Stories tagged evolution
What makes humans unique? Do we have characteristics that make us different from other animals? PBS will be broadcasting a three-part series on the topic this fall. In advance of the series premiere, the producers want you to tell them why humans are special. You can submit a photo, a video, or text. Some entries will appear on screen, so make a grab for your 15 seconds of fame, and send in your ideas.
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Giant tortoise under threatCourtesy sly06 (adapted by Mark Ryan)Evolution of mosquitoes on the Galapagos Islands could endanger the islands’ famous giant tortoises and other reptile wildlife. On the mainland the black marsh mosquito Aedes taeniorhynchus normally feeds on mammals and birds, but scientists from the University of Leeds, the Zoological Society of London (ZSL), the University of Guayaquil and the Galapagos National Park have discovered that the island version of the blood-sucking insect has evolved a craving for reptilian blood, particularly that of the Galapagos tortoises and marine iguanas.
Genetic studies show the mosquitoes arrived on the archipelago about 200,000 years ago, giving them plenty of time to adapt to the island environment. Unlike its mainland counterpart which lives and breeds mainly in the lowlands and coastline salt marshes, the island mosquito can also breed as much as 15 miles inland and at altitudes up to 2000 feet above sea-level.
“The genetic differences of the Galapagos mosquitoes from their mainland relatives are as large as those between different species, suggesting that the mosquito in Galapagos may be in the process of evolving into a new species,” said Arnaud Bataille, PhD student at the University of Leeds and ZSL.
Mosquitoes can carry diseases such as West Nile and avian malaria that could potentially devastate the island fauna. Although none of these diseases have been detected in the Galapagos mosquitoes the researchers fear an infected mosquito brought in from the mainland via such modes as tourist transportation could potentially infect the island mosquitoes. If that happens the islands’ wildlife population could be at risk, because the long isolated Galapagos fauna wouldn’t have built up immunities to such an invasion.
But as a countermeasure, the Ecuadorian government has introduced a requirement for planes flying to Galapagos to be treated with insecticide before each flight, although similar controls have yet to be implemented for ships traveling to the islands.
“It is absolutely vital that these control measures are maintained and carried out rigorously, otherwise the consequences could be very serious indeed,” said Dr Simon Goodman, of Leeds’ Faculty of Biological Sciences and Co-author of the study which is published online in the US journal Proceedings of the National Academy of Sciences.
Darwinius masillaeCourtesy PLoSThere you were, thinking that lemurs were barely your relatives. It’s okay, I understand. I mean, Prosimians? Really? Sure, we’re all members of the primate family, but, like, two steps removed, like those cousins in Kentucky your mom pretends don’t exist. Or something. Prosimians are the non-human evolutionary line, how primitive. Prosimians are like NASCAR, and Anthropoids, like apes and humans, are like the DAR.
But, just like every president has an embarrassing brother, so too are we related to those furry simple primates. Now, we have proof! Scientists have found a 47 million years old human ancestor, the link between these early primates and human evolutionary lineage.
“Ida,” or Darwinius masillae, was actually discovered in 1983 by a private collector, although the fossil now belongs to the Natural History Museum of Oslo. An international team of scientists has been secretly conducting an in-depth study of Ida for the past two years. Now her skeleton is 95 percent complete.The fossil is significantly older than most fossils that explain human evolution, and, unlike Lucy and other famous primate fossils, this fossil was not found in Africa’s Cradle of Mankind; Ida is a European fossil (someone call Guinness, I just set a world record for using the word “fossil” the most times in a sentence).
Arms and hands of Darwinius masillaeCourtesy PLoSIda was preserved with a full stomach, so we know that she was an herbivore. I hope that in 47 million years, scientists discover me and determine that humans subsisted mainly on a diet of Cheetos and grape soda. That would be pretty awesome. Her skeleton is pretty similar to that of modern-day lemurs, but she lacks a grooming claw and a row of teeth fused together called a “toothcomb.” She also has nails instead of claws, and teeth similar to small monkeys. She had forward facing eyes, like ours, and opposable thumbs.
Foot structure of Darwinius masillaeCourtesy PLoSWhat really links Ida to humans is a bone in her foot, called the talus. Her talus is nearly identical to your talus, only a lot smaller. Ida serves as a sort of “missing link,” a key part of the story of human evolution. So, you know, no big.
Banded snailCourtesy mer de glaceRegular folks across Europe are being asked to take part in what’s being touted as one of the largest studies of evolution ever done.
Evolution MegaLab is requesting people living in the United Kingdom and the European continent to check the snail population in their areas and report their findings to the MegaLab website. The research study which was just launched by The Open University, will end six months from now and hopefully show how changes in climate and predation have affected the snail population over a relatively short span of time. Project researchers are specifically interested in two banded snail species, Cepaea hortensis and Cepaea nemoralis.
“Banded snails wear their genes on their backs,” said Professor Jonathan Silvertown of The Open University. “Their colors and banding patterns are marvelously varied – but the darker shell types are more common in woodland, where the background color is brown, while in grass banded snails tend to be lighter-colored, yellow and stripier. These differences are thought to have evolved over time because they provide camouflage from thrushes, which like to eat the snails.”
“However, there has been a big decrease in the numbers of song thrushes in some places over the last 30 years and we’d like the public to help us to find out whether, with fewer predators about, the different snail types are less faithful to their particular habitats.”
As this video explains, it’s fairly easy to distinguish one snail species from the other. The edge of the shell opening (known as the lip) is white on C. horntensis, and brown (or black) on C. nemoralis. The species come in three different colors, yellow, pink, and brown, and can display three different styles of banding: no bands, single band (mid-band), or many bands. These variations in coloring and banding help the snails survive in the environments they happen to be living and the MegaLab researchers are interested in how recent changes in climate and predator populations have changed the snails’ appearances.
Everything the public needs to participate in the study can be found at the MegaLab website, including instructions and downloadable documents to help gather data. Observers are asked to look for snails in their areas, record specifics characteristics about what they find, and then report the findings to the Evolution MegaLab site. The collected data will then be compared with historical records to see if any noticeable evolutionary changes have taken place. The site cautions that only adult snails should be studied and recorded as many of the snails’ specific characteristics are missing in the juvenile or infant stages of the animals.
Kids in the UK are already showing interest. Here’s a cute video documenting one group’s efforts to help gather data.
For now the banded snail observation project, which is supported by the Royal Society and British Council, is limited to the United Kingdom and Europe but who knows, maybe a similar project will be started up in the United States.
LINKS
Story at The Open University site
Video of Cepaea nemoralis taking a long walk
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.
A confined chimp working things out in his head: Should we be worried?Courtesy tim ellisA dozen years ago guards at a Swedish prison north of Stockholm discovered a secret cache of weapons hoarded by an inmate named Santino. Certain that some kind of trouble was brewing, prison officials put the otherwise model prisoner under close observation. And it was fortunate they did. Santino was observed several times using his rock arsenal as missiles that he hurled at visitors to the prison. No one was seriously injured in the assault and Santino was disciplined for his actions. But since then subsequent lockdowns have resulted in the discovery and confiscation of hundreds of similar ammunition stockpiles in Santino’s cell. And officials fear the prisoner is planning other attacks.
Normally this wouldn’t be that unusual a scenario. Prison life can be difficult and sometimes the frustrations of incarceration cause detainees to act out against their captors and society in general.
But in this case the prison is actually a zoo and the trouble-making prisoner is a chimpanzee.
When the male chimp’s weapons cache was first discovered, zoo officials called in Mathias Osvath, a cognitive scientist from Sweden’s Lund University and Santino’s behavior was monitored closely. Not only was the 31 year-old ape observed throwing stones at zoo visitors, but was he also observed searching out weaknesses in the walls of his enclosure, digging out loosened chunks of concrete, and hiding them for future barrages.
"These observations convincingly show that our fellow apes do consider the future in a very complex way," Osvath said. "It implies that they have a highly developed consciousness, including lifelike mental simulations of potential events."
And if that’s not disturbing enough:
“It could be that he is a genius, only more research will tell. On the other hand our research showed the same in orangutans and bonobos so he is not alone," said Joseph Call, a co-author of the study, which appeared in the journal Current Biology.
Oh, Santino’s a genius all right – an evil genius – and one with a nasty grudge against humanity.
“It is extremely frustrating for him that there are people out of his reach who are pointing at him and laughing," Osvath said. "It cannot be good to be so furious all the time."
If that's the case, I think Sweden should consider buying Gitmo for a more secure confinement of the unruly primate. In the meantime, let’s hope Santino doesn’t start enriching uranium.
SOURCES
BBC story
Earthlink.net story
Evolution: We're all tall enough to rideCourtesy kevindooleyWhen and where in Africa did modern humans evolve?
Jim Fairman, the director of the Science Museum of Minnesota's Science Division invites you to find out at a lecture this Wednesday night.
The Science Division is pleased to co-sponsor a lecture by Dr. Curtis Marean on March 11, 2009 in the auditorium of the Science Museum at 7 p.m. Dr. Marean, is a paleoanthropologist and expert on human origins. In this lecture he will broach the questions "where in Africa did modern humans evolve?" and "when did they become behaviorally modern and why then and at that place?" This lecture is free and open to the public, but seating may be limited (currently we have about 150 reservations, maximum seating 275). Please call the ticket office at 651-221-9444 and mention this lecture on March 11th. This free, public lecture is part of Marean’s residency through the Rydell Professorship at Gustavus funded by the Drs. Robert E. and Susan T. Rydell.
Marean is currently a professor at the Institute of Human Origins as part of the School of Human Evolution & Social Change at Arizona State University in Tempe. He teaches courses on the Stone Age of Africa, prehistoric and historic hunger-gatherers, zooarchaeology, and paleoecology. During the last decade he has put more effort into on-site archaeological excavations. In 2007, Marean and colleagues announced that they had found the oldest known evidence for the use of coastal resources, dating back to about 164,000 years ago, in Cave 13B at Pinnacle Point, on the South African coastline near Mossel Bay within the Cape Floral Kingdom.
The Rydell Professorship at Gustavus is a scholar-in-residence program designed to bring Nobel laureates, Nobel Conference lecturers, and similarly distinguished scholars to the campus as catalysts for enhancing learning and teaching. It was established in 1995 by Drs. Robert E. and Susan T. Rydell of Minnetonka, Minn., to give students the opportunity to learn from and interact with leading scholars.
Charles Darwin: The naturalist was often caricatured in publications for his views on evolution.Courtesy Courtesy Wikimedia CommonsThe first of two international conferences marking the 150th anniversary of the publication of Charles Darwin's On the Origin of Species is taking place this week at the Vatican. Scientists, theologians, and philosophers from around the globe are gathering at the Pontifical Gregorian University in Rome to discuss the compatibility of the Church's teaching with Darwin's theory of evolution.
This is a far cry from the Church's reaction to Galileo Galilei’s scientific writings when the scientist was put under house arrest for heresy in 1633 (Pope John Paul II vindicated Galileo in 1992 and eight years later included the scientist’s trial in a blanket apology for all the Church’s past errors).
The International Conference on "Biological Evolution: Facts and Theories" runs from March 3-7.
LINKS
Conference website
BBC story
The fossil record strongly supports evolutionCourtesy Mark RyanEducators and students to our south (Iowa –not Mexico) are up in arms about a bill in committee in the Iowa legislature that they say is just another wolf-in-sheep’s-clothing attempt from anti-evolutionists to inject creationism into school curricula.
House File 183, aka the “Evolution Academic Freedom Act” would allow educators in public elementary, secondary, and post-secondary schools to teach “the full range of scientific views regarding chemical and biological evolution” without fear of dismissal, discrimination or being disciplined. But what exactly the full range of scientific views is, they don't say. That's because evolution is by far the best scientific explanation of biological life on Earth that we have at this time.
This attempt to open the way for getting non-scientific views about evolution into the schools is nothing new. The same tactic has been tried recently in other states, and all but one failed. The unfortunate exception was a bill in Louisiana which governor Bobby Jindal, a creationism supporter, recently signed into law.
Opposition to the Iowa legislation is being organized across the state.
“The bill sounds good in its language, but the reality is 99 percent of scientists believe in evolution,” said Hector Avalos, a professor of philosophy and religious studies at Iowa State University. “It is all about Teach the Controversy strategy — the idea it’s fair to teach both sides.”
Fifty-six professors from across Iowa and more than 220 other people have signed an Iowa faculty petition which calls for the legislature to reject HF 183.
“The premise of the petition is that this [legislation] is ridiculous. Let’s stop it here,” said John Logsdon, a University of Iowa associate professor of evolutionary molecular genetics. “It is teaching something that is not science cloaked in an academic freedom issue.”
Opponents say the wording in the bill smacks of the propaganda disseminated by the Discovery Institute, a Seattle-based purveyor of so-called Intelligent Design (creationism all dressed up as science and looking for love). In 2005, a court ruling ( Kitzmiller v. Dover) in Pennsylvania concluded that Intelligent Design is not science, and could not “uncouple itself from its creationist, and thus religious, antecedents.”
Another favorite creationist tactic is to create controversy where there is none. For example, HF 183 states “instructors have experienced or feared discipline, discrimination, or other adverse consequences as a result of presenting the full range of scientific views regarding chemical and biological evolution.” But in reality state education departments have found no such cases of discrimination nor have sponsors of the bill provided any.
HF 183 is supported mainly by conservative religious groups and not from any legitimate scientific or educational organizations. The bill’s sponsor is Rod Roberts, a five-term representative, and ordained minister who also works as Development Director for Christian Churches-Church of Christ in Iowa.
Both the Iowa State Education Association and the Iowa Department of Education oppose the bill.
LINKS
National Science Teachers Association evolution resources
Uwire story
National Center for Science Education story
This bear is full of love, questions: Although I'd like to trade a capitalization for an apostrophe.Courtesy aussiegallTo quote the wise and indomitable Tyra Banks: “Hey y’all!”
It’s Friday (I think) and relationships still exist (that’s what I hear) so it’s time again for everybody’s favorite Friday Science Buzz feature: The Friday Relationship Extravaganza!
This week’s relationship feature promises to be especially… extravagasmic, because today we’re pairing it up with some good old fashioned random questions.
See, on Thursday night, all the Buzz blog features went out for drinks after work. Random Questions promised itself that it would just have two drinks, but you know how that sort of thing goes… Pretty soon the ginger ale was flowing, and next thing you know Random Questions is waking up in Extravaganza’s bed.
OMG, right?
But don’t even worry about it. Nothing happened. Extravaganza slept on the couch. Still, these are work friends, not friend friends, and they had to talk about something when they got to the office. And so…
Friday Relationship Extravaganza: Random Questions Edition
So paddle around with me in the HMS Puddleduck, won’t you?
Question: Why do praying mantis females eat their mates?
Answer: Hmm… This is a hard one. If relationships weren’t tricky enough, relationships that involve cannibalism are particularly troublesome. I mean, look at Jeffrey Dahmer.
It’s also difficult to answer because it seems like scientists are sure exactly why mantises behave this way. Originally it was thought that female mantises bit off their mates’ heads because removing the head caused the male to start, er, mating like crazy (and why not, I guess.) Plus, the lady mantis gets a snack.
Then, some scientists pointed out that this behavior could be influenced by the fact that the mantises were being watched—whether in the field or in a laboratory, the bright lights and steamy glasses of sweaty-palmed scientists might be a little distracting and stressful for mantis lovers, and could cause them to behave a little irrationally.
Other scientists then observed that if a female were fed before mating, she would be less likely to snap at her mate (as it were). With the threat of having his head bitten off lessened, a male mantis will sometimes even engage in elaborate courtship behavior (and why not, I guess.)
Recently, researchers have determined that male mantises, in fact, don’t like getting eaten, and will approach a female with tremendous caution and attempt to couple from a greater distance to avoid it.
So, what are we left with? Removing a mating male’s head can increase that male’s chance of successfully reproducing (because of the mating like crazy thing). But not getting killed on a lucky date can also increase a male’s chance of reproducing (because he can maybe go on to have more dates with other females). And being watched my scientists while having sex can be stressful. And being hungry while having sex can lead lady mantises to do things they might later regret.
Is that close enough to a real answer?
Question: (This question card is actually two questions. “Why can’t boys have babies?” was written first, and then scratched out. A more logical rephrasing of the question follows: “How long would it take to grow a boyfriend?” Because I’m the acting commander of the HMS Puddleduck, choosing which question to answer is my prerogative. So I will answer both. This is an extravaganza, after all.)
Why can’t boys have babies?
Answer: Well… I can see why you decided to re-write this question. Because, of course, boys can have babies. If I were to see a baby sitting on the street, and if I were to take that baby, guess what? I’d technically have a baby. (And don’t get all sassy about how I shouldn’t go around just taking babies willy-nilly. Would you rather I left that baby sitting in the street?)
Also, according to the research presented in Junior, men can make their own babies, no problem. But until that technology is released to fertility clinics, boys can’t have babies because… well, just because. That’s how things worked out.
We have evolved to use internal fertilization—that is, we don’t just release eggs and sperm into the ocean in the hopes that they’ll mix around on their own. And thank God, because where would the Relationship Extravaganza be if we all acted like fish and amphibians? No place good.
And so, I don’t know… one of the two sexes got stuck with carrying fertilized eggs/babies around, and it’s usually the female (Seahorses are an interesting counterexample, however). And, at this point, human males couldn’t really do it, because we haven’t got the equipment. I mean, the underwhelming birth canal is really the least of the issues here (and that’s saying something.)
Sorry if I’m being vague on this answer, but I think it might be a good question for our current Scientist on the Spot, PZ Myers. I think this question comes down to evolution, and why it makes sense for just one sex to carry developing offspring. PZ is the expert on evolution, so click on these pink words and see if he has any thoughts on the subject.
How long would it take to grow a boyfriend?
Answer: I guess it depends on how you like your boyfriends. If you like your men young, I’d say you could have a boyfriend ready in about nine months. If you want some kind of loving, responsible and mature boyfriend, you might have to wait… what, about 35 years? Yeah, that sounds about right.
Then again, “accelerated aging” seems to be a staple of all cloning-related sci-fi, so maybe we should look into that…
When a mad scientist makes my perfect double to replace me after I get kidnapped, accelerated aging techniques will be essential to ensuring that the clone and I are indistinguishable. After all, a regular (non-mad) scientist might be able to clone me now, but the clone would be a baby, and it wouldn’t be a very convincing replacement. (I pee my pants so rarely these days, it’s hardly worth brining up.)
However, it seems like accelerated aging might be an unintended consequence of some cloning techniques already, and doesn’t even require special tanks and serums. When Dolly the sheep was cloned, scientists found that she suffered from arthritis and lung disease at a relatively young age, leading them to believe that she was prematurely aging. One thought is that Dolly’s telomeres were too short. Telomeres are pieces of DNA at the ends of chromosomes, and their deterioration is responsible for aging. Telomeres prevent chromosomes from accidentally combining with each other. If the chromosomes were to combine with each other, it could result in the cell becoming cancerous, so when a telomere runs out or wears down, the cell is usually destroyed. The shortening of telomeres puts a limit on the number of times a cell can divide, and when cells don’t divide anymore, you start to age. They aren’t sure exactly what caused Dolly’s telomeres to be short (if that was indeed the cause of her rapid aging).
But that’s sort of the downhill part of aging—if you were to clone or genetically engineer your perfect boyfriend, and somehow shorten his telomeres (if it didn’t happen automatically from the cloning) you’d probably end up with some sort of odd Benjamin Button situation, and that might not be what you want.
To even things out, you might have to affect the pituitary gland in some way. The pituitary controls hormones that cause growth, and disorders with the pituitary gland can sometimes cause kids to grow very large very quickly. Many of the world’s tallest people have had pituitary disorders.
I’m thinking that you’d still need eight or nine years to balance out the pituitary and telomere stuff in your grown boyfriend. And he might not thank you for it.
And there we are! Another heartwarming Relationship Extravaganza, spiced with random questions. But the Puddleduck must be off—I still have a stack of questions here that require answers from the far off reaches of knowledge. And several of them have swearwords in them that I have to rephrase, which isn’t easy, if you want to keep the spirit of the original question. (And I do.)
