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One Intriguing Shift In Our Anatomy Proves Human Evolution Certainly Hasnít Slowed Down

Mar 9, 2021

Image: Human evolution of sorts - clipartpanda.com

On the surface, the human race appears to be a well-formed species today following centuries of evolution according to scientificmirror.com. But did you know that a certain part of your anatomy could still be changing even now? What might it be? To answer that question, a group of researchers produced a fascinating paper on the matter in September 2020.

So how long have we been evolving as a species? When did it all start? Well, according to the Smithsonian National Museum of Natural History’s website, it began in the distant past. Specifically, we’re looking at roughly 6 million years. Yet one of the most significant changes happened a bit later.

Yes, walking on two legs – bipedalism to give the phenomenon its technical name – didn’t crop up for another 2 million years. And once we started to walk upright, our species slowly evolved in several other ways too – from growing bigger brains to formulating words to talk. As per the museum’s website, some of the more “advanced traits” only began to appear within the last 100,000 years.

Pretty interesting right? But the discussion surrounding human evolution was blown wide open at the end of the 1850s. At that point, one man wrote his name into the history books after producing a seminal work. Of course, we’re referring to Charles Darwin and his masterpiece, On the Origin of Species.

In that book, Darwin proposed that species evolve due to “natural selection.” So what does that mean? Simply put, the famous biologist suggested that natural genetic changes in life-forms would mean some would suit their surroundings better, and over time these individuals would prosper at the expense of those without such alterations. At length, then, these naturally selected adaptations would spread throughout the species.

Darwin’s fascinating proposal is often referred to as “survival of the fittest” for that reason. And it could be argued that natural selection is still in play now. You see, five researchers came together at Cyprus’ University of Nicosia to conduct an experiment, before sharing their findings in October 2017.

The paper, which appeared in the Personality and Individual Differences journal, focused on just under 2,000 students. By the end, the authors discovered that a large portion of them were struggling to find a partner. The reason? Those individuals couldn’t keep up with the myriad of changes in “social technology.”

We’re sure some of you can relate to that! After all, social media is an ever-evolving beast. Anyway, the project’s leader went into a bit more detail while speaking to the Live Science website in February 2018. His name is Menelaos Apostolou, and he taught social sciences at the Cyprus college.

Apostolou told the website, “Nearly one in two individuals faces considerable difficulties in the domain of mating. In most cases, these difficulties are not due to something wrong or broken. But [it’s] due to people living in an environment which is very different from the environment they evolved to function in.”

It’s cool to think that this very modern issue could have ties to a theory that emerged over 150 years ago. But are humans still capable of adapting to their surroundings? Have we ever stopped evolving as a species? Well, two people in particular believe that we’ve been static for a long time now.

One of those was a paleontologist named Stephen Jay Gould. Back in the year 2000, he made a very bold claim that continues to reverberate even now. He said, “There’s been no biological change in humans in 40,000 or 50,000 years.” Meanwhile, Sir David Attenborough agreed that our species hasn’t really evolved beyond a certain point – physically at least.

In 2013 Attenborough informed magazine the Radio Times, “We stopped natural selection as soon as we started being able to rear 90 to 95 percent of our babies that are born. [But it’s] not as important, or depressing, as it might sound – because our evolution is now cultural. We can inherit a knowledge of computers or television, electronics, airplanes, and so on.”

Despite those claims, though, there is evidence that humans have been going through physical changes in the last few hundred years. For example, a doctor in Germany produced a publication in the late 1860s which defined our “normal” temperature. The figure stood at approximately 98.6℉. From there, it became the go-to number when looking at body heat.

Yet in January 2020, the eLife science journal shared a paper that changed everything. In that report, it was suggested a human’s “average temperature” now sat at 97.9℉. How did the researchers reach that conclusion? Well, they looked through medical data that stretched back as far as two centuries.

And as the group went along, they realized that the recorded temperatures were slowly dropping. Specifically, the number was falling on average by 0.05℉ every ten years. Wow! So why were our bodies becoming cooler? In the opinion of the project’s leader, it had to do with the drop in “infectious diseases” going around.

You see, these illnesses led people’s bodies to become inflamed. As a result of that, their metabolism would go into overdrive and raise their core temperature. But when these ailments became rarer, the head researcher suggested that the average temperature went down too. On top of that, living conditions might’ve been another factor to consider.

To explain more, Stanford University’s Julie Parsonnet spoke to the Inverse website in February 2020. She said, “We don’t have to work terribly hard to be at physiologically neutral temperatures that don’t tax our metabolism. We’re so much healthier than 19th-century humans. [But] can we get cooler still? I expect so, but I’m not sure how much.”

It’ll be interesting to see those figures in a few years! Anyway, height is another topic when discussing human evolution. Using America as an example, people were much smaller back in the 1700s than they are now. Older houses are proof of that with the position of their ceilings: they’re not very high.

And it doesn’t just apply to America. During that same time period, the Dutch military was full of troopers who measured an average 5’5” tall. Even the U.S. soldiers were bigger than that! As the years rolled on, though, humans grew in size – but people in the Netherlands raced ahead of everyone else.

Now, Dutch guys are roughly 8 inches taller than they were 150 years ago. Men from the U.S. are only a bit more than 2 inches bigger in comparison. How did that happen? Well, a paper from the Proceedings of The Royal Society B suggested that natural selection was at play in the Netherlands.

According to the researchers behind that project, ladies in the Netherlands seemed to be drawn towards taller guys as time went on. As a result of that, there was a good chance that they’d start families together. And the figures back that idea up: bigger men fathered more kids than their smaller counterparts.

Plus, taller women gave birth to more kids than their smaller counterparts too, according to the research. So, by factoring all of that in, the average size of Dutch citizens naturally shot up across the country. It’s an interesting situation that highlights how genetics and evolution can change people over time.

On that note, let’s switch our focus back to the study from September 2020. What part of the human anatomy is showing signs of change today? It’s actually an internal tweak, so you won’t notice it when looking at a person’s body. You see, certain individuals have managed to retain three arteries in their forearms.

We know you’re thinking, “How is that possible?” Well, to better understand the alteration, here’s a crash-course in baby biology. Before you hit the eight-week mark in your mom’s womb, you have a big vein in your forearm called the “median artery.” But once you cross the aforementioned date, it usually gets replaced by two other arteries.

Those vessels are the ulnar and radial arteries. Yet as it turns out, the median vessel doesn’t always disappear. Researchers have been fascinated with this for the last 300 years, as more people seem to be retaining that third blood pipe. At the same time, though, the true scope of it didn’t come to light until 2020.

The study’s authors, who came from the University of Adelaide and Flinders University, examined the bodies of people who passed away from 2015 to 2016. Their ages ranged between 51 and 101. Incredibly, the group discovered 26 median arteries all together from nearly 80 forearms. It was the equivalent of roughly 30 percent.

To go into more detail, one of the researchers behind the paper spoke to British newspaper the Daily Express in October 2020. Dr. Teghan Lucas said, “Since the 18th century, anatomists have been studying the prevalence of this artery in adults and our study shows it’s clearly increasing. The prevalence was around 10 percent in people born in the mid-1880s.”

“[Then it was] 30 percent in those born in the late 20th century, so that’s a significant increase in a fairly short period of time when it comes to evolution,” Dr. Lucas continued. “This increase could’ve resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually.”

At that point, Lucas then finished on an intriguing note. She added, “If this trend continues, a majority of people will have a median artery of the forearm by 2100.” That’s quite the claim! But you can’t argue with it after seeing the figures. So does this third vein have an impact on the body?

Potentially speaking, it does: the extra vessel could provide your body with more blood capacity than a normal person. Plus, the median artery might play a vital role when you have an operation as well. You see, with an additional major tube, you’ll pretty much have a “backup” ready to go if something goes wrong.

To sum it up, Professor Maciej Henneberg shared his thoughts with the Daily Express. Much like Lucas, he worked on the project that was published by the Journal of Anatomy too. Henneberg explained, “This is micro evolution in modern humans. And the median artery is a perfect example of how we’re still evolving.”

In keeping with that last point, there have been other fascinating markers regarding our evolution going forward. For instance, wisdom teeth seem to be disappearing at a very notable rate. That was proved in a research project from 2013, which revealed 35 percent of the subjects didn’t have these rearmost gnashers.

Now wisdom teeth can be more trouble than they’re worth, so it’s certainly not a bad thing! But why is this happening? Well, the explanation might surprise you. As our brains are bigger than they were in the past, the organ requires extra space inside our skulls. So the large gnashers are believed to have been sacrificed to free up the area.

It’s pretty much the evolutionary equivalent of getting thrown out of a crowded house. Then again, while a missing wisdom tooth isn’t that big a deal, there are experts who hold grander theories about our future. Yuval Harari is one such individual; he spoke on BBC Radio 4 in August 2016.

Harari works at the Hebrew University of Jerusalem, plying his trade as a history teacher. And away from the college, he’s also written books about human evolution. Keeping that in mind, the academic shared a truly “out-there” idea regarding the next step for our species. We hope you’re sitting down!

Harari told BBC Radio 4, “All big changes frighten people. We’re probably one of the last generations of Homo sapiens. In a century or two we will either destroy ourselves, or far more likely is that we will use technology to upgrade ourselves into something different.” Yes, you’ve read that correctly.

It sounds like a sci-fi film pitch! Anyway, Harari went into a bit more detail following that intro. He continued, “For 4 billion years of evolution, life evolved by natural selection and was confined to the organic realm. [But] life will evolve by intelligent design and break out of the organic realm into the inorganic, with the creation of the first inorganic life-forms.”

From there, Harari made an intriguing comparison between his vision of the future and our evolution up to now. The lecturer said, “There will still be beings, entities on planet Earth. But they will probably be much more different from us than we are different from neanderthals, or from chimpanzees. It’s a complete game-changer.”

It’s an interesting theory, we have to admit. Yet it could be argued that Harari still had one ace up his sleeve. You see, this speculated jump won’t just affect how we operate on Earth. In his mind, the evolutionary step will open up a myriad of opportunities beyond our home planet. Yes: he’s referring to deep-space travel.

Harari concluded, “It’s almost impossible to sustain human life, or organic life in general, in outer space and on other planets. But once you make the switch from the organic to the inorganic, there’s no problem sustaining artificial intelligence.” Whatever our future holds, the human species clearly hasn’t finished changing yet.

With the human body changing every day, it’s hardly surprising that researchers continue to make such monumental discoveries about our biology. Yep, in laboratories all across the world, scientists peering down microscopes are always looking for more incredible insights into our complex genetic makeup. And back in 2019, experts at Harvard university struck gold with a find that could completely transform how we treat illness.

At Harvard University, a pair of scientists are busy studying DNA in their laboratory. But while such investigations are nothing out of the ordinary at the Ivy League institution, on this occasion the researchers uncover something truly special. Yes, during their work, the duo make a pivotal discovery – and it’s one that may lead to some incredible changes in the world of medicine.

Perhaps, then, the specialists involved in this breakthrough will ultimately see their names in history books. And if they do, they’ll be following in the footsteps of Benjamin Waterhouse, who was among the faculty at Harvard Medical School in the late 18th and early 19th centuries. Famously, Waterhouse pioneered the use of vaccination for smallpox in the U.S., and in doing so he arguably saved countless lives.

Similarly, Harvard alumnus Reginald Heber Fitz – who was also employed as a professor at the college – made his mark in the late 19th century by recording the symptoms and potential outcomes of patients with appendicitis. Fitz was also among those who promoted the removal of the affected organ as a means by which to save a sufferer of this particular ailment.

The researchers working at Harvard in 2019 were looking to make their mark, however. With assistant professor Mansi Srivastava leading the charge, the scientists were investigating a theory about DNA that, if completely realized, could be especially groundbreaking. And what they discovered may even come to revolutionize how we live our lives.

Yes, thanks to these experts and many like them, much progress in the field of medicine is still being made today. But while some diseases and medical ailments may be relatively simple to understand – especially if your health is suffering as a result of them – the intricacies of DNA are a little more complicated.

So, what exactly is DNA, and why is it so important? Well, the U.S. National Library of Medicine (NLM) has fortunately provided a thorough explanation that ought to clue you in. And if your knowledge of DNA only extends to what you’ve found out through 23andMe, then you should definitely read on.

The post on the NLM website explains, “DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. [And while] most DNA is located in the cell nucleus… a small amount of DNA can also be found in the mitochondria.”

And now you’re probably wondering, what are mitochondria? The NLM says that these are “structures within cells that convert the energy from food into a form that cells can use.” Then, the website shed light on something truly incredible. It turns out, in fact, that all humans have more in common than you may realize.

According to the NLM, “The information in DNA is stored as a code made up of four chemical bases. [These are] adenine (A), guanine (G), cytosine (C) and thymine (T).” But while, as the website explains, “human DNA consists of about three billion bases,” it turns out that “more than 99 percent of those bases are the same in all people.”

So, if every human being is so incredibly similar in this way, what accounts for all of our physical differences? That’s partly down to how that small number of bases – less than 1 percent of the total, remember – combine when we’re growing in the womb. And these so-called variants, some of which may be inherited, are what make each of us stand out from the crowd.

DNA itself, meanwhile, is often depicted in strands that seem to resemble winding staircases. And this recognizable structure is typically referred to as a “double helix.” As that name suggests, then, each double helix is made of two strands of DNA that are joined together in a distinctive spiral pattern.

The NLM’s website also states, “An important property of DNA is that it can replicate or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide, because each new cell needs to have an exact copy of the DNA present in the old cell.”

Given the many complexities of DNA, then, it’s perhaps no surprise that scientists are still trying to determine exactly how it affects our appearance, health and even our personality traits. And, of course, humans aren’t the only ones with distinctive genomes or collections of genetic material. Other members of the animal kingdom possess these, too, and their biological make-up can sometimes give them incredible abilities.

For instance, geckos use a pretty bizarre trick to help them survive in the wild. Yes, even though the lizards are often prey for other creatures, they can stop any pursuit in its tracks. Thanks to their genetics, you see, they can cleanly detach their tails – thus throwing hunters off of their scent and allowing them to get away.

But don’t worry, a gecko isn’t left tailless for long; within just a couple of months, they’ll have grown a completely new one. Salamanders have a similar regenerative ability, too, although in their case, it’s even more useful. If, for example, one of these amphibians loses a leg – entirely possible if it finds itself in the jaws of a raccoon – then it’s no problem. Yes, you’ve guessed it: eventually, the limb will simply grow back.

However, both sea anemones and planarian worms take things to a whole new level. These creatures, you see, can rebuild large portions of their bodies after they’ve succumbed to damaging attacks. The planarian worm can essentially multiply itself in those situations as well – and again, that’s all thanks to its DNA.

If a single planarian worm gets sliced in half, you see, both of those pieces can ultimately become separate living things. These incredible creatures may even multiply in greater numbers depending on the severity of the injury that the original worm has sustained. So, it’s a jaw-dropping process that shows off the intricacy of their genetics.

Jellyfish are equipped with some staggering abilities, too. Much like planarian worms and sea anemones, these aquatic lifeforms can also restore their own bodies. But that’s certainly not all. Indeed, back in the 1990s, a group of researchers uncovered a truly remarkable phenomenon when studying the Turritopsis dohrnii jellyfish.

Upon closer inspection, the team realized that this particular species of jellyfish could physically change itself from a mature adult to an undeveloped infant and vice versa. And owing to this astonishing process, these ocean-dwellers may even be able to ward off death in perpetuity. It’s no wonder, then, that Turritopsis dohrnii has been referred to as “the immortal jellyfish.”

In 2016, meanwhile, a scientist from Japan noticed something both strange and wonderful about his pet jellyfish. That’s right, months after his aquatic creature had seemingly passed away, it somehow managed to revive itself. And from there, his pet went on to age in reverse – much in the same manner as Turritopsis dohrnii.

This incredible regenerative process is understandably something that the Harvard researchers wanted to learn more about. During their work, then, the scientists were looking at the DNA of a creature known as Hofstenia miamia – or the three-banded panther worm. And as they investigated the worm’s genetic material, they made a potentially game-changing discovery.

As previously mentioned, Srivastava was in charge of this particular project, with the zoologist accompanied in her study by postdoctoral researcher Andrew Gehrke. And after the pair had made their momentous find, the details of their work went on to be published in a March 2019 edition of the journal Science.

But what exactly did Srivastava and Gehrke uncover? Well, within their DNA, animals also harbor what are known as “non-coding controls.” And while some experts have previously dismissed these sequences as being unimportant, the Harvard scientists discovered that they were, in fact, quite the opposite. In short, they realized that a particular piece of non-coding DNA may actually play a big role in regeneration.

Furthermore, through their examination of the three-banded panther worm, Srivastava and her colleague saw that the non-coding DNA kick-started a “master control gene.” This gene is otherwise known as early growth response (EGR). And when talking to The Harvard Gazette in March 2019, Gehrke explained exactly what EGR does.

Gehrke told the outlet, “What we found is that this one master gene comes on [and activates] genes that are turning on during regeneration. Basically, what’s going on is [that] the non-coding regions are telling the coding regions to turn on or off. So, a good way to think of it is as though they are switches.”

And Srivastava then revealed why the three-banded panther worm made the ideal subject for such tests. According to the assistant professor, you see, Hofstenia miamia could potentially give unparalleled insights into exactly how some animals manage to regenerate parts of themselves. This, in turn, could even have ramifications for us humans further down the line.

Speaking to The Harvard Gazette, Srivastava explained, “Previous work on other species helped us learn many things about regeneration. But there are some reasons to work with these new worms. The way they’re related to other animals allows us to make statements about evolution. [And] they’re really great lab rats.”

“I collected [three-banded panther worms] in the field in Bermuda a number of years ago during my [postdoctoral studies],” Srivastava continued. “And since we’ve brought them into the lab, they’re amenable to a lot more tools than some other systems.” But not every creature has the regenerative potential of Hofstenia miamia, as Srivastava went on to make clear.

The associate professor added, “We were able to decrease the activity of [EGR], and we found that if you don’t have [it], nothing happens. The animals just can’t regenerate.” That’s right, if you’re not biologically equipped with the master control gene, you won’t automatically be able to grow new limbs.

If you think that Homo sapiens doesn’t have the capacity for this ability, though, then the following information may just catch you off guard. Indeed, Gehrke told The Harvard Gazette, “It turns out that EGR, the master gene, and the other genes that are being turned on and off downstream are present in other species – including humans.”

Meanwhile, Srivastava explained, “The reason we called this gene in the worms EGR is because when you look at its sequence, it’s similar to a gene that’s already been studied in humans and other animals. If you have human cells in a dish and stress them, they’ll express EGR right away.”

Bearing that in mind, then, you may be wondering why the human body doesn’t simply grow back any parts that may be missing. And in an attempt to explain this, Srivastava went back to the switch comparison. She hinted that, ultimately, there may come a time when the secret is unlocked.

“If humans can turn on EGR – and not only turn it on but do it when our cells are injured – why can’t we regenerate?” Srivastava pondered. “The answer may be that if EGR is the power switch, we think [that] the wiring [in humans] is different. What EGR is talking to in human cells may be different than what it’s talking to in the three-banded panther worm.”

Srivastava added, “And what [Gehrke] has done with this study is come up with a way to get at this wiring. So, we want to figure out what those connections are and then apply that to other animals. [This would include] vertebrates that can only do more limited regeneration.”

Ultimately, then, there could be an exciting future ahead for human medicine. After all, if Srivastava, Gehrke and their peers in the field can understand our internal “wiring,” regeneration may well follow. But as you would imagine, there’s still a lot to figure out before such a process even becomes feasible.

Nonetheless, Srivastava and Gehrke are continuing their work on the subject. “Now that we know what the switches are for regeneration, we are looking at the switches involved in development and whether they are the same,” Srivastava told The Harvard Gazette. “Do you just do development over again, or is a different process involved?”

Gehrke added, “Only about 2 percent of the genome makes things like proteins. We wanted to know: what is the other 98 percent of the genome doing during whole-body regeneration? People have known for some time that many DNA changes that cause disease are in non-coding regions.”

“But [non-coding regions have] been underappreciated for a process like whole-body regeneration,” Gehrke continued. “I think we’ve only just scratched the surface.” So, what does this all mean for humans? Well, Srivastava touched on the matter – and suggested how any further studies may proceed – when talking to The Harvard Gazette.

In particular, Srivastava seemed to suggest that people would now be more inclined to think about the possibility of human regeneration. She said, “It’s a very natural question to look at the natural world and think, ‘If a gecko can do this, why can’t I?’ There are many species that can regenerate and others that can’t.”

The assistant professor concluded, “It turns out [that] if you compare genomes across all animals, most of the genes that we have are also in the three-banded panther worm. So, we think that some of these answers are probably not going to come from whether or not certain genes are present but from how they are wired together. That answer can only come from the non-coding portion of the genome.”



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