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Humans are still evolving, and maybe faster now than ever
The sudden prevalence of an artery in the forearm is evidence that we're still very much a work in progress.
- Australian scientists see signs of accelerating human evolution.
- Exhibit A is the rapid rise in the prevalence of the median artery in adults.
- Other emerging traits, like shorter baby jaws, support their finding.
There's no reason to think humans have stopped evolving. We see natural selection causing change in other animals all the time. For example, there has been an increase in tuskless elephants in Africa as a response to the poaching of ivory, and the skulls of urban foxes have changed as they adapt to scavenge cities. Within our bodies, scientists estimate there are trillions of mutations occurring each day. Meanwhile, our species eagerly awaits the emergence of a trait that allows us to put down our phones.
A new study finds evidence that not only are humans continuing to evolve, but we may be doing so at a faster rate than seen before. The research cites several examples of rapidly emerging traits such as an increasing lack of wisdom teeth, the shortening of babies' faces with smaller jaws, the increased presence of a fabella (the small bone in the back of the knee joint) and extra bones in the feet.
The report's primary focus, though, is a sudden increase in the appearance of the median artery in the adult human forearm.
The researchers say these trends constitute "micro evolution."
The rise of the median artery
The median artery supplies blood to a fetus' forearm in the womb during early gestation. It typically atrophies and is replaced by the radial and ulna arteries before birth. Few adults have historically had all three arteries — median, radial, and ulna — but this has been changing.
The study's senior author Maciej Henneberg says, "This is micro evolution in modern humans and the median artery is a perfect example of how we're still evolving because people born more recently have a higher prevalence of this artery when compared to humans from previous generations."
The phenomenon was first noticed in the 18th century, and a study of the artery's persistence was conducted in 1995. The more recent study extends that work, finding that the occurrence of the artery trio is accelerating.
"The prevalence was around 10% in people born in the mid-1880s compared to 30% in those born in the late 20th century," says lead author Teghan Lucas, "so that's a significant increase in a fairly short period of time, when it comes to evolution."
Why this is occurring isn't clear. "This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually," says Lucas.
However, she says, one thing is clear: "If this trend continues, a majority of people will have median artery of the forearm by 2100."
(Fore)armed with insight
The researchers tracked the presence the median artery in cadavers. They examined the 78 upper limbs obtained from Australians who died between 2015 and 2016. The deceased were from 51 to 101 years of age at death. In 26 of the limbs, the median artery was present.
Says Henneberg, "We've collected all the data published in anatomical literature and continued to dissect cadavers donated for studies in Adelaide, and we found about one third of Australians have the median artery in their forearm and everyone will have it by the end of the century if this process continues."
The scientists' conclusion is that we're evolving more quickly now than at any point in the last 250 years of study.
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What is human dignity? Here's a primer, told through 200 years of great essays, lectures, and novels.
- Human dignity means that each of our lives have an unimpeachable value simply because we are human, and therefore we are deserving of a baseline level of respect.
- That baseline requires more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose.
- We look at incredible writings from the last 200 years that illustrate the push for human dignity in regards to slavery, equality, communism, free speech and education.
The inherent worth of all human beings<p>Human dignity is the inherent worth of each individual human being. Recognizing human dignity means respecting human beings' special value—value that sets us apart from other animals; value that is intrinsic and cannot be lost.</p> <p>Liberalism—the broad political philosophy that organizes society around liberty, justice, and equality—is rooted in the idea of human dignity. Liberalism assumes each of our lives, plans, and preferences have some unimpeachable value, not because of any objective evaluation or contribution to a greater good, but simply because they belong to a human being. We are human, and therefore deserving of a baseline level of respect. </p> <p>Because so many of us take human dignity for granted—just a fact of our humanness—it's usually only when someone's dignity is ignored or violated that we feel compelled to talk about it. </p> <p>But human dignity means more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose—a freedom that can be hampered by restrictive social institutions or the tyranny of the majority. The liberal ideal of the good society is not just peaceful but also pluralistic: It is a society in which we respect others' right to think and live differently than we do.</p>
From the 19th century to today<p>With <a href="https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&content=human+dignity&corpus=26&smoothing=3&direct_url=t1%3B%2Chuman%20dignity%3B%2Cc0" target="_blank" rel="noopener noreferrer">Google Books Ngram Viewer</a>, we can chart mentions of human dignity from 1800-2019.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODU0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MTUwMzE4MX0.bu0D_0uQuyNLyJjfRESNhu7twkJ5nxu8pQtfa1w3hZs/img.png?width=980" id="7ef38" class="rm-shortcode" data-rm-shortcode-id="9974c7bef3812fcb36858f325889e3c6" data-rm-shortcode-name="rebelmouse-image" />
American novelist, writer, playwright, poet, essayist and civil rights activist James Baldwin at his home in Saint-Paul-de-Vence, southern France, on November 6, 1979.
Credit: Ralph Gatti/AFP via Getty Images
The future of dignity<p>Around the world, people are still working toward the full and equal recognition of human dignity. Every year, new speeches and writings help us understand what dignity is—not only what it looks like when dignity is violated but also what it looks like when dignity is honored. In his posthumous essay, Congressman Lewis wrote, "When historians pick up their pens to write the story of the 21st century, let them say that it was your generation who laid down the heavy burdens of hate at last and that peace finally triumphed over violence, aggression and war."</p> <p>The more we talk about human dignity, the better we understand it. And the sooner we can make progress toward a shared vision of peace, freedom, and mutual respect for all. </p>
Scientists find that bursts of gamma rays may exceed the speed of light and cause time-reversibility.
- Astrophysicists propose that gamma-ray bursts may exceed the speed of light.
- The superluminal jets may also be responsible for time-reversibility.
- The finding doesn't go against Einstein's theory because this effect happens in the jet medium not a vacuum.
Jet bursting out of a blazar. Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope.
Cosmic death beams: Understanding gamma ray bursts<div class="rm-shortcode" data-media_id="cu2knVEk" data-player_id="FvQKszTI" data-rm-shortcode-id="c6cfd20fdf31c82cb206ade8ce21ba3f"> <div id="botr_cu2knVEk_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/cu2knVEk-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"></script> </div>
Philosophers have been asking the question for hundreds of years. Now neuroscientists are joining the quest to find out.
- The debate over whether or not humans have free will is centuries old and ongoing. While studies have confirmed that our brains perform many tasks without conscious effort, there remains the question of how much we control and when it matters.
- According to Dr. Uri Maoz, it comes down to what your definition of free will is and to learning more about how we make decisions versus when it is ok for our brain to subconsciously control our actions and movements.
- "If we understand the interplay between conscious and unconscious," says Maoz, "it might help us realize what we can control and what we can't."
We’ve mapped a million previously undiscovered galaxies beyond the Milky Way. Take the virtual tour here.
See the most detailed survey of the southern sky ever carried out using radio waves.
Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way, in the most detailed survey of the southern sky ever carried out using radio waves.
A new study shows our planet is much closer to the supermassive black hole at the galaxy's center than previously estimated.