Daily Archives: May 13, 2017

If you took a high school biology class, youre probably familiar with Jean-Baptiste Lamarcks theory of evolution and its emphasis on the inheritance of acquired characteristics think giraffes stretching their necks longer to reach the leaves high in trees. In textbooks Lamarcks theory is often presented as a rival to Charles Darwins theory of evolution by natural selection. The simplistic storyline is that the two theories battled it out in the 19th century and that Darwinism won, leading to Lamarckisms demise and the rise of what biologists call the Modern Synthesis.

But recent discoveries have exhibited a remarkably Lamarckian flavor. One example is the CRISPR-Cas system, which enables bacteria to pass information about viruses they have encountered to their offspring. There are also clear-cut examples of transgenerational epigenetic inheritance, in which higher animals affected by environmental factors transmit favorable genetic changes to their offspring across generations. Such mechanisms make sense to us as designers: An animal should pass on, in its genes, information that it has gained about the environment. Such discoveries have sparked debate about the possibility of an update to the Modern Synthesis. Is there a role for Lamarckian mechanisms in modern evolutionary theory?

At the level of specific mechanisms, yes. At a deeper level of causes, though, the answer is a resounding no natural selection reigns supreme. How can that be, you ask? The simplistic juxtaposition of Darwin and Lamarck in elementary biology courses is a false equivalence. If Lamarckian patterns of inheritance do exist, and are indeed beneficial to the organism (that is, they are evolutionary adaptations), then the only way that they could have arisen and been maintained over evolutionary time is by Darwinian natural selection. Theres simply no way around it. Our puzzles for this month explore a simple version of transgenerational epigenetic inheritance and show how natural selection across multiple generations can, under certain conditions, favor the individuals who possess such mechanisms.

First, lets recap the differences between Lamarcks and Darwins ideas by revisiting that frequently cited example: the giraffes long neck. According to Lamarck, the giraffe got its long neck because its ancestors stretched theirs to eat leaves that were just out of reach. This stretching of the neck was passed on to their offspring, over generations, until it reached its current length. On the other hand, the mainstream Darwinian view is that, within the giraffes ancestors, there was a variation in neck sizes, as there is in any population. The giraffes with longer necks were more successful in getting food and produced more longer-necked offspring. Long necks were thus selected for in every generation, gradually lengthening the giraffes neck over evolutionary time. The reason we no longer believe Lamarcks version is that genetic material is transmitted to the next generation through germ cells, and most acquired changes simply do not influence germ cells; they are, to a large extent, isolated from the environment. If this were not true, mice whose tails are cut off for many generations, as the scientist August Weismann tried to do, would be born without tails. (They are not!) Furthermore, Jewish and Muslim males would be born without foreskins. (Despite many generations of circumcision, mohels can still make a living.)

But there is an obvious way that germ cells can be affected by the environment when the changes are caused by ill health and are deleterious. Infections, toxins or just old age can affect germ cells and produce offspring that are less healthy in various ways. We dont really think of this as unusual, or as anything to do with evolution. But what if the changes turned out to be good? A famous Swedish study of 300 people who were exposed to famines in the early 1900s, the verkalix study, showed a remarkable result. The amount of food supply that a persons grandparents were exposed to in their pre-pubertal years had a measurable effect on that persons cardio-vascular risk two generations later. In one specific association, men who were were exposed to a poor food supply at a critical age were found, two generations later, to have conferred a measurably lower risk of cardiovascular death to their grandchildren. Apparently it helps to have had a paternal grandfather who starved between the ages of 9 and 12! Similar changes have been found in animal experiments. For instance, survivors of famines among nematode worms are smaller and less fertile than normal worms, but they acquire a toughness that lasts at least two generations. Whats more, scientists have also found that such transmission across generations does not happen through a change in DNA coding in the genes in the manner heredity usually works, but rather through epigenetic mechanisms such as the inactivation of certain genes by the attachment of methyl groups (DNA methylation) or through changes in the configuration of the protein that packages the DNA (histone modification). These non-standard Lamarckian mechanisms certainly do have the potential to confer good or adaptive changes on individuals, and they could spur evolution. But how could they have arisen, and how are they maintained? Well, it has to be by random variation and standard Darwinian natural selection, of course! Lets explore this in our puzzle questions.

Imagine there exists an animal that has a new generation every year. Every normal individual has an average of 1.6 surviving offspring in a normal year, which can be defined as the animals fitness (lets call it f), after which the animal dies. During a famine year, f falls to 1.3. Now suppose there are a bunch of smaller individuals whose f values are 1.5 in normal years but 1.35 in famine years: their smaller food requirement helps them survive famines better. How long would a famine have to last for the small individuals to do better than normal ones? How many famine years before small individuals make up 90 percent of the population?

Suppose there exists an initially normal mutant group of individuals called Epi2s, whose germ cells are affected by a year of famine in such a way that their progeny changes to the small type for two generations before they revert back to normal in the third generation, through epigenetic mechanisms. Consider a 13-year period that starts and ends with normal years but has a one-year famine, two two-year famines and a three-year famine in between. Which of the three groups (normal, small, Epi2s) will be most successful? Are there famine patterns in which Epi2s overwhelm the other two groups over the very long term?

Lets add another type of animal to the above: the Epi1s, which like the Epi2s switch to small progeny after a famine, but in this case the progeny revert back to normal after just one generation. Over a period of 20 years, can you come up with a famine-year schedule such that all four types of animals (normal, small, Epi1s and Epi2s) exist in virtual equilibrium over this time period?

As these vignettes show, it does not matter to natural selection whether characteristics are controlled by genetic or epigenetic mechanisms. What matters is the fitness advantage that is selected by an organisms environment. If the conditions that confer a fitness advantage on a given group last long enough and select that group across multiple generations, then that group will dominate the population, and the species characteristics will change. So if there is a sizable subset of a population that exhibits advantageous epigenetic inheritance, natural selection is very likely to maintain it. On the other hand, if epigenetic modifications in a population are deleterious, natural selection will eliminate it. There is no top-down, purposeful information passing across generations here, no matter how sensible that seems to us. Based on these considerations, can you speculate how the elegant information transfer across generations that is embodied by the CRISPR-Cas system in bacteria could have evolved?

So deep and so inexorable is the blind, bottom-up process of natural selection in evolution that there is no way to contain its potency, and no rival mechanism for creating adaptation. It is no wonder that the philosopher Daniel Dennett has likened natural selection to a universal acid that cannot be contained. Natural selection and its analogs in non-biological spheres may well be the major or only processes that create complex novelty at all levels of the universe. And that includes the complex novelty created by us.

Editors note: The reader who submits the most interesting, creative or insightful solution (as judged by the columnist) in the comments section will receive a Quanta Magazine T-shirt. And if youd like to suggest a favorite puzzle for a future Insights column, submit it as a comment below, clearly marked NEW PUZZLE SUGGESTION. (It will not appear online, so solutions to the puzzle above should be submitted separately.)

Note that we may hold comments for the first day or two to allow for independent contributions by readers.

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Can Darwinian Evolution Explain Lamarckism? - Quanta Magazine

NOGALES, Ariz. (KGUN9-TV) - There are three ports of entry that make up the Nogales Port of Entry, facilitating traffic between the United States and Mexico -- the Mariposa Port of Entry, the DeConcini Port of Entry, and the Morley Port of Entry. Officers at these ports of entry are challenged by drug smugglers every day, and are consistently finding ways with new means of smugglers trying to get them across the border.

"It's a challengethat officers have to deal with on a daily basis," Port of NogalesSupervisor Marcia Armendariz said.

Armendarizhas 15 years of experience working at the border. She explained the drug officers used to find the most was Marijuana. However, she said now they're dealing with much harder drugs.

.@CBPArizona officers finding more hard drugs at border, including #Fentanyl -- like from this April 4th bust. Story tomorrow @ 10 on @kgun9 pic.twitter.com/ZLWB6YVYWk

"We are experiencing a lot more of the hard narcotics," Armendariz said. "Cocaine, Heroin, Methamphetamine, and now -- Fentanyl. This drug is very, very dangerous, and people do not realize it's a deadly drug."

With more than a decade of experience in a variety of roles, Armendariz explained people will hide drugs anywhere.

"We've seen it inside tortillas, we've seen it inside a game console," she said. "We've seen inside an accordion."

1 of many ways people may try to get drugs into US. Meth tortillas found in Oct. at AZ port. More on evolution of drug smuggling, Thurs @ 10 pic.twitter.com/NiL3Y1rfqL

One of the ways the evolution of drug smuggling has evolved, in her eyes? More body carriers, many of them often just kids.

"A lot of the drug cartels recruit these young kids, and, most of the time they probably tell them -- "you're a juvenile, they're not going to do anything to you, you can't get prosecuted," Armendariz said. "But, you can get prosecuted, they are going to get booked in jail, they are going to get arrested."

Security at all three of the ports is taken very seriously. At the DeConcini Port of Entry, there are eight lanes of traffic coming into the United States. Deputy Port Director Joe Agosttini showed KGUN9 some of the different ways officers are constantly monitoring the traffic coming into the United States.

"You have the license plate readers," Agosttini said. "You have the cameras taking pictures of the driver and passengers, the scanner that is reading all of the documents."

Like Armendariz, he has a significant amount of experience working at the border: 31 years under his belt. With more than three decades of experience, he's witnessed the evolution of drug smuggling first hand.

"You make every effort in good faith to stop the illegal drugs from coming into the United States," he said.

While going over documents and a typical line of questioning,Agosttiniexplained officers have about two minutes or less to make a decision whether or not to send someone to secondary inspection.

"Once you're satisfied that they can come into the country, then you move into, "is there anything illegal here?" he said. "You need to couple the behavior along with what you see in the vehicle."

He added it's better to send someone to secondary inspection if there is any suspicion of illicit activity.

"It's better to send a vehicle to secondary than to let it go," Agosttini said. "So you've got to make the right decision."

That being said, both Agosttini and Armendarizbelieve almost everyone coming into the country are "honest, law abiding citizens." However, the challenge they say is to address the "2%, maybe 1.5%," that are not.

When it comes to searching a car, it will first go through an X-Ray scanner -- then officers will meticulously go through areas of the car that could be hiding places.

"Bumper to bumper, they'll put their drugs inside those areas," Armendariz said.

Agosttinielaborated even more --

"Inside the tires, inside the drive shaft, inside the panels, the dashboard, the roof," he said. "Just about every area that has a void from the factory will be used to bring in narcotics."

With his experience, Agosttini said this is a problem officers at the border will continue to face for years to come.

"What we'll never be able to change," he said. "The fact that there are people out there that will always attempt to bring narcotics into the US."

But it's their job to continue to be vigilant in the battle to keep the drugs out of the country.

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Evolution of drug smuggling at the border - KGUN9.com - KGUN

Andrew Harnik/Associated Press

BOSTON Al Horford is a pretty even-keeled guy. "He's just easy, man," says Charlotte Hornets forward Marvin Williams, who played five seasons alongside Horford on the Atlanta Hawks. "Nothing ruffles his feathers." This might actually be one of the few things fans know about the reserved 30-year-old and four-time All-Star, which is why the following story, courtesy of Al's younger half-brother, Jon, might surprise you.

Back when he was a high school kid in Lansing, Michigan, Al's family loved sitting around the house and playing games. Al's father, Tito, a former NBA player himself, had imparted his competitive spirit onto his offspring, and Al, who was born in the Dominican Republic before joining Tito and Tito's second wife in Lansing for high school, was a quick learner. Dominoes and cards were frequent family pastimes, but Monopoly was a particular favorite. After all, there were four children in the Horford householda perfect amount to fight over ownership of various Atlantic City properties.

As Jon tells it, one day he, Al and a cousin were sitting around the living room playing Monopoly. Jon, who plays in the D-League now, was around nine at the time, five years younger than Al, and he says he remembers the scene vividly. There he was, the younger brother finally keeping up with the older sibling, getting every roll he needed, racking up the cash and assets, and yet, somehow, Al's stack of green and pink and yellow paper bills remained intact.

The battle raged on for a while, as Monopoly games tend to do,with this cycle repeating itself over and over. It didn't matter how many hotels Jon built, or how many of those spots Al landed on. Al just wouldn't lose.

Then, toward the end of the game, Jon caught Al sliding his hand beneath an adjacent couch. Underneath it was one of the family's spare Monopoly boards. Jon examined the set. Thanks to Al's sticky fingers, chunks of cash were missing from the bank.

"That's just Al," Jon says. "He's super competitive, the kind of guy that will do anything to win."

Of course, this narrativeStar Player Is So Great Because He's So Competitiveisn't exactly an exceptional one. The world's sports pages are littered with stories of professional athletes professing their addiction to victory and of the not-always-legal lengths they'll go to stave off defeat.

Few, though, have gone about doing so the way Horford has.

It started in college, where he helped lead the Florida Gators to consecutive NCAA titles. It continued in Atlanta, where he helped transform the once-lowly Hawks into a playoff mainstay. And in this, his first season with the Boston Celtics, he's helped elevate his new team to the top of the Eastern Conference and brought them to within one win of the conference final.

Everywhere Al Horford goes, his teams win. Could this be a coincidence? Sure. Or maybe there's something about Horfordsomething beyond his pedestrian career averages of 14.3 points and 8.7 reboundsthat brings out the very best in those he plays with. As Jon says, "He's the ultimate glue guythe guy who does all the little things on the floor."

But, yes, that's another cliche, even if in this case it's true, even if Horford's affinity for team basketball, lack of a major flaw and ability to be in the right spot at the right time does seem to always instantaneously lift whatever team he plays on.

Thing is, there's more to Horford adapting this role of being the ultimate glue than him just wanting to fulfill the dreams of Hoosiers-loving coaches everywhere.

"He does all those things because of how competitive he is," Jon says, "because winning is all that matters to him and he knows those plays are needed to win."

You see, in a way, it's actually a selfishness that has driven Horford to perfect seemingly every one of basketball's secondary skills, which have served as the catalyst for his relentlessly selfless play.

Al Horford might not bark as much as LeBron or scowl as much as Kobe, but that doesn't mean he doesn't want to win as badly as they and other stars do. It's just that long ago he recognized there are other ways for a player to dominate a game and so he perfected them, and in doing so, he morphed into one of the best, most underappreciated and distinctive basketball players in the world and a beacon for what prioritizing team glory over individual accolades looks like.

So what exactly is it that separates Horford from every other would-be glue guy to step foot on an NBA floor? How is it that a player who often puts up middling box scores can rank third in the NBA in win shares in the postseason, according to Basketball Reference, trailing only one-name studs like LeBron and Kawhi?

"His ability to make people around him better has been very helpful to our team, obviously," Celtics head coach Brad Stevens told reporters Wednesday night following Boston's 123-101 Eastern Conference semifinal victory over the visiting Washington Wizards in Game 5. Not exactly enlightening, but it's blunt statements like those that at times are most revealing.

After all, Stevens had just watched Horford torch Washington with a 19-point, seven-assist, six-rebound, three-block effort. It was exactly the kind of performance Boston hoped it'd get from Horford this season after handing him a four-year, $113 million contract over the summer and beating out other playoff teams like the Thunder, Hawks and, yes, the Wizards, whose front office no doubt spent part of Wednesday evening wondering what could have been as they watched Horford dominate on both ends.

There he was, pulling down defensive rebounds and taking the ball coast-to-coast. There he was, using his 6'10", 245-pound frame to stifle the electric John Wall anytime he dared to wander into the paint. There he was, setting back-breaking screens and tossing pinpoint passes and leveraging the threat of his much-improved outside shot (more on that later) into wide driving lanes for his teammates all over the floor.

"I think Al brings so much to this team," Celtics guard Avery Bradley told reporters after that game. "He's a veteran leader. He's been in this position before. Oh, man, I just really enjoy playing with him."

Bradley isn't the first one of Horford's teammates to feel this way. Which brings us back to the original question: What is it that makes Horford so good at turning an ability to execute the so-called little things into such game-changing plays?

"He really doesn't have any weaknesses," says Celtics big man Tyler Zeller. "He kind of does a little bit of everything."

OK, we're getting somewhere, but that's still not really answering the question. Maybe one of Horford's former teammates can provide a bit more insight? Williams, the former Hawk who's now with the Charlotte Hornets, is quick to point out that Horford always makes the right basketball play, be it the extra pass or sliding over into the paint to help stifle an opposing drive. But then he brings up something else.

"When you go over a scouting report, everyone knows where they're supposed to be, but still, not everyone does it every single time," Williams says. "With Al, though, that's not the case. He's going to be where he's supposed to every time down the floor, and that's contagious."

We can all agree: That stuff is great. Sharing the ball and playing a beautiful team-first style and all the rest. It's wonderful and inspiring and certainly has played a role in the Celtics' recent ascension.

But much of that talk overshadows just how skilled Horford is and just how perfectly his game jells with the new space-and-pace, guard-dominant NBA. After all, so much of what the Celtics do on offenseand remember, this was a team that had the NBA's eighth-best offensive rating during the regular seasoncan only be done because of what Horford is able to do.

Despite his height, Horford has always been a strong ball-handler and adept passer. This year, though, those skills have been utilized more than ever before, and even more so in the playoffs.

He's been Boston's second-most prolific passertrailing only Isaiah Thomas in assist points created per game.He's drilled 53.6 percent of the 2.6 three-pointers he's attempted per contest (to go along with 15.5 points, 7.9 rebounds and 6.0 assists). He's also assisted on a team-high 11 of Thomas' baskets, many of which have come off dribble handoff play that allows Thomas, who not coincidentally morphed into an MVP candidate the moment Horford joined his team, to operate off the ball and that the two have perfected. During Game 5 the Celtics even ran a pick-and-roll with Thomas as the screen and Horford the ball-handler.

"What makes Al unique is that he's playing center, but he's such a great shooter," says Kyle Korver, who played with Horford in Atlanta. "That makes any action with him and Isaiah really hard to guard. You have to stick with both, and that opens up all sorts of lanes."

None of this came to be so by happenstance. For years, Horford has worked with a shooting coach named Larry Turnbow. When he was younger, Horford, while shooting, would cup the front of the ball with his off-hand. It took years to fix the flaw, and it wasn't until last year that Horford even began regularly launching shots from downtown.

"His outside shooting is the biggest improvement I've seen in his game," Williams says. "And him being able to stand out there and knock it down, giving the Celtics five guys on the floor who can shoot, it really changes the game."

Turnbow also drilled into Horford the importance of hitting shooters squarely in the hands right above the waist, an area where Korver says Horford now excels.

All the while, Horford's also been tasked with manning the Celtics' defensive back line, making him the rare player who can play like a guard but defend like a big man.

He evolved his skill set, at 30, into exactly what the Celtics needed to win.

And if that's not enough, don't be surprised to see him sneaking his hand under the couch to pull out whatever extra they need.

All stats via NBA.com unless otherwise noted.

Yaron Weitzman covers the NBA and other things for Bleacher Report. Follow him on Twitter:@YaronWeitzman.

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The Evolution of Al Horford: How Boston's $113 Million Investment Is Paying Off - Bleacher Report

Expect the unexpected, goes the saying. And thats archaeologyjust when you think its all sorted out, you turn a spade full of earth over (usually on the last day of the dig) and there it is, the find that changes everything. Perhaps we should not have been so surprised at Homo naledithere are, after all, precedents for the unprecedented.

No one ever dreamed of Homo floresiensis, the "hobbit"from the Indonesian island of Flores, a hominin with a brain the size of an Australopithecine, an extinct genus of hominin that lived between four and two million years ago that includes the famous "Lucy"specimen. Yet there it is. Whats more, recent work on Flores suggests it had emerged as a species by 700,000 years ago and lasted until at least 100,000 years ago. So, tucked away on its island retreat, it spanned the time Homo sapiens evolved and left Africa maybe 100,000 years ago.

Homo naledi is similar. Yet it was not hidden away on a far flung island. Archaeologists found it in an area rich in hominin species and their archaeologythe so called Cradle of Humanity in South Africa. Scientists discovered H. naledi remains within chamber in a cave in South Africa in 2013. The species was officially described two years latera hominin species new to science.

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Front view of the near-complete H. naledi skull archaeologists discovered in South Africa. Wits University/John Hawks

The first discovery was a surprisebut even greater surprises were to come. Archaeologists announced on Tuesday they had found another chamber containing H. naledi remains. Combined, the discoveries are raising major questions about the evolution of our early ancestors.

The date just announced for the first lot of remains discovered is between 330,000 and 230,000 years ago. It has a mixture of traits seen on older, contemporary and younger species of Homo (the genus to which modern humans belong), and even from other genera like Australopithecus. This is puzzling. What was natural selection up to?

At such a late date (evolutionarily speaking) it shouldnt look like it does. Before the dating was announced, many of these features led some researchers to suggest it was old, existing near the end of the Australopithecines and near the beginning of early Homo, maybe two million years ago.

Now it seems H. naledi lived at a time when Homo heidelbergensis in Africa (sometimes called Homo rhodesiensis) was fully established. At this time, H. heidelbergensis was making Acheulean hand axes and possibly even the more advanced Middle Stone Age tool industries.

A recreation of Homo naledi by paleoartist John Gurche. Mark Thiessen / National Geographic

Some researchers like to suggest that at this point in time, we have a new species called Homo helmei. They believe this species transitioned to the earliest Homo sapiens. There is a lot of debate about this.

The oldest modern humans are about 195,000 years old from East Africaand thats awfully close to the youngest potential age for H. naledi. To turn H. naledi into H. sapiens is a big jump in a short period of timeand there are much better candidates.

So where does H. naledi fit? Are these the remains of an isolated species coming to their end of their evolutionary history, a side branch in our story? Or are they the result of multiple interbreeding events between different species as the authors suggest might be one explanation? We didnt expect there to be evidence of species interacting in such a way a few years ago, but now we arent so surprisedwe now know early humans mated with Neanderthals, for example.

Map of the Rising Star cave system in South Africa where H. naledi was discovered. Marina Elliott/Wits University

Or alternatively, is this mish-mash of anatomical traits a result of H. naledi being an ancient species, never before discovered, from which later species emerged, accentuating some of those traits in favor of others as selection shaped them to their environments? We just dont know.

Where H. naledi was discovered is a puzzle too. Its deep in a cave systemthe Rising Starthat is difficult to get to. The first finds were made in the Dinaledi chamber. Now new finds have been announced in the Lesedi Chamber. There is no connection between the two. There may be upwards of 15 individuals in the Dinaledi, and perhaps three or more in the Lesedi.

Why are they there? There is no evidence that either chamber was a living space, and there are no carnivore remains to suggest they were dragged there as supper for hyena or other carnivores.

Curiously there are no stone tools either. Did they fall in? Were they pushed? Why are they in two different chambers so difficult to access?

The authors of the new articles would like us to believe they were put there by others of their kind, but there is a long way to go before we can be certain of thatbut archaeology has revealed stranger things before.

One thing is for surethere will be more surprises.

John McNabb is a senior lecturer in paleolithic archaeology at the University of Southampton, U.K.

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Homo Naledi: The Mystery Hominin Species Raising Huge Questions About Human Evolution - Newsweek

In these days of anti-ID consensus, dont expect to find science journals publishing overt statements like, Well, what do you know! Stephen Meyer and the intelligent design people were right! Darwinian natural selection must remain omnipotent. Observational evidence, however, is more powerful than the language used to suppress it. Here are a couple of examples.

Rapid Arthropods

We reported two years about Marble Canyon, a remarkable Cambrian fossil deposit in British Columbia that rivals the famous Burgess Shale in significance. More extensive and detailed than its famous neighbor 26 miles to the northwest, Marble Canyon will likely provide years of discoveries to illuminate the Cambrian explosion. The site is of special interest because it was announced a year after Darwins Doubt (2013) was published.

Meet Tokummia, a creature found at Marble Canyon. The Calgary Sun calls it an ancient arthropod with gnarly claws. By all appearances, this four-inch animal was highly complex, possessing over 50 pairs of jointed legs, a shell, antennae, pincers, eyes, and mouth parts (implying a gut). Undoubtedly it was capable of sexual reproduction and partial metamorphosis, as are other arthropods. It is assigned a date of 508 million years old.

Jean-Bernard Caron, the discoverer of the Marble Canyon fossil trove (who also found a vertebrate fish there), with colleague Cdric Aria from the University of Toronto, studied 21 specimens of Tokummia. They tried to figure out where it fits in the evolutionary scheme. Writing in Nature, they conclude that it might have represented the start of the taxon Mandibulate (biting things). The Editors Summary offers hope that a gap has been partially filled:

Fossils from the famous 508-million-year-old Burgess Shale in Canada have been vital for shaping our understanding of the origin and early evolution of arthropods, the group of invertebrate animals recognized by their segmented bodies with jointed limbs and an exoskeleton. In recent years, research has found support for a single group of arthropods known as mandibulates that comprises insects, crustaceans and myriapods (centipedes and millipedes) but excludes chelicerates (spiders, scorpions and their allies). Few fossils have been found to illuminate the earliest mandibulates. Cdric Aria and Jean-Bernard Caron now show that this gap is partially filled by the arrival of the Burgess Shale fossil Tokummia katalepsis, whose anatomy allows the reconstruction of the anatomical and evolutionary history of this important animal group. [Emphasis added.]

Its hard to find, however, more than mere suggestions that certain protrusions on the face of this animal might suffice to partially fill the gap. They present a theory story that modern mandibulates emerged from larval forms:

The presence of crustaceomorph traits in the Cambrian larvae of various clades basal to Mandibulata is reinterpreted as evidence for the existence of distinct ontogenetic niches among stem arthropods. Larvae would therefore have constituted an important source of morphological novelty during the Cambrian period, and, through heterochronic processes, may have contributed to the rapid acquisition of crown-group characters and thus to greater evolutionary rates during the early radiation of euarthropods.

Pause to understand what they are saying. This statement does nothing more than push the lucky mutations into the larva instead of the adult. Instead of the adult constituting an important source of morphological novelty (i.e., body luck), the larva becomes the source. Then, through heterochronic [different-time] processes, some things evolved more rapidly than others. Presto! You greater evolutionary rates in the Cambrian, speeding up the acquisition of arthropod traits. A more vacuous suggestion could hardly be concocted: basically, some things happened, and some of them happened faster. Now, watch how some things happened over and over:

The integration of larval taxa in the phylogeny (Extended Data Fig. 10 and Supplementary Discussion) suggests that morphological traits typically associated with crustaceans or their larvae (large labrum, segmented cephalic exopods, antennule-like frontalmost appendages) have occurred across multiple euarthropod clades (Cheiromorpha, Artiopoda, Pycnogonida) with non-mandibulate adult morphologies.

From there, they launch into full-bore storytelling mode. Putting the lucky mutations into the larvae open up wondrous possibilities:

This implies that crustacean-like characters appeared early in the evolution of euarthropods, as a result of adaptation to ecological niches specific to ontogenetic stages, and may have persisted across the ancestors of major clades before their paedomorphic appearance in adult mandibulates. Because ontogenetic niches create new characters upon which natural selection can act intraspecifically, the emergence of specialized larval forms may have constituted an important catalyst for the rapid evolution of euarthropods during the Cambrian period, and a notable source of morphological novelty for the first mandibulates.

Imagine that lucky mutations appeared in larvae, which exposed them to new ecological niches where natural selection could act. Those that stayed young-looking as adults (paedomorphs) emerged as new kinds of arthropods. That emergence triggered rapid evolution. This explanation is indistinguishable from magic. It should be dismissed as a non-scientific affirmation of presumptive Darwinian belief.

Whats more interesting for design advocates is their admission of rapid evolution of euarthropods during the Cambrian period, and rapid acquisition of crown-group characters, viz., the Cambrian explosion. You cant hide an explosion in post-hoc distractions like emergence and acquisition and arrival. Like all the other Marble Canyon fossils, Tokummia appears in the rock record fully formed as a complex, successful animal.

Elsewhere in their paper, they admit to serious problems in the evolutionary story of arthropods, the most diverse and successful animals in all of nature:

(Regarding the arthropod head problem, see here.)

Its clear that putting lucky mutations into larvae is not going to solve any of these problems. Meyers book stands unanswered.

Unrelated Ediacarans

What about earlier Ediacaran organisms? Can they be considered ancestral? Meyer dealt with one called Parvancorina on page 89, refuting suggestions that it had superficial resemblances to an ancestral trilobite-like body plan.

A new paper in Nature Scientific Reports focuses on another topic, a suggestion that Parvancorina displayed an early instance of rheotaxis (active alignment with a fluid current). The evidence, however, is circumstantial and admittedly open to interpretation. The authors do not present any evidence of organs, genes, or tissues capable of controlling movement.

Of more interest to us is their affirmation of Meyers view, that the Ediacaran animals bear no ancestral relationship with the Cambrian animals. Here, in regard to one of the leading candidates of such a relationship, these authors say, Apart from possessing a bilaterally symmetrical body, there are no unequivocal morphological characters to support placement of Parvancorina within the Euarthropoda or even the Bilateria.

These papers show that four years after Meyers book, and 13 years after his paper in the Smithsonian journal, evolutionists are still failing to come up with plausible evolutionary hypotheses for the sudden appearance of the Cambrian animals. As paleontologists hold these stunning fossils in their hands, they need to stop the storytelling about magic appearances, the desperate attempts to force-fit the fossils into mythical evolutionary trees, and take seriously Meyers proposal that intelligent design provides the best explanation.

Photo: Parvancorina fossils, Australia, compared with a size of a coin, by EOL Learning and Education Group [CC BY 2.0], via Wikimedia Commons.

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More Admissions of Cambrian Explosiveness - Discovery Institute