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Number Of Humans Who Have Ever Lived
This article lists current estimates of the world population in history. In summary, estimates for the progression of world population since the Late Middle Ages are in the following ranges: Estimates for pre-modern times are necessarily fraught with great uncertainties, and few of the published estimates have confidence intervals; in the absence of a straightforward means to assess the error of such estimates, a rough idea of expert consensus can be gained by comparing the values given in independent publications. Population estimates cannot be considered accurate to more than two decimal digits; for example, the world population for the year 2012 was estimated at 7.02, 7.06, and 7.08 billion by the United States Census Bureau, the Population Reference Bureau, and the United Nations Department of Economic and Social Affairs, respectively, corresponding to a spread of estimates of the order of 0.8%. Deep prehistory As a general rule, the confidence of estimates on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projections Of Population Growth
Human population projections are attempts to extrapolate how human populations will change in the future. These projections are an important input to Forecasting, forecasts of the population's impact on this planet and humanity's future well-being. Models of population growth take trends in Human development (economics), human development and apply projections into the future. These models use trend-based-assumptions about how populations will respond to economic, social and technological forces to understand how they will affect Total fertility rate, fertility and Mortality rate, mortality, and thus population growth. The 2022 projections from the United Nations Department of Economic and Social Affairs, United Nations Population Division (chart #1) show that annual world population growth peaked at 2.3% per year in 1963, has since dropped to 0.9% in 2023, equivalent to about 74 million people each year, and could drop even further to minus 0.1% by 2100. Based on this, the UN pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hunter-gatherer
A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived Lifestyle, lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources, especially wild edible plants but also insects, Fungus, fungi, Honey hunting, honey, Eggs as food, bird eggs, or anything safe to eat, or by hunting game (pursuing or trapping and killing Wildlife, wild animals, including Fishing, catching fish). This is a common practice among most vertebrates that are omnivores. Hunter-gatherer Society, societies stand in contrast to the more Sedentism, sedentary Agrarian society, agricultural societies, which rely mainly on cultivating crops and raising domesticated animals for food production, although the boundaries between the two ways of living are not completely distinct. Hunting and gathering was humanity's original and most enduring successful Competition (biology), competitive adaptation in the nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Overpopulation
Human overpopulation (or human population overshoot) is the idea that human populations may become too large to be sustainability, sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities. Since 1804, the global living human population has World population milestones, increased from 1 billion to 8 billion due to Modern medicine, medical advancements and improved agricultural productivity. Annual world population growth peaked at 2.1% in 1968 and has since dropped to 1.1%. According to the most recent Projections of population growth, United Nations' projections, the global human population is expected to reach 9.7 billion in 2050 and would peak at around 10.4 billion people in the 2080s, before decreasing, noting that fertility rates are falling worldwide. Other models agree that the population will stabilize before or after 2100. Conversely, some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Explosion
Overpopulation or overabundance is a state in which the population of a species is larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale migration, leading to an overabundant species and other animals in the ecosystem competing for food, space, and resources. The animals in an overpopulated area may then be forced to migrate to areas not typically inhabited, or die off without access to necessary resources. Judgements regarding overpopulation always involve both facts and values. Animals are often judged overpopulated when their numbers cause impacts that people find dangerous, damaging, expensive, or otherwise harmful. Societies may be judged overpopulated when their human numbers cause impacts that degrade ecosystem services, decrease human health and well-being, or crowd other species out of existence. Background In ecology, overpopulation is a concept used primarily in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Population Size
The effective population size (''N''''e'') is the size of an idealised population that would experience the same rate of genetic drift as the real population. Idealised populations are those following simple one- locus models that comply with assumptions of the neutral theory of molecular evolution. The effective population size is normally smaller than the census population size ''N'', partly because chance events prevent some individuals from breeding, and partly due to background selection and genetic hitchhiking. The same real population could have a different effective population size for different properties of interest, such as genetic drift (or more precisely, the speed of coalescence) over one generation vs. over many generations. Within a species, areas of the genome that have more genes and/or less genetic recombination tend to have lower effective population sizes, because of the effects of selection at linked sites. In a population with selection at many loci an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Geophysical Research
The ''Journal of Geophysical Research'' is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the understanding of the Earth, Sun, and Solar System. It has seven sections: A (Space Physics), B (Solid Earth), C (Oceans), D (Atmospheres), E (Planets), F (Earth Surface), and G (Biogeosciences). All current and back issues are available online for subscribers. History The journal was originally founded under the name ''Terrestrial Magnetism'' by the American Geophysical Union's president Louis Agricola Bauer in 1896. It was renamed to ''Terrestrial Magnetism and Atmospheric Electricity'' in 1899 and in 1948 it acquired its current name. In 1980, three specialized sections were established: ''A: Space Physics'', ''B: Solid Earth'', and ''C: Oceans''. Subsequently, further sections have been added: ''D: Atmospheres'' in 1984, ''E: Planets' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Human Evolution
The ''Journal of Human Evolution'' is a monthly peer-reviewed scientific journal that concentrates on publishing the highest quality papers covering all aspects of human evolution. JHE was established in 1972 by Academic Press in the United Kingdom and is currently published by Elsevier. The central focus of JHE is aimed jointly at paleoanthropological work, covering human and primate fossils, and at comparative studies of living species, including both morphological and molecular evidence. These include descriptions of new discoveries, analyses and interpretations of new and previously described material, and assessments of the phylogeny and paleobiology of primate species. In addition to original research papers, space is allocated for the rapid publication of short communications on new discoveries, such as exciting new fossils, as well as lead book reviews, obituaries and review papers of exceptionally high quality. The journal received a 2023 impact factor of 3.656. The edi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homo Sapiens
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing#Evolution of hairlessness, hairlessness, bipedality, bipedalism, and high Human intelligence, intelligence. Humans have large Human brain, brains, enabling more advanced cognitive skills that facilitate successful adaptation to varied environments, development of sophisticated tools, and formation of complex social structures and civilizations. Humans are Sociality, highly social, with individual humans tending to belong to a Level of analysis, multi-layered network of distinct social groups — from families and peer groups to corporations and State (polity), political states. As such, social interactions between humans have established a wide variety of Value theory, values, norm (sociology), social norms, languages, and traditions (co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toba Catastrophe Theory
The Toba eruption (also called the Toba supereruption and the Youngest Toba eruption) was a supervolcanic eruption that occurred around 74,000 years ago, during the Late Pleistocene, at the site of present-day Lake Toba, in Sumatra, Indonesia. It was the last in a series of at least four caldera-forming eruptions there, the earlier known caldera having formed about 1.2 million years ago. This, the last eruption, had an estimated volcanic explosivity index of 8, making it the largest known explosive volcanic eruption in the Quaternary, and one of the largest known explosive eruptions in the Earth's history. Eruption Chronology of the Toba eruption The exact date of the eruption is unknown, but the pattern of ash deposits suggests that it occurred during the northern summer because only the summer monsoon could have deposited Toba ashfall in the South China Sea. The eruption lasted perhaps 9 to 14 days. The most recent two high-precision argon–argon datings dated the erupt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as genocide, speciocide, widespread violence or intentional culling. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring. Genetic diversity remains lower, increasing only when gene flow from another population occurs or very slowly increasing with time as random mutations occur. This results in a reduction in the robustness of the population and in its ability to adapt to and survive selecting environmental changes, such as climate change or a shift in available resources. Alternatively, if survivors of the bottleneck are the individuals with the greatest genetic fitness, the frequency of the fitter genes within the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoanthropology
Paleoanthropology or paleo-anthropology is a branch of paleontology and anthropology which seeks to understand the early development of anatomically modern humans, a process known as hominization, through the reconstruction of evolutionary kinship lines within the family Hominidae, working from biological evidence (such as petrified skeletal remains, bone fragments, footprints) and cultural evidence (such as stone tools, artifacts, and settlement localities). The field draws from and combines primatology, paleontology, biological anthropology, and cultural anthropology. As technologies and methods advance, genetics plays an ever-increasing role, in particular to examine and compare DNA structure as a vital tool of research of the evolutionary kinship lines of related species and genera. Etymology The term paleoanthropology derives from Greek palaiós (παλαιός) "old, ancient", ánthrōpos (ἄνθρωπος) "man, human" and the suffix -logía (-λογία) "study of". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Paleolithic
The Upper Paleolithic (or Upper Palaeolithic) is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 12,000 years ago (the beginning of the Holocene), according to some theories coinciding with the appearance of behavioral modernity in early modern humans. It is followed by the Mesolithic. Anatomically modern humans (i.e. ''Homo sapiens'') are believed to have emerged in Africa around 300,000 years ago. It has been argued by some that their ways of life changed relatively little from that of archaic humans of the Middle Paleolithic, until about 50,000 years ago, when there was a marked increase in the diversity of Artefact (archaeology), artefacts found associated with modern human remains. This period coincides with the most common date assigned to early human migrations, expansion of modern humans from Africa throughout Asia and Eurasia, which may have contributed to the Neanderthal extinction, extinction of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
