(Press-News.org) Archaeological and genetic evidence suggests that modern humans (the modern form of Homo sapiens, our species) originated in Africa during the Stone Age, between 30,000 and 280,000 years ago. The latest archaeological excavations in southern Africa have shown that technological innovation, linked to the emergence of culture and modern behaviour, took place abruptly: the beginnings of symbolic expression, the making of tools from stone and bone, jewellery or the first agricultural settlements.
An international team of researchers has linked these pulses of innovation to the climate that prevailed in sub-Saharan Africa in that period.
Over the last million years the global climate has varied between glacial periods (with great masses of ice covering the continents in the northern hemisphere) and interglacial periods, with changes approximately every 100,000 years. But within these long periods there have been abrupt climate changes, sometimes happening in the space of just a few decades, with variations of up to 10ºC in the average temperature in the polar regions caused by changes in the Atlantic ocean circulation. These changes affected rainfall in southern Africa.
The researchers have pieced together how rainfall patterns varied in southern Africa over the last 100,000 years, by analysing river delta deposits at the edge of the continent, where every millimetre of sediment core corresponds to 25 years of sedimentation. The ratio of iron (dissolved from the rocks by the water during the rains) to potassium (present in arid soils) in each of the millimetre layers is a record of the sediment carried by rivers and therefore of the rainfall throughout the whole period.
The reconstruction of the rainfall over 100,000 years shows a series of spikes that occurred between 40,000 and 80,000 years ago. These spikes show rainfall levels rising sharply over just a few decades, and falling off again soon afterwards, in a matter of centuries. This research has shown that the climate changes coincided with increases in population, activity and production of technology on the part of our ancestors, as seen in the archaeological records. In turn, the end of certain stone tool industries of the period coincides with the onset of a new, drier climate.
The findings confirm one of the principal models of Palaeolithic cultural evolution, which correlates technological innovation with the adoption of new refuges and with a resulting increase in population and social networks.
For these researchers, the bursts of demographic expansion caused by climate change in southern Africa were probably key factors in the origin of modern humans' behaviour in Africa, and in the dispersal of Homo sapiens from his ancestral home.
###
The study forms part of the GATEWAYS project of the European Commission's 7th Framework Programme, coordinated by Rainer Zahn, a researcher with the Institute for Environmental Science and Technology (ICTA-UAB) and the UAB's Department of Physics, and taking part in it was Martin Ziegler, a post-doctoral researcher at the School of Earth and Ocean Sciences of the University of Cardiff (UK) and scientists from the Natural History Museum, London (UK).
Stone Age technological and cultural innovation accelerated by climate
The need to find refuge from sudden changes in climate led to the appearance of modern humans
2013-06-18
ELSE PRESS RELEASES FROM THIS DATE:
Scientists find potential genetic drivers behind male heart disease risk
2013-06-18
University of Leicester scientists have discovered a potential genetic contributor to the increased risk of heart disease among men.
A team of researchers including clinicians and scientists have made an important step forward in search of the mechanisms underlying increased risk of coronary artery disease in men who carry a particular type of the Y chromosome (haplogroup I).
The team, from the University's Department of Cardiovascular Sciences and Department of Health Sciences, have followed up their recent award-winning study showing that men with haplogroup I of ...
Seismic gap outside of Istanbul
2013-06-18
Earthquake researchers have now identified a 30 kilometers long and ten kilometers deep area along the North Anatolian fault zone just south of Istanbul that could be the starting point for a strong earthquake. The group of seismologists including Professor Marco Bohnhoff of the GFZ German Research Centre for Geosciences reported in the current online issue of the scientific journal Nature (Nature Communications, DOI: 10.1038/ncomms2999) that this potential earthquake source is only 15 to 20 kilometers from the historic city center of Istanbul.
The Istanbul-Marmara region ...
The secret of DNA methylation
2013-06-18
Methylation refers to a chemical modification of DNA and this modification can occur in millions of positions in the DNA sequence. Until now, scientists believed that this epigenetic phenomenon actively reduced the expression of certain genes. Today, a team of researchers from the University of Geneva (UNIGE), Switzerland, led by Emmanouil Dermitzakis, Louis-Jeantet Professor at the Faculty of Medicine, reveals that this is not always the case and that DNA methylation may play both a passive and active role in gene regulation. The mechanistic relationships between DNA sequence ...
Pioneering breakthrough of chemical nanoengineering to design drugs controlled by light
2013-06-18
The scientific cooperation between chemists, biotechnologists and physicists from various Catalan institutes, headed by Pau Gorostiza, from the Institute for Bioengineering of Catalonia (IBEC), and Ernest Giralt, from the Institute for Research in Biomedicine (IRB Barcelona), has led to a breakthrough that will favor the development of light-regulated therapeutic molecules. The breakthrough published online today in the German journal of reference in chemistry Angewandte Chemie has received recognition as a "Very Important Paper", a distinction that only 5% of the articles ...
Feline behavior experts release guidelines to improve the welfare of cats
2013-06-18
LA, London (18 June 2013). A team of internationally recognized feline experts including veterinarians and feline scientists co-chaired by Dr Sarah Ellis from the University of Lincoln, U.K. and Dr Ilona Rodan, Director of Cat Care Clinic, Wisconsin, U.S.A. were invited by the International Society of Feline Medicine (ISFM) and the American Association of Feline Practitioners (AAFP) to compile guidelines for veterinarians, owners and those working with cats on how to meet the environmental needs of the domestic cat. The new guidelines appear in the Journal of Feline Medicine ...
Rice blast research reveals details on how a fungus invades plants
2013-06-18
Like a stealthy enemy, blast disease invades rice crops around the world, killing plants and cutting production of one of the most important global food sources. Now a study by an international team of researchers has shed light on how the rice blast fungus, Magnaporthe oryzae, invades plant tissue. The finding is a step towards learning how to control the disease, which by some estimates destroys enough rice to feed 60 million people annually.
The team, from the Halpin Laboratory at the University of Exeter, in collaboration with Kansas State University and the Iwate ...
It's the way you tell em': Study discovers how the brain controls accents and impersonations
2013-06-18
A study, led by Royal Holloway University researcher Carolyn McGettigan, has identified the brain regions and interactions involved in impersonations and accents.
Using an fMRI scanner, the team asked participants, all non-professional impressionists, to repeatedly recite the opening lines of a familiar nursery rhyme either with their normal voice, by impersonating individuals, or by impersonating regional and foreign accents of English.
They found that when a voice is deliberately changed, it brings the left anterior insula and inferior frontal gyrus (LIFG) of the ...
Study shows how the Nanog protein promotes growth of head and neck cancer
2013-06-18
COLUMBUS, Ohio-– A study led by researchers at The Ohio State University Comprehensive Cancer Center-– Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC–James) has identified a biochemical pathway in cancer stem cells that is essential for promoting head and neck cancer.
The study shows that a protein called Nanog, which is normally active in embryonic stem cells, promotes the growth of cancer stem cells in head and neck cancer. The findings provide information essential for designing novel targeted drugs that might improve the treatment ...
Why is it easier to lose 2-4 pounds rather than 3 pounds?
2013-06-18
Consumers are more likely to pursue goals when they are ambitious yet flexible, according to a new study in the Journal of Consumer Research.
"Whether a goal is a high-low range goal (lose 2 to 4 pounds this week) or a single number goal (lose 3 pounds this week) has a systematic effect on goal reengagement. High-low range goals influence consumer goal reengagement through feelings of accomplishment, which itself is driven by the attainability and challenge of the goal," write authors Maura L. Scott (Florida State University) and Stephen M. Nowlis (Washington University ...
Iodine in bread not enough for pregnant women
2013-06-18
Research from the University of Adelaide shows that iodized salt used in bread is not enough to provide healthy levels of iodine for pregnant women and their unborn children.
The study-– led by researchers from the University's Robinson Institute – has prompted calls for pregnant women to keep taking iodine supplements.
Iodine deficiency is recognized by the World Health Organization (WHO) as the most common preventable cause of brain damage in the world.
"Iodine is an essential element which is important for human brain development and thyroid function," says one ...
LAST 30 PRESS RELEASES:
Osteoporosis treatment benefits people older than 80
Consuming more protein may protect patients taking anti-obesity drug from muscle loss
Thyroid treatment may improve gut health in people with hypothyroidism
Combination of obesity medication tirzepatide and menopause hormone therapy fuels weight loss
High blood sugar may have a negative impact on men’s sexual health
Emotional health of parents tied to well-being of children with growth hormone deficiency
Oxytocin may reduce mood changes in women with disrupted sleep
Mouse study finds tirzepatide slowed obesity-associated breast cancer growth
CMD-OPT model enables the discovery of a potent and selective RIPK2 inhibitor as preclinical candidate for the treatment of acute liver injury
Melatonin receptor 1a alleviates sleep fragmentation-aggravated testicular injury in T2DM by suppression of TAB1/TAK1 complex through FGFR1
Single-cell RNA sequencing reveals Shen-Bai-Jie-Du decoction retards colorectal tumorigenesis by regulating the TMEM131–TNF signaling pathway-mediated differentiation of immunosuppressive dendritic ce
Acta Pharmaceutica Sinica B Volume 15, Issue 7 Publishes
New research expands laser technology
Targeted radiation offers promise in patients with metastasized small cell lung cancer to the brain
A high clinically translatable strategy to anti-aging using hyaluronic acid and silk fibroin co-crosslinked hydrogels as dermal regenerative fillers
Mount Sinai researchers uncover differences in how males and females change their mind when reflecting on past mistakes
CTE and normal aging are difficult to distinguish, new study finds
Molecular arms race: How the genome defends itself against internal enemies
Tiny chip speeds up antibody mapping for faster vaccine design
KTU experts reveal why cultural heritage is important for community unity
More misfolded proteins than previously known may contribute to Alzheimer’s and dementia
“Too much going on”: Autistic adults overwhelmed by non-verbal social cues
What’s driving America’s deep freezes in a warming world?
A key role of brain protein in learning and memory is deciphered by scientists
Heart attacks don’t follow a Hollywood script
Erin M. Schuman wins 2026 Nakasone Award for discovery on neural synapse function and change during formation of memories
Global ocean analysis could replace costly in-situ sound speed profiles in seafloor positioning, study finds
Power in numbers: Small group professional coaching reduces rates of physician burnout by nearly 30%
Carbon capture, utilization, and storage: A comprehensive review of CCUS-EOR
New high-temperature stable dispersed particle gel for enhanced profile control in CCUS applications
[Press-News.org] Stone Age technological and cultural innovation accelerated by climateThe need to find refuge from sudden changes in climate led to the appearance of modern humans