RANGE OF HOMO ERECTUS
Java Man Homo erectus remains have been found in East Africa, southern Africa, Morocco, Algeria, Georgia, China, Indonesia and one site in Europe. Most scientists think Homo erectus originated in Africa and migrated to Asia and Europe.
As far as we can ascertain Homo erectus never made it to America or Australia. It seems to have made it as far east as the Indonesian island of Bali, which was separated from the eastern islands of Indonesia, New Guinea and Australia by a trench of deep water. Sumatra, Java and Bali were connected to Southeast Asia by land bridges created when the sea levels dropped during the paleolithic ice ages. Homo erectus may have made it the Indonesian island of Flores, which was not connected by land bridges to Southeast Asia. See Early Crossings of the Wallace Line
Wilford Wolpoff of the University of Michigan says that Homo erectus left Africa "because they wanted to, because they had to, and especially because they could." For a long time it was thought that it took Homo erectus a million years to migrate out of Africa to eastern Asia. Some scientists felt the invention of advanced tools or a climatic change was necessary to allow such a migration to take place.
Scientists still debate whether or not Homo erectus made it to Europe. The cooler climate in Europe would have at least kept the tropical species from prospering there, especially during the ice ages. The only European remains attributed to Homo erectus are skull fragments excavated in Europe came from Mauer, Germany. The fragments seem to be consistent with other Homo erectus skulls but the results are far from conclusive.
Websites and Resources: Modern Human Origins modernhumanorigins.com ; Talk Origins Index talkorigins.org/origins ; Hall of Human Origins American Museum of Natural History amnh.org/exhibitions ; Time Space Chart Hominin Fossils Pictures msu.edu/~heslips ; Smithsonian Human Origins Program humanorigins.si.edu ; Wikipedia article on Human Evolution Wikipedia ; Becoming Human University of Arizona site becominghuman.org ; Human Evolution Images evolution-textbook.org ;Hominin Species talkorigins.org ; Institute of Human Origins iho.asu.edu ; Paleoanthropology Link talkorigins.org ; Britannica Human Evolution britannica.com/EBchecked/topic/275670/human-evolution ;Modern Human Origins modernhumanorigins.com ; Human Evolution handprint.com ; Paleoanthropology and Evolution Links unipv.it/webbio/dfpaleoa ;National Geographic Atlas of the Human Journey genographic.nationalgeographic.com/genographic/atlas ; Yale Peabody Museum peabody.yale.edu/exhibits/fossils ; Humin Origins Washington State University wsu.edu/gened/learn-modules ; Book: The Human Evolution Source Book
Meat and Migration
Homo erectus model The move to carnivorous eating is thought to have required more sophisticated skills and tools than collecting plants and fruits, pushing hominins to develop a larger brain.
Pennsylvania State paleontologist Alan Walker believes that the transition of hominins from plant to meat eaters was an important factor in migration of Homo erectus . Herbivores usually stay close to familiar plant species. "Meat is meat," Walker told National Geographic. "Once you start eating it, you can take advantage of other animals' adaptions to the various plants and spread over enormous distances."
Walker told Time; "If you spread 20 miles every 20 years, it wouldn't take long to go that far...Once you become carnivore the world is different. Carnivores need immense home ranges. There was a qualitative difference between these creatures and other primates. I think they actively hunted. I've always said that they should have gotten out of Africa as soon as possible."
Nick Toth, an archaeologist from Indiana University, told National Geographic: "Meat gave them a new way to survive when the climate changed and their staple vegetation disappeared." Some scientists believe that Homo erectus was more of a scavenger than a hunter. They speculate it may have followed after lions and leopards as they migrated in pursuit of prey and used circling vultures to locate kills while scavenging.
Study: Female Ancestors Wandered, Males Stayed Put
Seth Borenstein of AP wrote, “In modern times, men explored the New World. But 2 million years earlier, the men among our pre-human forerunners stayed put and it was the women who traveled to start new families, a study of fossil teeth from Africa suggests. The findings, published in the journal Nature, indicate females from two pre-human species seemed to move out of their birth homes and journey elsewhere, probably to prevent inbreeding, researchers said. Chimpanzees, our closest living primate relative, also have females that travel to mate and raise families. That's in contrast to lower primates and most mammals where it is the males that have the wanderlust. [Source: Seth Borenstein, AP, June 1, 2011]
Researchers studied 19 teeth, including eight from Australopithecus africanus individuals, a species considered a probable ancestor from about 2.2 million years ago. The other 11 were from Paranthropus robustus individuals, a dead-end species that was not our direct ancestors but more like prehistoric aunts and uncles from 1.8 million years ago.They looked for the mineral strontium in the teeth because that element varies by landscape. The idea was to see if they moved to different areas during various seasons. The research didn't show that, but something else popped up: The bigger teeth showed almost no mineral variation while more than half of the smaller teeth indicated they were from individuals that grew up elsewhere. So the researchers figure this was a male-female difference. Other scientists not involved in the research, though, said the tooth sample may be too small to draw that conclusion.
The study's lead author, Sandi Copeland, a paleoanthropologist at the University of Colorado, said the switch from male to female dispersal may indicate the start of a sense community, which has its evolutionary advantages. And it continues in many societies to this day. In less evolved animals, it makes evolutionary sense for the male to wander and impregnate many females and show might. In this case, the female moving could show that males in a community have bonded and cooperated, maybe for common defense. So it makes sense for the men to settle, while the females disperse, Copeland said. "There must be an evolutionary benefit for females to disperse," Copeland said.
University of Oxford archaeologist Michael Petraglia, who wasn't part of the study, said the research was intriguing, showing that our forerunners' "social relations and mating patterns are more in line with ours than with gorillas." But like Richard Potts of the Smithsonian Institution, Petraglia worried that the research may be drawing too many conclusions from a small number of teeth from a large time period. Study co-author Darryl de Ruiter at Texas A&M University said researchers were limited in how many samples they could use because tests destroyed parts of the fossil and they only used the largest and smallest teeth.
Out of Africa Theory
There are various theories describing how migration patterns played a part in the development of early humans. The traditional, widely-accepted "Single Origin, Out of Africa Theory" of human evolution posits that earliest hominins evolved in Africa; that Australopithecus species evolved into Homo species in Africa; that early Homo species migrated to Asia and the Old World from Africa between a million and two million years ago; and that Homo sapiens also evolved in Africa.
According to the “Out of Africa" theory there were two migration of African-born Homo species. First, Homo erectus began slowly moving into the Middle East, Europe and Asia between a million and two million years ago. Homo erectus splintered into numerous colonies that developed separately from one another. None of the colones outside of Africa contributed to the development of Homo sapiens , which also originally evolved in Africa.
The traditional, widely-accepted "Single Origin, Out of Africa Theory" of human evolution posits that: 1) earliest hominids evolved in Africa; 2) Australopithecus species evolved into Homo species in Africa; 3) early Homo species migrated to Asia and the Old World from Africa between a million and two million years ago; and 4) Homo sapiens also evolved in Africa and migrated outward from there.
The traditional "Out of Africa" theory holds that there were two migration of African-originating species. First, Homo erectus began slowly moving into the Middle east, Europe and Asia around 1.8 million years ago. And second, Homo sapiens began migrating into the same areas starting around 100,000 year ago. Scientists that uphold this theory argue that all modern humans have evolved from African Homo sapiens.
Chris Stringer wrote in The Guardian: According to the "Out of Africa" theory “Homo erectus survived in East Asia and Indonesia but evolved into Homo heidelbergensis in Europe and Africa. (This last species had been named from a 600,000-year-old jawbone found in Germany in 1907.) Then, about 400,000 years ago, H. heidelbergensis underwent an evolutionary split: north of the Mediterranean it developed into the Neanderthals, while to the south, in Africa, it became us, modern humans. Finally, about 60,000 years ago Homo sapiens began to leave Africa and by 40,000 years ago, with the advantages of more complex tools and behaviours, spread into Asia and Europe, where we replaced the Neanderthals and all the other archaic people outside of Africa. In other words, under our skins, we are all Africans. [Source: Chris Stringer, The Guardian, June 19, 2011. Stringer is head of human origins at the Natural History Museum in London]
Out of Africa Theory and Homo Erectus
Proponents of the Out of Africa theory argue that Homo erectus spread across Africa during the first 800,000 years after first appearing 1.8 million years ago. It moved to Asia but for some reason stayed out Europe. They argue that all modern humans have evolved from African Homo species.
Recent dating of fossils in Georgia, China and Indonesia suggests that Homo erectus may have migrated into Asia as early as 2 million years ago and migrated across the continent very quickly. This conclusion is based on fossils found in Georgia, China and Indonesia that have been dated to be between 1.7 million and 1.9 million years old.
Scientists believe that the effects of climate on food sources and habitat played a major part in the migration. Richard Leakey thinks that Homo erectus migrated out of Africa along the Nile. Many think Homo erectus ventured through the Middle East to places such as Dmanisi in Geogia.
Hominins are thought to have most likely migrated across what is called the Levantine Corridor through what is now Israel, Jordan, and Lebanon. It embraces the Jordan River and the Dead Sea and a geologic zone that included the Red Sea which began opening up between the African and Arabian tectonic plates around 2 million years ago, the time the first migrants were thought to have emerged from Africa. At that time the Levantine Corridor was a verdant area with lakes and lots of animals and plants that could have been consumed as food.
Evidence for Out of Africa Theory
Evidence for the “Out of Africa” theory includes a trail of stone tools, including carefully-crafted hand axes, that appear to have originated in Africa. Scientists also point out that many sophisticated hand ax are found in Africa but none have been found in Asia.
Thousands of primitive 1.5-million- to 1.4-million-year-old hand axes have been found in Ubeidya, Israel in the Levantine Corridor. Ubeidya is a vanished lake just south of the Sea of Galilee. Stone tools and fossils of large mammals found near the tools have been dated to 1.4 million years ago. Hand axes similar to one found there have been found throughout Europe and Asia. Hand axes found north of Lake Tiberias suggests there was another round migration through the Levantine Corridor around 780,000 years ago.
The earliest known Oldowan tools date from 2.6 million years ago and were in Gona, Ethiopia. After this date, the Oldowan Industry spread throughout much of Africa. Archaeologists are currently unsure which Hominin species first developed them, with some speculating that it was Australopithecus garhi, and others saying it was Homo habilis. Homo habilis used them for a long period. About 1.9-1.8 million years ago Homo erectus inherited them. The Industry flourished in southern and eastern Africa between 2.6 and 1.7 million years ago, but also spread out of Africa and into Eurasia with homo erectus, who took Oldowan tool as far east as Java by 1.8 million years ago and Northern China by 1.6 million years ago. +
The Dmanisi hominins are the earliest hominins of the Homo genus found outside Africa José María Bermúdez de Castro at the National Research Centre on Human Evolution in Burgos, Spain told New Scientist.“In my view, after that first demographic spread out of Africa, a rapid expansion to the east and west could happen,” he says. “It is very probable that hominins arrived in the extreme parts of the Eurasian continent by 1.6 million years.” Warm and humid conditions at the time helped speed up the migration, Bermúdez de Castro thinks. “It is important to remember that we are ‘tropical’ primates,” he says. “The Sierra de Atapuerca is 1000 metres above sea level. So we assume the climate was warmer than today when hominins arrived there.” [Source: Colin Barras, New Scientist, 26 March 2008]
Genetic studies of 28 of China's 56 ethnic groups, published by the Chinese Human Genae Diversity Project in 2000, indicate that the first Chinese descended from Africans who migrated their way along the Indian Ocean and made their way to China via Southeast Asia.
Out of Africa, Multiregional and Assimilation Models
There are various theories describing how migration patterns played a part in the development of early humans.Charles Q. Choi wrote in Live Science: “The most bitterly debated question in the discipline of human evolution is likely over where modern humans evolved. The out-of-Africa hypothesis maintains that modern humans evolved relatively recently in Africa and then spread around the world, replacing existing populations of archaic humans. The multiregional hypothesis contends that modern humans evolved over a broad area from archaic humans, with populations in different regions mating with their neighbors to share traits, resulting in the evolution of modern humans. The out-of-Africa hypothesis currently holds the lead, but proponents of the multiregional hypothesis remain strong in their views.”[Source: Charles Q. Choi, Live Science, February 22, 2011]
Chris Stringer wrote in The Guardian: The idea of multiregional evolution” is ”an updated version of ideas from the 1930s. It envisaged deep parallel lines of evolution in each inhabited region of Africa, Europe, Asia and Australasia, stretching from local variants of H. erectus right through to living people in the same areas today. These lines did not diverge through time, since they were glued together by interbreeding across the ancient world, so modern features could gradually evolve, spread and accumulate, alongside long-term regional differences in things like the shape of the face and the size of the nose. [Source: Chris Stringer, The Guardian, June 19, 2011 ><]
“The assimilation model “took the new fossil and genetic data on board and gave Africa a key role in the evolution of modern features. However, this model envisaged a much more gradual spread of those features from Africa than did mine. Neanderthals and archaic people like them were assimilated through widespread interbreeding. Thus the evolutionary establishment of modern features was a blending process rather than a rapid replacement.” ><
The redating of Java Man to be 1.7 million years old instead of 1 million years old and the discovery of some old hominin fossils in China has led some scientists question the "Out of Africa Theory" and suggest a more complex the "Multiregional Hypothesis." According to "Multiregional Hypothesis," separate regional populations of Homo Erectus may have evolved into Homo Sapiens while intermingling with one another. Other suggest that a separate Asian and African species arose and that the Asian species later died out. [Source: Michael Lemonick, Time, March 14, 1994]
According to the "Multiregional Theory" Homo erectus evolved in Africa but it was a highly variable species whose descendants formed regional races after it migrated into Asia and Europe. Traces of the regional difference can still be found in modern races today (i.e., the shovel-like shape of the incisor teeth of East Asian people). The races evolved in near isolation but there was enough intermingling so that didn't evolve into separate species.
Proponents of the Multiregional Theory refute the genetic diversity argument of the Out of Africa theorists by arguing that population size could account for the differences. In the 19th century viewpoints similar to the Multiregional Theory were used to support racist views that some races were inferior to others and to justify slavery. Recent discoveries of early modern man in Ethiopia and South Africa and Homo erectus in Dmanisi Georgia have led most scientists to throw out Multiregional Theory.
Map of modern human migrations (not Homo erectus) beginning
140,000 years ago based on genetic evidence
Candelabra Versus Multiregional Hypothesises
Saioa López, Lucy van Dorp and Garrett Hellenthal of University College London wrote: “The debate dominating much of the anthropological discourse throughout the second half of the 20th century focused on where and when archaic hominins evolved into modern Homo sapiens, which we refer to as anatomically modern humans (AMH) throughout. Two main hypotheses dominated the discourse: the multiregional and the replacement hypotheses. The original multiregional model was proposed by the anthropologist Weidenreich in 1946 and advocated significant gene flow among subpopulations of Homo erectus living in different parts of the globe throughout the Pleistocene, so that modern humans trace their ancestry to multiple hominin groups living in multiple regions. Confusingly, the term “multiregional” model often has been used synonymously with the so-called candelabra model, originally proposed by Coon in 1962. [Source: Saioa López, Lucy van Dorp and Garrett Hellenthal of University College London, “Human Dispersal Out of Africa: A Lasting Debate,” Evolutionary Bioinformatics, April 21, 2016 *~*]
“The candelabra model hypothesizes that our early hominin ancestors, after leaving Africa 1 million years ago and migrating to other continents, independently evolved anatomically modern features. Under this model, the modern human form arose autonomously at multiple times and locations worldwide within the last 1 million years, so that modern non-African populations each primarily descended from separate evolutions of these Homo species. This is in contrast to the traditionally proposed multiregional model, which importantly does not propose independent parallel evolution of Anatomically modern humans features. *~*
“The main fossil evidence in support of the multiregional and candelabra hypotheses was the discovery of the Dali Man in China. For multiregionalists or candelabra supporters, the mixture of archaic and modern features was evidence of a midway stage between early and modern hominins. That said, these fossils are poorly preserved, and some authors have suggested that these anatomical characteristics are in fact shared by other Homo worldwide, and thus were not unique to Asia. Some genetic studies also offered support to a multiregional and candelabra models, inferring the origin of a few genetic loci outside of the African continent. Examples include the oldest haplotype in the human dystrophin gene, which was found to be absent in Africans, although this was later explained as resulting from adaptive introgression from Neanderthals rather than providing support for the candelabra model.” *~*
Candelabra Versus Replacement (Out of Africa) Hypothesis
Saioa López, Lucy van Dorp and Garrett Hellenthal of University College London wrote: “Opposition to the candelabra hypothesis has come from both paleontological and genetic studies. The replacement, or out of Africa (OoA), model proposes a single and relatively recent transition from archaic hominins to Anatomically modern humans in Africa, followed by a later migration to the rest of the world, replacing other extant hominin populations. Under this model, these hominins were driven to extinction, so that most of the genetic diversity in contemporary populations descends from a single or multiple groups of Anatomically modern humans who spread out of Africa sometime in the last 55,000–200,000 years, although debate remains on the precise timings (note that, in light of admixture from extinct hominin groups, the Out of Africa model is consistent with the original multiregional model but not the candelabra model). [Source: Saioa López, Lucy van Dorp and Garrett Hellenthal of University College London, “Human Dispersal Out of Africa: A Lasting Debate,” Evolutionary Bioinformatics, April 21, 2016 *~*]
“The first genetic evidence consistent with the Out of Africa model was provided by the study of mitochondrial DNA (mtDNA) phylogenetic trees, which identified Africa as the source of human mtDNA gene pool.11,16–18 It was shown that all mtDNA haplogroups outside of Africa can be attributed to either the M or N haplogroups, which arose around 60,000–65,000 years ago in South Asia19 and are thought to descend from the L3 haplogroup postulated to have arisen in East Africa around 80,000 years ago. This was supported by further studies of mtDNA, Y chromosome, and autosomal regions that suggested the existence of a common African ancestor. More recently, multilocus studies of genome-wide data have demonstrated that genetic diversity decreases as a function of geographic distance from East or South Africa, for example, as shown by an approximately linear decrease in heterozygosity and increase in linkage disequilibrium (LD), a finding consistent with the Out of Africa model. *~*
“Several further replacement models exist, which differ in their emphasis. Harding and McVean, for example, proposed a more complex meta-population system for the origins of the first Anatomically modern humans. The authors highlight evidence suggesting that the ancestral African population from which modern humans arose was genetically structured, so that extant populations at the time contributed unequally to the gene pool of individuals migrating out of the continent. The effects of ancient population structure on patterns of modern day genetic variation have also been suggested in several more recent papers, which assess the impact of ancient hybridization on modern day genetic diversity through modeling and data-driven analyses. In addition to genetic studies, structure in the ancestral African population has also been supported through archeological and palaeoenvironmental models. *~*
In 1987, the paper "Mitochondrial DNA and Human Evolution", was published by Rebecca Cann, Mark Stoneking and Allan Wilson. It put modern human origins on the front pages of newspapers all over the world for the first time for it showed that a tiny and peculiar part of our genome, inherited only through mothers and daughters, derived from an African ancestor about 200,000 years ago. This woman became known as Mitochondrial Eve. [Source: Chris Stringer, The Guardian, June 19, 2011. Stringer is head of human origins at the Natural History Museum in London]
Chris Stringer wrote in The Guardian: “Now, the advent of huge amounts of DNA data, including the Neanderthal and Denisovan genomes, has halted and even reversed that pendulum swing, away from absolute replacement. Instead we are looking at a mixed replacement-hybridisation or "leaky replacement" model. This dynamism is what makes studying human evolution so fascinating. Science is not about being right or wrong, but about gradually approaching truth about the natural world. |=|
“The big picture is that we are still predominantly of recent African origin (more than 90 percent of our genetic ancestry). But is there a special reason for this observation? Overall, the pre-eminence of Africa in the story of our origins does not involve a special evolutionary pathway but is a question of the continent's consistently large habitable areas which gave greater opportunities for morphological and behavioural variations, and for genetic and behavioural innovations to develop and be conserved. "Modernity" was not a package that had an origin in one African time, place and population, but was a composite whose elements appeared at different times and places, and then gradually coalesced to assume the form we recognise today. |=|
Out of Asia Theory
Some scientists have theorized that an early hominin such as homo habilis left Africa two million years ago and moved into Asia, where it evolved into Homo erectus then spread to Europe and back to Africa. This theory is based on the fact that the Homo erectus specimens found in Asia are older than those found in Africa.
Evidence for this theory includes extraordinarily old dates for Homo species that appeared in Indonesia and China just as Homo erectus was emerging in Africa. Berkeley's Carl Swisher told Time magazine that "elephants left Africa several times during their history" and "lots of animals expand their ranges. the main factor may have been an environmental change that made the expansion easier. No other animals needed stone tools to get out of Africa." [Source: Michael Lemonick, Time, March 14, 1994]
One primatologist told National Geographic: "The idea that all hominins originated in Africa is a myth created by people working in Africa. Sure, they've found a lot there, but if we'd invested that much time and money in Asia we would find fossil hominins just as old there too."
Homo erectus tools have been found in Africa and Europe but not in Asia. Scientists say that the reason for this is that they may have used equally effective bamboo tools--- instead of stone ones---that decay and leave behind no evidence.
Are Hobbits Evidence That Homo Habalis or an Australopithecus Species Left Africa Before Homo Erectus?
The origin of Homo floresiensis (the hobbits of Indonesia) raises some interesting questions, one being that they could be descendants of predecessor of homo erectus —homo habalis or even a Australopithecus species — and this in turn could mean homo habalis or Australopithecus species could have emerged from Africa before Homo erectus.
Deborah Netburn wrote in the Los Angeles Times: “One hypothesis posits that Homo floresiensis descended from the large-bodied hominin Homo erectus that lived between 1.89 million and 143,000 years ago. Scientists say it is possible that Homo erectus may have arrived on Flores from Java, perhaps after being washed out to sea by a tsunami. Over time, this species began to shrink on its new island home – a relatively common phenomenon known as island dwarfism. “Lots of animals that end up on islands get smaller for a variety of reasons like limited food sources, or because there are no large predators to stay big for,” said Karen Baab, a paleoanthropologist at Midwestern University in Glendale, Ariz., who was not involved in the study. “We even see it in modern humans in certain environments that are home to pygmy populations.” [Source: Deborah Netburn, Los Angeles Times, June 8, 2016 \*/]
“The other hypothesis states that Hobbits descended from smaller and more ancient hominins like Australopithecus africanus or Homo habilis that were already diminutive at the time they reached the island. Both theories have challenges. One might accept that Homo erectus grew smaller in stature by two-thirds over time. After all, a smaller body is easier to feed. But for some scientists, it is hard to believe that it made evolutionary sense for its brain to shrink by half. Losing brain power doesn’t seem like a likely evolutionary development. On the other hand, if you buy that Homo floresiensis was descended from Australopithecus or Homo habilis, then you have to explain how either of these species made their way to Indonesia when their remains have never been found outside of Africa. \*/.
A bone study published in 2017 in the Journal of Human Evolution showed there was nothing to support claims that Homo floresiensis evolved from Homo erectus, which scientists say was an ancestor of modern humans, and thus did not have any direct links modern humans. Teeth similarities had been suggested as evidence that homo erectus and hobbits were linked.
Melissa Davey wrote in The Guardian: “The study, led by the Australian National University researcher Dr Debbie Argue from the school of archaeology and anthropology, found there was no evidence Homo floresiensis evolved from the much larger Homo erectus, the only other early hominin known to have lived in the region. It was one of several theories about the origins of the “hobbit” species. Since it was discovered, researchers have tried to determine whether Homo floresiensis was a species distinct from humans. [Source: Melissa Davey, The Guardian, April 21, 2017]
“The findings add support to the theory that the species evolved from one in Africa, most likely Homo habilis, and that the two species shared a common ancestor. It was possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa and then evolved into Homo floresiensis somewhere, the researchers concluded. Prof Mike Lee of Flinders University and the South Australian Museum used statistical modelling to analyse the data collected by the researchers. He said the findings were clear. Homo floresiensis occupied a very primitive position on the human evolutionary tree,” Lee said. “We can be 99 percent sure it’s not related to Homo erectus and nearly 100 percent it isn’t a malformed Homo sapiens.” |=|
There is a good evidence that a relatively large human that lived 700,000 years ago and shrunk quickly and stayed that size ago is an ancestor of Homo floresiensis according to two studies published in Nature in June 2016. Marlowe Hood of AFP wrote: “A modest haul of teeth and bones from an adult and two children has bolstered the theory that Homo floresiensis arrived on Flores island as a different, larger species of hominin, or early man, probably about a million years ago. And then, something very strange happened. These upright, tool-wielding humans shrank, generation after generation, until they were barely half their original weight and height. [Source: Marlowe Hood, AFP, June 9, 2016 \^/]
Image Sources: Wikimedia Commons except range maps Palomar College and site map Nature
Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Ancient Foods ancientfoods.wordpress.com ; Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP, Lonely Planet Guides, World Religions edited by Geoffrey Parrinder (Facts on File Publications, New York); History of Warfare by John Keegan (Vintage Books); History of Art by H.W. Janson (Prentice Hall, Englewood Cliffs, N.J.), Compton’s Encyclopedia and various books and other publications.
Last updated September 2018