every 12 to 15 years. The demographic transition sees a sharp drop in mortality due to factors such as vaccination, sanitation, and improved food supply; the population boom that follows is due to increased survival rates among children and higher life expectancy among the general population; and fertility then drops in response to this population growth. Regional differences The demographic transition is a global phenomenon, but it has taken place at different times across the world. The industrialized countries of Europe and North America were the first to go through this process, followed by some states in the Western Pacific. Latin America's population then began growing at the turn of the 20th century, but the most significant period of global population growth occurred as Asia progressed in the late-1900s. As of the early 21st century, almost two-thirds of the world's population lives in Asia, although this is set to change significantly in the coming decades. Future growth The growth of Africa's population, particularly in Sub-Saharan Africa, will have the largest impact on global demographics in this century. From 2000 to 2100, it is expected that Africa's population will have increased by a factor of almost five. It overtook Europe in size in the late 1990s, and overtook the Americas a few years later. In contrast to Africa, Europe's population is now in decline, as birth rates are consistently below death rates in many countries, especially in the south and east, resulting in natural population decline. Similarly, the population of the Americas and Asia are expected to go into decline in the second half of this century, and only Oceania's population will still be growing alongside Africa. By 2100, the world's population will have over three billion more than today, with the vast majority of this concentrated in Africa. Demographers predict that climate change is exacerbating many of the challenges that currently hinder progress in Africa, such as political and food instability; if Africa's transition is prolonged, then it may result in further population growth that would place a strain on the region's resources, however, curbing this growth earlier would alleviate some of the pressure created by climate change.

The earliest point where scientists can make reasonable estimates for the population of global regions is around 10,000 years before the Common Era (or 12,000 years ago). Estimates suggest that Asia has consistently been the most populated continent, and the least populated continent has generally been Oceania (although it was more heavily populated than areas such as North America in very early years). Population growth was very slow, but an increase can be observed between most of the given time periods. There were, however, dips in population due to pandemics, the most notable of these being the impact of plague in Eurasia in the 14th century, and the impact of European contact with the indigenous populations of the Americas after 1492, where it took almost four centuries for the population of Latin America to return to its pre-1500 level. The world's population first reached one billion people in 1803, which also coincided with a spike in population growth, due to the onset of the demographic transition. This wave of growth first spread across the most industrially developed countries in the 19th century, and the correlation between demographic development and industrial or economic maturity continued until today, with Africa being the final major region to begin its transition in the late-1900s.

Throughout most of human history, global population growth was very low; between 10,000BCE and 1700CE, the average annual increase was just 0.04 percent. Therefore, it took several thousand years for the global population to reach one billion people, doing so in 1803. However, this period marked the beginning of a global phenomenon known as the demographic transition, from which point population growth skyrocketed. With the introduction of modern medicines (especially vaccination), as well as improvements in water sanitation, food supply, and infrastructure, child mortality fell drastically and life expectancy increased, causing the population to grow. This process is linked to economic and technological development, and did not take place concurrently across the globe; it mostly began in Europe and other industrialized regions in the 19thcentury, before spreading across Asia and Latin America in the 20th century. As the most populous societies in the world are found in Asia, the demographic transition in this region coincided with the fastest period of global population growth. Today, Sub-Saharan Africa is the region at the earliest stage of this transition. As population growth slows across the other continents, with the populations of the Americas, Asia, and Europe expected to be in decline by the 2070s, Africa's population is expected to grow by three billion people by the end of the 21st century.

description: The Anthropogenic Biomes of the World, Version 2: 2000 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture and urbanization c. 2000. Potential natural vegetation, biomes, such as tropical rainforests or grasslands, are based on global vegetation patterns related to climate and geology. Anthropogenic transformation within each biome is approximated using population density, agricultural intensity (cropland and pasture) and urbanization. This data set is part of a time series for the years 1700, 1800, 1900, and 2000 that provides global patterns of historical transformation of the terrestrial biosphere during the Industrial Revolution.; abstract: The Anthropogenic Biomes of the World, Version 2: 2000 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture and urbanization c. 2000. Potential natural vegetation, biomes, such as tropical rainforests or grasslands, are based on global vegetation patterns related to climate and geology. Anthropogenic transformation within each biome is approximated using population density, agricultural intensity (cropland and pasture) and urbanization. This data set is part of a time series for the years 1700, 1800, 1900, and 2000 that provides global patterns of historical transformation of the terrestrial biosphere during the Industrial Revolution.

In the past four centuries, the population of the United States has grown from a recorded 350 people around the Jamestown colony of Virginia in 1610, to an estimated 331 million people in 2020. The pre-colonization populations of the indigenous peoples of the Americas have proven difficult for historians to estimate, as their numbers decreased rapidly following the introduction of European diseases (namely smallpox, plague and influenza). Native Americans were also omitted from most censuses conducted before the twentieth century, therefore the actual population of what we now know as the United States would have been much higher than the official census data from before 1800, but it is unclear by how much. Population growth in the colonies throughout the eighteenth century has primarily been attributed to migration from the British Isles and the Transatlantic slave trade; however it is also difficult to assert the ethnic-makeup of the population in these years as accurate migration records were not kept until after the 1820s, at which point the importation of slaves had also been illegalized. Nineteenth century In the year 1800, it is estimated that the population across the present-day United States was around six million people, with the population in the 16 admitted states numbering at 5.3 million. Migration to the United States began to happen on a large scale in the mid-nineteenth century, with the first major waves coming from Ireland, Britain and Germany. In some aspects, this wave of mass migration balanced out the demographic impacts of the American Civil War, which was the deadliest war in U.S. history with approximately 620 thousand fatalities between 1861 and 1865. The civil war also resulted in the emancipation of around four million slaves across the south; many of whose ancestors would take part in the Great Northern Migration in the early 1900s, which saw around six million black Americans migrate away from the south in one of the largest demographic shifts in U.S. history. By the end of the nineteenth century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. Twentieth and twenty-first century The U.S. population has grown steadily throughout the past 120 years, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. In the past century, the U.S. established itself as a global superpower, with the world's largest economy (by nominal GDP) and most powerful military. Involvement in foreign wars has resulted in over 620,000 further U.S. fatalities since the Civil War, and migration fell drastically during the World Wars and Great Depression; however the population continuously grew in these years as the total fertility rate remained above two births per woman, and life expectancy increased (except during the Spanish Flu pandemic of 1918).

Since the Second World War, Latin America has replaced Europe as the most common point of origin for migrants, with Hispanic populations growing rapidly across the south and border states. Because of this, the proportion of non-Hispanic whites, which has been the most dominant ethnicity in the U.S. since records began, has dropped more rapidly in recent decades. Ethnic minorities also have a much higher birth rate than non-Hispanic whites, further contributing to this decline, and the share of non-Hispanic whites is expected to fall below fifty percent of the U.S. population by the mid-2000s. In 2020, the United States has the third-largest population in the world (after China and India), and the population is expected to reach four hundred million in the 2050s.

ResourcesMapTeacher guide Student worksheetGet startedOpen the map.Use the teacher guide to explore the map with your class or have students work through it on their own with the worksheet.New to GeoInquiriesTM? See Getting to Know GeoInquiries.Social Studies standardsC3: D2.His.14.9-12 – Analyze multiple, complex causes and effects of past events.C3: D2.Geo.2.9-12 – Use maps, satellite images, photographs, and other representations to explain relationships between the locations.C3: D2.Geo.7.9-12 – Analyze the reciprocal nature of how historical events and the spatial diffusion of ideas, technologies, and cultural practices have influenced migration patterns and the distribution of human population.Learning outcomesStudents will use geographic data to analyze climate characteristics of the 13 American colonies.Students will analyze population growth of the 13 American colonies.

We exploit regional variation in suitability for cultivating potatoes, together with time variation arising from their introduction to the Old World from the Americas, to estimate the impact of potatoes on Old World population and urbanization. Our results show that the introduction of the potato was responsible for a significant portion of the increase in population and urbaniza- tion observed during the eighteenth and nineteenth centuries. According to our most conservative estimates, the introduction of the potato accounts for approximately one-quarter of the growth in Old World population and urbanization between 1700 and 1900. Additional evidence from within-country comparisons of city populations and adult heights also confirms the cross-country findings.

During the eighteenth century, it is estimated that France's population grew by roughly fifty percent, from 19.7 million in 1700, to 29 million by 1800. In France itself, the 1700s are remembered for the end of King Louis XIV's reign in 1715, the Age of Enlightenment, and the French Revolution. During this century, the scientific and ideological advances made in France and across Europe challenged the leadership structures of the time, and questioned the relationship between monarchial, religious and political institutions and their subjects. France was arguably the most powerful nation in the world in these early years, with the second largest population in Europe (after Russia); however, this century was defined by a number of costly, large-scale conflicts across Europe and in the new North American theater, which saw the loss of most overseas territories (particularly in North America) and almost bankrupted the French crown. A combination of regressive taxation, food shortages and enlightenment ideologies ultimately culminated in the French Revolution in 1789, which brought an end to the Ancien Régime, and set in motion a period of self-actualization.

War and peace

After a volatile and tumultuous decade, in which tens of thousands were executed by the state (most infamously: guillotined), relative stability was restored within France as Napoleon Bonaparte seized power in 1799, and the policies of the revolution became enforced. Beyond France's borders, the country was involved in a series of large scale wars for two almost decades, and the First French Empire eventually covered half of Europe by 1812. In 1815, Napoleon was defeated outright, the empire was dissolved, and the monarchy was restored to France; nonetheless, a large number of revolutionary and Napoleonic reforms remained in effect afterwards, and the ideas had a long-term impact across the globe. France experienced a century of comparative peace in the aftermath of the Napoleonic Wars; there were some notable uprisings and conflicts, and the monarchy was abolished yet again, but nothing on the scale of what had preceded or what was to follow. A new overseas colonial empire was also established in the late 1800s, particularly across Africa and Southeast Asia. Through most of the eighteenth and nineteenth century, France had the second largest population in Europe (after Russia), however political instability and the economic prioritization of Paris meant that the entire country did not urbanize or industrialize at the same rate as the other European powers. Because of this, Germany and Britain entered the twentieth century with larger populations, and other regions, such as Austria or Belgium, had overtaken France in terms of industrialization; the German annexation of Alsace-Lorraine in the Franco-Prussian War was also a major contributor to this.

World Wars and contemporary France

Coming into the 1900s, France had a population of approximately forty million people (officially 38 million* due to to territorial changes), and there was relatively little growth in the first half of the century. France was comparatively unprepared for a large scale war, however it became one of the most active theaters of the First World War when Germany invaded via Belgium in 1914, with the ability to mobilize over eight million men. By the war's end in 1918, France had lost almost 1.4 million in the conflict, and approximately 300,000 in the Spanish Flu pandemic that followed. Germany invaded France again during the Second World War, and occupied the country from 1940, until the Allied counter-invasion liberated the country during the summer of 1944. France lost around 600,000 people in the course of the war, over half of which were civilians. Following the war's end, the country experienced a baby boom, and the population grew by approximately twenty million people in the next fifty years (compared to just one million in the previous fifty years). Since the 1950s, France's economy quickly grew to be one of the strongest in the world, despite losing the vast majority of its overseas colonial empire by the 1970s. A wave of migration, especially from these former colonies, has greatly contributed to the growth and diversity of France's population today, which stands at over 65 million people in 2020.

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Abstract of associated article: This paper explores the role of two foods, potatoes and milk, in explaining the increase in economic development experienced throughout the Old World in the 18th and 19th centuries. Nunn and Qian (2011) show the introduction of the potato from the New World has a significant explanatory role for within country population and urbanization growth over this period. I expand on this by considering the role of milk consumption, which is hypothesized to be a complement in diet to potatoes due to a differential composition of essential nutrients. Using a country-level measure for the suitability of milk consumption, the frequency of lactase persistence, I show that the marginal effect of potatoes on post-1700 population and urbanization growth is positively related to milk consumption. As the frequency of milk consumption approaches unity, the marginal effect of potatoes more than doubles in magnitude compared to the baseline estimate of Nunn and Qian.

Natural history collections are often thought to represent environments in a pristine natural state, free from human intervention – the so-called “wild”. In this study, we aim to assess the level of human influence represented by natural history collections of wild-collected primates over 120 years at the Smithsonian Institution’s National Museum of Natural History (NMNH). Our sample consisted of 875 catarrhine primate specimens in NMNH collections, representing 13 genera collected in 39 countries from 1882 to 2004. Using archival and accession information, we determined the approximate locations from which specimens were collected. We then plotted location coordinates onto publicly available anthrome maps created by Ellis et al. (2010), which delineate terrestrial biomes of human population density and land use worldwide since the 1700s. We found that among primates collected from their native ranges, 92% were from an environment that had some level of human impact, suggesting that the majority of presumed wild-collected primate specimens lived in an environment influenced by humans during their lifetimes. The degree to which human-modified environments may have impacted the lives of primates currently held in museum collections has been historically ignored, implicating unforeseen consequences for collections-based research. While unique effects related to commensalism with humans remain understudied, effects currently attributed to natural phenomena may, in fact, be related to anthropogenic pressures on unmanaged populations of primates.

Methods Sample

The study sample consisted of 875 specimens of nonhuman catarhine primates. These specimens are part of collections held by the Mammals Division of the Department of Vertebrate Zoology at the National Musuem of Natural History (NMNH), representing specimens collected in 39 countries over more than 120 years (1882-2004). All specimens were recorded as having been "wild collected" in NMNH accession records. The sample contained 13 catarrhine genera, including 344 individuals from secen genera of apes (Bunopithecus, Gorilla, Hylobates, Nomascus, Pan, Pongo, and Symphalangus), and 531 individuals from six genera of cercopithecine monkeys (Allenopithecus, Cercopithecus, Chlorocebus, Erythrocebus, Macaca, and Papio).

Methods

We utilized the anthrome global biome maps published by Ellis et al. (2010), showing a terrestrial classification range based on human population density and land use, derived largely from archaeological and ecological data sources. Configurations of anthropogenic landscape changes were assessed globally across terestrial biomes at 5' resolution (Ellis et al., 2010). Anthrome distribution was determined by combining potential vegetation makes (Ramankutty and Foley, 1999) with anthrome maps (Ellis and Ramankutty, 2008) at century intervals from 1700 to 2000, using overlay analysis. Anthromes are classified into 19 distinct types and grouped into common land-use schemes: dense settlements, villages, croplands, rangelands, seminatural areas, and wildlands. Data are provided for the 19th - 21st centuries across the vast majority of known terrestrial biomes for anthrome type descriptions (Ellis et al., 2010); all spatial data are publically available for download (http://ecotype.org/anthrome/v2).

Using the software tools of QGIS (Version 3.16, QGIS Development Team, 2021), collection points for each specimens and the anthrome map layers were imported into a single map for each relevant century interval. Based on the year of acquisition, primate specimens were grouped into the 19th, 20th, or 21st century anthrome map. From QGIS, specimens and corresponding anthrome data were exported into MS Excel (2021, v. 16.47.1) for analysis.

Sources

Ellis, E.C. & Ramankutty, N., 2008. Putting people in the map: anthropogenic biomes of the world. Frontiers in Ecology and the Environment, 6, pp. 439–447.

Ellis, E. C., Klein Goldewijk, K., Siebert, S., Lightman, D., & Ramankutty, N., 2010. Anthropogenic transformation of the biomes, 1700 to 2000. Global ecology and biogeography, 19(5), pp. 589-606.

Ramankutty, N. & Foley, J.A., 1999. Estimating historical changes in global land cover: croplands from 1700 to 1992. Global Biogeochemical Cycles, 13, pp. 997–1027.

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Many animal populations are under stress and declining. For numerous marine bird species, only recent or sparse monitoring data are available, lacking the appropriate temporal perspective needed to consider natural, long-term population dynamics when developing conservation strategies. Here we use a combination of established paleoenvironmental approaches to examine the millennial-scale dynamics of the world's largest colony (representing ~50% of the global population) of the declining and vulnerable Leach's Storm-petrel (Hydrobates leucorhous). By reconstructing the last ~1,700 years of the colony's population trends, we corroborate recent surveys indicating rapid declines since the 1980s. More surprisingly, however, was that population size was smaller and has changed strikingly in the past, even prior to the introduction of human stressors. Our results challenge notions that very large colonies are generally stable in the absence of anthropogenic pressures and speak to an increasingly pressing need to better understand inter-colony movement and recruitment when inferring range- and species-wide trends. While the recently documented decline in storm-petrels clearly warrants conservation concern, we show that colony size was consistently much lower in the past and changed markedly in the absence of major anthropogenic activity. In response, we emphasize the need for enlarged protected area networks to maintain natural population cycles, coupled with continued research to identify the driver(s) of the current global seabird decline.

Dutch, French, Italian (1818-1940): http://www.nber.org/chapters/c7435.pdf Dutch (1955-2009): http://www.nature.com/pr/journal/v73/n3/pdf/pr2012189a.pdf Swedish (1841-1952): http://pediatrisk-endokrinologi.no/2008/1/Werner_2008_1.pdf Danish and Germans (1856-1980): http://privatewww.essex.ac.uk/~hatton/Tim_height_paper.pdf Americans (1710-1980): http://www.cambridge.org/us/academic/subjects/history/economic-history/changing-body-health-nutrition-and-human-development-western-world-1700 All 2013 heights: http://www.averageheight.co/average-male-height-by-country Means and medians are not too different (rarely more than 1 cm difference) because within-country heights for specific gender are generally normally distributed.

Abstract

At the onset of the 2008-2009 global economic crisis, the Open Society Institute-Sofia and the World Bank partnered to implement Crisis Monitoring Survey (CMS). The CMS is a multi-topic household survey that followed three nationally representative cross-sections of about 2,400 households, including a panel of about 1,700 Bulgarian households, during February 2010, October 2010 and February 2011. The survey included a detailed income module, but no consumption module. It tracked the incidence of income shocks, the coping strategies used by affected households to mitigate the income losses, and the impact of public polices - social protection in particular - in alleviating the effects of the crisis. In particular, the survey investigated in some depth how households used the labor market to mitigate the impact of the crisis, whether formal social protection programs protected households against sliding into poverty, and the effectiveness of informal safety nets.

Given the special need to study the more vulnerable ethnic minority Roma population, an independent "booster sample" of about 300 households was selected in settlements and neighborhoods identified as predominantly Roma.

The first round of Crisis Monitoring Survey was conducted in February 2010. The data from this round is documented here.

Geographic coverage

National

Analysis unit

• households,
• individuals

Kind of data

Sample survey data [ssd]

Sampling procedure

Two samples were used in Crisis Monitoring Survey: main sample and booster sample.

The main sample was created in two stages.

First, the population was stratified by district (NUTS 3) and type of settlement. In Bulgaria, there are 28 administrative districts. For the type of settlement three categories were defined - rural, urban (with population under 50,000) and metropolitan (with population over 50,000). Bulgaria's capital, Sofia, is include in the metropolitan category. In this way 28 x 3=84 categories (strata) were defined and proportional allocation was made. The method of selecting settlements from each stratum is simple random sampling with replacement, weighted by the number of households in the settlement.

In the second stage, voting stations were chosen in each settlement. Voting stations were used as a type of cluster. Voting stations were selected with probability proportional to the number of voters in each station. In each cluster, (voting station), 20 household addresses were randomly selected from the list of all addresses in the station. The first 10 addresses, which had to be visited mandatorily, formed the main list. If there was a refusal in a household of the main list, this household had to be replaced with an address from the list of reserves (the last 10 addresses).

For the Roma booster sample, an expert database was used. It contained basic information for all segregated neighborhoods in the country like locality (district, municipality and settlement), an experts' approximation for the number of population, number of households, number of houses and other characteristics. The planned booster size sample was 300 households. Simple random sampling without replacement was used in segregated neighborhoods, weighted by their population. In this way, 30 segregated neighborhoods in 20 districts were selected. In each district, 10 randomly sampled households had to be interviewed. GPS sampling was used to identify households in each cluster.

Mode of data collection

Face-to-face [f2f]

Research instrument

The survey collected information about household demographics (roster), labor market participation and earnings, housing, durables, access to and receipts of social protection programs, informal safety nets and remittances, other income, credit, self-reported impact of the crisis, coping and mitigation mechanisms.

The Bulgaria Crisis Monitoring Survey combines modules that have been used in crisis surveys in a number of countries (including crisis-specific labor, credit, and coping strategies modules) with uniquely detailed modules on income and social assistance.

Response rate

The planned size of the main sample in the first round was 2,400 households, 2,384 households were interviewed. The planned size of the Roma booster sample was 300 households, 296 households were interviewed.

For each cluster, there was a list of 10 addresses that had to be visited by the interviewer and an additional 10 addresses in reserve. If any of the first 10 addresses did not exist, dwellings were locked for a long time or the people refused to be interviewed, the additional ones were used. According to instructions, the interviewer had to visit each address in the main list three times, unless the building (or apartment) was obviously uninhabited. The interviewer had to write down what happened at each visit to each address on the list. At addresses where the interview did not take place, the interviewer noted the reason. Once an interview was done, the questionnaire got an ID that showed whether the address was on the original list or not.

A global map of anthropogenic transformations of terrestrial biomes has been produced to characterize the ecosystem changes due to anthropogenic influences before and during the Industrial Revolution, from 1700 to 2000. Patterns of anthropogenic transformations were assessed at 5 min resolution by comparing potential natural vegetation maps (Ramankutty and Foley, 1999; Olson et al., 2001) with the anthrome map of Ellis and Ramankutty (2008) circa 2000, global, historical gridded data for human population density and agricultural and urban land use from the HYDE data model (Klein Goldewijk and van Drecht, 2006), ORNL LandScan population data, irrigated land data (Siebert et al., 2007), rice cover data (Monfreda et al., 2008), and other agricultural census data at century intervals (1700, 1800, 1900, and 2000). The investigators used overlay analysis and other analytical geographic information system (GIS) software tools to produce the four data sets and maps. For more information, see Ellis, E.C., Kees Klein Goldewijk, K., Siebert, S., Lightman, D., and Ramankutty, N. 2010. Anthropogenic transformation of the biomes, 1700 to 2000. Global Ecology and Biogeography 19: 589-606. References: Ellis, E.C., and N. Ramankutty. 2008. Putting people in the map: anthropogenic biomes of the world. Frontiers in Ecology and the Environment 6(8): 439-447. Monfreda, C., N. Ramankutty, and J. A. Foley. 2008. Farming the planet: 2. Geographic distribution of crop areas, yields, physiological types, and net primary production in the year 2000, Global Biogeochem. Cycles, 22, GB1022, doi:10.1029/2007GB002947; Ramankutty, N., A.T. Evan, C. Monfreda, and J.A. Foleyl. 2008. Farming the planet: 1. Geographic distribution of global agricultural lands in the year 2000. Global Biogeochemical Cycles 22, GB1003, doi:10.1029/2007GB002952; Siebert, S., P. Doll, S. Feick, J. Hoogeveen, and K. Frenken. 2007. Global map of irrigation areas version 4.0.1. Johann Wolfgang Goethe University, Frankfurt am Main, Germany/Food and Agriculture Organization of the United Nations, Rome, Italy; Oak Ridge National Laboratory (2006) LandScan Global Population Database. Oak RidgeNational Laboratory, Oak Ridge, TN. [http://www.ornl.gov/landscan]; and Olson, D.M., E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N Powell, E.C. Underwood, J.A. D’Amico, I. Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, T.H. Ricketts, Y. Kura, J.F. Lamoreux, W.W. Wettengel, P. Hedao, and K.R. Kassem. 2001. Terrestrial ecoregions of the world: a new map of life on Earth. BioScience 51: 933–938.

At over four kilometers above sea level, Potosí, Bolivia is one of the highest cities in the world. According to census data from 2012, the population of Potosí was almost 176,000 people; a figure that is barely 16 thousand more than its estimated population four centuries before. It is estimated that the population of Potosí grew from 14 thousand in 1547, to 150 thousand by the turn of the 17th century (and some estimates suggest that it exceeded 200,000 in subsequent decades). With this explosion in population growth, Potosí quickly became the most populous city in the Americas, and was even larger than most European cities in the 17th century. This growth came following the discovery of silver deposits in 1545 in a nearby mountain, later named Cerro Rico ("Rich Hill"); this silver would provide a significant share of the Spanish crown's wealth during the 16th century, helping Spain grow to become the most powerful nation on earth at this time. Forced labor Following the defeat of the Incas in 1536, Spanish colonizers then subjugated the native populations of the Andes and put them to work. As it was impractical and expensive to transport African slaves to this region of the Andes, and the New Laws of 1542 prohibited the enslavement of indigenous Americans, the Spanish simply used violence and intimidation to force local populations to mine the silver at Potosí. The Incan tradition of Mit'a; where adult males were drafted to provide mandatory labor for the betterment of local infrastructure and facilities; was eventually appropriated by Spanish authorities as the legal basis of their demand for labor from local areas. It is estimated that one in every seven indigenous adult males was drafted from nearby communities to work in the mines of Potosí. Some reports suggest that the locals viewed this work as a death sentence, as the survival rate among drafted workers was fewer than 15 percent in some periods. There are further reports that forced laborers were expected to do the most strenuous tasks, which included carrying 25 or 45 kilogram sacks of silver along 300 meter shafts, as often as 25 times per day. The high death rate was not only due to over-intensive labor, accidents and injuries (cave-ins were common), but also malnutrition, disease and extreme temperatures and altitudes, as well as respiratory illnesses caused by the inhalation of dust, mercury and arsenic, among others.

"Valer un Potosí" Around the turn of the 17th century, the Spanish Americas produced almost all of the silver mined in the world. The Spanish crown claimed a significant share of this silver, and in some years, Potosí silver was responsible for a quarter of all Spanish revenues. This silver also played a significant part in the emergence of inter-continental trade, as a large portion of it was eventually used as currency for trade with China; some historians define this as the birth of the global economy. Eventually, the legend of Potosí grew, attracting thousands of voluntary workers from all over the Americas, as well as large numbers of Europeans in search of fortune. The silver deposits began to dry up in the mid-1600s, and the population dropped to just 60,000 by the end of the century, when silver output was just one third of its peak level. As time passed, the silver all but disappeared, and miners turned to other materials such as tin, zinc and copper (which continue to be procured today); however the legacy of Potosí's wealth continues and is used in the Spanish language when describing something of considerable value as being; "valer un Potosí" (worth a Potosí).

The region of present-day China has historically been the most populous region in the world; however, its population development has fluctuated throughout history. In 2022, China was overtaken as the most populous country in the world, and current projections suggest its population is heading for a rapid decline in the coming decades. Transitions of power lead to mortality The source suggests that conflict, and the diseases brought with it, were the major obstacles to population growth throughout most of the Common Era, particularly during transitions of power between various dynasties and rulers. It estimates that the total population fell by approximately 30 million people during the 14th century due to the impact of Mongol invasions, which inflicted heavy losses on the northern population through conflict, enslavement, food instability, and the introduction of bubonic plague. Between 1850 and 1870, the total population fell once more, by more than 50 million people, through further conflict, famine and disease; the most notable of these was the Taiping Rebellion, although the Miao an Panthay Rebellions, and the Dungan Revolt, also had large death tolls. The third plague pandemic also originated in Yunnan in 1855, which killed approximately two million people in China. 20th and 21st centuries There were additional conflicts at the turn of the 20th century, which had significant geopolitical consequences for China, but did not result in the same high levels of mortality seen previously. It was not until the overlapping Chinese Civil War (1927-1949) and Second World War (1937-1945) where the death tolls reached approximately 10 and 20 million respectively. Additionally, as China attempted to industrialize during the Great Leap Forward (1958-1962), economic and agricultural mismanagement resulted in the deaths of tens of millions (possibly as many as 55 million) in less than four years, during the Great Chinese Famine. This mortality is not observable on the given dataset, due to the rapidity of China's demographic transition over the entire period; this saw improvements in healthcare, sanitation, and infrastructure result in sweeping changes across the population. The early 2020s marked some significant milestones in China's demographics, where it was overtaken by India as the world's most populous country, and its population also went into decline. Current projections suggest that China is heading for a "demographic disaster", as its rapidly aging population is placing significant burdens on China's economy, government, and society. In stark contrast to the restrictive "one-child policy" of the past, the government has introduced a series of pro-fertility incentives for couples to have larger families, although the impact of these policies are yet to materialize. If these current projections come true, then China's population may be around half its current size by the end of the century.

In vitro and in vivo evolution experiments on Escherichia coli revealed several principles of bacterial adaptation. However, few data are available in the literature describing the behavior of E. coli in its natural environment. We attempted here to study the evolution in the human gut of a commensal dominant E. coli clone ED1a belonging to B2 phylogroup, through a longitudinal genomic study. We sequenced 24 isolates sampled at three different time points within a healthy individual over almost a year. We computed amutation rate of 6.90x10-7 per base per year of the chromosome for E. coli ED1a in healthy human gut. We observed a very limited genomic diversity, and could not detect any evidence of selection contrary to what is observed in experimental evolution over similar length of time. We therefore suggest that ED1a being well adapted to the healthy human gut evolves mostly neutrally with a low effective population size (Ne ≈ 500 – 1700).