New species of early human found in the Philippines
New species of early human found in the Philippines
An international team of researchers have uncovered the remains of a new species of human in the Philippines, proving the region played a key role in hominin evolutionary history. The new species, Homo luzonensis is named after Luzon Island, where the more than 50,000 year old fossils were found during excavations at Callao Cave.
Co-author and a lead member of the team, Professor Philip Piper from The Australian National University (ANU) says the findings represent a major breakthrough in our understanding of human evolution across Southeast Asia.
The researchers uncovered the remains of at least two adults and one juvenile within the same archaeological deposits.
"The fossil remains included adult finger and toe bones, as well as teeth. We also recovered a child's femur. There are some really interesting features - for example, the teeth are really small," Professor Piper said.
"The size of the teeth generally, though not always, reflect the overall body-size of a mammal, so we think Homo luzonensis was probably relatively small. Exactly how small we don't know yet. We would need to find some skeletal elements from which we could measure body-size more precisely" Professor Piper said.
"It's quite incredible, the extremities, that is the hand and feet bones are remarkably Australopithecine-like. The Australopithecines last walked the earth in Africa about 2 million years ago and are considered to be the ancestors of the Homo group, which includes modern humans.
"So, the question is whether some of these features evolved as adaptations to island life, or whether they are anatomical traits passed down to Homo luzonensis from their ancestors over the preceding 2 million years."
While there are still plenty of questions around the origins of Homo luzonensis, and their longevity on the island of Luzon, recent excavations near Callao Cave produced evidence of a butchered rhinoceros and stone tools dating to around 700,000 years ago.
"No hominin fossils were recovered, but this does provide a timeframe for a hominin presence on Luzon. Whether it was Homo luzonensis butchering and eating the rhinoceros remains to be seen," Professor Piper said.
"It makes the whole region really significant. The Philippines is made up of a group of large islands that have been separated long enough to have potentially facilitated archipelago speciation. There is no reason why archaeological research in the Philippines couldn't discover several species of hominin. It's probably just a matter of time."
Homo luzonensis shares some unique skeletal features with the famous Homo floresiensis or 'the hobbit', discovered on the island of Flores to the south east of the Philippine archipelago.
In addition, stone tools dating to around 200,000 years ago have been found on the island of Sulawesi, meaning that ancient hominins potentially inhabited many of the large islands of Southeast Asia.
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The project team was led by Dr Armand Mijares of the University of the Philippines, and includes Dr. Florent Détroit of the National Museum of Natural History in Paris and researchers from the University of Bordeaux, Paul Sabatier University and the University of Poitiers in France, as well as Griffith University in Australia.
The research has been published in the journal Nature.
Press release from the Australian National University.
Beer and fodder crop has been deteriorating for 6,000 years
Beer and fodder crop has been deteriorating for 6,000 years
The diversity of the crop Sorghum, a cereal used to make alcoholic drinks, has been decreasing over time due to agricultural practice. To maintain the diversity of the crop and keep it growing farmers will need to revise how they manage it.
Sorghum bicolor is a crop widely used for animal feed, and making beer.
The history of sorghum from its original domesticated state to todays domesticated cereal has been found to be heavily influenced by human action, continuing to treat the plant as we currently do could mean the continued degradation of the crop.
One current type of sorghum harvested is called Sorghum bicolor, but there are several different sorghum types, and in the past they have been saving each other by sharing undamaged genes, in a process called introgression.
The wild ancestors of sorghum represent genomes that have not been damaged through cultivation. Although we don't harvest the wild ancestors of sorghum it's necessary to keep them alive as the ability to adapt to their surroundings by introgression could be crucial in the future of Sorghum bicolor to threats of climate change, meaning crops have to adapt to new environments.
In Sorghum bicolor, damage to their genes is happening by the way it's farmed, meaning their core genome functions are accumulating damage over time, therefore we need to repair the crops genomic damage or productivity could decline.
Professor Robin Allaby, from the School of Life Sciences at the University of Warwick comments:
"Sorghum bicolor is the world's fifth most important cereal crop and the most important crop in arid zones. It's used for animal feed and beer and is grown particularly in North-Eastern Africa generating an economy there.
"If we can't save sorghum's ancestors and use those genes to help Sorghum bicolor repair its genomic damage we could risk damaging the crop further. This could mean less animal feed, food and beer, as well as potentially damaging trade in North-East Africa."
Woolly mammoths and Neanderthals may have shared genetic traits
Woolly mammoths and Neanderthals may have shared genetic traits
Findings point to molecular resemblance in climate adaptation traits of the two species, Tel Aviv University researchers say
A new Tel Aviv University study suggests that the genetic profiles of two extinct mammals with African ancestry -- woolly mammoths, elephant-like animals that evolved in the arctic peninsula of Eurasia around 600,000 years ago, and Neanderthals, highly skilled early humans who evolved in Europe around 400,000 years ago -- shared molecular characteristics of adaptation to cold environments.
The research attributes the human-elephant relationship during the Pleistocene epoch to their mutual ecology and shared living environments, in addition to other possible interactions between the two species. The study was led by Prof. Ran Barkai and Meidad Kislev of TAU's Department of Archaeology and Ancient Near Eastern Cultures and published on April 8 in Human Biology.
"Neanderthals and mammoths lived together in Europe during the Ice Age. The evidence suggests that Neanderthals hunted and ate mammoths for tens of thousands of years and were actually physically dependent on calories extracted from mammoths for their successful adaptation," says Prof. Barkai. "Neanderthals depended on mammoths for their very existence.
"They say you are what you eat. This was especially true of Neanderthals; they ate mammoths but were apparently also genetically similar to mammoths."
To assess the degree of resemblance between mammoth and Neanderthal genetic components, the archaeologists reviewed three case studies of relevant gene variants and alleles -- alternative forms of a gene that arise by mutation and are found at the same place on a chromosome -- associated with cold-climate adaptation found in the genomes of both woolly mammoths and Neanderthals.
The first case study outlined the mutual appearance of the LEPR gene, related to thermogenesis and the regulation of adipose tissue and fat storage throughout the body. The second case study engaged genes related to keratin protein activity in both species. The third case study focused on skin and hair pigmentation variants in the genes MC1R and SLC7A11.
"Our observations present the likelihood of resemblance between numerous molecular variants that resulted in similar cold-adapted epigenetic traits of two species, both of which evolved in Eurasia from an African ancestor," Kislev explains. "These remarkable findings offer supporting evidence for the contention regarding the nature of convergent evolution through molecular resemblance, in which similarities in genetic variants between adapted species are present.
"We believe these types of connections can be valuable for future evolutionary research. They're especially interesting when they involve other large-brained mammals, with long life spans, complex social behavior and their interactions in shared habitats with early humans."
According to the study, both species likely hailed from ancestors that came to Europe from Africa and adapted to living conditions in Ice Age Europe. The species also both became extinct more or less at the same time.
"It is now possible to try to answer a question no one has asked before: Are there genetic similarities between evolutionary adaptation paths in Neanderthals and mammoths?" Prof. Barkai says. "The answer seems to be yes. This idea alone opens endless avenues for new research in evolution, archaeology and other disciplines.
"At a time when proboscideans are under threat of disappearance from the world due to the ugly human greed for ivory, highlighting our shared history and similarities with elephants and mammoths might be a point worth taking into consideration."
Tongzi hominids are potentially a new human ancestor in Asia
Tongzi hominids are potentially a new human ancestor in Asia
The CENIEH has been participating in a comparative research about human teeth discovered in this Southern China site which has revealed that Tongzi's teeth do not fit the morphological pattern of traditional Homo erectus.
The Researchers María Martinón-Torres and José María Bermúdez de Castro have co-authored a research about the hominids from Tongzi which was published in the Journal of Human Evolution from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) which reveals that Tongzi teeth do not fit the morphological pattern of traditional Homo erectus and that these teeth could potentially represent the highly targeted "Denisovans".
Between 1972 and 1983, the four teeth were discovered in the Yanhui Cave in Tongzi, Southern China. Their chronology is between 172,000 and 240,000 years old and they were originally identified as late Homo erectus or ancient Homo sapiens.
This research was led by Song Xing from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing (IVVP). The morphology of hominid teeth has been reassessed by geometric morphometrical analysis and Micro-Computed Tomography (micro-CT) as well as through morphological standard comparisons.
Tongzi teeth have been primarily compared with hominids during the same chronological period (Late Middle Pleistocene) and/or in the same geographical region (East Asia). However, the comparative sample includes a wide range of hominids.
More generally, the results indicate the existence of more than one human population in East Asia during this period: one which may be taxonomically classified as Homo erectus (exemplified by fossils such as Zhoukoudian, Hexian and Yiyuan); and a second which may be characterized by the existence of derived traits more commonly observed in recent species of the Homo genus, such as crown symmetry, tongue thrusting and the simplified dentine surface of the third premolar.
"More genetic and fossil discoveries would be necessary to evaluate the taxonomy of the "non-erectus" populations of the Middle Pleistocene, such as the Tongzi hominids, which could be good candidates for the Denisovan ancestry," says María Martinón-Torres.
The Denisovans
These populations are related to the Neanderthals who lived in Asia during the Late Middle Pleistocene and the Upper Pleistocene period which was discovered in 2010 from the genetic analysis of a phalanx and a tooth found in the Denisova cave in the Altai massif (Russia). An abundant amount of genetic information has been collected from the Denisovans but there are very few fossil remains. Therefore, both their physical appearance and their identification in the fossil record remain a mystery.
Full bibliographic information
Press release from Centro Nacional de Investigación sobre la Evolución Humana CENIEH/ (ES)
Trees in Amazonia reveal pre-colonial human disturbance
Human history through tree rings: Trees in Amazonia reveal pre-colonial human disturbance
New study shows that tropical trees act as a living record of past human activity in the Amazon
The Brazil nut tree (Bertholletia excelsa) is well known around the world today and has been an important part of human subsistence strategies in the Amazon forest from at least the Early Holocene. These trees can live for hundreds of years and are managed today by humans for their valuable, energy-filled nuts. Patterns in the establishment and growth of living Brazil nut trees in Central Amazonia reflect over 400 years of changes in human occupation, politics, and socio-economic activities in the region.
In a new paper published in PLOS ONE, an international team of scientists reports the combined use of dendrochronology and historical survey to investigate the effects of societal and demographic changes on forest disturbances and growth dynamics in a neotropical tree species, the Brazil nut tree. The study, led by scientists from the National Institute for Amazonian Research, alongside colleagues from the Max Planck Institute for the Science of Human History, shows the influence of human populations and their management practices on the domestication of rainforest landscapes. The researchers used non-destructive sampling, in which small samples are removed from the bark to the center of the trees, and compared tree-ring data from cores of 67 trees. This is the first study of human influence on the growth of trees that extends as far back as 400 years, to pre-colonial times in that region of Brazil. This work also reinforces that pre-colonial populations left important imprints in the Amazon, contributing to changing forest structure and resources through time.
Domesticated Amazonia
Until recently, forests in the Amazon Basin have often been argued to be "pristine" or the site of only small-scale human occupation and use prior to the arrival of European explorers in the 16th century. However, recent archaeobotanical, archaeological, palaeoenvironmental, and ecological research has highlighted extensive and diverse evidence for plant domestication, plant dispersal, forest management, and landscape alteration by pre-Columbian societies.
Nevertheless, human management of tropical forests has undergone a number of drastic changes with the rise of global industrialized societies. Many economically important trees dominate modern Amazonian forests, some of which have undergone domestication processes. Therefore, understanding the changes in forest management witnessed by Amazonian forests over the course of the last centuries has significant implications for ongoing human interaction with these threatened ecosystems.
"The results of this study demonstrate that Brazil nut tree growth reflects human occupation intensity and management. This is one more step to understanding the crucial interactions that led the Amazon forest to be the dynamic, humanized landscape it is today", says Victor Caetano Andrade, lead author of the study, of the Max Planck Institute for the Science of Human History.
A history recorded in rings
Recently, dendroecological studies have emerged as a promising avenue for the investigation of changes in the environment in tropical forests. These studies evaluate the rings formed annually in some tree species to obtain information on their age and annual growth, as is the case with the Brazil nut tree. Patterns of establishment and abrupt changes in tree growth, which are visible in a tree's rings, provide insights into past local environmental conditions. In the current study, the researchers worked in an area of Central Amazonia near Manaus with high Brazil nut tree density, known locally as castanhais. Through non-destructive sampling, in which small samples are removed from the bark to the center of the trees, they compared tree-ring data from cores of 67 trees with the available historical information on the political, economic, and human demographic changes in the region over the last 400 years.
Indigenous and colonial: a change in the way of living with the forest
Based on their interpretation of the tree rings, the researchers were able to construct a picture of the life-histories of these nut trees and how they correlate with pre- and post-colonial human forest management. The management of trees in Amazon forest often involves practices that include the clearance of the understory, opening of the forest canopy, cutting down woody vining plants, and active protection of individuals. The researchers undertook the study hoping to find evidence of these practices in tree rings.
The researchers gathered historical information about the Mura indigenous people, who inhabited the region before the establishment of the Portuguese colonial administration and witnessed their own population decline from the 18th century onwards, followed by the emergence of a new post-colonial society. During the transition between Indigenous population decline and the expansion of a post-colonial political center (the city of Manaus), human population was low, coinciding with a period during which no new trees were established in the region.
This gap in the establishment of new trees suggests that there was an interruption of indigenous management practices likely due to population collapse, as in many other pre-Columbian societies. A later period of renewed tree establishment, also associated with changes in growth rates of existing trees, aligns with a shift to modern exploitation of the forest in the late 19th and 20th century.
Understanding how forest management has changed following the arrival of European colonists and the rise of industrial powers over the course of the past centuries has implications for the future of sustainable forestry and conservation in Amazonia. "Our findings shed light on how past histories of human-forest interactions can be revealed by the growth rings of trees in Amazonia," explains Caetano Andrade. "Future interdisciplinary analysis of these trees, including the use of genetics and isotopes, should enable more detailed investigations into how human forest management has changed in this part of the world, through pre-colonial, colonial, and industrial periods of human activity, with potential implications for conservation."
Press release from the Max Planck Institute for the Science of Human History/Max-Planck-Institut für Menschheitsgeschichte (MPI-SHH)
The oldest assemblage of antler mining tools in the Iberian Peninsula undergoes restoration
The oldest assemblage of antler mining tools in the Iberian Peninsula undergoes restoration
The team at the Conservation and Restoration Laboratory at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) has just concluded its intervention on the oldest assemblage of antler mining tools in the Iberian Peninsula, dated to around 6,000 years old, and recovered during the 2018 excavation campaign directed by the CENIEH geologist Andoni Tarriño Vinagre.
This consists of seven remains of red deer antlers encountered in the quarry of Pozarrate (Treviño, Burgos), one of Spain's most important Neolithic flint mining operations. These tools are at least 1000 years older than other similar antler tools associated to prehistoric copper mining.
The intervention, comprising curative conservation and restoration work, was made complex by the conditions of preservation of the antlers, due in turn to their morphology and composition, aggravated by damp and the type of sediment present in the quarry. “A process of controlled desiccation was necessary so that the morphology and inherent information in the pieces was not lost”, explains Pilar Fernández Colón, head of the Conservation and Restoration Laboratory at the CENIEH.
Once restored, these tools will be studied by specialists in bone industry, and will be analyzed using non-destructive techniques, such as as micro-computed tomography. And Antonio Tarriño will present these findings to the scientific community at the international conference on mining archeology organized by the UISPP Commission on Flint Mining in Pre-and Protohistoric Times, in Warsaw, where the greatest specialists in the field will meet in September.
2019 Excavation campaign
In this year's excavation campaign, which is to take place during the month of July, work is going to continue on exposing the rocky substrate with flint which was the object of the mining activity, and it is hoped to reach a depth of at least 5 meters in the bottom of the quarry.
“We also expect to continue recovering more antler tools among the utensils employed in the operation, such as: ophite sledgehammers, flint picks and hammers and tens of thousands of fragments of waste flint from the operation”, says Tarriño.
This project by the CENIEH is receiving financial and infrastructure support from the Ayuntamiento de Treviño, the Universidad del País Vasco (UPV/EHU), the Junta de Castilla y León and the Diputación Foral de Álava. “Moreover, given the complexity and interest of the data we are getting, we have managed to extend the duration of the MINECO Project which this research is part of (HAR2015-67429-P), for one year”, he adds.
Press release from Centro Nacional de Investigación sobre la Evolución Humana CENIEH/ (ES)
A 5,000-year-old barley grain discovered in Finland changes understanding of livelihoods
A 5,000-year-old barley grain discovered in Finland changes understanding of livelihoods
New findings reveal that hunter-gatherers took to farming already 5,000 years ago in eastern Sweden, and on the Aland Islands, located on the southwest coast of Finland
On the basis of prior research, representatives of the Pitted Ware Culture from the Stone Age have been known as hard-core sealers, or even Inuits of the Baltic Sea. Now, researchers have discovered barley and wheat grains in areas previously inhabited by this culture, leading to the conclusion that the Pitted Ware Culture adopted agriculture on a small scale.
A study carried out in cooperation with parties representing the discipline of archaeology and the Department of Chemistry at the University of Helsinki, as well as Swedish operators in the field of archaeology (The Archaeologists, a governmental consultant agency, and Arkeologikonsult, a business), found grains of barley and wheat in Pitted Ware settlements on Finland's Aland Islands and in the region of modern Stockholm.
The age of the grains was ascertained using radiocarbon dating. Based on the results, the grains originated in the period of the Pitted Ware culture, thus being approximately 4,300-5,300 years old. In addition to the cereal grains, the plant remnants found in the sites included hazelnut shells, apple seeds, tuberous roots of lesser celandine and rose hips.
The study suggests that small-scale farming was adopted by the Pitted Ware Culture by learning the trade from farmers of the Funnel Beaker Culture, the latter having expanded from continental Europe to Scandinavia.
Other archaeological artefacts are also evidence of close contact between these two cultures.
"The grains found on Aland are proof that the Pitted Ware Culture introduced cultivation to places where it had not yet been practised," says Santeri Vanhanen, a doctoral student of archaeology at the University of Helsinki.
Cereal perhaps used to brew beer?
The 5,000-year-old barley grain found on Aland is the oldest grain of cereal ever found in Finland. The researchers also found a handful of barley and wheat grains a few hundred years younger, representing either common wheat or club wheat.
"We also dated one barley grain found in Raseborg, southern Finland. This grain and the other earliest grains found in mainland Finland date back some 3,500 years, some 1,500 years behind Aland according to current knowledge," Vanhanen explains.
In prior studies, it has been extremely difficult to demonstrate that the hunter-gatherer population would have adopted farming during recorded history, let alone in the Stone Age. Research on ancient DNA has in recent years proven that the spread of agriculture in Europe was almost exclusively down to migrants.
"We find it possible that this population, which was primarily specialised in marine hunting, continued to grow plants as the practice provided the community with social significance."
From time to time, an abundance of pig bones are found at Pitted Ware sites, even though pigs were not an important part of their daily nourishment. For instance, the bones of more than 30 pigs were found in a grave located on the island of Gotland.
"Members of the Pitted Ware culture may have held ritual feasts where pigs and cereal products were consumed. It's not inconceivable that grains might even have been used to brew beer, but the evidence is yet to be found," Vanhanen continues.
Grain age determined through radiocarbon dating
The research relies primarily on archaeobotanical methodology, which helps examine plant remains preserved in archaeological sites. In this study, soil samples were collected from the sites, from which plant remains were extracted using a flotation method. The plant remains are charred; in other words, the grains and seeds have turned into carbon after having come to contact with fire.
Plant remains can be identified by examining them through a microscope and comparing them to modern plant parts. The age of individual grains can be determined with radiocarbon dating, based on the fractionation of the radioactive carbon-14 isotope. This way, the age of a grain aged several millennia can be determined with a precision of a few centuries.
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The study was published in the Scientific Reports journal on 20 March 2019. The research article, entitled "Maritime Hunter-Gatherers Adopt Cultivation at the Farming Extreme of Northern Europe 5000 Years Ago", is freely available on the journal's website: https:/
This is how the Inuit culture of the Baltic Sea was born. Read more on the University of Helsinki website: https:/
Press release from the University of Helsinki
Saffron comes from Attica - origin of the saffron crocus traced back to Greece
Saffron comes from Attica - origin of the saffron crocus traced back to Greece
The origin of C. sativus has long been the subject of speculation and research, as this knowledge would enable breeders to introduce genetic diversity into the otherwise genetically uniform plant species. Two new studies have now shown that the saffron crocus originated from a Greek ancestor.
Since ancient times, saffron has been giving dishes a golden-yellow hue and an aromatic flavour. The use of the stigmas of the saffron crocus (Crocus sativus) is depicted in frescos from Crete and Santorini, which are as old as 3600 years. Nowadays, the valuable plant is mainly cultivated in Iran accounting for more than 90% of the saffron production. Due to its hardiness, small batches of the saffron crocus are even grown and harvested in more unlikely countries such as Switzerland and Germany. Possibly partially due to its widespread agricultural adoption, the origin of saffron has until recently been a subject of speculation. Now, two independent studies have been able to trace the roots of C. sativus back to Greece.
The saffron crocus is a triploid and male-sterile plant. This means that the plant can only be propagated vegetatively. In this case, parts of the corms (bulb-like structures of the stem) of the saffron plants are broken off and then these daughter-corms are used to grow new adult plants. A consequence of this form of reproduction is that there is no room for improving saffron quality by crossing different cultivars. Thus all modern saffron plants are genetically nearly identical. Knowing the origin, in particular the originating plant species, would enable saffron breeders to use new genotypes to broaden the diversity of the saffron crocus.
Researchers of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK Gatersleben) decided to tackle the mystery of saffron's origin, by comparing molecular markers of wild crocus species with those of our cultivated saffron crocus. In the research group of Frank Blattner, plant material was obtained through sample-collecting excursions from native stands of all relevant species. Through the analyses of genome-wide single-nucleotide polymorphisms (SNPs) and the investigation of the chloroplast genomes of the different crocus species, the researchers were able to pinpoint the species with the highest genetic similarity to C. sativus. As such, the wild crocus species C. cartwrightianus from Greece was identified as the sole progenitor of the modern saffron plant, and the area in the vicinity of the Greek capital Athens as the region where it evolved.
C. cartwrightianus had already been postulated as a possible progenitor of C. sativus, however the high intra-specific genetic diversity present in C. cartwrightianus had led to unclear results during previous investigations. Now, in the IPK-study, an unambiguous total of 99.3% of the alleles of C. sativus could be recovered in C. cartwrightianus.
These results were confirmed by an independent complementary study performed by researchers at TU Dresden. The Dresden scientists in Thomas Schmidt's group performed comparative chromosome analysis with fluorescence in situ hybridization (FISH) of different crocus species, and could also demonstrate that C. sativus resulted from the fusion of the genomes of two C. cartwrightianus plants, an event called "autopolyploidisation".
A slight surprise for all of the involved researchers was that the main growing regions for saffron are clearly located outside the distribution area of its progenitor C. cartwrightianus, with C. sativus prospering in drier regions and at higher elevations. They suspect that the explanation to this also lies within the origin story of saffron - it was probably the genome-fusing autopolyploidisation event that led to ecological shift of saffron, away from the habitats in the Mediterranean vegetation zone of Greece.
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Summary
- Saffron, the dried stigmas of the saffron crocus (Crocus sativus), is the most expensive spice worldwide. The male-sterile triploid plant has been propagated vegetatively for at least 3600 years, but the origin of the saffron crocus have long been subject of speculation.
- A study analysing the chloroplast genomes and genome-wide DNA polymorphisms in crocus species was performed at the IPK Gatersleben. It shows that saffron evolved in Attica, Greece, through the combination of two different genotypes of the wild crocus C. cartwrightianus. The findings are supported by a recent independent study performed at TU Dresden.
- This clarification of the parent species will probably enable plant breeder to overcome the low genetic diversity of the saffron crocus by creating new saffron genotypes with C. cartwrightianus individuals.
- Studies available through https:/
/ doi. org/ 10. 1016/ j. ympev. 2019. 03. 022 and https:/ / doi. org/ 10. 1111/ nph. 15715.
Press release from Leibniz Institute of Plant Genetics and Crop Plant Research (IPK Gatersleben)
Food for thought: Why did we ever start farming?
Food for thought: Why did we ever start farming?
The reason that humans shifted away from hunting and gathering, and to agriculture -- a much more labor-intensive process -- has always been a riddle. It is only more confusing because the shift happened independently in about a dozen areas across the globe.
"A lot of evidence suggests domestication and agriculture doesn't make much sense," says Elic Weitzel, a Ph.D. student in UConn's department of anthropology. "Hunter-gatherers are sometimes working fewer hours a day, their health is better, and their diets are more varied, so why would anyone switch over and start farming?"
Weitzel sought to get to the root of the shift in his new paper in American Antiquity, by looking at one area of the world, the Eastern United States.In a nutshell, he looked for evidence to support either of two popular theories.
One theory posits that in times of plenty there may have been more time to start dabbling in the domestication of plants like squash and sunflowers, the latter of which were domesticated by the native peoples of Tennessee around 4,500 years ago.
The other theory argues that domestication may have happened out of need to supplement diets when times were not as good. As the human population grew, perhaps resources shifted due to reasons such as over-exploitation of resources or a changing climate. "Was there some imbalance between resources and the human populations that lead to domestication?"
Weitzel tested both hypotheses. He did this by analyzing animal bones from the last 13,000 years and taken from a half-dozen archeological sites in northern Alabama and the Tennessee River valley, where human settlements and their detritus give clues about how they lived, including what they ate. He coupled the findings with pollen data taken from sediment cores collected from lakes and wetlands, cores that serve as a record about the types of plants present at different points in time. The findings are ... mixed.
Weitzel found pollen from oak and hickory, leading to the conclusion that forests composed of those species began to dominate the region as the climate warmed, but also led to decreasing water levels in lakes and wetlands. Along with the decreasing lakes, the bone records showed a shift from diets rich in water fowl and large fishes to subsistence on smaller shellfish.
Taken together, that data provides evidence for the second hypothesis: There was some kind of imbalance between the growing human population and their resource base, effected perhaps by exploitation and also by climate change.
But Weitzel also saw support for the first hypothesis in that an abundance of oak and hickory forest supported an equally prevalent game species population. "That is what we see in the animal bone data," says Weitzel. "Fundamentally, when times are good and there are lots of animals present, you'd expect people to hunt the prey that is most efficient," says Weitzel. "Deer are much more efficient than squirrels for example, which are smaller, with less meat, and more difficult to catch."
A single deer or goose can feed several people, but if over-hunted, or if the landscape changes to one less favorable for the animal population, humans must subsist on other smaller, less efficient food sources. Agriculture, despite being hard work, may have become a necessary option to supplement diet when imbalances like these occurred.
Despite the mixed results, the findings supporting domestication happening in times when there was less than an ideal amount of food is significant, says Weitzel.
"I think that the existence of declining efficiency in even one habitat type is enough to show that ... domestication happening in times of plenty isn't the best way to understand initial domestication." The broader context of this research is important, says Weitzel, because looking to the past and seeing how these populations coped and adapted to change can help inform what we should do as today's climate warms in the coming decades.
"Having an archaeological voice backed by this deep-time perspective in policy making is very important."
Press release from the University of Connecticut
Uncovering the secrets of ancient rock art using 'X-ray vision'
Uncovering the secrets of ancient rock art using 'X-ray vision'
ORLANDO, Fla., April 1, 2019 -- Prehistoric rock paintings are a source of fascination across the world. Aside from their beauty, there's deep meaning in these strokes, which depict ancient rituals and important symbols. To learn more about these murals, researchers have historically resorted to sampling methods that are damaging to the artwork, contradicting the archaeological tenets of conservation. Today, scientists report use of "X-ray vision" to gain brand-new insights about the layers of paint in rock art in Texas without needless damage.
The researchers will present their results today at the American Chemical Society (ACS) Spring 2019 National Meeting & Exposition. ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features nearly 13,000 presentations on a wide range of science topics.
"In this particular work, we used a technique called portable X-ray fluorescence spectroscopy (pXRF), in which a handheld instrument can be carried to a site and used right there, on the spot," says Karen Steelman, Ph.D., who led the study. "It gives you the elemental analysis of a specific material, and is the first step in figuring out how ancient artists used different materials to make their paintings."
Steelman's research focuses on the analysis of rock and cave art, particularly in the Lower Pecos Canyonlands in Texas. She and her colleagues at the Shumla Archaeological Research & Education Center have previously analyzed the composition of pigments at more than 10 sites in the region, but had been unable to see the bigger picture of how these pictographs were composed. Other pigment analysis methods, such as inductively coupled plasma mass spectrometry, require a sample of the rock art in question, which results in damage to the site, and field microscopes are unable to detect layers of paint in a complex mural.
For this particular study, Steelman and her colleagues visited the Rattlesnake Canyon Site along the Rio Grande, known for its array of pictographs. Using a 105-foot wide mural as their testing canvas, they used pXRF to measure 138 areas where the composition indicated overlapping pigments of red, black, white and yellow. In addition, measurements were taken at 90 locations of unpainted limestone, which provided insight into the makeup of the geological canvas.
Using the large amount of data collected from Rattlesnake Canyon, the team could determine a pattern to the layers of pigment, as well as their elemental makeup. The pXRF measurements revealed previously unseen layers of black pigment under layers of red, which were made with manganese and iron oxide, respectively. These complex layers of pigment indicated a level of sophistication seen in other Lower Pecos sites, which ethnographers have determined are a series of religious murals that revealed the complex nature of the hunter-gatherer society that occupied the region from 2500 BCE to 500 CE.
In addition to their findings on the composition of the pictographs, Steelman, along with fellow Shumla collaborators Victoria Roberts and Carolyn Boyd, Ph.D., discovered that the site appeared to contain gunshot damage. To confirm their suspicions, they again turned to pXRF to identify any trace elements that could have come from ammunition. "Unfortunately, we often see suspected bullet impacts at rock art sites," Steelman says. "Most of this is older types of vandalism from the early 1900s, and we used the portable X-ray to determine what trace elements were present." At the impact sites, pXRF revealed traces of lead, mercury and selenium, which were not present in the undamaged areas. There is a bright side to this discovery; finding damage at archaeologically significant sites is an opportunity to petition state and federal agencies for conservation funds to use for more extensive preservation measures, Steelman explains.
With over 350 known rock art sites in the Lower Pecos Canyonlands alone, Steelman and team plan to continue using pXRF to see the full picture of the tapestry of color and symbol woven throughout the region. Flooding along the Rio Grande is a major threat to what the researchers describe as "the oldest books in North America," and they are on a mission to document and analyze as many sites as possible to preserve these stories for future generations.
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