Remains of first modern humans in Europe found
The discovery may change what we know about early humans in Europe.
- Newly found human remains in Bulgaria have pushed back the date of Homo sapiens arriving in Europe by thousands of years.
- The site was also littered with animal remains and stone tools.
- These humans were not part of the tool-making culture that replaced the Neanderthals, leaving the fate of the discovered group a mystery.
Scientists working in a cave in Bulgaria have discovered bone fragments of the first examples of Homo sapiens to tread the European continent. Dating back to around 45,000 years ago, this new record holder beats the previous one by two and a half thousand years. While the residents of Bacho Kiro Cave don't appear to have stayed in Europe for long, they may have left an influence felt long after they departed.
The first modern humans in Europe?
One of the more popular models for the spread of anatomically modern humans out of Africa suggests that they reached the Middle East 50,000 years ago and then began to move into Europe. This discovery lends weight to that theory, as it would fit the timeline very nicely.
The cave also had a variety of stone tools and ornaments inside. These were made from quality flint brought with them over great distances and refined in ways particular to the Initial Upper Paleolithic time frame, giving even more evidence of exactly when these people lived.
The similarities between some of the ornaments found, including jewelry made from animal teeth, to items found at Neanderthal sites from thousands of years later led the authors to speculate that these first arrivals from the Middle East may have influenced the Neanderthals.
Of course, you mustn't forget Neanderthals were already doing their own thing for a while, including making tools and jewelry. While it is possible that the newcomers influenced them, it is also possible that they weren't. As the Neanderthals were ultimately replaced by later arriving Homo-Sapiens, known as the Aurignacian culture, this new group may have been a mere blip on their Paleolithic radar.
There is also the highly controversial claim that a 210,000-year-old skull belonging to an anatomically modern human was found in Greece a while back. However, that finding was unable to confirm exactly what species the skull in question belonged to.
The Bulgarian discovery also adds a curious chapter into human history, as the members of this group were not members of the group of modern humans that ultimately replaced the Neanderthals, albeit with some interbreeding with their neighbors. That latter group dates back to 43,000 years ago at most, meaning that the residents of Bacho Kiro Cave were a few thousand years too early to the party.
For whatever reason, their attempt to move into Europe was either a failure, too limited in size and scope to be part of the replacement of the Neanderthals, or was somehow otherwise unable to gain a foothold on the continent. Finding out why this is will be a very interesting topic for future research.
Perhaps they only found Europe to be a nice place to visit.
Young people could even end up less anxiety-ridden, thanks to newfound confidence
- The coronavirus pandemic may have a silver lining: It shows how insanely resourceful kids really are.
- Let Grow, a non-profit promoting independence as a critical part of childhood, ran an "Independence Challenge" essay contest for kids. Here are a few of the amazing essays that came in.
- Download Let Grow's free Independence Kit with ideas for kids.
Researchers in Mexico discover the longest underwater cave system in the world that's full of invaluable artifacts.
New research establishes an unexpected connection.
- A study provides further confirmation that a prolonged lack of sleep can result in early mortality.
- Surprisingly, the direct cause seems to be a buildup of Reactive Oxygen Species in the gut produced by sleeplessness.
- When the buildup is neutralized, a normal lifespan is restored.
We don't have to tell you what it feels like when you don't get enough sleep. A night or two of that can be miserable; long-term sleeplessness is out-and-out debilitating. Though we know from personal experience that we need sleep — our cognitive, metabolic, cardiovascular, and immune functioning depend on it — a lack of it does more than just make you feel like you want to die. It can actually kill you, according to study of rats published in 1989. But why?
A new study answers that question, and in an unexpected way. It appears that the sleeplessness/death connection has nothing to do with the brain or nervous system as many have assumed — it happens in your gut. Equally amazing, the study's authors were able to reverse the ill effects with antioxidants.
The study, from researchers at Harvard Medical School (HMS), is published in the journal Cell.
An unexpected culprit
The new research examines the mechanisms at play in sleep-deprived fruit flies and in mice — long-term sleep-deprivation experiments with humans are considered ethically iffy.
What the scientists found is that death from sleep deprivation is always preceded by a buildup of Reactive Oxygen Species (ROS) in the gut. These are not, as their name implies, living organisms. ROS are reactive molecules that are part of the immune system's response to invading microbes, and recent research suggests they're paradoxically key players in normal cell signal transduction and cell cycling as well. However, having an excess of ROS leads to oxidative stress, which is linked to "macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging." To prevent this, cellular defenses typically maintain a balance between ROS production and removal.
"We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation," says senior study author Dragana Rogulja, admitting, "We were surprised to find it was the gut that plays a key role in causing death." The accumulation occurred in both sleep-deprived fruit flies and mice.
"Even more surprising," Rogulja recalls, "we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies." Fruit flies given any of 11 antioxidant compounds — including melatonin, lipoic acid and NAD — that neutralize ROS buildups remained active and lived a normal length of time in spite of sleep deprivation. (The researchers note that these antioxidants did not extend the lifespans of non-sleep deprived control subjects.)
Image source: Tomasz Klejdysz/Shutterstock/Big Think
The study's tests were managed by co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows at HMS.
You may wonder how you compel a fruit fly to sleep, or for that matter, how you keep one awake. The researchers ascertained that fruit flies doze off in response to being shaken, and thus were the control subjects induced to snooze in their individual, warmed tubes. Each subject occupied its own 29 °C (84F) tube.
For their sleepless cohort, fruit flies were genetically manipulated to express a heat-sensitive protein in specific neurons. These neurons are known to suppress sleep, and did so — the fruit flies' activity levels, or lack thereof, were tracked using infrared beams.
Starting at Day 10 of sleep deprivation, fruit flies began dying, with all of them dead by Day 20. Control flies lived up to 40 days.
The scientists sought out markers that would indicate cell damage in their sleepless subjects. They saw no difference in brain tissue and elsewhere between the well-rested and sleep-deprived fruit flies, with the exception of one fruit fly.
However, in the guts of sleep-deprived fruit flies was a massive accumulation of ROS, which peaked around Day 10. Says Vaccaro, "We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut." She adds, "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."
The experiments were repeated with mice who were gently kept awake for five days. Again, ROS built up over time in their small and large intestines but nowhere else.
As noted above, the administering of antioxidants alleviated the effect of the ROS buildup. In addition, flies that were modified to overproduce gut antioxidant enzymes were found to be immune to the damaging effects of sleep deprivation.
The research leaves some important questions unanswered. Says Kaplan Dor, "We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal." He hypothesizes, "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."
The HMS researchers are now investigating the chemical pathways by which sleep-deprivation triggers the ROS buildup, and the means by which the ROS wreak cell havoc.
"We need to understand the biology of how sleep deprivation damages the body so that we can find ways to prevent this harm," says Rogulja.
Referring to the value of this study to humans, she notes,"So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it. We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies."
We must rethink the "chemical imbalance" theory of mental health.
- A new review found that withdrawal symptoms from antidepressants and antipsychotics can last for over a year.
- Side effects from SSRIs, SNRIs, and antipsychotics last longer than benzodiazepines like Valium or Prozac.
- The global antidepressant market is expected to reach $28.6 billion this year.