Darwin Loved Worms. They May Have Just Proved Him Wrong About Evolution.
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links."
Here's what you'll learn when you read this story:
Is evolution a gradual process or a punctuated one, with rapid evolution taking hold in fits and starts?
A new study suggests the latter, as researchers analyzed the genomes of annelids, like earthworms, and found that these creatures experienced rapid evolution when they transitioned to land hundreds of millions of years ago.
This supports the idea—first proposed in the early 1970s—of 'punctuated equilibrium,' where evolution kicks in rapidly after a period of relative genetic stability.
The famed naturalist and geologist Charles Darwin is, of course, best known for his works on evolution—specifically On the Origin of Species and the Descent of Man. However, one year before his death, he wrote a little-known work excellently titled The Formation of Vegetable Mould, Through the Action of Worms, which detailed the important contributions of the world's 'lowly' creatures.
'It may be doubted,' Darwin wrote, 'if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures.'
Now, worms are poised to change the world again—this time in a way that even Darwin couldn't foresee. In a new study published in the journal Nature Ecology & Evolution, scientists from the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF) in Barcelona, Spain, sequenced the genomes of various earthworms. Upon doing so, they found that these species (in the phylum Annelida) didn't quite follow Darwin's ideas of evolution, in which change was a gradual process that played out relatively consistently over time. Instead, they followed an evolutionary path first explored in the 1970s called 'punctuated equilibrium.'
The idea is simple. According to Darwin's theory, the fossil record should be filled with 'missing link' species that display minute differences over time. But instead, what we see in our geology appears to be whole missing chapters of a genetic mutation. In an attempt to explain this, punctuated equilibrium posits that rapid evolution can occur periodically after millions of years of relative genetic stability. This would explain why we don't see as many 'missing links' as we might expect.
By synthesizing the complete genomes of these earthworms and comparing them to other annelid species (such as bristle worms and leeches), the researchers were able to travel back some 200 million years and find one such episode of rapid genetic evolution—when these ancient animals transitioned to living on land.
'This is an essential episode in the evolution of life on our planet, given that many species, such as worms and vertebrates, which had been living in the ocean, now ventured onto land for the first time," Rosa Fernández, lead researcher at the Institute of Evolutionary Biology (part of the CSIC) and senior author of the study, said in a press statement. 'The enormous reorganization of the genomes we observed in the worms as they moved from the ocean to land cannot be explained with the parsimonious mechanism Darwin proposed.'
By analyzing the genetic changes happening in this species during this period of rapid evolution, the scientists confirmed that these marine annelids experienced a top-down reorganization of their genetic structure, leaving them unrecognizable. Turns out the humble worm has more to teach us than we thought—though, that likely wouldn't surprise Darwin in the least bit.
You Might Also Like
The Do's and Don'ts of Using Painter's Tape
The Best Portable BBQ Grills for Cooking Anywhere
Can a Smart Watch Prolong Your Life?
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
9 hours ago
- Yahoo
Earth's Magnetic Field Might Weirdly Be Controlling the Air We Breathe, Scientists Say
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Earth's oxygenated atmosphere and magnetic field make life possible, but scientists have discovered that there's a hidden link between the two that's stronger than we originally imagined. Comparing 540 million years of data from charcoal deposits and magnetic crystals formed from ancient volcanic eruptions, scientists found that the processes creating both increase at the same rate over time, and even experience the same jump in activity levels around 330 million years ago. Scientists aren't yet certain which mechanism is impacting the other—or if there is a third mechanism impacting them both. If you list all of the things that had to go right to make life on Earth possible, our minuscule existence (cosmically speaking) seems all the more amazing. Our Sun is a G-type star with moderate radiation output that doesn't tidally lock our planet. The Earth is situated in our Sun's habitable zone. The planet has maintained a robust atmosphere for hundreds of millions of years, and the dynamo at the planet's heart generates a magnetic field that protects us from the most harmful effects of space radiation. Earth truly is a paradise for life. Although scientists have known about these life-giving aspects of Earth for centuries, they're still discovering surprising connections between them. In a new study published last week in the journal Science Advances, scientists from NASA, the University of Washington, and the University of Leeds in the U.K. discovered a surprising connection between two of Earth's most important life-sustaining features—its oxygenated atmosphere and its magnetic field. It's hardly surprising that the existence of one of these features might impact the existence of the other. After all, Mars (which is also in the Sun's habitable zone) used to have an atmosphere, but without a robust magnetic field, the Red Planet eventually lost that atmosphere to the unrelenting lashing of solar winds. However, the authors of this new paper found that, on Earth, the correlation between these two systems runs much deeper than we previously imagined. 'We find that both exhibit strong linearly increasing trends, coupled with a large surge in magnitude between 330 and 220 million years ago,' the authors wrote. 'Our findings suggest unexpected strong connections between the geophysical processes in Earth's deep interior, the surface redox budget, and biogeochemical cycling.' Analyzing data stretching back to the Cambrian some 541 million years ago, the researchers found that the rise in Earth's magnetic field and the rise in its oxygen levels were very closely aligned—slowly increasing overtime, except for one bout of increased activity lasting from 330 million to 220 million years ago. To map this comparison over the course of hundreds of millions of years, the researchers couldn't rely on direct data—there is no such record for atmospheric oxygen levels, for example. However, they could track the strength of wildfires, which show up as charcoal deposits in the geologic record. This would provide a clue, since a stronger, longer-lasting fire means that there was more oxygen in the atmosphere to fuel said fire. To compare this record with Earth's magnetic field history, the team analyzed certain magnetic crystals that formed in ancient volcanoes and—due to their composition—essentially act like a 'compass frozen in time,' according to Nature. Once plotted side-by-side, the team noticed that the two processes largely increased in lockstep with one another, and even experienced the same increase 330 million years ago. Interestingly, this coincides with the formation of Pangea, though scientists aren't sure exactly if the formation of the supercontinent is related to the increase or a coincidence, as the data does stretch back far enough to compare levels to other supercontinents in Earth's history. So, what's going on here? Well, the researchers aren't exactly sure, but they have a few guesses. The most likely one is that Earth's magnetic field directly impacts oxygen levels, as it protects Earth (and oxygen-producing plants) from solar radiation. However, it's also possible that increased oxygenation coupled with plate tectonics—which drive oxygen toward the liquid outer core that produces the magnetic field—could also play a role. The authors also aren't ruling out the idea that a third, currently unknown mechanism could provide an explanation for this steadily upward trend. 'One single mind cannot comprehend the whole system of the Earth,' Ravi Kopparapu, a co-author of the study from NASA, told Live Science. 'We're like kids playing with Legos, with each of us having a separate Lego piece. We're trying to fit all of it together and see what's the big picture.' While 540 million years is an unfathomably long time compared to our human lifespan (or even our species' existence), it's only around 12 percent of Earth's entire existence, so these trends could simply be coincidental. All we can do is continue searching for answers among the clues that we do have, and try to grasp just how wondrous our home planet really is. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
9 hours ago
- Yahoo
Darwin Loved Worms. They May Have Just Proved Him Wrong About Evolution.
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Is evolution a gradual process or a punctuated one, with rapid evolution taking hold in fits and starts? A new study suggests the latter, as researchers analyzed the genomes of annelids, like earthworms, and found that these creatures experienced rapid evolution when they transitioned to land hundreds of millions of years ago. This supports the idea—first proposed in the early 1970s—of 'punctuated equilibrium,' where evolution kicks in rapidly after a period of relative genetic stability. The famed naturalist and geologist Charles Darwin is, of course, best known for his works on evolution—specifically On the Origin of Species and the Descent of Man. However, one year before his death, he wrote a little-known work excellently titled The Formation of Vegetable Mould, Through the Action of Worms, which detailed the important contributions of the world's 'lowly' creatures. 'It may be doubted,' Darwin wrote, 'if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures.' Now, worms are poised to change the world again—this time in a way that even Darwin couldn't foresee. In a new study published in the journal Nature Ecology & Evolution, scientists from the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF) in Barcelona, Spain, sequenced the genomes of various earthworms. Upon doing so, they found that these species (in the phylum Annelida) didn't quite follow Darwin's ideas of evolution, in which change was a gradual process that played out relatively consistently over time. Instead, they followed an evolutionary path first explored in the 1970s called 'punctuated equilibrium.' The idea is simple. According to Darwin's theory, the fossil record should be filled with 'missing link' species that display minute differences over time. But instead, what we see in our geology appears to be whole missing chapters of a genetic mutation. In an attempt to explain this, punctuated equilibrium posits that rapid evolution can occur periodically after millions of years of relative genetic stability. This would explain why we don't see as many 'missing links' as we might expect. By synthesizing the complete genomes of these earthworms and comparing them to other annelid species (such as bristle worms and leeches), the researchers were able to travel back some 200 million years and find one such episode of rapid genetic evolution—when these ancient animals transitioned to living on land. 'This is an essential episode in the evolution of life on our planet, given that many species, such as worms and vertebrates, which had been living in the ocean, now ventured onto land for the first time," Rosa Fernández, lead researcher at the Institute of Evolutionary Biology (part of the CSIC) and senior author of the study, said in a press statement. 'The enormous reorganization of the genomes we observed in the worms as they moved from the ocean to land cannot be explained with the parsimonious mechanism Darwin proposed.' By analyzing the genetic changes happening in this species during this period of rapid evolution, the scientists confirmed that these marine annelids experienced a top-down reorganization of their genetic structure, leaving them unrecognizable. Turns out the humble worm has more to teach us than we thought—though, that likely wouldn't surprise Darwin in the least bit. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
17 hours ago
- Yahoo
Humans Already Have the Ingredients to Regrow Limbs, Scientists Find
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Axolotls are known for their ability to grow back just about any body part that is bitten off by a predator, but the trigger for this regeneration was a mystery until now. It turns out that retinoic acid and the enzyme CYP26B1 are heavily involved in regrowing missing limbs, determining what goes where before forming new tissue. Future technology inspired by axolotls could possibly help humans regenerate limbs—we have what is needed, but need to find out how to make those pieces communicate like they do in axolotls. In the 1995 cyberpunk film Virtuosity, the genes of android villain SID 6.7 are merged with snake DNA, giving him the superhuman ability to regrow lost limbs. Axolotls can do that without even trying—in fact, it is possible for an axolotl to lose virtually any body part (even its brain and internal organs) and fully regenerate it. Mysteries surrounding these virally adorable amphibians' regenerative powers have fueled the sci-fi dreams (and frustrations) of scientists for almost two centuries, but not until recently did anyone understand the mechanism behind this ability. Now, molecular biologist James Monaghan of Northeastern University has made a breakthrough that has allowed us to identify the driving force of regeneration—and maybe, one day, we will be able to give this power to humans. Positional memory means that an axolotl somehow knows if it needs to grow back a lost finger, hand, or entire arm. This was already known to be the basic mechanism behind vertebrate regeneration, but what Monaghan found was that it begins with retinoic acid and the enzyme CYP26B1. Neither of these chemicals are exclusive to axolotls—both are also found in the human body. It is just a matter of axolotls being able to use them differently. Larger limbs at proximal sites closer to the body, such as arms, contain more retinoic acid and less CYP26B1 (which breaks the retinoic acid down). And in smaller sites further from the body, like hands, there is less retinoic acid and more CYP26B1. 'Regenerating limbs retain their proximodistal (PD) positional identity following amputation. This positional identity is genetically encoded by PD patterning genes that instruct blastema cells to regenerate the appropriate PD limb segment,' Monaghan and his team said in a study recently published in the journal Nature Communications. When a predator bites an arm (or anything else) off of an axolotl, retinoic acid is synthesized in the middle layer of skin and spreads to the limb bud. This helps generate fibroblasts, which are connective tissue cells in humans, but regenerative cells in these creatures. Fibroblasts form blastema, or limb progenitor cells, which then grow and differentiate to recreate the particular limb that is missing. Blastema mirror the behaviors of limb buds that grow as an embryo develops, and in both embryos and adult axolotls that have been injured, positional information is exchanged between stem cells in the blastema and other cells in this budding limb to ensure that the appropriate tissues regenerate where they are supposed to grow. The gene Hoxa13 activates CYP26B1, which breaks down retinoic acid where it is not needed and uses it to create a pattern for the limb being regenerated. This breakdown determines how much retinoic acid is at an amputation site and, consequently, the position and structure of the limb which is regrown. Higher levels of retinoic acid activate the Shox gene—a transcription factor that both gives directions for producing a protein that regulates what other genes do and is involved with forming the skeleton. As Monaghan found out, defects such as skeletal abnormalities can occur if this process is disrupted. Raising levels of retinoic acid in an axolotl's hand caused it to grow not just another hand, but a whole new arm. Eliminating Shox with CRISPR-Cas9 resulted in normal hands but short arms, with bones that did not harden properly. This also occurs in humans with Shox mutations. What is especially amazing about axolotls is that they regenerate the limb in the exact same form it took before amputation. Some other animals that regenerate, like lizards, may grow back the end of a missing tail, but in a simpler form than the original. Much more research will be needed to transfer this ability to humans, but the materials are there. Healing wounds without scarring might even be possible in the near future. What we need to do next to make that future a reality is find out what happens inside blastema cells during regeneration, and which parts of these cells are targeted by retinoic acid. 'If we can find ways of making our fibroblasts listen to these regenerative cues, then they'll do the rest,' Monaghan said in a recent press release. 'They know how to make a limb already because, just like the salamander, they made it during development.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
