Dilip Simeon's blog

It’s been 27 years since geologist David Roberts identified some of  the oldest footprints of our species ever discovered . The trackway of three footprints was found on the surface of a cemented sand dune (called an aeolianite) near Langebaan on South Africa’s west coast. The tracks were later dated to 117,000 years and were attributed to  Homo sapiens ; they became popularly known as “ Eve’s footprints ”. They were airlifted to Cape Town, where they are housed in the  Iziko South Africa Museum . A replica is on exhibit at the Geelbek Visitor Centre in the  West Coast National Park . There has been international debate since then about whether or not “Eve’s footprints” really were human tracks, due to their relatively poor level of preservation. No further fossilised human tracks have been discovered in the area since then – but a  recent find  by our research team, also near Langebaan, changes this.  These two tracks, discovered in what is today th...

Until a couple of centuries ago, more than a quarter of children died before their first birthday, around half before their fifth. In “Extra Life,” Steven Johnson, a writer of popular books on science and technology, tells the stories behind what he calls, in an understatement, “one of the greatest achievements in the history of our species.”  Steven Johnson:  A Short History of Living Longer Reviewed by Steven Pinker Starting in the second half of the 19th century, the average life span began to climb rapidly, giving humans not just extra life, but  an  extra life. In rich countries, life expectancy at birth hit 40 by 1880, 50 by 1900, 60 by 1930, 70 by 1960, and 80 by 2010. The rest of the world is catching up. Global life expectancy in 2019 was 72.6 years, higher than that of any country, rich or poor, in 1950. People in the shortest-lived countries today will, on average, outlive those of your grandparents’ generation. “Life expectancy” is a statistical ab...

Swan’s book is staggering in its findings. “In some parts of the world, the average twentysomething woman today is less fertile than her grandmother was at 35,” Swan writes. In addition to that, Swan finds that, on average, a man today will have half of the sperm his grandfather had. “The current state of reproductive affairs can’t continue much longer without threatening human survival,” writes Swan, adding: “It’s a global existential crisis.”    The end of humankind? It may be coming sooner than we think, thanks to hormone-disrupting chemicals that are decimating fertility at an alarming rate around the globe. A new book called Countdown, by Shanna Swan, an environmental and reproductive epidemiologist at Icahn School of Medicine at Mount Sinai in New York, finds that sperm counts have  dropped almost 60% since 1973 . Following the trajectory we are on, Swan’s research  suggests  sperm counts could reach zero by 2045. Zero. Let that sink in. That would mean no...

She unearthed fantastic prehistoric creatures that had been lost to the sands of time, and her achievements -- overlooked and uncredited while she was alive -- also almost remained buried. An unsung pioneer of paleontology, Mary Anning is finally getting some of the recognition she deserves thanks to the tireless work of academics and campaigners. A new movie starring Kate Winslet called "Ammonite," which will be released on streaming services in the United Kingdom March 26 and is already available in the US, shines a fresh light on her life. Anning made several pivotal fossil discoveries in the early 1800s on the beaches of Dorset in southwest England -- now known as the Jurassic Coast -- despite living in dire poverty and lacking a formal education. She forged an unusual path in the face of the deeply ingrained sexism and rigid social structures of the Victorian era.  "Mary Anning is recognized by many as the first female vertebrate paleontologist and an ext...

Thousands of  rock art pictures  depicting huge Ice Age creatures such as mastodons have been revealed by researchers in the  Amazon rainforest . The paintings were probably made around 11,800 to 12,600 years ago, according to a press release from researchers at Britain's University of Exeter. The paintings are set over three different rock shelters, with the largest, known as Cerro Azul, home to 12 panels and thousands of individual pictographs. Rock art across Africa is dying, say experts Located in the Serranía La Lindosa in modern-day Colombia, the rock art shows how the earliest human inhabitants of the area would have coexisted with Ice Age megafauna, with pictures showing what appear to be giant sloths, mastodons, camelids, horses and three-toed ungulates with trunks. "These really are incredible images, produced by the earliest people to live in western Amazonia," said Mark Robinson, an archaeologist at the University of Exeter…. https://edition.cnn.com/style/...

The  asteroid strike that doomed the dinosaurs  is an event that many people are aware of. It wiped out more than three-quarters of all life on Earth 66 million years ago. But it was only one of the Big Five mass extinctions the planet has experienced since living organisms evolved 3.5 billion years ago, and wasn't the worst. Now, scientists say they have identified evidence of a new mass extinction event in the fossil record, and it's one that allowed dinosaurs to dominate the Earth for more than 200 million years. It took place   232 million to 234 million years ago and has been called the Carnian Pluvial Episode. "So far, palaeontologists had identified five 'big' mass extinctions in the past 500 million years of the history of life," said study co-author   Jacopo Dal Corso, a geologist at China University of Geosciences at Wuhan, in a news statement. "Each of these had a profound effect on the evolution of the Earth and of life. We have identified a...

Deep time represents a certain displacement of the human and the divine from the story of creation. Yet in the Anthropocene, we humans have become that sublime force, the agents of a fearful something that is greater than ourselves. A single mine in Canada’s tar sands region moves 30 billion tonnes of sediment annually, double the quantity moved by all the worlds’ rivers. The weight of the fresh water we have redistributed has slowed the Earth’s rotation. The mass extinction of plant and animal species is unlikely to recover for 10 million years... Late one summer night in 1949, the British archaeologist Jacquetta Hawkes went out into her small back garden in north London, and lay down. She sensed the bedrock covered by its thin layer of soil, and felt the hard ground pressing her flesh against her bones. Shimmering through the leaves and out beyond the black lines of her neighbours’ chimney pots were the stars, beacons ‘whose light left them long before there were eyes on this plan...

NB : Harari uses the sentence ' The Cognitive Revolution kick-started history about 70,000 years ago'.  This is problematic.  Kick-started history ? 'History' is just a name for human experience. Here's another view on the origins of that experience:  Henry Plotkin's lecture   Cognition and History: The Evolution of Intelligence and Culture . The lecture is little less than Harari's God's Eye View. With YNH's stratospheric detachment, indeed, nothing seems to matter that much. But if our ancestors - as much as us today - were so detached, there would have been no history. Beauty, goodness, justice and truth mattered millenia ago, and they matter now.  DS In 2008, Yuval Noah Harari, a young historian at the Hebrew University of Jerusalem, began to write a book derived from an undergraduate world-history class that he was teaching. Twenty lectures became twenty chapters. Harari, who had previously written about aspects of medieval and early-modern...

Early human ancestors living millions of years ago may have triggered extinctions, even before our species evolved, a study suggests. A decline in large mammals seen in Eastern Africa may have been due to early humans, researchers propose. Extinction rates started to increase from around four million years ago. This coincides with the period when ancient human populations were living in the area, as judged by fossil evidence. "We are now negatively impacting the world and the species that live in it more than ever before. But this does not mean that we used to live in true harmony with nature in the past," said study researcher, Dr Søren Faurby of the University of Gothenburg. "We are extremely successful in monopolising resources today, and our results show that this may have also been the case with our ancestors.".. https://www.bbc.com/news/science-environment-51068816

A bird that previously went extinct rose from the dead after it evolved all over again, scientists have found. The last surviving flightless species of bird in the Indian Ocean, a type of rail, has actually been around before, the research found. It came back through a process called "iterative  evolution ", which saw it emerge twice over, the researchers found. It means that on two separate occasions – tens of thousands of years apart – a species of rail was able to colonise an atoll called Aldabra. In both cases it eventually became flightless, and those  birds  from the latter time can still be found on the island now. Iterative evolution happens when the same or similar structures evolve out of the same common ancestor, but at different times – meaning that the animal actually comes about twice over, completely separately. The white-throated rail has made a surprising return. (Charles J Sharp) This is the first time it has been seen in rails, and o...

A "fierce" new species of little  dinosaurs  with bat-like wings has been discovered in China.  Palaeontologists have uncovered the fossilised remains of a 163-million-year-old creature that would have been around the size of a magpie, weighing just 300g. Named  Ambopteryx longibrachium , it had bat-like membrane wings which were previously unknown among predatory theropod dinosaurs. This suggests that when dinosaurs were beginning to fly they were experimenting with a range of wing structures.  The find "completely changes our idea of dinosaur  evolution ", lead researcher Min Wang from the Chinese Academy of Sciences told  The Independent .  "We imagine dinosaurs have feathered wings but this latest discovery changes how we understand the origins of flight," he said... read more: https://www.independent.co.uk/news/science/new-species-dinosaurs-batlike-wings-discovered-china-a8905206.html

Homo luzonensis  fossils found in Luzon island cave,   dating back up to 67,000 years A new species of ancient human, thought to have been under 4ft tall and adapted to climbing trees, has been discovered in the  Philippines , providing a twist in the story of human evolution. The specimen, named  Homo luzonensis , was excavated from Callao cave on Luzon island in the northern Philippines and has been dated to 50,000-67,000 years ago – when our own ancestors and the  Neanderthals  were spreading across Europe and into Asia. Florent Détroit, of the Natural History Museum in Paris and the paper’s first author, said the discovery provided the latest challenge to the fairly straightforward prevalent narrative of human evolution.  It was once thought that no humans left Africa until about 1.5 million years ago, when a large-bodied ancient human called  Homo erectus  set off on a dispersal that ultimately allowed it to occupy territory sp...

The story of humankind may need some editing. A collection of 2.4-million-year-old stone tools has been found in Algeria, throwing into question the long-held theory that humanity emerged in East Africa. The discovery of the 250 tools, found alongside 296 animal bones, suggests early humans were butchering meat in North Africa about 600,000 years before scientists had thought they arrived in the region. It was previously believed that early humans, known as hominins, originated and stayed in East Africa for hundreds of millions of years, before beginning to move across the continent. But the new discovery "shows that our ancestors ventured into all corners of Africa, not just East Africa," Mohamed Sahnouni, who led the project and  detailed the findings in the journal Science, said in a statement.  "The evidence from Algeria changes the earlier view that East Africa was the cradle of humankind. Actually, the whole of Africa was the cradle of humankind," he ad...

Ancient DNA and the New Science of the Human Past by David Reich Reviewed by Shobhit Mahajan Paleogenetics: A Leap Into Our Branches In 2010, a team of paleo geneticists at the Max Planck Institute for Evolutionary Anthropology, led by the Swedish biologist Svante Pääbo published an astonishing result- they had managed to sequence the entire Neanderthal genome and found that there had been interbreeding between the Neanderthals and the West Eurasian humans. In a sense, the field of paleo genetics had finally come of age. Paleo genetics or the science of using genetics to study ancient humans and other populations relied heavily on the enormous advances in the technology to extract and sequence genomes since the Human Genome project. David Reich, a member of this team went on to establish his own laboratory at Harvard. Reich’s new book is a popular exposition of the revolutionary potential of paleo genetics to understand humanity’s origins and “histories”. The workhorse of pa...

“We now come to the Island of Celebes, in many respects the most remarkable and interesting in the whole region, or perhaps on the globe, since no other island seems to present so many curious problems for solution.”  ( Wallace 1876 ) Wedged in between the continental landmasses of south-east Asia and Australia lies the vast island realm of Wallacea. Named after Alfred Russel Wallace, the 19th-century explorer and naturalist who traversed this area, it hosts floras and faunas that are incredibly rich and often include species found nowhere else on Earth. The natural history of Wallacea is complicated, and heavily dictated by geological forces such as plate tectonics and volcanism. As the oldest and largest island within Wallacea, Sulawesi (formerly known as Celebes) hosts a rich fauna with a large number of species that are unique to the island. Although its fauna is pre-dominantly Asian in origin, it is the only island in south-east Asia with marsupials (the bear cuscus a...

A study of ancient DNA has shed light on the epic journeys that led to the settlement of the Pacific by humans. The region was one of the last on Earth to be permanently settled by humans who used canoes to traverse hundreds of miles of open ocean.  Two different studies tracked changes over time in the genetic make-up of people inhabiting Vanuatu - regarded as a gateway to the rest of the Pacific. The work appears in Nature Ecology & Evolution and Current Biology.  Prof David Reich, from Harvard Medical School, said the region had a "tremendous" range of human diversity, adding that Vanuatu itself had an "extraordinary diversity of languages" in a relatively small area. The number of languages spoken in the tiny island state is thought to number more than 130, though several are endangered with just a small number of speakers. Prof Reich, who is lead author of the study in Current Biology, added that Vanuatu was a "gateway to the remote Pacific isl...

The Neanderthal hand is the first evidence ever found of another species showing cultural self-consciousness. It’s not so very far from a hand print to a self-portrait to a diary to a novel. This discovery dethrones the modern human mind.  If you go to the painted caves of  Spain  and France, crawl through narrow passages and keep your balance on slippery rock floors, you reach the hidden places where ice age hunters made their marks tens of thousands of years ago. Nothing seems more startling than the way they placed hands against the cold rock and blew red ochre out of their mouths to leave fiery images. Of what though? Leaving a mark … a colour-enhanced hand stencil from La Pasiega in northern  Spain, now dated back 66,700 years. Photograph: Reuters Up to now we called it the human presence. “The print of the hand says, ‘This is my mark. This is man’,” declared the scientist Jacob Bronowski when he visited caves in northern Spain in his classic TV se...

Evolution  will no longer be taught in Turkish schools, a senior education official has said, in a move likely to raise the ire of the country’s secular opposition. Alpaslan Durmuş, who chairs the board of education, said evolution was debatable, controversial and too complicated for students. “We believe that these subjects are beyond their [students] comprehension,” said Durmuş in a  video  published on the education ministry’s website. Durmuş said a chapter on evolution was being removed from ninth grade biology course books, and the subject postponed to the undergraduate period. Another change to the curriculum may reduce the amount of time that students spend studying the legacy of secularism. Critics of the government believe public life is being increasingly stripped of the secular traditions instilled by the nation’s founder, Mustafa Kemal Atatürk. The secular opposition has long argued that the government of Recep Tayyip Erdoğan  is pursuing a covert ...

The Anthropocene is not only a period of manmade disruption. It is also a moment of blinking self-awareness, in which the human species is becoming conscious of itself as a planetary force. We’re not only driving global warming and ecological destruction; we know that we are.  Advertisement  One of Morton’s most powerful insights is that we are condemned to live with this awareness at all times. It’s there not only when politicians gather to discuss international environmental agreements, but when we do something as mundane as chat about the weather, pick up a plastic bag at the supermarket or water the lawn. We live in a world with a moral calculus that didn’t exist before. Now, doing just about anything is an environmental question. That wasn’t true 60 years ago ... Over the past decade, Morton’s ideas have been spilling into the mainstream. Hans Ulrich Obrist, the artistic director of London’s Serpentine gallery, and perhaps  the most powerful figure  in the c...

Fossils recovered from an old mine on a desolate mountain in Morocco have rocked one of the most enduring foundations of the human story: that  Homo sapiens  arose in a  cradle of humankind in East Africa  200,000 years ago. Archaeologists unearthed the bones of at least five people at Jebel Irhoud, a former barite mine 100km west of Marrakesh, in excavations that lasted years. They knew the remains were old, but were stunned when dating tests revealed that a tooth and stone tools found with the bones were about 300,000 years old.  “My reaction was a big ‘wow’,” said Jean-Jacques Hublin, a senior scientist on the team at the Max Planck Institute for Evolutionary  Anthropology  in Leipzig. “I was expecting them to be old, but not that old.” Hublin said the extreme age of the bones makes them the oldest known specimens of modern humans and poses a major challenge to the idea that the earliest members of our species evolved in a “Garden of Eden” ...