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Evidence that human evolution driven by major environmental pressures discovered

The genes of ancient humans might have changed substantially due to environmental pressures and change, say an international team of researchers. A widely held belief related to human evolution is that our ancient ancestors’ ability to fashion tools, shelter, and use advanced communication skills may have helped to shield them from large environmental impacts such as changing climate, disease and exposure to other events affecting mortality. But research led out of Australian Centre for Ancient DNA at the University of Adelaide suggests that beneficial genes may have played a more important role in preserving our ancestors. Until now, the sudden increase in frequency of these genes in human groups was masked by the exchange of DNA between people during reproduction. Now, analyses of more than one thousand ancient genomes dating as far back as 45,000 years ago have found historic signals showing genetic adaptation was more common than previously thought. The study of evolutionary events, says the study’s co-lead author Dr Yassine Souilmi, has increased substantially in recent years, as these are the points where human genetics take historic turns. “Evolutionary events [are] exactly what shape our genetic diversity today,” Souilmi tells Cosmos. “That’s what makes us vulnerable to certain diseases [and] resistant to others. “Having a good understanding of evolution, we can have a better understanding of who we are.” Previous research by the Centre has uncovered a range of evolutionary trends, from historic climate change causing the demise of ancestral lions and bears, to the first interactions between humans and coronaviruses 20,000 years ago. And the broader field of research into ancient DNA has shed light on important moments in human history. Only recently did analyses of ancient genes uncover locations on the human genome associated with surviving Yersinia pestis – the bacterium that causes the bubonic plague. <h2>Single events probably triggered selection</h2> This study, published in Nature Ecology and Evolution, has similarly found environmental events might have been more influential on evolution among Eurasian groups. Such events might lead to a point of natural selection. Take, for instance, the emergence of a pathogen. If such a disease could kill people, those who managed to survive and continue reproducing would pass down favourable traits to subsequent generations. “Natural selection acts in two different mechanisms,” says Souilmi. “It only cares about whether you’re procreating successfully… when it acts, it’s either killing a lot of people, [preventing] some people from reproducing successfully, or some people are just not finding mates because they have some sort of ailment that’s not allowing them to mate successfully, or might make them undesirable. “What we’re finding is that the signal of natural selection we detected in this [research] was likely a single event, because the signal is clustered in time in a very early migration out of Africa. “Not all of the [events] we detected occurred at the same time, but the bulk of them did.” <h2>A mirror to the present</h2> This ‘agnostic’ study did not seek to identify the external pressures leading to the selection events indicated in these ancient genes, but future research by the team will seek to uncover that information. Studies like this, or those into specific pressures like the influence of the Black Death or coronaviruses on humans, show the impact of environmental change on our genetics. Souilmi says this is both insightful and cautionary, as environmental change in the present could be studied by humans in the future. He speculates that changes in the Earth’s climate, or the emergence of new pathogens, likely imposed selection pressures on ancient groups, whether through forcing shortages or changes to food supply or imposing physiological stressors. “Very likely, it’s the environment, the temperature, the weather patterns, that would have somewhat impacted the dietary regime of our ancestors out of Africa, and pathogens would have driven this [genetic] adaptation, which has shaped our genetic diversity now,” Souilmi says. “The direct lesson, socially, now, is that if we’re ever faced with events that are similar to that, we are not as immune to extreme episodes of adaptation where a lot of people might die, or be unable to reproduce. “Unless we do something to counteract the environmental changes, or viruses, bacterial or other pandemics, it could be a bad thing.” This article originally appeared on <a href="https://cosmosmagazine.com/science/human-evolution-driven-by-environment/" target="_blank" rel="noopener">cosmosmagazine.com</a> and was written by Matthew Agius. Image: Shutterstock

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This giant kangaroo once roamed New Guinea – descended from an Australian ancestor that migrated millions of years ago

Long ago, almost up until the end of the last ice age, a peculiar giant kangaroo roamed the mountainous rainforests of New Guinea. Now, research to be <a href="https://doi.org/10.1080/03721426.2022.2086518" target="_blank" rel="noopener">published</a> on Thursday by myself and colleagues suggests this kangaroo was not closely related to modern Australian kangaroos. Rather, it represents a previously unknown type of primitive kangaroo unique to New Guinea. The age of megafauna Australia used to be home to all manner of giant animals called megafauna, until most of them went extinct about 40,000 years ago. These megafauna lived alongside animals we now consider characteristic of the Australian bush – kangaroos, koalas, crocodiles and the like – but many were larger species of these. There were giant wombats called Phascolonus, 2.5-metre-tall short-faced kangaroos, and the 3-tonne Diprotodon optatum (the largest marsupial ever). In fact, some Australian megafaunal species, such as the red kangaroo, emu and cassowary, survive through to the modern day. The fossil megafauna of New Guinea are considerably less well-studied than those of Australia. But despite being shrouded in mystery, New Guinea’s fossil record has given us hints of fascinating and unusual animals whose evolutionary stories are entwined with Australia’s. Palaeontologists have done sporadic expeditions and fossil digs in New Guinea, including digs by American and Australian researchers in the 1960s, ’70s and ’80s. It was during an archaeological excavation in the early 1970s, led by Mary-Jane Mountain, that two jaws of an extinct giant kangaroo were unearthed. A young researcher (now professor) named Tim Flannery called the species Protemnodon nombe. The fossils Flannery described are about 20,000–50,000 years old. They come from the Nombe Rockshelter, an archaeological and palaeontological site in the mountains of central Papua New Guinea. This site also delivered fossils of another kangaroo and giant four-legged marsupials called diprotodontids. An unexpected discovery Flinders University Professor Gavin Prideaux and I recently re-examined the fossils of Protemnodon nombe and found something unexpected. This strange kangaroo was not a species of the genus Protemnodon, which used to live all over Australia, from the Kimberley to Tasmania. It was something a lot more primitive and unknown. In particular, its unusual molars with curved enamel crests set it apart from all other known kangaroos. We moved the species into a brand new genus unique to New Guinea and (very creatively) renamed it Nombe nombe. <figure><iframe src="https://player.vimeo.com/video/724328370" width="500" height="281" frameborder="0" allowfullscreen="allowfullscreen"></iframe><figcaption>A 3D surface scan of a specimen of Nombe nombe, specifically a fossilised lower jaw from central Papua New Guinea. (Courtesy of Papua New Guinea Museum and Art Gallery, Port Moresby).</figcaption></figure> Our findings show Nombe may have evolved from an ancient form of kangaroo that migrated into New Guinea from Australia in the late Miocene epoch, some 5–8 million years ago. In those days, the islands of New Guinea and Australia were connected by a land bridge due to lower sea levels – whereas today they’re separated by the Torres Strait. This “bridge” allowed early Australian mammals, including megafauna, to migrate to New Guinea’s rainforests. When the Torres Strait flooded again, these animal populations became disconnected from their Australian relatives and evolved separately to suit their tropical and mountainous New Guinean home. We now consider Nombe to be the descendant of one of these ancient lineages of kangaroos. The squat, muscular animal lived in a diverse mountainous rainforest with thick undergrowth and a closed canopy. It evolved to eat tough leaves from trees and shrubs, which gave it a thick jawbone and strong chewing muscles. The species is currently only known from two fossil lower jaws. And much more remains to be discovered. Did Nombe hop like modern kangaroos? Why did it go extinct? As is typical of palaeontology, one discovery inspires an entire host of new questions. Strange but familiar animals Little of the endemic animal life of New Guinea is known outside of the island, even though it is very strange and very interesting. Very few Australians have much of an idea of what’s there, just over the strait. When I went to the Papua New Guinea Museum in Port Moresby early in my PhD, I was thrilled by the animals I encountered. There are several living species of large, long-nosed, worm-eating echidna – one of which weighs up to 15 kilograms. <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471027/original/file-20220627-22-91nec3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" alt="Author Isaac Kerr poses for a photo, holding an Australian giant kangaroo jaw in his left hand" /></a><figcaption>I’m excited to start digging in New Guinea’s rainforests! Author provided</figcaption></figure> There are also dwarf cassowaries and many different wallaby, tree kangaroo and possum species that don’t exist in Australia – plus many more in the fossil record. We tend to think of these animals as being uniquely Australian, but they have other intriguing forms in New Guinea. As an Australian biologist, it’s both odd and exhilarating to see these “Aussie” animals that have expanded into new and weird forms in another landscape. Excitingly for me and my colleagues, Nombe nombe may breathe some new life into palaeontology in New Guinea. We’re part of a small group of researchers that was recently awarded a grant to undertake three digs at two different sites in eastern and central Papua New Guinea over the next three years. Working with the curators of the Papua New Guinea Museum and other biologists, we hope to inspire young local biology students to study palaeontology and discover new fossil species. If we’re lucky, there may even be a complete skeleton of Nombe nombe waiting for us.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/185778/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/isaac-alan-robert-kerr-1356949" target="_blank" rel="noopener">Isaac Alan Robert Kerr</a>, PhD Candidate for Palaeontology, <a href="https://theconversation.com/institutions/flinders-university-972" target="_blank" rel="noopener">Flinders University</a> This article is republished from <a href="https://theconversation.com" target="_blank" rel="noopener">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/this-giant-kangaroo-once-roamed-new-guinea-descended-from-an-australian-ancestor-that-migrated-millions-of-years-ago-185778" target="_blank" rel="noopener">original article</a>. Image: Supplied

Domestic Travel

4 things our ancestors can teach us about caregiving

Human life expectancy has <a href="https://ourworldindata.org/life-expectancy" target="_blank">come a long way</a> in an incredibly short amount of time, so you would be forgiven for thinking that the custom of caring for our elders is a similarly recent development in human culture. However, studies are showing that caring for the ageing members of society is something that humans have been doing for millennia. CaringNews.com explored the evidence and studies supporting this theory, and presented some pretty compelling things we can learn from our ancestors. 1. Caregiving is genetic Anthropologist Erik Trinkaus <a href="http://onlinelibrary.wiley.com/doi/10.1002/ajpa.1330570108/abstract" target="_blank">presented evidence</a> of the burial, some 50,000 years ago, of a Neandertal individual who not only had debilitating injuries, but lived with them for some time. According to Trinkaus, this individual has lost a forearm, suffered from a limp, and was deaf. Without help from their fellows, it would have been very difficult for this individual to survive. 2. People depended on their elders Despite their typical slowness and frailty, the older members of society still had much to offer – taking the time to pass down their knowledge. Those elders were regarded as experts in the day-to-day necessities of crafting weapons, telling edible plants from poisonous, and turning animal skins into clothing and bedding. Around 50,000 years ago, an increase in general human longevity is believed to have led to marked cultural advances for humans. 3. Caregiving is a virtue Ancient civilisations in China and Rome considered showing respect and caring for one’s elders was a mark of honour. Confucianism refers to this as filial piety. The idea that elders would regularly be sent to die alone on an ice floe is now regarded as a myth – an unthinkable action that would likely only have occurred in times of desperate need or hardship. 4. It takes a village In ancient times, when society was much less developed than today, humans needed to hunt and forage daily just to survive, meaning that the task of caring for elders and the injured was likely shared by those beyond the immediate family. How do you think caregiving will develop as human society progresses in the future?

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9 weird and wonderful facts about death and funeral practices

It might not be something you want to think about very often, but it turns out that the way we treat our dead in the modern age is heavily influenced by the way our ancestors treated theirs. When you look at death and funeral practices through the ages, repeated patterns of behaviour emerge, making it easy to see where some of our modern ideas about death – such as keeping an urn on your mantelpiece or having a gravestone – have come from. So here are nine surprising facts about death and funeral practices through the ages: 1. Some prehistoric societies de-fleshed the bones This was done with sharp knives. And we know this because human skeletons buried during this period show the traces of many <a href="http://www.dailymail.co.uk/sciencetech/article-3633135/Grisly-Stone-Age-pits-Orkney-islanders-chopped-dead-relatives-mixing-mass-graves.html">cut marks</a> to the skulls, limbs and other bones. During the medieval period, bodies that needed to be transported over long distances for burial were also defleshed – by dismembering the body and boiling the pieces. The bones were then transported, while the soft tissues were buried close to the place of death. 2. Throwing spears at the dead During the Middle Iron Age, “speared-corpse” burials were a pretty big deal in east Yorkshire. <a href="https://remembermeproject.wordpress.com/2016/09/30/the-speared-corpse-burials-of-iron-age-east-yorkshire/">Spears were thrown or placed into the graves</a> of some young men – and in a couple of instances they appear to have been thrown with enough force to pierce the body. It is unclear why this was done, but it may have been a military send-off – similar to the 21-gun salute at modern military funerals. 3. The Romans introduced gravestones As an imported practice, the first gravestones in Britain were concentrated close to Roman military forts and more urbanised Romano-British settlements. Back then, gravestones were more frequently dedicated to <a href="https://romaninscriptionsofbritain.org/">women and children than Roman soldiers</a>. This was most likely because Roman soldiers were not legally allowed to marry, so monuments to their deceased family members legitimised their relationships in death in a way they couldn’t be in life. After the end of Roman control in Britain in the fifth century, gravestones fell out of favour and did not become widely popular again until the modern era. 4. The Anglo Saxons preferred urns During the early Anglo-Saxon period, cremated remains were often kept within the community for some time before burial. We know this because <a href="https://www.academia.edu/29693509/Ethnographies_for_Early_Anglo-Saxon_Cremation">groups of urns were sometimes buried together</a>. Urns were also included in burials of the deceased – who were likely their relatives. 5. Lots of people shared a coffin During the medieval period, many parish churches had <a href="http://wasleys.org.uk/eleanor/churches/england/yorkshire/east_riding/east_two/howden/index.html">community coffins</a>, which could be borrowed or leased to transport the deceased person from the home to the churchyard. When they arrived at the graveside, the body would be removed from the coffin and buried in a simple shroud. 6. And rosemary wasn’t just for potatoes Sprigs of rosemary were often carried by people in the funeral procession and cast onto the coffin before burial, much as roses are today. And as an evergreen plant, rosemary was associated with eternal life. As a fragrant herb, it was also often placed inside coffins to <a href="https://nourishingdeath.wordpress.com/2014/05/10/rosemary-thats-for-remembrance/">conceal any odours that might be emerging from the corpse</a>. This was important because bodies often lay in state for days and sometimes weeks before burial, while preparations were made and mourners travelled to attend the funeral. 7. Touching a murderer could heal Throughout early modern times, and up until at least the mid-19th century, it was a common belief that the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4623855/">touch of a murderer</a> – executed by hanging – could cure all kinds of illnesses, ranging from cancer and <a href="http://www.nhs.uk/Conditions/Goitre/Pages/Introduction.aspx">goitres</a> to skin conditions. Afflicted persons would attend executions hoping to receive the “death stroke” of the executed prisoner. 8. There are still many mysteries For almost a thousand years, during the British Iron Age, archaeologists don’t really know what kinds of funeral practices were being performed across much of Britain. And human remains only appear in a few places – like the burials in east Yorkshire. So for much of Britain, <a href="https://www.cambridge.org/core/journals/proceedings-of-the-prehistoric-society/article/div-classtitleiron-age-burial-in-southern-britaindiv/D617DE25F4F6814D343B498B3DC21631">funeral practices are almost invisible</a>. We suspect bodies were either exposed to the elements in a practice known as “excarnation”, or cremated and the ashes scattered. 9. But the living did respect the dead Across time, people have engaged with past monuments to the dead, and it is common for people to respect older features of the landscape when deciding where to place new burials. Bronze Age people created new funeral monuments and buried their dead in close proximity to Neolithic funeral monuments. This can be seen in the landscape around Stonehenge, which was created as an ancestral and funeral monument – and is full of Bronze Age burial mounds known as <a href="http://web.org.uk/barrowmap/">round barrows</a>. And when the Anglo-Saxons arrived in Britain, they frequently buried their dead close to Bronze and Iron Age monuments. Sometimes they dug into these older monuments and reused them to bury their own dead. Even today, <a href="http://www.goodfuneralguide.co.uk/find-a-funeral-director/what-is-a-green-funeral/">green burial grounds</a> tend to respect preexisting field boundaries. And in at least one modern cemetery, burials are placed in alignment with medieval “ridge and furrow”. These are the peaks and troughs in the landscape resulting from <a href="https://en.wikipedia.org/wiki/Ridge_and_furrow">medieval ploughing</a>. Written by Yvonne Inall. First appeared on <a href="https://theconversation.com/">The Conversation.</a> Related links: <a href="http://www.oversixty.co.nz/health/caring/2016/12/web-funerals-make-mourners-lazy/">Web funerals “are making mourners lazier”</a> <a href="http://www.oversixty.co.nz/health/caring/2016/10/what-people-in-their-90s-think-about-death/">What people in their 90s really think about death</a> <a href="http://www.oversixty.co.nz/health/caring/2016/09/4-things-your-body-goes-through-in-grief/">4 surprising things your body goes through when you grieve</a>

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Evidence that human evolution driven by major environmental pressures discovered

This giant kangaroo once roamed New Guinea – descended from an Australian ancestor that migrated millions of years ago

4 things our ancestors can teach us about caregiving

9 weird and wonderful facts about death and funeral practices