Stories tagged Heredity
Help this little boy find his parents: Sorry. I couldn't find any pictures from Encino Man.
Courtesy coteIt’s a weird suggestion, I know, because you probably give a lot of thought to whom the various cavemen had sex with anyway, regardless of the weather. But give it a little extra thought today. Because it’s nice out, and the dark corners of your brain could use the sunlight.
So, you guys all know that we aren’t the only human species ever to exist, right? The human family tree had other branches before it got to us (take a look at our Human Spark feature for more on that), and there were times when more than one species lived in the same area, and—in all probability—had interactions with each other. Neanderthals, for instance, lived alongside modern humans for many thousands of years in ice age Europe. Keep in mind, “Neanderthal” isn’t just a synonym for “cave-man.” Neanderthals were a distinct species—they had heavier, longer skulls, and thick, strong bodies. The modern humans of ice age Europe would have looked, more or less, like us. And because the two species were living in the same area for so long, it seems pretty likely that they interacted. But did those interactions include, you know, dinner, dancing, and romantic music?
Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Germany says yes, for sure they were having sex.
On one hand, these are sort of fightin’ words. People have suggested that Neanderthals faded into extinction as they interbred with modern humans, but when human DNA was compared with a sequence of Neanderthal DNA, it didn’t look like there was any overlap. That is, if there was any interbreeding, the Neanderthal contributions to our genes have been so diluted with human genes that it doesn’t appear that we have any Neanderthals in our family at all.
On the other hand… Well… I mean… People do all sorts of stuff… We all just want someone to love, right? Or, you know, just think of what a puppy will do to a piece of furniture. And humans and Neanderthals are a lot more similar to each other than puppies and ottomans. Too much? I don’t think so. Look at ligers. Or tigons. Or mules. Similar animals interbreed all the time, but very often they have infertile offspring. And that would explain why we don’t see any Neanderthal genes around today—everybody could have been doing it like it was 2012, but if the offspring couldn’t reproduce it wouldn’t matter to future generations.
Another factor that could explain the lack of genetic overlap (despite Paabo’s certainty of caveman/Neanderthal sexiness) is that our Neanderthal DNA sample just isn’t good enough. Mitochondrial DNA from Neanderthals doesn’t show up in modern humans, and while that’s an incredibly valuable genetic marker, it only makes up a tiny fraction of an organism’s total DNA. The Neanderthal genome hasn’t been completely sequenced yet, and that’s what Paabo means to do. Once we can fully compare the genomes, we can see if the two species became at all mixed.
Because they were definitely doing it.
Tags : A woman in China woke up to some scratching sounds and discovered a snake clinging to her bedroom wall by a single clawed leg. Mrs Duan of Suining of southwest China panicked and beat the snake to death with a shoe, then preserved it in a bottle of alcohol.
The snake measures 16 inches long and the foot and claw are “clearly part of the snake” according to Dr. Long Shai, a snake expert.
"Snakes and lizards have common ancestors going back millions of years but we won't know if this is connected until we can examine the body."
The evolutionary throwback - if that's what it is - is now being studied at the Life Sciences Department at China's West Normal University in Nanchang.
Bird song crosses species boundary
in Life Science, Diversity of Organisms, Heredity, and Biological Populations Change Over Time
And Your Bird Can Sing: Celine Dion (right) faces off with some sort of antbird in a battle of song. Stranger things have happened in nature.
Courtesy kookr and McflyIer (composite) via FlickrRemember how odd it felt to learn the Rolling Stones' song, I Wanna Be Your Man, was written by the Beatles' Lennon & McCartney? Or that off-putting twinge of “hmmm” you experienced when hunky hipster Tom Jones covered Kiss, a song written and originally performed by Prince (AKA The Artist Formerly Known as Prince, AKA His Glyphship, AKA The Artist, AKA Prince (again))? Or the unsettling angst brought on by Celine Dion screaming through AC/DC’s You Shook Me All Night Long? In each case, it’s not like they were terrible renditions (I’ll leave that judgement to the music critics), but there was just something not quite right about it. They all just seemed so... unnatural.
Well, as it turns out, it may be a more common natural phenomenon than previously thought. At least in the world of birds. And I’m not talking about Roger McGuinn’s band.
Researchers at Oxford have discovered two different species of antbird in South America whistling the same territorial tune to help eliminate mating competition. They’re claiming it’s the first such discovery.
Although the two birds belong to the same family (Thamnophilidae) they are distinct species (Hypocnemis peruviana and Hypocnemis subflava). Genetic tests done by the researchers showed the two species separated from a common ancestor about three millions years ago. This means the territorial song developed before they split off from their common ancestor.
During the study (the results of which appear in the current issue of Evolution) the scientists made recordings of the songs of males of both species listen here and played them back to competitors in their territories. The reaction in each was similar.
"When we played the song of the [rival] species, the resident bird responded as aggressively as it did to its own species," said Dr Joe Tobias, who led the research along with colleague Nathalie Seddon.
Even though the territorial songs remained similar after the split, other characteristics (such as plumage color and mating calls) diverged along very different paths, and probably aid in preventing confrontation and crossbreeding between the two species.
In effect, the territorial songs of these birds are more or less interchangeable in design and function. Given that they last shared a common ancestor more than 3 million years ago, it is almost equivalent to humans and chimpanzees - which diverged around 5 million years ago - using the same language to settle disputes over resources.
– Dr. Joe Tobias in a press release
So, this kind of cross-species convergence - with different types singing the same song - may not be such an unnatural thing. But then again, Britney Spears did do a cover of the Stones’ (I Can’t Get No) Satisfaction.
SOURCES and LINKS
BBC.com story
Ecological Society of America blog
Colleen McLinn and animal communications
Some other interesting songbird behavior
Warmer climate accelerates evolution in mammals
in Life Science, Cells, Diversity of Organisms, Heredity, and Biological Populations Change Over Time
Warmer climate boosts evolution: Okay, so iguanas aren't mammals, and I doubt Charles Darwin ever visited Sloppy Joe's in Key West, Florida, but the graphic still illustrates the point.
Courtesy Apollo13Ma (background photo), public domain and Mark RyanA study out of New Zealand says a warmer climate speeds up molecular evolution in mammals. The concept isn’t exactly a new one. Scientists have known that a warmer environment increases the pace of microevolution for other types of life, such as some plants and marine animals, but evidence that it affects mammals – which are warm-blooded (meaning their temperature is regulated internally) – has not been observed before.
Lead researcher, Len Gillman from Auckland University of Technology, said the result of the study was “unexpected”.
""We have previously found a similar result for plant species and other groups have seen it in marine animals. But since these are 'ectotherms' - their body temperature is controlled directly by the environment - everyone assumed that the effect was caused by climate altering their metabolic rate.""
Since DNA can potentially mutate each time a cell divides into two copies of itself, the faster (and more often) these divisions take place, the more chances advantageous mutations will be passed onto subsequent generations, and the faster microevolution takes place.
Gillman and his crew traced and compared small genetic changes in 130 pairs of related species that lived in different latitudes, focusing on a single gene in each pair. They then compared the gene against that of a common ancestor, and were able to determine which of the two mammals’ DNA had mutated (microevolved) more rapidly. The changes were small-scale, but the species living in the more tropical environment showed a faster pace in its level of molecular evolution.
The results of the study appear in Proceedings of the Royal Society B.
LINKS
Discover magazine story
BBC story
More about evolution
Matthias Buchinger: The (astounding) Little Man from Nuremburg
in Life Science, Diversity of Organisms, Heredity, Historic Perspectives, and Human Organism
Self-portrait by Matthias Buchinger: The forward-most curls on Buchinger's left shoulder near his collar are magnified on the right to show the inscribed hidden biblical text.
Courtesy Public domain via WikipediaI recently (and literally) stumbled upon a web page about this remarkable man from the 17th century. His name was Matthias Buchinger, and despite being born without hands, legs or thighs, this guy managed to live a full and amazing life with no less than 4 wives (!?), and fathering something like 11-14 children depending on the source. But even more incredible was how - despite his severe physical deformations - Buchinger was able to rise above Nature’s challenges and become an accomplished musician, inventor, artist, model-in-a-bottle builder, and magician.
Born in Anspach, Germany in 1674, he was the youngest of nine children, and became widely known as “The Little Man from Nuremburg” performing his feats of wonder across much of Great Britain and Europe. Buchinger was only 29 inches tall, and for hands had "two excrescences which grew from his shoulder-blades, like fingers without nails" but his skills in magic, marksmanship, and music were legendary. He played several musical instruments, some of which he invented himself, was accomplished at skittles (bowling), and could dance a hornpipe as well as anyone. He was also a talented calligrapher. His engraving skills are evident by the self-portrait to the right. Hidden within his curls are seven psalms and the Lord’s Prayer written in tiny letters. Buchinger lived much of his adult life in England and Ireland, and performed before King George and many of Europe’s royalty. He died in Cork, Ireland in 1732.
I don’t know about you but I find Buchinger quite inspiring. You can read more about this human marvel in the links below.
Matthias Buchinger
More about Matthias Buchinger
And yet another site
It will be a brutal fight: No one should expect to emerge unchaffed.
Courtesy Joe ShlabotnikFor years now, members of the robust camp of biologists—paleontologists in particular—arguing that birds evolved directly from dinosaurs have kneeled on the thighs and arms of paleontologists who believe that birds did not evolve from dinosaurs, slapped their scrawny bellies pink, and rubbed dirt and grass in their bifocaled faces. And it was only right—the birds from dino people are bigger, and their veiny biceps ripple with the science of a substantial fossil record, while the clammy palms and toast-rack ribcages of the alternate theory paleontologists positively reek of onions and contrary opinions for the sake of argument. It’s only natural.
I mean, we have fossil impressions of feathers on dinosaurs, analogous bones and body-structures in birds and theropod dinosaurs (theropods, again, are two-legged meat-eaters, like T-Rex, velociraptor, etc.), similar bird-dinosaur proteins (take a look at that last link—Liza listed a bunch of other stories in that post)… the list goes on. Some paleontologists pretty much consider birds to be dinosaurs themselves (little dinos that never went extinct). The book is closed. It’s not even fun beating up on those other paleontologists anymore, because… what’s the point? You wouldn’t beat up on a worm, would you?
Ah, but these worms may have gotten their hands on something soft in this fight, and they’re about to give it a twist…
Check it out—like a hammer from nowhere, or sudden and blatant disregard for the no-scratching rule, the birds-didn’t-evolve-from-dinosaurs people have a new weapon, and they’re back on their feet.
Before we go on, I’m just going to emphasize something real quick here: nobody is saying that birds didn’t evolve, or that they didn’t evolve from something very different from birds as we know them. The question is, from what did birds first evolve, and when?
See, the winning theory is that some theropod dinosaurs began getting smaller and more birdlike in the Jurassic period (with a couple interesting exceptions eventually getting bigger and more birdlike later on, but that’s a different story.) These dinosaurs got little, and feathery, and probably started living in trees, and adapted to leaping, gliding, and eventually flying. By the late Jurassic, we have the archaeopteryx, a feathered, toothed, clawed, and bony-tailed flying machine. By the Cretaceous, there are plenty of pretty normal-looking birds around. Easy-peasy, and there are all those fossils I mentioned before.
“Oh yeah?” say the other paleontologists, “Well what about… this?!” And with that, they flick the back of their hand into the crotch of the unsuspecting bird-dino scientists.
“What are you… aaaaaaahh….” They ask.
Birds, say the alternate theory dudes, don’t have the right legs to be descended from dinosaurs. It’s so obvious, even jerks like you should have seen it.
See, birds need to breath lots of air to be able to fly (it’s hard, I’ve tried). To breath more efficiently, birds have air-sacs in addition lungs. Running all over their bodies (even in their bones) the air-sacs help pump lots of air through the birds' respiratory systems. Fossilized bones appear to show the presence of air sacs in some dinosaur species, too, and this has been seen as further evidence for the bird dinosaur link.
The new argument doesn’t dispute that everybody loves air-sacs. It points out that birds can only move their legs in a very limited way, to keep from collapsing some of their air-sacs when they breath. Birds’ femurs (their thigh bones) are largely fixed—when they walk or run, most of the movement comes from their lower legs. All other walking and running animals—including dinosaurs—have moveable thighs.
This difference, some scientists believe, is great enough that fixed-legged birds couldn’t have evolved from moving-legged dinosaurs. They might have evolved alongside dinosaurs, sharing a common ancestor, possibly one of the thecodonts. Thecodonts were dinosaur-like (but definitely not dinosaurs) and they lived during the Triassic period. Some thecodonts evolved into dinosaurs, and the group died off by the end of the Triassic.
“That’s… all?” says mainstream paleontology, straightening up and cracking its knuckles. “Someone is about to get slapped.”
“…Hiss!” say the other guys, squaring their Gollum-like shoulders.
Until I know a little more about the research, I think I have to side with the traditional birds evolved from dinosaurs argument. The alternative theory folks point out that birds are found much earlier in the fossil record than the dinosaurs they are supposed to have evolved from, but it seems to me that that’s more of a problem of overlap than of a gap—couldn’t later bird-like dinosaurs just be the descendants of the dinosaur-to-bird transitional species? It’s not as if anyone thinks that we look at individuals in the fossil record and say, “ok, you evolved from this one, which evolved from this one” etc. If birds didn’t evolved from dinosaurs like the ones we find from the Cretaceous, then we’re left with a huge gap between thecodonts and archaeopteryx and his pals. And it would have to be some pre-dinosaur thecodont, because I feel like the independent evolution of air-sacs, feathers, and everything else in both lines would be a little too much convergent evolution otherwise.
Plus… I’m not clear on why dinosaurs couldn’t have just evolved to have a fixed leg later on, when they needed more efficient respiratory systems for flying. Their mode of locomotion would have necessarily been changing anyway…
“Hiss!!”
Interesting, though, right?
What do y’all think? Is this ridiculous? Or are we too attached to the mainstream model of bird evolution that we’re unable to keep an open mind to new ideas?
Dinos of a feather: New fossil discoveries throw the origin of feathers into confusion. Or possibly Confucian.
Courtesy treehouse1977
Science has known for a while that birds evolved from dinosaurs. We’ve discussed this before on Science Buzz, particularly here and here.
Now a new fossil has emerged from China that is complicating the picture. Tianyulong confuciusi was a small, two-legged plant-eater that lived in northeastern China about 130 million years ago. Its recently-discovered fossil included clear signs of feathers. This is nothing unusual—lots of dino fossils, especially from this part of China, have feathers.
What is unusual is that Tianyulong is not related to any previously known feather-bearing dinosaur. Not even remotely. All previously know dino feathers come from theropods, the two-legged meat-eaters like T. rex. Tianyulong was a type of hadrosaur—sometimes known as a “duck-billed dinosaur.” And the last time hadrosaurs and theropods shared a common ancestor was 230 million years ago!
This discovery raises several intriguing possibilities:
1. Perhaps feathers evolved very early in dinosaur history, far earlier than we now suspect. If the very first dinosaurs had feathers, then all other dinosaurs could inherit them, even after the various branches of the dino family tree split up and went their separate ways. But if that’s true, then why have we not found feathers on more dino skeletons?
2. Perhaps feathers evolved twice—once in the theropods, and once in the hadrosaurs. That would be pretty unusual. Right now, there seems to be no information on whether these new feathers are very similar to previously-known feathers, or completely different.
3. One thing has always bugged me about the whole bird-dino link. All dinosaurs fall into two major groups: those with hips shaped like those found in modern lizards, and those with hips shaped like those found in modern birds. But all the previous bird-like features, including feathers, come from the lizard-hipped group. Seems odd to me that nature would evolve bird-like hips twice. Maybe—just maybe—birds evolved from the bird-hipped dinosaurs.
Now, there’s tons of other evidence besides just hips to link birds to theropods, so nobody is going to be re-writing the bird family tree any time soon. All we can do is keep our eyes peeled for more interesting discoveries.
The Long and Short of Human Toes
in Heredity, Biological Populations Change Over Time, and Human Organism
Are these the toes of royalty, or just a marathon runner?
Courtesy jameiah
Ever look down at your feet and wonder why your toes look and move the way they do? You might even have heard the myth that having a second toe longer than your first (something orthopaedic surgeon Dudley Morton dubbed Morton's Toe) means you are more likely to be a criminal, or part of a royal family.
While having toes of different lengths (some longer or shorter than others) is completely normal, some people are so concerned about the size and shape of their toes that they get them shortened by a cosmetic surgeon. Other people need surgery on their toes and feet because the shape makes walking painful.
We all have toes of slightly different shapes and sizes, but did you know that human beings as a whole have comparatively shorter toes than most primates, including our closest relative, the chimpanzee? Compare us to other animals like cats and dogs, and you'll notice that their toes are REALLY short compared to the rest of their paws. What's going on here?
The researchers behind a new paper about the evolution of human toes think that the answer to why humans evolved such short toes might be related to long-distance running. According to researchers, having shorter toes - along with a number of other adaptations - probably gave our ancestors an edge when it came to endurance running, which was necessary to kill and eat large animals. This article from Wired Science explains:
"...many modern anatomical features make sense in the context of savannah marathons. Achilles tendons act as springs to store energy. Our hind limbs have extra-large joints. Our buttocks muscles are perfect for stabilization, as are regions of the brain uniquely sensitive to the physical pitching generated by the motion of running. Toes may belong to this class of adaptations."
I've never been able to run a marathon, but this is still pretty cool news. Now, you might be asking yourself what will happen over time to the shape of human toes now that we no longer have to run down our dinner? According to toe researcher Campbell Rolian, "that's generally a question you could ask about many features of the human anatomy," said Rolian. Because it isn't required to push off, he said, "There's talk about whether the pinkie toe is eventually going to disappear."
Not the pinkie toe?! That one is my favorite.
Source: Wired Science
Evolutionary trees like the one Charles Darwin scribbled to illustrate his epiphany are still used today to help biologists understand and communicate the diversity of life. Like Darwin and his contemporaries, today’s evolutionary biologists are part of an ongoing effort to figure out how Earth's many species are related. As new tools help biologists to analyze evolutionary relationships, the tree of life changes and grows ever more complex.
How will biologists today and in the future to organize all of this information? No one knows for sure - but a number of computer scientists and software designers are taking a crack at it! In collaboration with biologists designers are creating programs that will allow researchers to share and search through enormous amounts of taxonomical information. Some programs, like UC Davis's paloverde, take cues from familiar web tools like WIkipedia and Google Earth, allowing users to search the tree of life from various perspectives and distances.
Beyond making research more accessible to scientists and the public, software tools like this will help scientists around the world work together in new ways - developing new medicines to treat constantly evolving diseases, new products and processes that take into account changing ecosystems, and to understand biodiversity on a local and global scale.
The potential of these tools is as big as the imagination of the designers and engineers behind them - what kind of tool would you create to help organize the tree of life?
Friday Relationship Extravaganza!
in Earth and Space Science, Diversity of Organisms, Interdependence of Life, Heredity, and Human Organism
Into flow charts?: This is a flow chart of a relationship. Start at the bioluminescent spike, and end at the parasitic gonads.
Courtesy steev-oIt’s Friday (T.G.I.F.), Buzzketeers, and you all know what that means. That’s right, it’s time for the Science Buzz Friday Relationship Extravaganza! (S.B.F.R.E.)
I know how much y’all like relationships, and how much you like talking about them, so it’s only natural that you clicked on the S.B.F.R.E. so quickly. But that’s not all! See, here at the S.B.F.R.E., “relationship” is also a code word for… S-E-X! Oh, naughtiest of naughties! It’s a red-letter day! Relationships and S-E-X-ual science… y’all had better sit down.
Seriously, sit down. Make yourselves comfortable. Now, I want y’all to know that this is a safe space, and we should be free to say whatever we’re feeling. Good, good… I think we’re about ready to start.
So… I understand that you feel like he has some real problems in communicating his feelings?
Why do you think that is?
No, I’m sorry, let’s let him finish—we’ll all have a chance to talk, and it’s his turn right now.
OK. I think I see what you’re saying. How do you want him to communicate? What do you wish he would say to you?
And how does that make you feel? Is that something you can do? OK… Why do you think you’re not being listened to?
I see.
Well, let’s look at it this way: at least y’all aren’t anglerfish. You know anglerfish, right, Buzzketeers? Anglerfish include those awful deep sea fish, with the big eyes, and teeth all over the place, and a glowing spike sticking out of their awful, lumpy heads. You know what I’m talking about. You saw those pictures, and then learned that they were only a few inches long, but were still kind of grossed out. And maybe some holier-than-thou biologist type pointed out to you that they weren’t gross, they were just fish that had made some spectacular adaptations to their environment, and were just living their lives like every other animal.
Well, don’t worry, you were right in the first place: angler fish really are awful and gross.
See, when they first discovered these creepy anglerfish, scientists were only finding female specimens. No males at all. So where’s the relationship relationship?
Well, eventually they did find some males, and some remarkable observations were made. The male anglerfish were pretty normal in their youth, but once they reached sexual maturity, their digestive systems degenerate. So they are unable to feed themselves. Naturally, what a mature male needs to do at that point is find a sugar momma. And fast (because, again, they’re starving to death). When the male tracks down a female anglerfish, he bites her, latching on to her body with his teeth. Enzymes in the male then break down its own mouth, as well as the female’s body, so that the two fish fuse together, to the point where they even share blood vessels. A source of sustenance now secured, the male kind of “lets itself go,” if you will. But instead of gaining weight and watching too much TV, the body of the male anglerfish, still fused with the female, degenerates, eventually becoming just a pair of gonads that hang off the female. When the first female anglerfish were discovered, scientists thought that they had parasites hanging off of them. Nope. Those were the remains of male anglerfish.
When the female is ready to release eggs, the gonads sense the change in hormone levels in the blood that still flows to them, and they release sperm, so that the eggs can be fertilized, and more horrible anglerfish can be created.
I don’t know who has it worse here—the female that has to nourish a pair of parasitic testicles (or multiple pairs), or the male, who has to latch on to a female to survive, and then becomes a pair of parasitic testicles. Either way, though, I think you’ll agree that your own messed up relationship seems pretty ideal right now, doesn’t it?
So remember, until the next Science Buzz Friday Relationship Extravaganza, keep your emotions bottled up, and if you’re ever feeling bummed out about things, just think of the never-lonely anglerfish.
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