How Human Population came from our ability to cooperate

Humans may owe their place as Earth's dominating species to their ability to share and cooperate with each other, according to a new study published in the Journal of Anthropological Research.
In "How There Got to Be So Many of Us: The Evolutionary Story of Population Growth and a Life History of Cooperation," Karen L. Kramer explores the deep past to discover the biological and social underpinnings that allowed humans to excel as reproducers and survivors. She argues that the human tendency to bear many children, engage in food sharing, division of labor, and cooperative childcare duties, sets us apart from our closest evolutionary counterparts, the apes.
In terms of population numbers, few species can compare to the success of humans. Though much attention on population size focuses on the past 200 years, humans were incredibly successful even before the industrial revolution, populating all of the world's environments with more than a billion people. Kramer uses her research on Maya agriculturalists of Mexico's Yucatan Peninsula and the Savanna Pumé hunter-gatherers of Venezuela to illustrate how cooperative childrearing increases the number of children that mothers can successfully raise and--in environments where beneficial--even speed up maturation and childbearing. Kramer argues that intergenerational cooperation, meaning that adults help support children, but children also share food and many other resources with their parents and other siblings, is at the center of humans' demographic success. "Together our diet and life history, coupled with an ability to cooperate, made us really good at getting food on the table, reproducing, and surviving," Kramer writes.
During her time with the Maya, Kramer constructed a demographic model that considered how much household members consume, as the family grows and matures across a mother's reproductive career, balanced against how much a mother, father, and their children contribute. She found that Maya children contributed a substantial amount of work to the family's survival, with those aged 7-14 spending on average 2 to 5 hours working each day, and children aged 15-18 spending as much as their parents, about 6.5 hours a day. Labor type varied, with younger children doing much of the childcare, older children and fathers fill in much of the day-today cost of growing and processing food and running the household. "If mothers and juveniles did not cooperate, mothers could support far fewer children over their reproductive careers," Kramer writes. "It is the strength of intergenerational cooperation that allows parents to raise more children than they would otherwise be able to on their efforts alone."
Kramer's second research population were the Savanna Pumé, hunter-gatherers in west-central Venezuela. The Savanna Pumé live in a high-mortality environment, with challenges such as seasonal undernutrition, high immunological stress, chronic intestinal parasite loads, endemic malaria, and no access to healthcare or immunization. Despite all this--or perhaps, in part, because of it--Savanna Pumé girls mature quickly and begin childbearing in their mid-teens. This pattern conforms with theoretic predictions that fast maturation optimizes fitness in a high-mortality environment. Early childbearing is also, however, associated with a higher probability of mothers losing their firstborn.
Kramer found that intergenerational cooperation mitigated these risks. "In this challenging environment, young Pumé females are buffered against seasonal fluctuations because food is shared with them, she writes. "If young Pumé mothers relied solely on their own efforts, they would have to delay childbearing until they matured as foragers and caretakers.
Humans' ability to reproduce more successfully than other great apes can be traced to differences in evolutionary strategy: humans bear more children, at a faster rate. They also provision food for juveniles, whereas other great apes stop helping children find food as soon as they have been weaned. Humans are able to shoulder the greater childcare burden through cooperation.
"Combined, these fertility parameters mean that if a natural fertility mother survives her reproductive career, she can have almost twice as many offspring as nonhuman great ape mothers," she writes. "Humans are an astonishingly successful ape."

Study reveals that humans migrated from Europe to the Levant 40,000 years ago

IMAGE: A view of Manot cave and a close up of the area where some of the teeth were found. view more 

Credit: Prof. Israel Hershkovitz/American Friends of Tel Aviv University.

Who exactly were the Aurignacians, who lived in the Levant 40,000 years ago? Researchers from Tel Aviv University, the Israel Antiquities Authority, and Ben-Gurion University now report that these culturally sophisticated yet mysterious humans migrated from Europe to the Levant some 40,000 years ago, shedding light on a significant era in the region's history.
The Aurignacian culture first appeared in Europe some 43,000 years ago and is known for having produced bone tools, artifacts, jewelry, musical instruments, and cave paintings. For years, researchers believed that modern man's entry into Europe led to the rapid decline of the Neanderthals, either through violent confrontation or wresting control of food sources. But recent genetic studies have shown that Neanderthals did not vanish. Instead, they assimilated into modern human immigrant populations. The new study adds further evidence to substantiate this theory.
Through cutting-edge dental research on six human teeth discovered at Manot Cave in the Western Galilee, Dr. Rachel Sarig of TAU's School of Dental Medicine and Dan David Center Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine in collaboration with Dr. Omry Barzilai of the Israel Antiquities Authority and colleagues in Austria and the United States, have demonstrated that Aurignacians arrived in modern-day Israel from Europe some 40,000 years ago -- and that these Aurignacians comprised Neanderthals and Homo sapiens alike.
A report on the new findings was published in the Journal of Human Evolution on October 11.
"Unlike bones, teeth are preserved well because they're made of enamel, the substance in the human body most resistant to the effects of time," Dr. Sarig explains. "The structure, shape, and topography or surface bumps of the teeth provided important genetic information. We were able to use the external and internal shape of the teeth found in the cave to associate them with typical hominin groups: Neanderthal and Homo sapiens."
The researchers performed in-depth lab tests using micro-CT scans and 3D analyses on four of the teeth. The results surprised the researchers: Two teeth showed a typical morphology for Homo sapiens; one tooth showed features characteristic of Neanderthals; the last tooth showed a combination of Neanderthal and Homo sapiens features.
This combination of Neanderthal and modern human features has, to date, been found only in European populations from the early Paleolithic period, suggesting their common origin.
"Following the migration of European populations into this region, a new culture existed in the Levant for a short time, approximately 2,000-3,000 years. It then disappeared for no apparent reason," adds Dr. Sarig. "Now we know something about their makeup."
"Until now, we hadn't found any human remains with valid dating from this period in Israel," adds Prof. Israel Hershkovitz, head of the Dan David Center, "so the group remains a mystery. This groundbreaking study contributes to the story of the population responsible for some of the world's most important cultural contributions."

Minoan treasures found on Libyan Sea island: Experts

A team excavating on the tiny island of Chrysi south of Crete for over a decade have unearthed a 3,800-year-old Bronze Age compound containing gold jewels, glass beads and the remains of bronze talents, the common unit of value of ancient Greece. © ΥΠΠΟΑ.

ATHENS (AFP).- Archaeologists in Greece have located a "major treasure" of Minoan origin in a Bronze Age settlement on a small island in the Libyan Sea, the culture ministry said Friday. A team excavating on the tiny island of Chrysi south of Crete for over a decade have unearthed a 3,800-year-old Bronze Age compound containing gold jewels, glass beads and the remains of bronze talents, the common unit of value of ancient Greece. Some of the beads are of Egyptian origin, the culture ministry said in a statement. The archaeologists also found ancient fish tanks and large amounts of porphyry -- a prized purple pigment of the ancient world derived from sea snails, and later the colour exclusively reserved for Roman emperors.

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The last Neanderthal necklace

IMAGE: This is a falange of imperial eagle with marks of court from Cave Foradada view more 

Credit: Antonio Rodríguez-Hidalgo

Eagle talons are regarded as the first elements used to make jewellery by Neanderthals, a practice which spread around Southern Europe about 120,000 and 40,000 years ago. Now, for the first time, researchers found evidence of the ornamental uses of eagle talons in the Iberian Peninsula. An article published in the cover of the journal Science Advances talks about the findings, which took place in the site of the cave Foradada in Calafell. The article was led by Antonio Rodríguez-Hidalgo, researcher at the Institute of Evolution in Africa (IDEA) and member of the research team in a project of the Prehistoric Studies and Research Seminar (SERP) of the UB.
The interest in these findings lies in the fact that it is the most modern piece of the kind so far regarding the Neanderthal period and the first one found in the Iberian Peninsula. This circumstance widens the temporary and geographical limits that were estimated for this kind of Neanderthal ornaments. This would be "the last necklace made by the Neanderthals", according to Antonio Rodríguez-Hidalgo.
"Neanderthals used eagle talons as symbolic elements, probably as necklace pendants, from the beginnings of the mid Palaeolithic", notes Antonio Rodríguez-Hidalgo. In particular, what researchers found in Cova Foradada are bone remains from Spanish Imperial Eagle (Aquila Adalberti), from more than 39,000 years ago, with some marks that show these were used to take the talons so as to make pendants. The found remains correspond to the left leg of a big eagle. By the looks of the marks, and analogy regarding remains from different prehistorical sites and ethnographic documentation, researchers determined that the animal was not manipulated for consumption but for symbolic reasons. Eagle talons are the oldest ornamental elements known in Europe, even older than seashells Homo sapiens sapiens perforated in northern Africa.
The findings belong to the châtelperronian culture, typical from the last Neanderthals that lived in Europe, and coincided with the moment when this species got in touch with Homo sapiens sapiens, from Africa -and expanding from the Middle East. Actually, Juan Ignacio Morales, researcher in the program Juan de la Cierva affiliated at SERP and signer of the article, presents this use of eagle talons as ornaments could have been a cultural transmission from the Neanderthals to modern humans, who adopted this practice after reaching Europe.
Cova Foradada covers the most meridional châtelperronian culture site in Europe. The discovery involved a change in the map of the territory where the step from Middle Palaeolithic to Upper Palaeolithic took place 40,000 years ago, and where interaction between Neanderthals and Homo sapiens sapiens probably took place. Studies in Cova Foradada started in 1997. At the moment, the supervision of the excavation is led by Juan Ignacio Morales and Artur Cebrià. The archaeological study of this site is included in a SERP project funded by the Department of Culture of the Catalan Government and another funded by the Ministry of Science, Innovation and Universities, headed by UB professor and SERP director Josep M Fullola.
The first signer of the article in Science Advances is Antonio Rodríguez Hidalgo, from the Institute of Evolution in Africa (IDEA). Other participants, apart from SERP members, are the researchers from Rovira i Virgili University, the Catalan Institute of Human Paleoecology and Social Evolution (IPHES), the Natural History Museum of Paris, the University of Salamanca, the University of Calgary (Canada) and the French National Centre for Scientific Research (CNRS).

Ground penetrating radar reveals why ancient Cambodian capital was moved to Angkor

IMAGE: Regional map of Koh Ker showing the location of the chute and key archaeological features. The detailed map area (top right) is shown as a white dashed box on the... view more 

Credit: Dr Ian Moffat, Flinders University

The largest water management feature in Khmer history was built in the 10th century as part of a short-lived ancient capital in northern Cambodia to store water but the system failed in its first year of operation, possibly leading to the return of the capital to Angkor.
An international team of researchers led by Dr Ian Moffat from Flinders University in Australia used ground penetrating radar to map the surface of a buried spillway in Koh Ker to better understand why the reservoir failed during its first year of use.
In a study published in Geoarchaeology, archaeologists explain that the 7km long embankment was designed to capture water from the Stung Rongea river but modelling indicates it was inadequate to contain the average water flow in the catchment, putting into question the legitimacy of Khmer kings, and forcing them to re-establish their capital in Angkor.
"At that time, embarking on projects of civil engineering such as temple building, urban renewal, and the development of water infrastructure was central to establishing the legitimacy of Khmer kings," says Dr Moffat
"It's not difficult to envisage that the failure of the embankment at Koh Ker--the largest and most ambitious infrastructure project of the era--may have had a significant impact on the prestige of the sovereign capital, and contributed to the decision to re-establish Angkor as the capital of the Khmer Empire."
"Our study shows that this ambitious engineering feat was always doomed to rapid failure."
The monumental complex of Koh Ker, located 90 km northeast of Angkor, remains relatively poorly understood even though it was briefly the capital in the middle of the 10th century CE under King Jayavarman IV, the only capital throughout six centuries to be established outside of the Angkor region.
The site is located in an area of gently sloping hills and stone outcrops, far removed from the low-lying floodplains that define the Khmer heartland.

1,400 year-old hammer and nails discovered at Usha show Byzantine inhabitants practiced metallurgy.

This past Sukkot, about 8,500 people participated in archaeological excavations and activities hosted by the Israel Antiquities Authority (IAA). One family, from Tur’an in the Lower Galilee, made a rare and informative discovery while volunteering at the IAA’s excavation of ancient Usha. The family discovered an iron hammer-head and nails dating to the Byzantine period, about 1,400 years ago.

According to Yair Amitzur and Eyad Bisharat, directors of the excavation on behalf of the IAA, “About 20 iron hammers are registered in the Israel Antiquities Authority records, only six of them from the Byzantine period.” While the hammer’s discovery is rare and exciting, the unattractive lump of iron slag found nearby may be more exciting still. The slag indicates Usha’s Byzantine inhabitants were manufacturing iron tools themselves, rather than importing them. 

“We already knew” says Amitzur, “that the Usha settlers extensively manufactured glass vessels, since we found many wine glasses and glass lamps together with glass lumps that were the raw material.” Amitzur also notes that ancient sources refer to a man who lived in Usha named Rabbi Yitzhak Nafha. The name ‘Nafha’ means ‘the blower,’ and suggests that the Rabbi probably worked as a glass manufacturer. While the glass industry at Usha has been known for some time, the discovery of the hammer, nails, and iron slag show that metallurgy was also practiced on site. 

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The homeland of modern humans

A study has concluded that the earliest ancestors of anatomically modern humans (Homo sapiens sapiens) emerged in a southern African 'homeland' and thrived there for 70 thousand years.
The breakthrough findings are published in the prestigious journal Nature today.
The authors propose that changes in Africa's climate triggered the first human explorations, which initiated the development of humans' genetic, ethnic and cultural diversity.
This study provides a window into the first 100 thousand years of modern humans' history.
DNA as a time capsule
"It has been clear for some time that anatomically modern humans appeared in Africa roughly 200 thousand years ago. What has been long debated is the exact location of this emergence and subsequent dispersal of our earliest ancestors," says study lead Professor Vanessa Hayes from the Garvan Institute of Medical Research and University of Sydney, and Extraordinary Professor at the University of Pretoria.
"Mitochondrial DNA acts like a time capsule of our ancestral mothers, accumulating changes slowly over generations. Comparing the complete DNA code, or mitogenome, from different individuals provides information on how closely they are related."
In their study, Professor Hayes and her colleagues collected blood samples to establish a comprehensive catalogue of modern human's earliest mitogenomes from the so-called 'L0' lineage. "Our work would not have been possible without the generous contributions of local communities and study participants in Namibia and South Africa, which allowed us to uncover rare and new L0 sub-branches," says study author and public health Professor Riana Bornman from the University of Pretoria.
"We merged 198 new, rare mitogenomes to the current database of modern human's earliest known population, the L0 lineage. This allowed us to refine the evolutionary tree of our earliest ancestral branches better than ever before," says first author Dr Eva Chan from the Garvan Institute of Medical Research, who led the phylogenetic analyses.
By combining the L0 lineage timeline with the linguistic, cultural and geographic distributions of different sub-lineages, the study authors revealed that 200 thousand years ago, the first Homo sapiens sapiens maternal lineage emerged in a 'homeland' south of the Greater Zambezi River Basin region, which includes the entire expanse of northern Botswana into Namibia to the west and Zimbabwe to the east.
A homeland perfect for life to thrive
Investigating existing geological, archeological and fossil evidence, geologist Dr Andy Moore, from Rhodes University, revealed that the homeland region once held Africa's largest ever lake system, Lake Makgadikgadi.
"Prior to modern human emergence, the lake had begun to drain due to shifts in underlying tectonic plates. This would have created, a vast wetland, which is known to be one of the most productive ecosystems for sustaining life," says Dr Moore.
Modern humans' first migrations
The authors' new evolutionary timelines suggest that the ancient wetland ecosystem provided a stable ecological environment for modern humans' first ancestors to thrive for 70 thousand years.
"We observed significant genetic divergence in the modern humans' earliest maternal sub-lineages, that indicates our ancestors migrated out of the homeland between 130 and 110 thousand years ago," explains Professor Hayes. "The first migrants ventured northeast, followed by a second wave of migrants who travelled southwest. A third population remained in the homeland until today."
"In contrast to the northeasterly migrants, the southwesterly explorers appear to flourish, experiencing steady population growth," says Professor Hayes. The authors speculate that the success of this migration was most likely a result of adaptation to marine foraging, which is further supported by extensive archaeological evidence along the southern tip of Africa.
Climate effects
To investigate what may have driven these early human migrations, co-corresponding author Professor Axel Timmermann, Director of the IBS Center for Climate Physics at Pusan National University, analysed climate computer model simulations and geological data, which capture Southern Africa's climate history of the past 250 thousand years.
"Our simulations suggest that the slow wobble of Earth's axis changes summer solar radiation in the Southern Hemisphere, leading to periodic shifts in rainfall across southern Africa," says Professor Timmermann. "These shifts in climate would have opened green, vegetated corridors, first 130 thousand years ago to the northeast, and then around 110 thousand years ago to the southwest, allowing our earliest ancestors to migrate away from the homeland for the first time."
"These first migrants left behind a homeland population," remarks Professor Hayes. "Eventually adapting to the drying lands, maternal descendants of the homeland population can be found in the greater Kalahari region today."
This study uniquely combined the disciplines of genetics, geology and climatic physics to rewrite our earliest human history.