Once a week.
Subscribe to our weekly newsletter.
How humans evolved to live in the cold
Humans evolved to live in the cold through a number of environmental and genetic factors.
- According to some relatively new research, many of our early human cousins preceded Homo sapien migrations north by hundreds of thousands or even millions of years.
- Cross-breeding with other ancient hominids gave some subsets of human population the genes to contend and thrive in colder and harsher climates.
- Behavioral and dietary changes also helped humans adapt to cold climates.
Humans emerged from a tropical environment. For the most part, our bodies are not well adapted to the cold. You might be feeling that this winter as you battle the frost winds and dream of sunnier days. The fact that we can live in cold climates is a result of many behavioral adaptations. Though, in recent years we've also found that some populations have genetically evolved to be able to better adapt and live in the cold.
The ability to survive and thrive in a cold environment comes from a few practical advances. One is the ability to adapt to the environment through clothing and shelter. Humans also have had to change their diet, as the local flora and fauna in colder areas doesn't contain those delicious primate fruits our early ape-like ancestors originally ate in the warm tropics.
Scientists have discovered that many early hominids left the cradle of humankind a lot sooner than we initially hypothesized. We've learned that through a combination of technology, cross-breeding hominids and some genetic mutations, humans were able to dominate all parts of the globe — even flourishing in the coldest of regions.
Environmental adaptation through early technology
Image source: Wikimedia Commons
Throughout human evolution, a wide range of environmental change was also taking place. Many climate fluctuations included drastic cooling and desertification. The origin and emergence of our species through early hominins was heavily influenced by these changes. Humans and chimpanzees branched off of a common ancestor some 6 to 8 million years ago.
One of our distant cousins, the Neanderthal, branched off into Europe before Homo sapiens left the African plains. We can learn a lot about human's eventual adaptation to the cold through this subspecies of human – Homo neanderthalensis. They endured many large shifts in climate as they contended with many waning glacial and interglacial periods. Neanderthals were able to adapt for example by hunting cold-adapted animals in the winter like reindeer and then hunting red deer in warmer periods. They also tended to migrate southwards during warmer conditions.
The first known stone tools that date back to around 2.6 million years ago were instrumental in allowing us to shift our diet and interact with our new surroundings. Simple tools, which included fractured stones, gave us a way to crush, slice and pound up new food sources.
These basic tools gave us the ability to eat a wide range of foods no matter where we migrated to. Meat, for example, is a food that could be obtained from whatever environment early humans encountered and moved to. This could be a major contributing factor in our collective human march northwards.
Early hominid migrations north
Scientists have found evidence that early hominids groups migrated to the far north in a much earlier timeframe than we had originally believed. The fossil evidence at Dmanisi shows that some hominids migrated to the Anti-Caucasus mountains, which is a similar northern latitude to modern day New York or Beijing. This would have been a very difficult place to exist in for a species that had just come from Africa.
Paleoanthropologist Martha Tappen, who was part of the Dmanisi research team stated:
In terms of hominids spreading out of Africa, it seems that they did not spread with other fauna. That they made it to the higher latitudes without other animals moving at the same time tells you humans made it out of Africa not because the environment was changing or because the biome was moving... They went of their own volition.
What confuses researchers is that these hominids were found thousands of miles north of Africa without having any advanced technology to take them there.
Tapper goes on to say:
At the higher latitudes, you're confronting seasonality for the first time. . . They were experiencing winter. No other primate lives where there's no fruit in winter. There may be a dry season, but there's not a cold winter like these individuals in Dmanisi were experiencing.It's believed that by shifting to a more meat-centric diet that they were able to live in such an environment. But dietary changes are just one piece of the puzzle for how and why humans were able to evolve and live in the cold.
Interbreeding with other hominid species
Research suggests that by cross-breeding with Denisovans, many subsets of the human population had a boosted immune system and alterations in skin color. This also led to other cold tolerance adaptations.
For example, the EPAS1 gene, which is found in Tibetan populations, allows them to function at higher and colder altitudes. It's believed that this originated in our Denisovans cousins. While Denisovans and also Neanderthals originated from a common ancestor in Africa as well, they also spent hundreds of thousands of years in Eurasia before modern humans migrated there as well.
Breeding with our other Eurasian cousins gave us some genetic chutzpah to brave the cold.
Researchers also found that another Denisovans gene gave us an additional ability to handle colder temperatures. To test this hypothesis, researchers reviewed genomic data from a number of Greenlandic Inuits and then compared that to certain genes with Denisovans data.
It was found that there were similarities in the TBX15 and WARS2 genes, both which increase heat generation from body fat. Their conclusion was that genes found in the Inuit population were divergent from nearly every other human population, thus suggesting these genes were from a much different gene pool. Either it was from the Denisovans or another ancient hominid species breeding with them.
Mitochondrial DNA mutations in cold environments
According to research from the Biological Sciences and Molecular Medicine at the University of California Irvine, scientists discovered that after early humans had migrated to colder climates, their chance of survival increased when their mtDNA was mutated and generated greater body heat production.
Professor Douglas C. Wallace states that:
In the warm tropical and subtropical environments of Africa it was most optimal for more of the dietary calories to be allocated to ATP to do work and less to heat, thus permitting individuals to run longer, faster and to function better in hot climates… In Eurasia and Siberia, however, such an allocation would have resulted in more people being killed by the cold of winter. The mtDNA mutations made it possible for individuals to survive the winter, reproduce and colonize the higher latitudes.
A combination of all of these factors eventually led us to where we are today.
- Just how cold was the Ice Age? New study finds the temperature. - Big Think ›
- Just how cold was the Ice Age? New study finds the temperature. - Big Think ›
- Early humans may have boiled their food in hot springs - Big Think ›
- Early humans may have boiled their food in hot springs - Big Think ›
- Humans and Neanderthals: We fought for over 100,000 years - Big Think ›
- Evidence emerges that our ancestors could have hibernated - Big Think ›
Scientists are using bioelectronic medicine to treat inflammatory diseases, an approach that capitalizes on the ancient "hardwiring" of the nervous system.
- Bioelectronic medicine is an emerging field that focuses on manipulating the nervous system to treat diseases.
- Clinical studies show that using electronic devices to stimulate the vagus nerve is effective at treating inflammatory diseases like rheumatoid arthritis.
- Although it's not yet approved by the US Food and Drug Administration, vagus nerve stimulation may also prove effective at treating other diseases like cancer, diabetes and depression.
The nervous system’s ancient reflexes<p>You accidentally place your hand on a hot stove. Almost instantaneously, your hand withdraws.</p><p>What triggered your hand to move? The answer is <em>not</em> that you consciously decided the stove was hot and you should move your hand. Rather, it was a reflex: Skin receptors on your hand sent nerve impulses to the spinal cord, which ultimately sent back motor neurons that caused your hand to move away. This all occurred before your "conscious brain" realized what happened.</p><p>Similarly, the nervous system has reflexes that protect individual cells in the body.</p><p>"The nervous system evolved because we need to respond to stimuli in the environment," said Dr. Tracey. "Neural signals don't come from the brain down first. Instead, when something happens in the environment, our peripheral nervous system senses it and sends a signal to the central nervous system, which comprises the brain and spinal cord. And then the nervous system responds to correct the problem."</p><p>So, what if scientists could "hack" into the nervous system, manipulating the electrical activity in the nervous system to control molecular processes and produce desirable outcomes? That's the chief goal of bioelectronic medicine.</p><p>"There are billions of neurons in the body that interact with almost every cell in the body, and at each of those nerve endings, molecular signals control molecular mechanisms that can be defined and mapped, and potentially put under control," Dr. Tracey said in a <a href="https://www.youtube.com/watch?v=AJH9KsMKi5M" target="_blank">TED Talk</a>.</p><p>"Many of these mechanisms are also involved in important diseases, like cancer, Alzheimer's, diabetes, hypertension and shock. It's very plausible that finding neural signals to control those mechanisms will hold promises for devices replacing some of today's medication for those diseases."</p><p>How can scientists hack the nervous system? For years, researchers in the field of bioelectronic medicine have zeroed in on the longest cranial nerve in the body: the vagus nerve.</p>
The vagus nerve<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTYyOTM5OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NTIwNzk0NX0.UCy-3UNpomb3DQZMhyOw_SQG4ThwACXW_rMnc9mLAe8/img.jpg?width=1245&coordinates=0%2C0%2C0%2C0&height=700" id="09add" class="rm-shortcode" data-rm-shortcode-id="f38dbfbbfe470ad85a3b023dd5083557" data-rm-shortcode-name="rebelmouse-image" data-width="1245" data-height="700" />
Electrical signals, seen here in a synapse, travel along the vagus nerve to trigger an inflammatory response.
Credit: Adobe Stock via solvod<p>The vagus nerve ("vagus" meaning "wandering" in Latin) comprises two nerve branches that stretch from the brainstem down to the chest and abdomen, where nerve fibers connect to organs. Electrical signals constantly travel up and down the vagus nerve, facilitating communication between the brain and other parts of the body.</p><p>One aspect of this back-and-forth communication is inflammation. When the immune system detects injury or attack, it automatically triggers an inflammatory response, which helps heal injuries and fend off invaders. But when not deployed properly, inflammation can become excessive, exacerbating the original problem and potentially contributing to diseases.</p><p>In 2002, Dr. Tracey and his colleagues discovered that the nervous system plays a key role in monitoring and modifying inflammation. This occurs through a process called the <a href="https://www.nature.com/articles/nature01321" target="_blank" rel="noopener noreferrer">inflammatory reflex</a>. In simple terms, it works like this: When the nervous system detects inflammatory stimuli, it reflexively (and subconsciously) deploys electrical signals through the vagus nerve that trigger anti-inflammatory molecular processes.</p><p>In rodent experiments, Dr. Tracey and his colleagues observed that electrical signals traveling through the vagus nerve control TNF, a protein that, in excess, causes inflammation. These electrical signals travel through the vagus nerve to the spleen. There, electrical signals are converted to chemical signals, triggering a molecular process that ultimately makes TNF, which exacerbates conditions like rheumatoid arthritis.</p><p>The incredible chain reaction of the inflammatory reflex was observed by Dr. Tracey and his colleagues in greater detail through rodent experiments. When inflammatory stimuli are detected, the nervous system sends electrical signals that travel through the vagus nerve to the spleen. There, the electrical signals are converted to chemical signals, which trigger the spleen to create a white blood cell called a T cell, which then creates a neurotransmitter called acetylcholine. The acetylcholine interacts with macrophages, which are a specific type of white blood cell that creates TNF, a protein that, in excess, causes inflammation. At that point, the acetylcholine triggers the macrophages to stop overproducing TNF – or inflammation.</p><p>Experiments showed that when a specific part of the body is inflamed, specific fibers within the vagus nerve start firing. Dr. Tracey and his colleagues were able to map these relationships. More importantly, they were able to stimulate specific parts of the vagus nerve to "shut off" inflammation.</p><p>What's more, clinical trials show that vagus nerve stimulation not only "shuts off" inflammation, but also triggers the production of cells that promote healing.</p><p>"In animal experiments, we understand how this works," Dr. Tracey said. "And now we have clinical trials showing that the human response is what's predicted by the lab experiments. Many scientific thresholds have been crossed in the clinic and the lab. We're literally at the point of regulatory steps and stages, and then marketing and distribution before this idea takes off."<br></p>
The future of bioelectronic medicine<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTYxMDYxMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjQwOTExNH0.uBY1TnEs_kv9Dal7zmA_i9L7T0wnIuf9gGtdRXcNNxo/img.jpg?width=980" id="8b5b2" class="rm-shortcode" data-rm-shortcode-id="c005e615e5f23c2817483862354d2cc4" data-rm-shortcode-name="rebelmouse-image" data-width="2000" data-height="1125" />
Vagus nerve stimulation can already treat Crohn's disease and other inflammatory diseases. In the future, it may also be used to treat cancer, diabetes, and depression.
Credit: Adobe Stock via Maridav<p>Vagus nerve stimulation is currently awaiting approval by the US Food and Drug Administration, but so far, it's proven safe and effective in clinical trials on humans. Dr. Tracey said vagus nerve stimulation could become a common treatment for a wide range of diseases, including cancer, Alzheimer's, diabetes, hypertension, shock, depression and diabetes.</p><p>"To the extent that inflammation is the problem in the disease, then stopping inflammation or suppressing the inflammation with vagus nerve stimulation or bioelectronic approaches will be beneficial and therapeutic," he said.</p><p>Receiving vagus nerve stimulation would require having an electronic device, about the size of lima bean, surgically implanted in your neck during a 30-minute procedure. A couple of weeks later, you'd visit, say, your rheumatologist, who would activate the device and determine the right dosage. The stimulation would take a few minutes each day, and it'd likely be unnoticeable.</p><p>But the most revolutionary aspect of bioelectronic medicine, according to Dr. Tracey, is that approaches like vagus nerve stimulation wouldn't come with harmful and potentially deadly side effects, as many pharmaceutical drugs currently do.</p><p>"A device on a nerve is not going to have systemic side effects on the body like taking a steroid does," Dr. Tracey said. "It's a powerful concept that, frankly, scientists are quite accepting of—it's actually quite amazing. But the idea of adopting this into practice is going to take another 10 or 20 years, because it's hard for physicians, who've spent their lives writing prescriptions for pills or injections, that a computer chip can replace the drug."</p><p>But patients could also play a role in advancing bioelectronic medicine.</p><p>"There's a huge demand in this patient cohort for something better than they're taking now," Dr. Tracey said. "Patients don't want to take a drug with a black-box warning, costs $100,000 a year and works half the time."</p><p>Michael Dowling, president and CEO of Northwell Health, elaborated:</p><p>"Why would patients pursue a drug regimen when they could opt for a few electronic pulses? Is it possible that treatments like this, pulses through electronic devices, could replace some drugs in the coming years as preferred treatments? Tracey believes it is, and that is perhaps why the pharmaceutical industry closely follows his work."</p><p>Over the long term, bioelectronic approaches are unlikely to completely replace pharmaceutical drugs, but they could replace many, or at least be used as supplemental treatments.</p><p>Dr. Tracey is optimistic about the future of the field.</p><p>"It's going to spawn a huge new industry that will rival the pharmaceutical industry in the next 50 years," he said. "This is no longer just a startup industry. [...] It's going to be very interesting to see the explosive growth that's going to occur."</p>
Japan looks to replace China as the primary source of critical metals
- Enough rare earth minerals have been found off Japan to last centuries
- Rare earths are important materials for green technology, as well as medicine and manufacturing
- Where would we be without all of our rare-earth magnets?
What are the rare earth elements?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA2MTM0Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzODExMjMyMn0.owchAgxSBwji5IofgwKtueKSbHNyjPfT7hTJrHpTi98/img.jpg?width=980" id="fd315" class="rm-shortcode" data-rm-shortcode-id="d8ed70e3d0b67b9cbe78414ffd02c43e" data-rm-shortcode-name="rebelmouse-image" />
(julie deshaies/Shutterstock)<p>The rare earth metals can be mostly found in the second row from the bottom in the Table of Elements. According to the <a href="http://www.rareearthtechalliance.com/What-are-Rare-Earths" target="_blank"><u>Rare Earth Technology Alliance</u></a>, due to the "unique magnetic, luminescent, and electrochemical properties, these elements help make many technologies perform with reduced weight, reduced emissions, and energy consumption; or give them greater efficiency, performance, miniaturization, speed, durability, and thermal stability."</p><p>In order of atomic number, the rare earths are:</p> <ul> <li>Scandium or Sc (21) — This is used in TVs and energy-saving lamps.</li> <li>Yttrium or Y (39) — Yttrium is important in the medical world, used in cancer drugs, rheumatoid arthritis medications, and surgical supplies. It's also used in superconductors and lasers.</li> <li>Lanthanum or La (57) — Lanthanum finds use in camera/telescope lenses, special optical glasses, and infrared absorbing glass.</li> <li>Cerium or Ce (58) — Cerium is found in catalytic converters, and is used for precision glass-polishing. It's also found in alloys, magnets, electrodes, and carbon-arc lighting. </li> <li>Praseodymium or Pr (59) — This is used in magnets and high-strength metals.</li> <li>Neodymium or Nd (60) — Many of the magnets around you have neodymium in them: speakers and headphones, microphones, computer storage, and magnets in your car. It's also found in high-powered industrial and military lasers. The mineral is especially important for green tech. Each <a href="https://www.reuters.com/article/us-mining-toyota/as-hybrid-cars-gobble-rare-metals-shortage-looms-idUSTRE57U02B20090831" target="_blank"><u>Prius</u></a> motor, for example, requires 2.2 lbs of neodymium, and its battery another 22-33 lbs. <a href="https://pubs.usgs.gov/sir/2011/5036/sir2011-5036.pdf" target="_blank"><u>Wind turbine batteries</u></a> require 450 lbs of neodymium per watt. </li> <li>Promethium or Pm (61) — This is used in pacemakers, watches, and research.</li> <li>Samarium or Sm (62) — This mineral is used in magnets in addition to intravenous cancer radiation treatments and nuclear reactor control rods.</li> <li>Europium or Eu (63) — Europium is used in color displays and compact fluorescent light bulbs.</li> <li>Gadolinium or Gd (64) — It's important for nuclear reactor shielding, cancer radiation treatments, as well as x-ray and bone-density diagnostic equipment.</li> <li>Terbium or Tb (65) — Terbium has similar uses to Europium, though it's also soft and thus possesses unique shaping capabilities .</li> <li>Dysprosium or Dy (66) — This is added to other rare-earth magnets to help them work at high temperatures. It's used for computer storage, in nuclear reactors, and in energy-efficient vehicles.</li> <li>Holmium or Ho (67) — Holmium is used in nuclear control rods, microwaves, and magnetic flux concentrators.</li> <li>Erbium or Er (68) — This is used in fiber-optic communication networks and lasers.</li> <li>Thulium or Tm (69) — Thulium is another laser rare earth.</li> <li>Ytterbium or Yb (70) — This mineral is used in cancer treatments, in stainless steel, and in seismic detection devices.</li> <li>Lutetium or Lu (71) — Lutetium can target certain cancers, and is used in petroleum refining and positron emission tomography.</li></ul>
Where Japan found is rare earths<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA2MTM0OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MTA0NzUxNn0.N3t_iKf6lnnoJ6yVUtl8-wNZICEG2ZxyPzm9ZdE99ks/img.jpg?width=980" id="021b7" class="rm-shortcode" data-rm-shortcode-id="d9dd843fde547a0b69f8798aca18a706" data-rm-shortcode-name="rebelmouse-image" />
Minimatori Torishima Island
(Chief Master Sergeant Don Sutherland, U.S. Air Force)<p>Japan located the rare earths about 1,850 kilometers off the shore of <a href="https://en.wikipedia.org/wiki/Minami-Tori-shima" target="_blank"><u>Minamitori Island</u></a>. Engineers located the minerals in 10-meter-deep cores taken from sea floor sediment. Mapping the cores revealed and area of approximately 2,500 square kilometers containing rare earths.</p><p>Japan's engineers estimate there's 16 million tons of rare earths down there. That's <a href="https://minerals.usgs.gov/minerals/pubs/historical-statistics/ds140-raree.xlsx" target="_blank"><u>five times</u></a> the amount of the rare earth elements ever mined since 1900. According to <a href="https://www.businessinsider.com.au/rare-earth-minerals-found-in-japan-2018-4?r=US&IR=T" target="_blank"><u>Business Insider</u></a>, there's "enough yttrium to meet the global demand for 780 years, dysprosium for 730 years, europium for 620 years, and terbium for 420 years."</p><p>The bad news, of course, is that Japan has to figure out how to extract the minerals from 6-12 feet under the seabed four miles beneath the ocean surface — that's the <a href="https://www.nature.com/articles/s41598-018-23948-5" target="_blank"><u>next step</u></a> for the country's engineers. The good news is that the location sits squarely within Japan's Exclusive Economic Zone, so their rights to the lucrative discovery will be undisputed.</p>
A physicist creates an AI algorithm that predicts natural events and may prove the simulation hypothesis.
- Princeton physicist Hong Qin creates an AI algorithm that can predict planetary orbits.
- The scientist partially based his work on the hypothesis which believes reality is a simulation.
- The algorithm is being adapted to predict behavior of plasma and can be used on other natural phenomena.
Physicist Hong Qin with images of planetary orbits and computer code.
Credit: Elle Starkman
Are we living in a simulation? | Bill Nye, Joscha Bach, Donald Hoffman | Big Think<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="4dbe18924f2f42eef5669e67f405b52e"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/KDcNVZjaNSU?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
How different people react to threats of violence.
Beyond making up 70% of the world's health workers, women researchers have been at the cutting edge of coronavirus research.