Surprising new feature of human evolution discovered
Research reveals a new evolutionary feature that separates humans from other primates.
07 March, 2021
Credit: Adobe Stock
- Researchers find a new feature of human evolution.
- Humans have evolved to use less water per day than other primates.
- The nose is one of the factors that allows humans to be water efficient.
<p>Scientists discovered a new feature that makes humans distinct from other primates like chimpanzees. The research shows that the human body uses 30% to 50% less water per day than our closest animal relatives.</p><p>Certainly, our brain power, and the ability to walk upright are key in making us special but the efficiency with which the human body uses up water is another major difference. This characteristic likely came about as an evolutionary adaptation in ancient hunter-gatherers, who had to venture out further and further from water sources in search of food, thinks the study's lead author Herman Pontzer, associate professor of evolutionary anthropology at Duke University.</p>
<p style="margin-left: 20px;">"Even just being able to go a little bit longer without water would have been a big advantage as early humans started making a living in dry, savannah landscapes," Pontzer <a href="https://phys.org/news/2021-03-humans-evolved-closest-primate-relatives.html" target="_blank">said</a>.</p><p>As our body constantly gets rid of water through processes like urinating or sweating, it is necessary for the water levels to be restored. "To sustain life, humans and other terrestrial animals must maintain a tight balance of water gain and water loss each day," as the paper's authors <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(21)00289-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS096098222100289X%3Fshowall%3Dtrue" target="_blank">write</a>. </p><p>For the study, the researchers looked at this cycle of water consumption and loss in 309 people from a variety of backgrounds. These included farmers, hunter-gatherers, and office workers, who were compared to 72 apes spread around zoos and sanctuaries.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTc5Mzg4NS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2Mjc5NDIxNX0.twc5eqzbcvstjN1fXX-egPqyRhL5ob1oxbmE7Vm_M4g/img.jpg?width=980" id="5b260" class="rm-shortcode" data-rm-shortcode-id="0410ac6c503e7f6c52ff043c1ffaa533" data-rm-shortcode-name="rebelmouse-image" data-width="2250" data-height="2250" />
A model of water turnover for humans and chimpanzees who have similar fat free mass and body water pools.
Credit: Current Biology
<p>The scientists calculated the water intake of each person in the study, whether it came from drinks or food. They also tracked how much water was lost through urine, sweat or the GI tract. With all the numbers added up, it became clear that an average person's body goes through about 3 liters of water every day. That's about 12 cups. A chimp or a gorilla goes through twice as much.</p><p>The results were surprising because humans tend to sweat more than other primates. In one square inch of skin, "humans have 10 times as many sweat glands as chimpanzees do," <a href="https://phys.org/news/2021-03-humans-evolved-closest-primate-relatives.html" target="_blank">explained</a> Pontzer. We can sweat out about a half gallon in a 30-minute workout. We also lead much more active lives than the apes at the zoo, with most apes only moving a couple of hours a day, according to the scientists. So how is it that we use up so much less water?</p>
<p>The researchers believe that the very real difference in water processing they observed in humans compared to other primates is related to evolutionary mechanisms. Our bodies had to adjust to need less water to stay healthy.</p><p>The scientists are now focused on figuring out how exactly this change occurred. The data suggests that our sense of thirst diverged from other ape relatives. We just don't want so much water. Notably, the ratio of water-to-calories is 25% less in human breast milk than in ape milk.</p><p>It is also possible that our nose has a lot to do with this. Fossils point to the fact that humans started to get more protruding noses than its evolutionary cousins about 1.6 million years ago, with the dawn of Homo erectus. In contrast, gorillas and chimp have flatter noses. </p>
<p>What's good about our noses? Since we tend to breathe out water vapor, the nasal passages actually cool and condense it, turning it back into liquid. This liquid gathers inside the nose and get reappropriated back into the body. Essentially, having a nose that juts out likely helped ancient humans keep more moisture when breathing.</p><p>Read the study published in <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(21)00289-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS096098222100289X%3Fshowall%3Dtrue" target="_blank">Current Biology. </a></p>
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Record for oldest DNA ever sequenced broken by mammoth remains
One million year old mammoth DNA more than doubles the previous record and suggests that even older genomes could be found.
20 February, 2021
Credit: Thomas Quine / Flickr
- Scientists extracting DNA from mammoth teeth have set a new record for the oldest DNA ever sequenced.
- The new record holder may also be a member of a new species of mammoth, but that remains to be proven.
- The findings suggest that DNA as old as 2.6 million years old could be decoded.
<p> Analysis of million-year-old mammoth remains has set a new record for the oldest DNA ever sequenced and revealed a potentially new mammoth species. The study containing these findings, published in <a href="https://www.nature.com/articles/d41586-021-00436-x" rel="noopener noreferrer" target="_blank">Nature</a>, sheds new light on the mammoth's evolutionary history and suggests that even older DNA samples could have survived to the present day. </p>
Mammoth Molars
<p> The DNA was taken from three sets of mammoth teeth discovered in Siberia in the 1970s. The three samples, named Krestovka, Adycha, and Chukochya, are too old for carbon dating techniques to be useful. Their ages were instead determined using methods such as <a href="https://en.wikipedia.org/wiki/Radiometric_dating" target="_blank" rel="noopener noreferrer">radiometric dating.</a> </p><p>Krestovka is the oldest of the three, dating back to about 1.1 or 1.2 million years ago. In addition to setting the record for the oldest animal to have DNA sequenced from it, Krestovka appears to be the first known example from a new lineage of mammoth. It seems to belong to another branch of the evolutionary tree that left no living decedents. However, some of its DNA also exists in the Colombian mammoth's genetics, which raises other questions.</p><p>While it is too soon to say that Krestovka is from a new mammoth species, the possibility is there. If it is, then it also suggests that the Columbia mammoth could be a hybrid species between this unknown branch and the woolly <a href="https://gizmodo.com/million-year-old-mammoth-teeth-contain-oldest-dna-ever-1846287115" target="_blank" rel="noopener noreferrer">mammoth</a>. This would be particularly exciting, as evidence for hybridization creating new species is rare.</p><p>Adycha dated back about one million years. It is thought to be a steppe mammoth, a larger, less hairy ancestor of the woolly mammoth. Steppe mammoths lived across Eurasia but were considered to be best suited for warmer climates than Siberia. Some of the DNA fragments also imply that adaptations for surviving in cooler temperatures, revealed in genes related to fat deposits, thermal regulation, and the circadian rhythm, appeared earlier in the evolutionary tree than previously thought. </p><p>Chukochya is the youngest of the three. Dated to some point between 500,000 and 800,000 years ago, it was an early example of a woolly mammoth. </p>Why is this exciting, exactly?
<iframe width="730" height="430" src="https://www.youtube.com/embed/gHbYJfwFgOU" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> DNA breaks down fairly quickly in most environments. Exposure to bacteria, water, ultraviolet light, or enzymes breaks it down. Even in the permafrost, where conditions are more favorable, these factors slowly whittle away at the information until little is left. That makes this find so exciting — it is remarkable that this much information endured a million years in the <a href="https://www.nytimes.com/2021/02/17/science/DNA-mammoth.html" target="_blank" rel="noopener noreferrer">ground</a>. </p><p>The previous record-holder was the DNA of a 750,000-year-old horse found in the permafrost of the <a href="https://www.sciencemag.org/news/2013/06/700000-year-old-horse-becomes-oldest-creature-sequenced-genome" target="_blank" rel="noopener noreferrer">Yukon</a>. In principle, it is possible to find DNA as old as the oldest permafrost: 2.6 million years old. Protein sequences last longer; the current <a href="https://elifesciences.org/articles/17092" target="_blank" rel="noopener noreferrer">record holder</a> is dated back to 3.8 million years but reveal much less information.</p><p>While the DNA from these mammoth teeth was quite fragmented, modern technology made putting the pieces together possible. By comparing what remained with the DNA of elephants and younger mammoth samples, the scientists could isolate the fragments that were unique to the specimen.</p><p>Ludovic Orlando, the head of the team which held the previous record, expressed his <a href="https://www.sciencemag.org/news/2021/02/mammoth-molars-yield-oldest-dna-ever-sequenced" target="_blank" rel="noopener noreferrer">excitement</a> at losing it, "I love this paper. I have been waiting since 2013 [for] our world record for the oldest genome to be broken."</p>So do these findings mean we’re getting mammoth clones?
<iframe width="730" height="430" src="https://www.youtube.com/embed/8c-EWSmOgDc" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> Not yet. As mentioned, these sequences are incomplete and damaged due to their age. The cloning of mammoths using more complete samples of their DNA is generally thought to be a bit <a href="https://www.washingtonpost.com/national/health-science/can-scientists-bring-mammoths-back-to-life-by-cloning/2015/02/06/2a825c8c-80ae-11e4-81fd-8c4814dfa9d7_story.html" target="_blank" rel="noopener noreferrer">unfeasible</a>. Even if it could be done, there is a question of what you'd do with the animal you've created. While some have suggested bringing the mammoths back and putting them in <a href="https://science.sciencemag.org/content/308/5723/796.1" target="_blank" rel="noopener noreferrer">Siberia</a>, the benefits of doing this remain unstated. </p><p>However, the findings shine a light on evolutionary paths previously unknown to us and prove that these methods can work on other samples, potentially including even older ones. </p><p> So, even if you're not going to see a cloned mammoth any time soon, you may see a better model of one at the natural history museum and a better picture of how life on Earth, including our species, changes over time in response to shifting environmental factors. It's a great takeaway from studying some old teeth.</p>
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Study reveals a "boring" era when Earth was flat, with no mountains
A study of europium crystals shows the planet was mostly flat during its middle ages.
16 February, 2021
Credit: green impact / Unsplash
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<p>Scientists discovered that Earth was likely quite flat during it's so-called middle ages. Not flat as in conspiracies that don't believe our planet is round, but lacking in mountains. It was also a period of little growth of life. In fact, this stretch of time from 1.8 billion to 0.8 billion years ago is also known as the "Boring Billion" and referred to as "the dullest period in Earth's history."</p><p>Nothing dull about what the researchers found, however, by studying the chemical element europium, embedded in zircon crystals. Their analysis revealed that during the Boring Billion, the absence of tectonic activity that's crucial to mountain creation also slowed the nutrient cycling vital for the evolution of life. </p>
<p><span style="background-color: initial;">The research involved studying zircon crystals from around the globe, carried out by teams from </span><span style="background-color: initial;">Peking University, the University of Toronto, Rutgers University, and the University of Science and Technology of China. They based their work on previous findings that showed a connection between the amount of europium located inside a zircon crystal and the thickness of the Earth's crust when the crystal was formed. A larger amount of the europium meant more pressure pushing down on it from above. This indicated that the crust was thicker.</span></p><p>The scientists, led by Ming Tang from Peking University, found that during the so-called middle or "Boring" period, Earth's crust was thinner than it is now. There were no mountains and the surface was all oceans and flat land masses. This indicated to the researchers that tectonic activity likely stopped or at least slowed majorly for about 1 billion years. Tectonic activity is known to push mountains up, leading also to erosion that enriches oceanic environments and fosters evolving life. If such a cycle was disrupted, evolution would have slowed to a crawl. This is what previous studies have suggested for that time period.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTY1MzQ3Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNDIyNTAyOH0.8dmdvyhNrwTYZJflxbZnPHIgvW8P-Y-8SgWZNKhemRc/img.jpg?width=980" id="23fd8" class="rm-shortcode" data-rm-shortcode-id="2344c487fdcc19137c73778b6768d141" data-rm-shortcode-name="rebelmouse-image" data-width="800" data-height="531" />
Europium crystal.
Credit: Alchemist-hp, CC0 public domain
<p>Why did the tectonic activity stop? And why for such a long time? The researchers do not know yet, but think the answers may lie in the creation of the ancient Nuna-Rodina supercontinent, which could have affected the thermal structure of the planet's mantle.</p><p>Check out the new paper on the history of mountain formation (or "orogenic") processes published in <a href="https://science.sciencemag.org/content/371/6530/728" target="_blank">Science</a>.</p>
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Why do some species evolve to miniaturize?
The island rule hypothesizes that species shrink or supersize to fill insular niches not available to them on the mainland.
12 February, 2021
Credit: Frank Glaw
- Brookesia nana, the nano-chameleon, may be the smallest vertebrate ever discovered.
- The "island rule" states that when new species migrate to islands, they may shrink or grow as they evolve to fill new ecological niches.
- It remains unclear whether the island rule can explain the nano-chameleon or nature's other extreme miniaturizations.
<ul class="ee-ul"></ul>
<p class=""><br></p>
<p>The newly discovered <a href="https://www.instagram.com/p/CKweWF5nZGc/" target="_blank" rel="noopener noreferrer">nano-chameleon</a> (<em>Brookesia nana</em>) is the latest contender for the title of the world's smallest reptile and <a href="https://www.britannica.com/animal/Amniota" target="_blank" rel="noopener noreferrer">amniote vertebrate</a>. <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0031314" target="_blank" rel="noopener noreferrer">Found in a mountainous region in northern Madagascar</a>, the males of this diminutive species sport a body size of 13.5 mm, meaning one could comfortably stand on the end of your finger.</p><p>Its wee challenger is the <a href="https://www.nature.com/news/2001/011206/full/news011206-3.html" target="_blank" rel="noopener noreferrer">Jaragua dwarf gecko</a> (<em>Sphaerodactylus ariasae</em>). These pocket-change-sized geckos—<a href="https://commons.wikimedia.org/wiki/File:Sphaerodactylus_parthenopion_004.jpg" target="_blank" rel="noopener noreferrer">the genus is often pictured snogging</a> the minted portraits of past presidents—come in at 16 mm from nose to tail. They were discovered in 2001 on Isla Beata, a small, forested Caribbean island just south of the Dominican Republic. </p><p>The title of the world's smallest, however, is difficult to award thanks to sexual size dimorphism. As Dr. Mark Scherz, herpetologist and evolutionary biologist, pointed out on his blog, nano-chameleon females are significantly larger than their male counterparts or Jaragua dwarf gecko females. "As a result, whether or not the new species is considered the smallest amniote in the world depends on whether we define that based on the male or female body size, or the midpoint of the two. It turns out this is quite a common problem in other species with size dimorphism as well, such as frogs," <a href="http://www.markscherz.com/archives/4800" target="_blank" rel="noopener noreferrer">Scherz writes</a>.</p><p>Beyond their shrimpy stature, these and <a href="https://www.bbc.com/news/science-environment-16491477#:~:text=A%20frog%20species%20that%20appears,%2C%20fish%2C%20birds%20and%20amphibians." target="_blank" rel="noopener noreferrer">other miniaturized species</a> have another thing in common: They live on islands. That fact may explain why evolution has pushed them to shrink in a world full of giant competition.</p>
Bigger isn't always better
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTYzNTY0OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNjM5MzYwMH0.ge-xLd6L6EXkTSUSDmAWCdoLsTsWmK0-54LILO_4pt8/img.jpg?width=1245&coordinates=0%2C279%2C0%2C280&height=700" id="1db5a" class="rm-shortcode" data-rm-shortcode-id="62958849d69721c1050aee9b45006650" data-rm-shortcode-name="rebelmouse-image" data-width="1245" data-height="700" />The New Zealand little spotted kiwi evolved to be small to fill an ecological niche. Before the arrival of humans, its island ecosystem contained no land mammals to prey on these flightless birds.
Credit: Wikimedia Commons
<p>Because of their geographic isolation, islands can have powerful effects on the evolution of their residential species. The massive Komodo dragon prowls its namesake island. The <a href="https://www.wired.com/2015/01/absurd-creature-of-the-week-barbados-threadsnake/" target="_blank" rel="noopener noreferrer">Barbados threadsnake</a> is thin enough to slither through a straw. And the fossil record recounts a history of unusually sized and bedecked creatures who established homes far from the mainland, such as <a href="https://prehistoric-fauna.com/Hoplitomeryx-matthei" target="_blank" rel="noopener noreferrer">the <em>Hoplitomeryx</em> of the Mikrotia fauna</a>.</p><p>One hypothesis for evolution's insular experimentation is "the island rule." The rule states that after establishing themselves on an island, smaller species will tend to evolve into oversized versions of their mainland ancestors. Meanwhile, larger species will tend to evolve into smaller variations. These processes are known as insular gigantism and insular dwarfism, respectively. They do this to fill the ecological niches available to them, which often differ from those they filled on the mainland.</p><p>The rule was first formulated by evolutionary biologist Leigh Van Valen and based on a <a href="https://www.nature.com/articles/202234a0" target="_blank" rel="noopener noreferrer">1964 study</a> by mammologist J. Bristol Foster—which is why it is also known as Foster's rule. Since then, many observational studies have corroborated the island rule, and there is <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0040334" target="_blank" rel="noopener noreferrer">even evidence</a> to suggest that new species introduced to islands will, for a time, evolve more rapidly to fill available niches.</p><p>A flock of migrant birds, for example, may find an island's lack of mammalian and reptilian predators opens the ground-living niche once forbidden to them. Such birds would then be free to grow larger, forage below the canopies, and lose the ability of flight.</p><p>This appears to be the origin story for New Zealand's flightless birds including <a href="http://nzbirdsonline.org.nz/species/south-island-giant-moa" target="_blank" rel="noopener noreferrer">the giant moa</a>, which, at six-feet tall, is the tallest bird on record. This megafauna enjoyed all the benefits of being large and in charge: fewer predators, wider ranges, access to more and varied foods, and the ability to better survive trying times. The species enjoyed island life until roughly 600 years ago, when humans arrived on the scene and <a href="https://www.sciencemag.org/news/2014/03/why-did-new-zealands-moas-go-extinct" target="_blank" rel="noopener noreferrer">hunted them to extinction</a>.</p><p>Conversely, large species may find island living restrictive as there's less room or food when compared to their mainland nurseries. Because of this, evolution may select for smaller body sizes as such bodies require less energy, and therefore fewer resources, to survive and reproduce. </p><p>This is the theory behind the miniaturization of the <a href="https://www.nps.gov/chis/learn/historyculture/pygmymammoth.htm" target="_blank" rel="noopener noreferrer">Channel Islands pygmy mammoths</a>. As the story goes, in the search for food, a herd of Columbian mammoths embarked on a journey to the super island Santaroasae. Over time, the island was cut off from the mainland. Food became scarce, and smaller mammoths had an easier time surviving and reproducing, thus passing on their Shrinky-Dink genes. Thanks to a lack of oversized predators, such evolution proved fruitful, and in less than 20,000 years, the giant Columbian mammoths evolved into a new species—the (relatively) pint-sized, 6.5-foot-tall pygmy mammoths.</p><p>To be clear, the island rule doesn't state that any species that washes ashore must go either Lilliputian or Brobdingnag. It only states that if an ecological niche becomes available and improves survival and reproductive success, then such a change is likely.</p>Thanks to that island living?
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c01cabce7b0b2b48a3734896c4a396db"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/SK7oHmJdDOM?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Such constrained growth may be the cause of the Jaragua dwarf gecko's bantam evolution. The <a href="https://science.psu.edu/news/worlds-smallest-lizard-discovered-caribbean" target="_blank" rel="noopener noreferrer">gecko eats tiny insects</a> and may be filling a niche that's unavailable on the North American continent with its many, many insectivores. In fact, the island rule may explain why islands are so rich with endemic species—particularly the Caribbean, which is considered <a href="https://www.oecs.org/perb_docs/bc_part2_intro_hotspot.pdf" target="_blank" rel="noopener noreferrer">a biodiversity hotspot</a>.</p><p>Of course, scientific rules are only provisional, and scientists are prepared to revise or completely disregard a hypothesis should new evidence appear. In a field as new as biogeography, the question of whether the island rule is truly a "rule" remains an open and hotly debated question. </p><p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jbi.13160" target="_blank" rel="noopener noreferrer">One systematic review</a> found empirical support for the island rule to be low, while <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2007.1056" target="_blank" rel="noopener noreferrer">another analysis</a> argued the rule is simply a recognition of "a few clade-specific patterns." The latter's authors conclude that "[i]nstead of a rule, size evolution on islands is likely to be governed by the biotic and abiotic characteristics of different islands, the biology of the species in question and contingency."</p><p>That brings us back to the newly discovered nano-chameleon. While it seems to follow the island rule—Madagascar being an island known for its rich biodiversity—there is a wrinkle. The species' closest relative lives right next door. <em>Brookesia karchei</em> is near twice the size of the nano-chameleon but ranges in the same mountains on mainland Madagascar. </p><p>If the nano-chameleon evolved to fill an ecological niche, why didn't those same environmental pressures miniaturize the karchei chameleon? If not the island rule, what did lead to the nano-chameleon's smaller size? As is often the case in science, further evidence may one day answer these questions.</p>
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The bacteria in our guts can tell time
For the first time, it was discovered that nonphotosynthetic bacteria have a circadian clock.
08 February, 2021
Credit: Paulista / Adobe Stock
- For the first time, nonphotosynthetic bacteria are shown to have a circadian clock.
- B. subtilis thrives in the gastrointestinal tracts of humans as well as grass-feeding ruminants.
- The researchers believe that this rhythm provides bacteria with an advantage.
<p>Despite an ancient warning from the Buddha, we still like to pretend that we're one self—a unified biological animal that persists through time. Sure, we know that our biological processes are <a href="https://bigthink.com/surprising-science/insomnia-brain-health" target="_self">dictated by circadian rhythms</a>. What we overlook is that we're really the sum of billions of different components, and some of those "parts" have their own clocks.</p><p>The Buddha might not have had a microscope, but his keen insight into human psychology translates well to biology. That's the word from a <a href="https://advances.sciencemag.org/content/7/2/eabe2086.full" target="_blank">new study</a>, published in Science Advances, that found the bacterium <em>Bacillus subtilis</em> is run by its own circadian rhythms. </p><p>Also known as "grass bacillus," <em>B. subtilis</em> thrives in the gastrointestinal tracts of humans as well as grass-feeding ruminants. You can easily and cheaply purchase bottles of this bacterium as a probiotic due to its <a href="https://bigthink.com/21st-century-spirituality/one-third-of-american-children-take-alternative-medicine-this-is-a-problem" target="_blank">supposed immune system-boosting properties</a>. The strain is found in soil, though you probably want to secure it by other means, making it a favorite of supplement companies. The European Food Safety Authority rates it as "<a href="https://www.efsa.europa.eu/en/efsajournal/pub/1944" target="_blank" rel="noopener noreferrer">Qualified Presumption of Safety</a>." </p><p>For this study, the European research team chose <em>B. subtilis </em>thanks to previous observations that, like humans, it seems to follow a 24-hour circadian clock. It also responds to red and blue lights (again, like humans), causing the researchers to believe that it entrains to environmental conditions. The team discovered this by enzymatically inducing bioluminescence in order to stare into this mysterious world. </p><p>Lead author, Professor Martha Merrow from Munich's Ludwig Maximilans University, <a href="https://www.eurekalert.org/pub_releases/2021-01/jic-bct010721.php" target="_blank" rel="noopener noreferrer">says</a></p><p style="margin-left: 20px;">"We've found for the first time that non-photosynthetic bacteria can tell the time. They adapt their molecular workings to the time of day by reading the cycles in the light or in the temperature environment."</p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="8a41d21f584ebc7b9518f51ff7ca9e08"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/UDSIteaF0TM?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Zeitgebers are cues (such as temperature fluctuations) that allow biological organisms to synchronize with their environment. In humans, it's what makes us sleepy as the sun sets and raises cortisol levels in our blood a few hours before sunrise. This bacterium appears to maintain a similar clock. Rather than only responding to light and dark, <em>B. subtilis</em> takes cues from temperature drops, hinting at a circadian rhythm.</p><p>Although bacteria comprise 15 percent of all living matter, the team notes that circadian clocks have not been identified in nonphotosynthetic bacteria—until now. They note that bacterium such as <em>Rhodospirillum rubrum</em> displays rhythmic processes such as enzymatic activity yet has no apparent circadian clock. </p><p>Co-author Dr. Antony Dodd, a researcher in the UK's John Innes Centre, <a href="http://www.sci-news.com/biology/bacillus-subtilis-circadian-clocks-09232.html" target="_blank">notes</a>:</p><p style="margin-left: 20px;">"Our study opens doors to investigate circadian rhythms across bacteria. Now that we have established that bacteria can tell the time we need to find out the processes that cause these rhythms to occur and understand why having a rhythm provides bacteria with an advantage."</p>Understanding the survival methods of bacterium clues us in on the long, slow process of evolution. While this new discovery does not state the purpose of the circadian clock in <em>B. subtilis</em>, it opens up a new line of research for one of the most perplexing components of human biology: our guts.<p><span></span><br></p>--<br><br><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a>. His most recent book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>
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