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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 ›
The COVID-19 pandemic is making health disparities in the United States crystal clear. It is a clarion call for health care systems to double their efforts in vulnerable communities.
- The COVID-19 pandemic has exacerbated America's health disparities, widening the divide between the haves and have nots.
- Studies show disparities in wealth, race, and online access have disproportionately harmed underserved U.S. communities during the pandemic.
- To begin curing this social aliment, health systems like Northwell Health are establishing relationships of trust in these communities so that the post-COVID world looks different than the pre-COVID one.
COVID-19 deepens U.S. health disparities<p>Communities on the pernicious side of America's health disparities have their unique histories, environments, and social structures. They are spread across the United States, but they all have one thing in common.</p><p>"There is one common divide in American communities, and that is poverty," said <a href="https://www.northwell.edu/about/leadership/debbie-salas-lopez" target="_blank">Debbie Salas-Lopez, MD, MPH</a>, senior vice president of community and population health at Northwell Health. "That is the undercurrent that manifests poor health, poor health outcomes, or poor health prognoses for future wellbeing."</p><p>Social determinants have far-reaching effects on health, and poor communities have unfavorable social determinants. To pick one of many examples, <a href="https://www.npr.org/2020/09/27/913612554/a-crisis-within-a-crisis-food-insecurity-and-covid-19" target="_blank" rel="noopener noreferrer">food insecurity</a> reduces access to quality food, leading to poor health and communal endemics of chronic medical conditions. The U.S. Centers for Disease Control and Prevention has identified some of these conditions, such as obesity and Type 2 diabetes, as increasing the risk of developing a severe case of coronavirus.</p><p>The pandemic didn't create poverty or food insecurity, but it exacerbated both, and the results have been catastrophic. A study published this summer in the <em><a href="https://link.springer.com/article/10.1007/s11606-020-05971-3" target="_blank">Journal of General Internal Medicine</a></em> suggested that "social factors such as income inequality may explain why some parts of the USA are hit harder by the COVID-19 pandemic than others."</p><p>That's not to say better-off families in the U.S. weren't harmed. A <a href="https://voxeu.org/article/poverty-inequality-and-covid-19-us" target="_blank" rel="noopener noreferrer">paper from the Centre for Economic Policy Research</a> noted that families in counties with a higher median income experienced adjustment costs associated with the pandemic—for example, lowering income-earning interactions to align with social distancing policies. However, the paper found that the costs of social distancing were much greater for poorer families, who cannot easily alter their living circumstances, which often include more individuals living in one home and a reliance on mass transit to reach work and grocery stores. They are also disproportionately represented in essential jobs, such as retail, transportation, and health care, where maintaining physical distance can be all but impossible.</p><p>The paper also cited a positive correlation between higher income inequality and higher rates of coronavirus infection. "Our interpretation is that poorer people are less able to protect themselves, which leads them to different choices—they face a steeper trade-off between their health and their economic welfare in the context of the threats posed by COVID-19," the authors wrote.</p><p>"There are so many pandemics that this pandemic has exacerbated," Dr. Salas-Lopez noted.</p><p>One example is the health-wealth gap. The mental stressors of maintaining a low socioeconomic status, especially in the face of extreme affluence, can have a physically degrading impact on health. <a href="https://www.scientificamerican.com/index.cfm/_api/render/file/?method=inline&fileID=123ECD96-EF81-46F6-983D2AE9A45FA354" target="_blank" rel="noopener noreferrer">Writing on this gap</a>, Robert Sapolsky, professor of biology and neurology at Stanford University, notes that socioeconomic stressors can increase blood pressure, reduce insulin response, increase chronic inflammation, and impair the prefrontal cortex and other brain functions through anxiety, depression, and cognitive load. </p><p>"Thus, from the macro level of entire body systems to the micro level of individual chromosomes, poverty finds a way to produce wear and tear," Sapolsky writes. "It is outrageous that if children are born into the wrong family, they will be predisposed toward poor health by the time they start to learn the alphabet."</p>Research on the economic and mental health fallout of COVID-19 is showing two things: That unemployment is hitting <a href="https://www.pewsocialtrends.org/2020/09/24/economic-fallout-from-covid-19-continues-to-hit-lower-income-americans-the-hardest/" target="_blank" rel="noopener noreferrer">low-income and young Americans</a> most during the pandemic, potentially widening the health-wealth gap further; and that the pandemic not only exacerbates mental health stressors, but is doing so at clinically relevant levels. As <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413844/" target="_blank" rel="noopener noreferrer">the authors of one review</a> wrote, the pandemic's effects on mental health is itself an international public health priority.
Working to close the health gap<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc5MDk1MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNTYyMzQzMn0.KSFpXH7yHYrfVPtfgcxZqAHHYzCnC2bFxwSrJqBbH4I/img.jpg?width=980" id="b40e2" class="rm-shortcode" data-rm-shortcode-id="1b9035370ab7b02a0dc00758e494412b" data-rm-shortcode-name="rebelmouse-image" />
Northwell Health coronavirus testing center at Greater Springfield Community Church.
Credit: Northwell Health<p>Novel coronavirus may spread and infect indiscriminately, but pre-existing conditions, environmental stressors, and a lack of access to care and resources increase the risk of infection. These social determinants make the pandemic more dangerous, and erode communities' and families' abilities to heal from health crises that pre-date the pandemic.</p><p>How do we eliminate these divides? Dr. Salas-Lopez says the first step is recognition. "We have to open our eyes to see the suffering around us," she said. "Northwell has not shied away from that."</p><p>"We are steadfast in improving health outcomes for our vulnerable and underrepresented communities that have suffered because of the prevalence of chronic disease, a problem that led to the disproportionately higher death rate among African-Americans and Latinos during the COVID-19 pandemic," said Michael Dowling, Northwell's president and CEO. "We are committed to using every tool at our disposal—as a provider of health care, employer, purchaser and investor—to combat disparities and ensure the <a href="https://www.northwell.edu/education-and-resources/community-engagement/center-for-equity-of-care" target="_blank" rel="noopener noreferrer">equity of care</a> that everyone deserves." </p><p>With the need recognized, Dr. Salas-Lopez calls for health care systems to travel upstream and be proactive in those hard-hit communities. This requires health care systems to play a strong role, but not a unilateral one. They must build <a href="https://www.northwell.edu/news/insights/faith-based-leaders-are-the-key-to-improving-community-health" target="_blank" rel="noopener noreferrer">partnerships with leaders in those communities</a> and utilize those to ensure relationships last beyond the current crisis. </p><p>"We must meet with community leaders and talk to them to get their perspective on what they believe the community needs are and should be for the future. Together, we can co-create a plan to measurably improve [community] health and also to be ready for whatever comes next," she said.</p><p>Northwell has built relationships with local faith-based and community organizations in underserved communities of color. Those partnerships enabled Northwell to test more than 65,000 people across the metro New York region. The health system also offered education on coronavirus and precautions to curb its spread.</p><p>These initiatives began the process of building trust—trust that Northwell has counted on to return to these communities to administer flu vaccines to prepare for what experts fear may be a difficult flu season.</p><p>While Northwell has begun building bridges across the divides of the New York area, much will still need to be done to cure U.S. health care overall. There is hope that the COVID pandemic will awaken us to the deep disparities in the US.</p><p>"COVID has changed our world. We have to seize this opportunity, this pandemic, this crisis to do better," Dr. Salas-Lopez said. "Provide better care. Provide better health. Be better partners. Be better community citizens. And treat each other with respect and dignity.</p><p>"We need to find ways to unify this country because we're all human beings. We're all created equal, and we believe that health is one of those important rights."</p>
With just a few strategical tweaks, the Nazis could have won one of World War II's most decisive battles.
- The Battle of Britain is widely recognized as one of the most significant battles that occurred during World War II. It marked the first major victory of the Allied forces and shifted the tide of the war.
- Historians, however, have long debated the deciding factor in the British victory and German defeat.
- A new mathematical model took into account numerous alternative tactics that the German's could have made and found that just two tweaks stood between them and victory over Britain.
Two strategic blunders<p>Now, historians and mathematicians from York St. John University have collaborated to produce <a href="http://www-users.york.ac.uk/~nm15/bootstrapBoB%20AAMS.docx" target="_blank">a statistical model (docx download)</a> capable of calculating what the likely outcomes of the Battle of Britain would have been had the circumstances been different. </p><p>Would the German war effort have fared better had they not bombed Britain at all? What if Hitler had begun his bombing campaign earlier, even by just a few weeks? What if they had focused their targets on RAF airfields for the entire course of the battle? Using a statistical technique called weighted bootstrapping, the researchers studied these and other alternatives.</p><p>"The weighted bootstrap technique allowed us to model alternative campaigns in which the Luftwaffe prolongs or contracts the different phases of the battle and varies its targets," said co-author Dr. Jaime Wood in a <a href="https://www.york.ac.uk/news-and-events/news/2020/research/mathematicians-battle-britain-what-if-scenarios/" target="_blank">statement</a>. Based on the different strategic decisions that the German forces could have made, the researchers' model enabled them to predict the likelihood that the events of a given day of fighting would or would not occur.</p><p>"The Luftwaffe would only have been able to make the necessary bases in France available to launch an air attack on Britain in June at the earliest, so our alternative campaign brings forward the air campaign by three weeks," continued Wood. "We tested the impact of this and the other counterfactuals by varying the probabilities with which we choose individual days."</p><p>Ultimately, two strategic tweaks shifted the odds significantly towards the Germans' favor. Had the German forces started their campaign earlier in the year and had they consistently targeted RAF airfields, an Allied victory would have been extremely unlikely.</p><p>Say the odds of a British victory in the real-world Battle of Britain stood at 50-50 (there's no real way of knowing what the actual odds are, so we'll just have to select an arbitrary figure). If this were the case, changing the start date of the campaign and focusing only on airfields would have reduced British chances at victory to just 10 percent. Even if a British victory stood at 98 percent, these changes would have cut them down to just 34 percent.</p>
A tool for understanding history<p>This technique, said co-author Niall Mackay, "demonstrates just how finely-balanced the outcomes of some of the biggest moments of history were. Even when we use the actual days' events of the battle, make a small change of timing or emphasis to the arrangement of those days and things might have turned out very differently."</p><p>The researchers also claimed that their technique could be applied to other uncertain historical events. "Weighted bootstrapping can provide a natural and intuitive tool for historians to investigate unrealized possibilities, informing historical controversies and debates," said Mackay.</p><p>Using this technique, researchers can evaluate other what-ifs and gain insight into how differently influential events could have turned out if only the slightest things had changed. For now, at least, we can all be thankful that Hitler underestimated Britain's grit.</p>
The next era in American history can look entirely different. It's up to us to choose.
- The timeline of America post-WWII can be divided into two eras, according to author and law professor Ganesh Sitaraman: the liberal era which ran through the 1970s, and the current neoliberal era which began in the early 1980s. The latter promised a "more free society," but what we got instead was more inequality, less opportunity, and greater market consolidation.
- "We've lived through a neoliberal era for the last 40 years, and that era is coming to an end," Sitaraman says, adding that the ideas and policies that defined the period are being challenged on various levels.
- What comes next depends on if we take a proactive and democratic approach to shaping the economy, or if we simply react to and "deal with" market outcomes.
A new MIT report proposes how humans should prepare for the age of automation and artificial intelligence.
- A new report by MIT experts proposes what humans should do to prepare for the age of automation.
- The rise of intelligent machines is coming but it's important to resolve human issues first.
- Improving economic inequality, skills training, and investment in innovation are necessary steps.