Showing posts with label evolution. Show all posts
Showing posts with label evolution. Show all posts

Sunday, July 06, 2014

Comedy vs. anti-science: 10 amazing videos that show how humor can make a difference

Comedy vs. anti-science: 10 amazing videos that show how humor can make a difference

From Colbert and Oliver to Sarah Silverman and Louis CK, comedians are torching anti-science activists with aplomb  

Click HERE to see VIDEOS


Salon

Comedy vs. anti-science: 10 amazing videos that show how humor <em>can</em> make a differenceJon Stewart, Sarah Silverman, Stephen Colbert (Credit: AP/Brad Barket/Jack Plunkett/Dave Allocca)
In the latest version of America’s long-running culture wars, conservatives (and even some liberals) have zeroed in what once might have seemed like an unlikely target. While all the usual suspects still find themselves in reactionary cross hairs — Hollywood, “lamestream”-media elites and the LGBT community to name a few — another group, the scientific establishment, has emerged as one of the most polarizing institutions in American political culture.
Climate change, vaccination and evolution — each of these are things that the scientific establishment overwhelmingly agrees on. But the anti-intellectual fury of climate deniers, anti-vaxxers and creationists is such that any empirical consensus gets overshadowed.
For better or worse, comedy has emerged as one of the most visible platforms for laying bare the insanity of anti-science reactionaries. Jon Stewart and his “Daily Show” correspondents, for example, have been scrutinizing such people for years, while John Oliver has emerged in recent months as a veritable pro-science powerhouse. Stephen Colbert has interviewed Neil deGrasse Tyson at least 10 times!
There’s never been a shortage of qualified experts to debunk anti-science, but few have generated the kind of heat that comedians have of late. Perhaps is the viral-friendly nature of social media, or the intrinsic advantage that satire enjoys over the cut-and-dried recitation of facts. Whatever the case, let’s take a lesson from these witty minds. Below are 10 sterling examples of comedy as an antidote to science-denialism.

1) John Oliver takes on climate skeptics

Many comedians have done a bang-up job showing that climate deniers are ridiculous, but nobody has done it better than John Oliver. On his HBO show, “Last Week Tonight,” Oliver hosts a statistically accurate mock debate between Bill Nye and climate skeptics.

2) Samantha Bee destroys anti-vaxx nuts

When celebrities give anti-vaccination hysteria a platform — and, as a result, we get outbreaks of measles and whooping cough — it feels like the nation is crawling backward. Despite the fact that research has conclusively shown that vaccinations are not linked to autism, many still refuse to vaccinate their kids. In this clip, Samantha Bee takes anti-vaxxers to task for their dangerous campaign.

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3) Stephen Colbert mocks creationism

Creationists believe that the Earth is only 6,000 years old, and that humans roamed the world with dinosaurs. (Spoiler: Scientist Clair Patterson found that the Earth is actually 4.5 billion years old, and humans evolved long after dinosaurs became extinct.) Though it sounds ridiculous, a recent Gallup Poll found that 42 percent of Americans believe in a creationist human origin. The most problematic issue is when their views infiltrate the education of children. Stephen Colbert proves this point in the great interview below:

4) John Oliver destroys Dr. Oz’s “cure-alls”

In June of 2014, TV personality and physician Dr. Oz testified at a congressional hearing that his “miracle” cure-alls “don’t have the scientific muster to present as fact.” Following this admission, John Oliver took him to task over his false science, and taking advantage of doctor-patient trust.

5) Lewis Black throws fossils at creationists

“I would love to have the faith to believe that [creation] took place in seven days,” Lewis Black says in the hilarious clip below. “But I have thoughts. And that can really fuck up the faith thing.”...

Thursday, April 17, 2014

Here's a challenge for both creationists and evolutionists: a really odd insect from a cave in Brazil


Brazilian cave insects (female in inset, and above the male in larger photo) Yoshizawa et al., Current Biology (2014)

For creationists, the problem here is to explain WHY God would specifically decide to create one insect species in which the females have a penis and the males have a vagina.

For evolutionists, the problem is to explain HOW this insect evolved. The second article below sets up the general requirements for the explanation, which will be every bit as fascinating as hearing a creationist explain why God made this animal. But I think I it's clear why God might have decided to hide the animal in caves in Brazil: he didn't want his loyal followers to break their brains thinking about it.

Scientists discover the first known case of sex-reversed genitals
The female insect has a penis and the male insect has a vagina. And that's not even the strangest part
Lindsay Abrams
Salon
Apr 17, 2014

Scientists discover the first known case of sex-reversed genitalsAn N. aurora female releases its penis-like organ, in preparation for mating.

It’s a big day for science. At NASA, they’ve announced the discovery of a new, Earth-like planet that could potentially harbor extraterrestrial life. And over in Brazil, they’ve discovered the first known case of “female penis.”

That’s right: as detailed in the journal Current Biology, four species of Brazilian insects sport sex-reversed genitalia. It’s not impossible, as the Verge explains: Rather than sex organs or chromosomes, biologists use gametes (sperm in males and oocytes in females) to determine sex. In this case, the females, which have the biggest gametes, also happen to have a penis. Here, courtesy of the journal, is what it looks like:

Smithsonian Mag has as weird an account of the bugs’ mating ritual that you can ever hope to read:

During mating, the female’s spiny penis gets tightly anchored to the male vagina’s sperm duct, allowing the female to receive the semen. In other words, this penis functions more like a straw than a spout. If the male tried to break away, his abdomen would rip open, and he would dramatically lose his genitals. These female insects also mate with multiple males and can store two batches of sperm in the body.


So that’s how that happens. The “why,” on the other hand, is a much bigger question. Here’s the Verge, again:

Michael Siva-Jothy, an entomologist at the University of Sheffield, UK, who didn’t participate in this study, said in an email to The Verge that the findings are “really, really exciting.” Examples like this, he noted, allow researchers to examine various factors that drive how these traits evolve. When asked how the female penis might have evolved, however, Siva-Jothy was stumped. “This is so bizarre,” he said. “I don’t know where to begin.”

Yoshizawa was equally surprised upon seeing these insects for the first time. “Usually, a new structure evolves as a modification of a previously existing structure,” he said. But this female penis has no precedent. Evolving a structure like this, Yoshizawa said, is “exceptionally difficult” because the development of this form of mating would have necessitated the harmonious evolutions of both male and female genitalia, and their exact match.


“Obviously more research is needed,” evolutionary biologist Marlene Zuk, who was not associated with the study, told Smithsonian, “but the whole thing is completely wild.”


ScienceShot: Females Sport Penises in Genital-Swapped Insects
Yoshizawa et al.
Current Biology
17 April 2014

Ecologists spelunking in a Brazilian cave have found a new variety of insect with an unusual sex life. Females of the newly discovered genus Neotrogla, 3-mm-long flylike insects, boast large, penislike structures called gynosomes (inset). Although other animals such as seahorses take on reversed gender roles, species in the new genus are the first to be found with swapped genital structures. During copulation—which lasts 40 to 70 hours—the female mounts the male from behind (as seen in the above photo), thrusting her gynosome into the male’s vaginalike opening. Once inside, the female uses spines on the gynosome to latch on to the potentially reluctant male. The lady’s grasp is so strong that when the researchers tried to separate a fornicating pair, the male’s abdomen was ripped from its body without breaking the genital link. During breeding, the male transfers a large amount of nutritious ejaculate via the gynosome to the female, the researchers report online today in Current Biology. The team suggests that in the resource-scarce cave system, this nutritious seminal gift causes females to compete for sustained breeding. Over time, the scientists believe this female-initiated intercourse could have led the insects to evolve reversed genitals. Still unclear is whether the females worry about the size of their gynosome.


Here's another article on the subject from Current Biology:

Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect
Kazunori Yoshizawaemail, Rodrigo L. Ferreira, Yoshitaka Kamimura, Charles Lienhard

Highlights

•Females of the cave insect genus Neotrogla have an elaborate penis-like organ
•The female penis acts as an intromittent organ and anchors the female to the male
•Correlated evolution is detected between the female penis and male genitalia

Summary

Sex-specific elaborations are common in animals and have attracted the attention of many biologists, including Darwin [ 1 ]. It is accepted that sexual selection promotes the evolution of sex-specific elaborations. Due to the faster replenishment rate of gametes, males generally have higher potential reproductive and optimal mating rates than females. Therefore, sexual selection acts strongly on males [ 2 ], leading to the rapid evolution and diversification of male genitalia [ 3 ]. Male genitalia are sometimes used as devices for coercive holding of females as a result of sexual conflict over mating [ 4, 5 ]. In contrast, female genitalia are usually simple. Here we report the reversal of intromittent organs in the insect genus Neotrogla (Psocodea: Prionoglarididae) from Brazilian caves. Females have a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such as numerous spines that fit species-specific pouches in the simple male genital chamber. During prolonged copulation (∼40–70 hr), a large and potentially nutritious ejaculate is transferred from the male via the gynosome. The correlated genital evolution in Neotrogla is probably driven by reversed sexual selection with females competing for seminal gifts. Nothing similar is known among sex-role reversed animals.

Tuesday, December 31, 2013

During the past four years, 19% of Republicans changed their minds about evolution. You'll never guess which direction they're going in


CREDIT: Shutterstock

Almost 1 in 5 Republicans has recently decided that science gets in the way of politics. And that it's the science, not the politics, that should be jettisoned. Who needs critical thinking?

Why Republicans Don’t Believe In Evolution Anymore
By Zack Beauchamp
Think Progress
December 31, 2013

The theory of evolution is right up there with the theory of gravity in terms of its universal acceptance among scientists. But, as we’ve learned from the climate change debate, politics has the power to trump science — and, according to a new Pew poll, it seems like political partisanship may be starting to take its toll on evolution. While a comfortable majority of Republicans accepted human evolution as fact in 2009, Pew finds a plurality now reject it — an astonishing 19 point reversal in four years.

It’s a finding that tells us a lot, both principally about the (ahem) evolution of the Republican Party in the past fours. In short, the kind of person who doesn’t believe in evolution is much more likely be a typical Republican today than four years ago — for reasons that have only a bit to do with the debate over evolution itself.

There are two keys to understanding what the Pew poll teaches us about Republicans. First, the drop in belief in evolution is among Republicans and, more or less, Republicans only. Acceptance of human evolution was basically the same among Democrats and independents in 2013 as it was in 2009. Second, the share of the total population that believes in evolution hasn’t changed at all. The drop in Republican belief doesn’t appear to be people changing their minds about evolution so much as people who already didn’t believe in evolution becoming Republicans.

Why might that be? The obvious explanation is the changing character of the Republican base. When Republicans win in recent years, those victories are won on the backs of old voters, white voters, and religious voters. While race isn’t super-important in predicting views on evolution, age and religion are. Each generation of Americans, Pew found, is increasingly more likely to accept natural human evolution; Americans 18-29 do so by a 68-27 margin, while the number for seniors (65+) is 49-36. Likewise, white evangelical protestants are the group most likely to reject evolution, while the religiously unaffiliated are by far the most likely to accept it.

The winnowing of self-identified Republicans to these demographic groups has been dramatic in recent years. The overall number of Americans who identify as Republicans hovered around 29 percent from from 2008-2012 as American seniors became dramatically more Republican, the pro-GOP margin shifting from 35-34 in 2008 to 39-29 in 2012. White evangelicals have become similarly more Republican at the same time.

So on one look, the decline in Republican belief in evolution is perfectly consistent with one of the most fundamental trends in American politics: a greying, born-again Republican Party increasingly out of step with the rest of America’s political views.

The Republican base’s increasing hostility to evolution could very well explain the rash of recent state-level debates on teaching evolution in schools. In the past four years, we’ve seen a slate of state controversies over school textbooks and curricula that teach creationism alongside evolution. States like Texas, Tennessee, Louisiana, Oklahoma, Kentucky, and New Mexico have all had versions of this fight — all controversies sparked by conservative state leaders that have heated up in the past two or three years. All of this anti-evolution activity makes much more sense if understood as Republican representatives and activists responding to incentives created by their increasingly homogenous base.

If that explanation is right, then we should expect to see similarly base-tailored legislation coming out of Republican state representatives in 2014 and beyond. The demographic trends concentrating the Republican base don’t appear to be slowing, which means that Republicans will have even stronger incentives over time to push legislation that appeals to the older, whiter, more religious demographic. This means that more issues like creationism in schools that don’t play on the national level, but can help local Republicans make a name for themselves inside the party, might make their way into state capitols in the coming year.

But the demographic explanation isn’t everything. Pew cautions that “differences in the racial and ethnic composition of Democrats and Republicans or differences in their levels of religious commitment do not wholly explain partisan differences in beliefs about evolution.” Put more simply, Republicans are more skeptical of evolution than you would expect even when you take into account the demographic character of its base.

This suggests another, more subtle effect at work. A wealth of research into political psychology shows that people’s partisan affiliations affect their beliefs on basic facts. Republicans are overwhelmingly more likely to think the economy is doing well when Republicans hold the Presidency, and ditto with Democrats when their guy holds the White House. A recent experiment found that even basic math is contaminated by politics; people are much more likely to correctly solve basic math problems when, in context, solving them correctly helps rather than hurts their party.

In the evolution context, this suggests a feedback effect at work among Republicans. As the GOP becomes more associated with the creationist cause as a consequence of demographic shifts, Republicans start to feel more like being skeptical of evolution is their “team” position. So even Republicans who are demographically more likely to accept the basic science of evolution start to reject it, because that belief best harmonizes their beliefs with the perceived interest of their political party.

Politics, it seems, really does ruin everything — including science.

Wednesday, November 27, 2013

7 Reasons Why It's Easier for Humans to Believe in God Than Evolution


The ascent of man? José-manuel Benitos/Wikimedia Commons. Photoillustration by Matt Connolly.

7 Reasons Why It's Easier for Humans to Believe in God Than Evolution
What science can tell us about our not-so-scientific minds.
By Chris Mooney
Mother Jones
Nov. 26, 2013

Late last week, the Texas Board of Education failed to approve a leading high school biology textbook—whose authors include the Roman Catholic biologist Kenneth Miller of Brown University—because of its treatment of evolution. According to The New York Times, critiques from a textbook reviewer identified as a "Darwin Skeptic" were a principal cause.

Yet even as creationists keep trying to undermine modern science, modern science is beginning to explain creationism scientifically. And it looks like evolution—the scientifically uncontested explanation for the diversity and interrelatedness of life on Earth, emphatically including human life—will be a major part of the story. Our brains are a stunning product of evolution; and yet ironically, they may naturally pre-dispose us against its acceptance.

"I don't think there's any question that a variety of our mental dispositions are ones that discourage us from taking evolutionary theory as seriously as it should be taken," explains Robert N. McCauley, director of the Center for Mind, Brain, and Culture at Emory University and author of the book Why Religion is Natural and Science is Not.

So what can science tell us about our not-so-scientific minds? Here's a list of cognitive traits, thinking styles, and psychological factors identified in recent research that seem to thwart evolution acceptance:

Biological Essentialism. First, we seem to have a deep tendency to think about biology in a way that is "essentialist"—in other words, assuming that each separate kind of animal species has a fundamental, unique nature that unites all members of that species, and that is inviolate. Fish have gills, birds have wings, fish make more fish, birds make more birds, and that's how it all works. Essentialist thinking has been demonstrated in young children. "Little kids as young as my 2 and a half year old granddaughter are quite clear that puppies don't have ponies for mommies and daddies," explains McCauley.

If essentialism is a default style of thinking, as much research suggests, then that puts evolution at a major disadvantage. Charles Darwin and his many scientific disciples have shown that essentialism is just plain wrong: Given enough time, biological kinds are not fixed but actually change. Species are connected through intermediate types to other species—and all are ultimately related to one another.

Teleological Thinking. Essentialism is just one basic cognitive trait, observed in young children, that seems to hinder evolutionary thinking. Another is "teleology," or the tendency to ascribe purposes to things and objects so as to assume they exist to serve some goal.

Recent research suggests that 4 and 5 year old children are highly teleological in their thinking, tending to opine, for instance, that clouds are "for raining" and that the purpose of lions is "to go in the zoo." The same tendency has been observed in 7 and 8 year olds who, when asked why "prehistoric rocks are pointy," offered answers like "so that animals could scratch on them when they got itchy" and "so that animals wouldn't sit on them and smash them."

Why do children think like this? One study speculates that this teleological disposition may be a "side [effect] of a socially intelligent mind that is naturally inclined to privilege intentional explanation." In other words, our brains developed for thinking about what people are thinking, and people have intentions and goals. If that's right, the playing field may be naturally tilted toward anti-evolutionist doctrines like "intelligent design," which postulates an intelligent agent (God) as the cause of the diversity of life on Earth, and seeks to uncover evidence of purposeful design in biological organisms.

Overactive Agency Detection. But how do you know the designer is "God"? That too may be the result of a default brain setting.

Another trait, closely related to teleological thinking, is our tendency to treat any number of inanimate objects as if they have minds and intentions. Examples of faulty agency detection, explains University of British Columbia origins of religion scholar Ara Norenzayan, range from seeing "faces in the clouds" to "getting really angry at your computer when it starts to malfunction." People engage in such "anthropomorphizing" all the time; it seems to come naturally. And it's a short step to religion: "When people anthropomorphize gods, they are inferring mental states," says Norenzayan.

There has been much speculation about the evolutionary origin of our anthropomorphizing tendency. One idea is that our brains developed to rapidly assume that objects in the world are alive and may pose a threat, simply because while wrongly mistaking a rustle of leaves for a bear won't get you killed, failing to detect a bear early (when the leaves rustle) most certainly will. "Supernatural agents are readily conjured up because natural selection has trip-wired cognitive schema for agency detection in the face of uncertainty," write Norenzayan and fellow origin of religion scholar Scott Atran.

Dualism. Yet another apparent feature of our cognitive architecture is the tendency to think that minds (or the "self" and the "soul") are somehow separate from brains. Once again, this inclination has been found in young children, suggesting that it emerges early in human development. "Preschool children will claim that the brain is responsible for some aspects of mental life, typically those involving deliberative mental work, such as solving math problems," write Yale psychologists Paul Bloom and Deena Skolnick Weisberg. "But preschoolers will also claim that the brain is not involved in a host of other activities, such as pretending to be a kangaroo, loving one's brother, or brushing one's teeth."

Dualistic thinking is closely related to belief in phenomena like spirits and ghosts. But in a recent study, it was also the cognitive factor most strongly associated with believing in God. As for evolutionary science? Dualism is pretty clearly implicated in resistance to the idea that human beings could have developed from purely natural processes—for if they did, how could there ever be a soul or self beyond the body, to say nothing of an afterlife?

Inability to Comprehend Vast Time Scales. According to Norenzayan, there's one more basic cognitive factor that prevents us from easily understanding evolution. Evolution occurred due to the accumulation of many small changes over vast time periods—which means that it is unlike anything we've experienced. So even thinking about it isn't very easy. "The only way you can appreciate the process of evolution is in an abstract way," says Norenzayan. "Over millions of years, small changes accumulate, but it's not intuitive. There's nothing in our brain that says that's true. We have to override our incredulity."

Group Morality and Tribalism. All of these cognitive factors seem to make evolution hard to grasp, even as they render religion (or creationist ideas) simpler and more natural to us. But beyond these cognitive factors, there are also emotional reasons why a lot of people don't want to believe in evolution. When we see resistance to its teaching, after all, it is usually because a religious community fears that this body of science will undermine a belief system—in the US, usually fundamentalist Christianity—deemed to serve as the foundation for shared values and understanding. In other words, evolution is resisted because it is perceived as a threat to the group.

So how appropriate that one current scientific theory about religion is that it exists (and, maybe, that it evolved) to bind groups together and keep them cohesive. In his recent book The Righteous Mind, moral psychologist Jonathan Haidt argues that religions provide a shared set of beliefs and practices that, in effect, serve as social glue. "Gods and religions," writes Haidt, "are group-level adaptations for producing cohesiveness and trust." The upside is unity; the downside, Haidt continues, is "groupishness, tribalism, and nationalism." Ideas and beliefs that threaten the group or the beliefs that hold it together—ideas like evolution—are bound to fare badly in this context.

Fear and the Need for Certainty. Finally, there appears to be something about fear and doubt that impels religiosity and dispels acceptance of evolution. "People seem to take more comfort from a stance that says, someone designed the world with good intentions, instead of that the world is just an intention-less, random place," says Norenzayan. "This is especially true when we feel a sense of threat, or a feeling of not being in control."

Indeed, in one amazing study, New Zealanders who had just suffered through a severe earthquake showed stronger religiosity, but only if they had been directly affected by the quake. Other research suggests that making people think about death increases their religiosity and also decreases evolution acceptance. It's not just death: It's also randomness, disorder. In one telling study, research participants who were asked to think of a situation in which they had lacked control and then to "provide three reasons supporting the notion that the future is (un-) controllable," showed a marked decline in their acceptance of evolution, opting instead for an intelligent design-style explanation. (Another study found that anti-evolutionists displayed higher fear sensitivity and a trait called the "need for cognitive closure," which describes a psychological need to find an answer that can resolve uncertainty and dispel doubt.)

Such is the research, and it's important to point out a few caveats. First, this doesn't mean science and religion are fundamentally incompatible. The conflict may run very deep indeed, but nevertheless, some individuals can and do find a way to retain their religious beliefs and also accept evolution—including the aforementioned biology textbook author Kenneth Miller of Brown University, a Catholic.

Second, while there are many reasons to think that the traits above comprise a core part of who we are, it doesn't automatically follow that religion is the direct result of evolution by natural selection. It is also possible that religion arises as a byproduct of more basic traits that were, in turn, selected for because they conferred greater fitness (such as agency detection). This "byproduct" view is defended by Steven Pinker here.

In any event, the evidence is clear that both our cognitive architecture, and also our emotional dispositions, make it difficult or unnatural for many people to accept evolution. "Natural selection is like quantum physics...we might intellectually grasp it, with considerable effort, but it will never feel right to us," writes the Yale psychologist Paul Bloom. Often, people express surprise that in an age so suffused with science, science causes so much angst and resistance.

Perhaps more surprising would be if it didn't.

Wednesday, September 25, 2013

New Approach to Explaining Evolution’s Big Bang

New Approach to Explaining Evolution’s Big Bang
Around 520 million years ago, many major groups of animals appear in the fossil record for the first time. Trilobites belonged to the same lineage as today's crustaceans and insects.
By CARL ZIMMER
New York Times
September 19, 2013

The name Myllokunmingia may not ring a bell, but it is worth knowing. This 520-million-year-old creature was the size of a guppy, with a tiny swordfish-like fin running high over its back. The fossils it has left behind preserve traces of a skull.

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Humans have a skull, too. This and a number of other traits we share with Myllokunmingia reveal it to be one of the oldest, most primitive vertebrates yet found. It is, in other words, a hint of where we came from.

Myllokunmingia emerged during one of the most important phases in the history of life, an evolutionary boom known as the Cambrian explosion (named for the geological period when it took place). Over the course of about 20 million years, the oldest known fossils of most of the major groups of living animals appear, revealing a rapid diversification of life that led directly to humans.

“It’s rapid in geological terms, but it’s probably not rapid to anyone who’s not a geologist,” said Paul Smith, the director of the Oxford Museum of Natural History.

By some estimates, the first animals evolved about 750 million years ago. But it’s not until around 520 million years ago that many major groups of living animals left behind their first fossils. For decades, scientists have searched for the trigger that set in motion this riot of diversity in the animal kingdom.

Recently, Dr. Smith and his colleague David Harper of the University of Durham took a look at the hypotheses that have been offered about what caused the Cambrian explosion. “It became apparent just how many hypotheses there were out there,” Dr. Harper said. “Thirty-plus over the past 10 years.”

The scientists found that many of those explanations had boiled the cause down to just one trigger. Geologists suggested geological causes. Ecologists proposed ecological ones. Many of those ideas have merit, Dr. Smith and Dr. Harper argue in a commentary in this week’s Science, but it’s a mistake to search for a single cause. They propose that a tangled web of factors and feedbacks were responsible for evolution’s big bang.

Long before the Cambrian explosion, Dr. Smith and Dr. Harper argue, one lineage of animals had already evolved the genetic capacity for spectacular diversity. Known as the bilaterians, they probably looked at first like little crawling worms. They shared the Precambrian oceans with other animals, like sponges and jellyfish. During the Cambrian explosion, relatively modest changes to their genes gave rise to a spectacular range of bodies.

But those genes evolved in bilaterians tens of millions of years before the Cambrian explosion put them to the test, notes Dr. Smith. “They had the capacity,” he said, “but it hadn’t been expressed yet.”

It took a global flood to tap that capacity, Dr. Smith and Dr. Harper propose. They base their proposal on a study published last year by Shanan Peters of the University of Wisconsin and Robert Gaines of Pomona College. They offered evidence that the Cambrian Explosion was preceded by a rise in sea level that submerged vast swaths of land, eroding the drowned rocks.

“There’s a big kick that correlates with the sea level rise,” Dr. Smith said of the fossil record. He and Dr. Harper propose that this kick happened thanks to the new habitats created by the sea level rise. These shallow coastal habitats were bathed in sunlight and nourished with eroding nutrients like phosphates. Animals colonized these new fertile habitats, Dr. Smith and Dr. Harper argue, and evolved to take up new ecological niches.

But these great floods also poisoned the ocean. The erosion of the coastlines released calcium, which can be toxic to cells. In order to survive, animals had to evolve ways to rid themselves of the poison. One solution may have been to pack the calcium into crystals, which eventually evolved into shells, bones, and other hard tissues. Dr. Smith doesn’t think it’s a coincidence that several different lineages of bilaterians evolved hard tissues during the Cambrian explosion, and not sooner.

These shells and other hard tissues sped up animal evolution even more. Predators could grow hard claws and jaws for killing prey, and their prey could evolve hard shells and spines to defend themselves. Animals became locked in an evolutionary arms race.

This new ecological food web grew even more complex. Bigger predators evolved that could eat smaller predators. Meanwhile, some bilaterians burrowed into the sea floor for the first time, allowing oxygen-rich seawater to flow into the sediment. Those first burrowers profoundly transformed the world’s oceans, creating yet another habitat that other oxygen-breathing animals could also invade. “That drives the diversification onward,” said Dr. Smith.

Kevin Peterson, a biologist at Dartmouth, praised Dr. Smith and Dr. Harper for pointing to the right way to study the Cambrian explosion. “We are long past identifying single triggers for the event,” he said. Dr. Peters agreed that taking a holistic view of the Cambrian explosion would lead to a better understanding of it. “It’ll be a fun next decade,” he predicted.

But Philip Donoghue of the University of Bristol does not think the links Dr. Smith and Dr. Harper use in their hypothesis are tight enough yet. Questions still remain, for example, about how long vertebrates and other animals groups already existed before they left behind fossils like Myllokunmingia. If animals diversified earlier, then scientists will need to look at earlier causes.

“Timing,” said Dr. Donoghue, “is everything.”

Wednesday, June 13, 2012

'Hippie chimp' genome may shed light on our dark side

'Hippie chimp' genome may shed light on our dark side
By Seth Borenstein
MSNBC
June 12, 2012

Behold the bonobo, our ape cousin that's kinder and gentler than the chimp or, well, us. Now scientists have mapped the primate's DNA, and some researchers say that may eventually reveal secrets about how the darker side of our nature evolved.

Scientists have found that we are as close genetically to the peace-loving but little-known bonobo as we are to the more violent and better understood chimpanzee. It's as if they are siblings and we are cousins, related to them both equally, sharing some traits with just bonobos and other characteristics with just chimps.

Bonobos and humans share 98.7 percent of the same genetic blueprint, the same percentage shared with chimps, according to a study released Wednesday by the journal Nature. The two apes are much more closely related to each other — sharing 99.6 percent of their genomes — said the study's lead author, Kay Prufer, a geneticist at the Max Planck Institute in Germany.

"Humans are a little like a mosaic of bonobo and chimpanzee genomes," she said. Bonobos and chimps have distinctly different behaviors that can be seen in humans, with bonobos displaying what might be thought of as our better angels, said Duke University researcher Brian Hare. Bonobos make love, not war. Chimps have been documented to kill and make war. Bonobos share food with total strangers, but chimps do not. Bonobos stay close to their mothers — who even pick out their sons' mates — long after infancy, like humans. But chimps tend to use tools better and have bigger brains, like humans.

"Is the bonobo genome the secret to the biology of peace?" asked Hare, who was not involved in the new research. "They have done something in their evolution that even humans can't do. They don't have the dark side we do.

"If we only studied chimps, we'd get a skewed view of human evolution," he said.

Bonobos, chimps and humans shared a single common ancestor from about 6 million years ago, Prufer said. Chimps and bonobos shared the same common ancestor until about a million years ago, when the Congo River formed. Then the bonobos developed on one side of the river, the chimps the other. They became different species, even though scientists didn't realize that until about 90 years ago.

Bonobo heads are slightly smaller and their teeth are arranged differently. In behavior, bonobos are far more tolerant, more social. They are inordinately sexual. Instead of releasing tension by fighting, they couple repeatedly, Hare said. Bonobos are ruled by alpha females, chimps by males.

The bonobo's mellow ways have led some to nickname them "hippie chimps." But in some ways — especially when looking at the physiology of the brain — it's more as if a bonobo is a juvenile chimp that doesn't develop, Hare said. Chimps get more violent as they age; bonobos don't.

While the scientific name for bonobos is Pan paniscus, "they should be Peter Pan," Hare said. "They never grow up and we have lots of data to support this idea. Much of their psychology seems to be frozen."

Some researchers say Hare has romanticized the bonobo too much. Emory University researcher Bill Hopkins says he has more bonobo scars than chimp scars on his body. Sure, bonobos will bite, but they won't kill, Hare said...

Wednesday, November 09, 2011

Fossil Teeth Put Humans in Europe Earlier Than Thought

New evidence reinforces the suspicion that modern humans exterminated their Neanderthal cousins. The other suspect is climate change.

Fossil Teeth Put Humans in Europe Earlier Than Thought
By JOHN NOBLE WILFORD
New York Times
November 2, 2011

The fossils seemed hardly worth a second look. The one from England was only a piece of jawbone with three teeth, and the other, from southern Italy, was nothing more than two infant teeth. But scientists went ahead, re-examining them with refined techniques, and found that one specimen’s age had previously been significantly underestimated and that the other’s dating and identity had been misinterpreted.

They had in fact discovered the oldest known skeletal remains of anatomically modern humans in the whole of Europe, two international research teams reported Wednesday.

The scientists who made the discovery and others who study human origins say they expect the findings to reignite debate over the relative capabilities of the immigrant modern humans and the indigenous Neanderthals, their closest hominid relatives; the extent of their interactions; and perhaps the reasons behind the Neanderthal extinction. The findings have already prompted speculation that the Homo sapiens migrations into Europe may have come in at least two separate waves, rather than just one.

In tests conducted at the Oxford Radiocarbon Accelerator Unit in England, the baby teeth from Italy were dated at 43,000 to 45,000 years old. Other analysis showed the teeth to be those of a modern human, not a Neanderthal, as previously thought when the fossil was unearthed in 1964 from the Grotta del Cavallo.

Similar tests at Oxford established that the age of the jawbone, from Kents Cavern near Torquay, Devon, had been significantly underestimated, by about 7,000 years, probably because of contamination when it was originally dated in 1989. The age is now set at 41,500 to 44,200 years old, making this the oldest known modern human fossil from northwestern Europe.

These dates are remarkable on several counts, scientists said. The earliest reliably dated European modern human specimen, up to now, came from the Pestera cu Oase site in Romania, a long way east from the English coast. The Romanian fossil’s age is estimated at 37,800 to 42,000 years old. No stone tools or other artifacts were found with it.

And in the absence of early fossils, archaeologists had not been sure who made some of the stone tools they were uncovering, the arriving humans or the Neanderthals. It had been generally assumed that modern humans probably entered Europe at least as early as 45,000 years ago, based on changing patterns of artifacts that soon followed.

The two papers describing the new research were published Wednesday by the journal Nature. The lead author of the jawbone report was Thomas Higham of the University of Oxford. The principal author of the report on the baby teeth from Cavallo was Stefano Benazzi of the University of Vienna.

Not only does the jawbone indicate “the wide and rapid dispersal of the earliest moderns across Europe” during the last ice age, more than 40,000 years ago, Dr. Higham’s team wrote, it was also found in cave layers associated with a technology that archaeologists call the Aurignacian culture. The scientists said this “fills a key gap” between the earliest human skeletal remains and the earliest dated stone and bone Aurignacian tools and weapons.

Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis and an author of the Higham paper, said the artifacts associated with the Kents Cavern fossil confirm “what researchers have long suspected, that the human newcomers spread the Aurignacian culture.”

In a statement issued by Oxford, Dr. Higham also pointed out that the earlier dates for these fossils meant “that early humans must have coexisted with Neanderthals in this part of the world, something which a number of researchers have doubted.”

The confirmed early appearance of modern humans in Europe gave them more time for contacts with Neanderthals before the latter’s extinction about 30,000 years ago. Although recent genetic research shows some evidence of interbreeding between the species, there was uncertainty as to how much contact the two had in Europe, as opposed to earlier interactions in western Asia. It is still not clear how widespread was the Neanderthal population in their final millenniums; after a steady decline, the last of them seemed to disappear in their cul-de-sac of a refuge in southern Iberia.

Determining the age for any samples more than 40,000 years old was no sure thing. At that age, levels of remaining radiocarbon are low, and contamination can be a serious problem. As an alternative, Katerina Douka of Oxford, a member of the team examining the Italian specimen, focused on the dating of marine shell beads found in the same archaeological levels as the teeth, a technique that has proven successful at other sites in Europe.

When the teeth had been classified as Neanderthal, it was assumed that artifacts in the Cavallo site — bone tools and ornaments in a style known as the Uluzzian culture — were also considered Neanderthal creations. Now archaeologists suspect that they should be attributed to modern humans.

Ian Tattersall, a paleoanthropologist at the American Museum of Natural History in New York who was not involved in the research, said, “The tendency right now is to downplay associating Neanderthals with any cultural developments after humans got to Europe.”

Chris Stringer and Tim Compton, both of the Natural History Museum, London, and members of the Higham group, obtained radiocarbon dates of animal bones found close to the jawbone in Kents Cavern and used a statistical modeling method to calculate the age of the human fossil. They further used CT scans to produce 3-D models of the worn teeth and thus confirm that the fossil was indeed from a human, not a Neanderthal.

“Everybody is going to wish some of that evidence was better,” Dr. Tattersall said. “It is pretty slender, but I have no reason to dispute it.”

Dr. Stringer elaborated in an e-mail on some possible implications of the two discoveries. Perhaps some of the “transitional cultures” that preceded the Aurignacian, he said, were introduced by “multiple early waves of modern humans coming into Europe.” For example, the Kents Cavern fossil might represent an early dispersal through Central Europe that crossed into Britain on a land bridge where the North Sea is now. The Cavallo remains might represent a possibly even earlier migration along the Soouthern European coasts.

Richard G. Klein, an archaeologist at Stanford University, said he was “really impressed” by the new findings. Hearing of Dr. Stringer’s idea, Dr. Klein joined in the spirit of conjecture, noting that Homo sapiens was on the move at that time, venturing as far as Australia by about 45,000 years ago.

Tuesday, November 16, 2010

Efforts to Improve Evolution Teaching Bearing Fruit

November 16, 2010
Efforts to Improve Evolution Teaching Bearing Fruit
Education Week
By Sarah D. Sparks

When a federal court in 2005 rejected an attempt by the Dover, Pa., school board to introduce intelligent design as an alternative to evolution to explain the development of life on Earth, it sparked a renaissance in involvement among scientists in K-12 science instruction.

Now, some of those teaching programs, studies, and research centers are starting to bear fruit.

The National Science Foundation, the National Academy of Sciences, and other groups have increased research investment on identifying essential concepts for teaching evolution, including creating the Evolution Education Research Centre, a partnership of Harvard, McGill, and Chapman universities, and launching the first peer-reviewed journal dedicated to the subject, Journal of Evolution: Education and Outreach.

Though only one of a long series of skirmishes in a conflict that goes back almost as far as public education in America, the Kitzmiller v. Dover Area School District trial, which took place five years ago this month, engaged the professional science community because it put on trial for the first time the scientific validity of intelligent design. The concept posits that the development of humans and other living things was designed by an unnamed guiding force, rather than being the result of natural selection based on random variations.

The school board in Dover argued that there were weaknesses in the theory of evolution, and that students should be exposed to the idea of intelligent design. Judge John E. Jones III of the U.S. District Court for the Middle District of Pennsylvania flatly rejected that argument, noting that evolution is one of the most strongly supported theories in all of science, backed by broad evidence from across the field. By contrast, he concluded that “the overwhelming evidence at trial established that ID [intelligent design] is a religious view, a mere relabeling of creationism, and not a scientific theory,” in his 139-page findingRequires Adobe Acrobat Reader of fact.
See Also
From the Archives: View an interactive timeline of historical highlights in the debate over teaching evolution.

The district chose not to appeal the ruling, limiting its legal jurisdiction. But, along with the rejection of efforts in Arkansas and Georgia to undermine evolution’s validity through disclaimer labels on textbooks and fights over state science standards in Kansas around the same time, the ruling ignited an unprecedented push by scientists and education researchers to become more directly involved in integrating evolution concepts in science classes.

“What it has done is made it clearer to the scientific community that they have to come out and make a stand; they can’t wait in the wings and hope it all blows over,” said E. Margaret Evans, an assistant research scientist in education at the Center for Human Growth and Development at the University of Michigan in Ann Arbor.
Classroom Model

One of the instructional-improvement projects is Evolution Readiness, a program devised by a team of researchers from the Concord, Mass.-based Concord Consortium and Boston College. It pairs computer modeling of natural selection with classroom activities and readings on evolution concepts. In the process of developing the program, the researchers have crafted the first evolution-content assessment for elementary students, based on 11 standards-based learning goals for Massachusetts, according to Camelia Rosca, a senior research associate at the Center for the Study of Testing Evaluation and Education Policy at Boston College.

At Elizabeth G. Lyons Elementary School in Randolph, Mass., one of a handful of states where the program is being tested, 4th graders have finished a unit on plant adaptation, in which they watched the changes to a water-sensitive-plant population as the amount of water available was altered. The class is now extending the computer model to include rabbits and will soon add hawks to illustrate a basic food chain, said lead researcher Paul Horwitz, a senior scientist at Concord.

“We thought deeply about how to teach concepts to kids this young,” Mr. Horwitz said. “I didn’t want children to ‘believe’ in science; I wanted them to understand it as an explanation for the natural world.”
Brandon Ho, a 4th grader at Elizabeth G. Lyons Elementary School in Randolph, Mass., responds to a computer-based teaching program on evolution that was created by the Concord Consortium. The program is among several projects scientists have launched in recent years that are aimed at improving students' understanding of that topic.

In addition to using the computer program, the children study a 25-foot-long timeline of species development, play games about food webs, and experiment with Fast Plants®, which germinate and flower within a month.

Now in the last year of a three-year study sponsored by the NSF, the project’s initial results with 200 students and 10 teachers in Massachusetts; San Juan, Texas; and North Kansas City, Mo., suggest that students who participate in the program show significantly better understanding than those in a control group of evolution concepts, such as the idea that changes in the environment will prompt changes in a population over time...

Thursday, September 02, 2010

Religious leaders should be held accountable when their irrational ideas turn harmful

Faith and Foolishness: When Religious Beliefs Become Dangerous
Religious leaders should be held accountable when their irrational ideas turn harmful
August 2010
Scientific American Magazine
By Lawrence M. Krauss

Every two years the National Science Foundation produces a report, Science and Engineering Indicators, designed to probe the public’s understanding of science concepts. And every two years we relearn the sad fact that U.S. adults are less willing to accept evolution and the big bang as factual than adults in other industrial countries.

Except for this time. Was there suddenly a quantum leap in U.S. science literacy? Sadly, no. Rather the National Science Board, which oversees the foundation, chose to leave the section that discussed these issues out of the 2010 edition, claiming the questions were “flawed indicators of scientific knowledge because responses conflated knowledge and beliefs.” In short, if their religious beliefs require respondents to discard scientific facts, the board doesn’t think it appropriate to expose that truth.

The section does exist, however, and Science magazine obtained it. When presented with the statement “human beings, as we know them today, developed from earlier species of animals,” just 45 percent of respondents indicated “true.” Compare this figure with the affirmative percentages in Japan (78), Europe (70), China (69) and South Korea (64). Only 33 percent of Americans agreed that “the universe began with a big explosion.”

Consider the results of a 2009 Pew Survey: 31 percent of U.S. adults believe “humans and other living things have existed in their present form since the beginning of time.” (So much for dogs, horses or H1N1 flu.) The survey’s most enlightening aspect was its categorization of responses by levels of religious activity, which suggests that the most devout are on average least willing to accept the evidence of reality. White evangelical Protestants have the highest denial rate (55 percent), closely followed by the group across all religions who attend services on average at least once a week (49 percent).

I don’t know which is more dangerous, that religious beliefs force some people to choose between knowledge and myth or that pointing out how religion can purvey ignorance is taboo. To do so risks being branded as intolerant of religion. The kindly Dalai Lama, in a recent New York Times editorial, juxtaposed the statement that “radical atheists issue blanket condemnations of those who hold religious beliefs” with his censure of the extremist intolerance, murderous actions and religious hatred in the Middle East. Aside from the distinction between questioning beliefs and beheading or bombing people, the “radical atheists” in question rarely condemn individuals but rather actions and ideas that deserve to be challenged.

Surprisingly, the strongest reticence to speak out often comes from those who should be most worried about silence. Last May I attended a conference on science and public policy at which a representative of the Vatican’s Pontifical Academy of Sciences gave a keynote address. When I questioned how he reconciled his own reasonable views about science with the sometimes absurd and unjust activities of the Church—from false claims about condoms and AIDS in Africa to pedophilia among the clergy—I was denounced by one speaker after another for my intolerance.

Religious leaders need to be held accountable for their ideas. In my state of Arizona, Sister Margaret McBride, a senior administrator at St. Joseph’s Hospital in Phoenix, recently authorized a legal abortion to save the life of a 27-year-old mother of four who was 11 weeks pregnant and suffering from severe complications of pulmonary hypertension; she made that decision after consultation with the mother’s family, her doctors and the local ethics committee. Yet the bishop of Phoenix, Thomas Olm­sted, immediately excommunicated Sister Margaret, saying, “The mother’s life cannot be preferred over the child’s.” Ordinarily, a man who would callously let a woman die and orphan her children would be called a monster; this should not change just because he is a cleric.

In the race for Alabama governor, an advertisement bankrolled by the state teachers’ union attacked candidate Bradley Byrne because he supposedly supported teaching evolution. Byrne, worried about his political future, felt it necessary to deny the charge.

Keeping religion immune from criticism is both unwarranted and dangerous. Unless we are willing to expose religious irrationality whenever it arises, we will encourage irrational public policy and promote ignorance over education for our children.

Monday, April 12, 2010

Peloza v. Capistrano Unified School District (1994): Is Evolution a Religion?

Peloza v. Capistrano Unified School District (1994)
About.com

Evolution & Creationism: Is Evolution a Religion?
Exploring: Church & State > Court Decisions > Evolution & Creationism

Some of those who object to evolution for religious reasons also argue that evolution itself is a religion or, sometimes, that it is a part of secular humanism which itself is a religion. Therefore, they conclude, teaching evolution in public schools violates the Establishment Clause (because it imposes a religion on students) and the Free Exercise Clause (in particular, of the teachers who are forced to teach it). But are such arguments valid? Is evolution a religion?

Background Information

High school biology teacher John E. Peloza brought action against the Capistrano School District, claiming that the school district's requirement that he teach "evolutionism," as well as a school district order barring him from discussing his religious beliefs with students, were infringements both on his rights to free speech and his rights to free exercise of religion.

According to Peloza, "evolutionism" is a religion and therefore being forced to teach it violated the Establishment Clause of the First Amendment. In Peloza's view, Evolutionism is an historical, philosophical and religious belief system, but not a valid scientific theory. Evolutionism is one of "two world views on the subject of the origins of life and of the universe." The other is "creationism" which also is a "religious belief system."

The belief system of evolutionism is based on the assumption that life and the universe evolved randomly and by chance and with no Creator involved in the process. The world view and belief system of creationism is based on the assumption that a Creator created all life and the entire universe.

Peloza also claimed that the district conspired to destroy and damage his professional reputation, career and position as a public school teacher. He had been reprimanded in writing for proselytizing to students and teaching religion in the classroom - according to him, they did this because they were hostile towards practicing Christians.

A District Court had dismissed the suit and awarded attorney fees to the school district, but Peloza appealed.

Court Decision

The Ninth Circuit Court of Appeals completely rejected all of Peloza's arguments. First, they noted that his claims were not entirely consistent - in some places he claimed that it is unconstitutional for the school district to require him to teach, as a valid scientific theory, that higher life forms evolved from lower ones, but at other times he claimed the district was forcing him to teach evolution as fact.

The Court also noted what just about every creationist seems to miss: the fact that evolution is about how life has developed and has nothing to do with the origins or development of the universe itself...

Wednesday, February 17, 2010

African gene trawl may provide secrets to long life


African gene trawl may provide secrets to long life
Maggie Fox
Feb 17, 2010
WASHINGTON (Reuters)

A genetic peek deep into the heart of Africa confirms that Africans have more genetic diversity than Europeans or Asians and provides insights into how to live a long life despite disease and famine.

Researchers sequenced the complete genomes of five southern Africans over the age of 80 -- Archbishop Desmond Tutu from South Africa and four Bushmen from Namibia.

"On average we found as many genetic differences between two Bushmen than between a European and an Asian," said Dr. Vanessa Hayes of the University of New South Wales in Australia, who worked on the study reported in Thursday's issue of the journal Nature...

Geneticists have long known that, on the level of DNA, there is no such thing as race.

They have also known that Africa, the source of all modern humans, also has more genetic diversity. This is probably because so many different peoples stayed and evolved there, while Europeans, Asians and other groups arose from smaller populations that migrated from the continent.

"To know how genes affect health we need to see the full range of human genetic variation, and Southern Africa is the place to look," said Webb Miller of Pennsylvania State University.

The team looked at some of the oldest Africans, both in terms of age and genetic roots. Tutu is an ethnic Bantu, while the four Bushmen all come from hunter-gatherer societies in the Kalahari desert of Namibia.

"The Bushmen participants have reached their advanced age despite living under harsh conditions due to periodical famine and untreated illness," the researchers wrote.

There were surprises. For instance, Tutu and one Bushman had many more different mutations known as single nucleotide polymorphisms or SNPs (pronounced "snips") than have been seen in sequencing other individuals.

They found differences in the genes that allow adults to digest cow milk, one related to having light-colored skin and SNPs that made all five men susceptible to malaria...

Saturday, February 06, 2010

Ancient Tribe, the Bo, Goes Extinct as Last Member Dies


From what I understand, the Bo belonged to the same group as the people who eventually populated Europe (and lost some skin pigment in the process). Boa Sr has dark skin, but she is among the people on earth most DISTANTLY related to today's black Africans. (The Australian aborigines are the most distantly related to black Africans.) Boa Sr is more closely related to white Europeans. Boa Sr looks like Europeans would look if they had gone south instead of north when they left Africa. Skin color has little to do with our distant origins, clearly, and everything to do with WHERE our ancestors lived in the more recent past. I understand that the human Y-chromosome evolved in southern Africa, probably among individuals with lighter skin. The human mitochondrial DNA, on the other hand, which is passed from mothers to each human being on earth, evolved in equatorial Africa. It would seem that Eve was probably very dark skinned. When southern and northern populations of human ancestors got together, a hybrid that was stronger than either parent group was produced: us. Among the eventual offspring were blacks, whites and Asians. I'm guessing that Asians left Africa with a trait they are famous for today: very little body hair. Quite possibly the extra fold in the eyelids of today's Asians evolved in the far north during the ice age.


Ancient Tribe Goes Extinct as Last Member Dies
David Knowles
Feb. 5, 2010

Marking the end of a language and an entire people, the last member of the Bo, an ancient tribe that lived in the Andaman Islands, has died.

When Boa Sr, as she was known, died last week, she was believed to be about 85 years old. Her husband had died years beforehand, and Boa, whose name means "land" or "earth" in the Bo language, had no children...

"She was the only person who spoke Bo," Anvita Abbi, a professor of linguistics at India's Jawaharlal National University, told The Times of London...

The Bo are believed to have first come to the Andaman Islands – located roughly 850 miles off India's east coast in the Bay of Bengal – 65,000 years ago. Bo was one of at least 10 pre-colonial languages spoken on the islands.

According to Survival International, an advocacy group for native peoples throughout the world, the Bo were one of the oldest surviving human cultures on earth.

Of the thousands of Great Andamanese who once inhabited the islands, only 52 people are still alive today...

Thursday, February 12, 2009

Fossils reveal truth about Darwin's theory

Dimetrodon

Transitional creatures found include the 'fishibian' and the 'frogamander'
MSNBC
By Robin Lloyd
Feb. 12, 2009

With the 200th anniversary of the birth of Charles Darwin this week, people around the world are celebrating his role as the father of evolutionary theory. Events and press releases are geared, in part, to combat false claims made by some who would discredit the theory.

One frequently cited "hole" in the theory: Creationists claim there are no transitional fossils, a.k.a. missing links. Biologists and paleontologists, among others, know this claim is false.

As key evidence for evolution and species' gradual change over time , transitional creatures should resemble intermediate species, having skeletal and other body features in common with two distinct groups of animals, such as reptiles and mammals, or fish and amphibians.

These animals sound wild, but the fossil record — which is far from complete — is full of them nonetheless, as documented by Occidental College geologist Donald Prothero in his book "Evolution: What the Fossils Say and Why It Matters" (Columbia University Press, 2007). Prothero discussed those fossils last month at the American Museum of Natural History in New York, along with transitional fossils that were announced since the book was published, including the "fishibian" and the "frogamander."

At least hundreds, possibly thousands, of transitional fossils have been found so far by researchers. The exact count is unclear because some lineages of organisms are continuously evolving.

Here is a short list of transitional fossils documented by Prothero and that add to the mountain of evidence for Charles Darwin's theory . A lot of us relate most to fossils of life closely related to humans, so the list focuses on mammals and other vertebrates, including dinosaurs.

Mammals, including us

* It is now clear that the evolutionary tree for early and modern humans looks more like a bush than the line represented in cartoons. All the hominid fossils found to date form a complex nexus of specimens, Prothero says, but Sahelanthropus tchadensis, found in 2001 and 2002, threw everyone for a loop because it walked upright 7 million years ago on two feet but is quite chimp-like in its skull size, teeth, brow ridges and face. It could be a common ancestor of humans and chimpanzees, but many paleoanthropologists will remain unsure until more fossils are found. Previously, the earliest ancestor of our Homo genus found in the fossil record dated back 6 million years.

* Most fossil giraffes have short necks and today's have long necks, but anatomist Nikos Solounias of the New York Institute of Technology's New York College of Osteopathic Medicine is preparing a description of a giraffe fossil, Bohlinia, with a neck that is intermediate in length.

* Manatees, also called sea cows, are marine mammals that have flippers and a down-turned snout for grazing in warm shallow waters. In 2001, scientists discovered the fossil of a "walking manatee," Pezosiren portelli, which had feet rather than flippers and walked on land during the Eocene epoch (54.8 million years ago to 33.7 million years ago) in what is now Jamaica. Along with skull features like manatees (such as horizontal tooth replacement, like a conveyor belt), it also had heavy ribs for ballast, showing that it also had an aquatic lifestyle, like hippos.

* Scientists know that mastodons, mammoths and elephants all share a common ancestor, but it gets hard to tell apart some of the earliest members of this group, called proboscideans, going back to fossils from the Oligocene epoch (33.7 million years ago to 23.8 million years ago). The primitive members of this group can be traced back to what Prothero calls "the ultimate transitional fossil," Moeritherium , from the late Eocene of Egypt. It looked more like a small hippo than an elephant and probably lacked a long trunk, but it had short upper and lower tusks, the teeth of a primitive mastodon and ear features found only in other proboscideans.

* The Dimetrodon was a big predatory reptile with a tail and a large sail or fin-back. It is often mistaken for a dinosaur, but it's actually part of our mammalian lineage and more closely related to mammals than reptiles, which is seen in its specialized teeth for stabbing meat and skull features that only mammals and their ancestors had. It probably moved around like a lizard and had a jawbone made of multiple bones, like a reptile...

Monday, February 09, 2009

Diego has no opinion on Darwin's theory of evolution

Diego is 150, living in the Galapagos Islands once again. He must have been born just a few years after Charles Darwin visited the Galapagos Islands.

Voice of San Diego has a great little story about Diego, who used to live at the San Diego Zoo.

Back in the 1950s, kids were allowed to ride the tortoises at the San Diego Zoo. I loved it. Actually, "ride" is probably the wrong word. As I recall, I just got a place to sit. I envied my brother, whose tortoise actually took off across the enclosed area at the Children's Zoo. But then, perhaps "took off" isn't the right word either.

Sunday, February 08, 2009

Lamarck is the skunk at Darwin's (200th) garden party


Lamarck thought that if you worked out faithfully, your children would have bigger muscles. This was wrong, but it turns out that Lamarck was partly right: genes do not entirely account for our hereditary traits. The "new" Lamarckism is gaining ground among scientists.


At tributes to Darwin, Lamarckism—inheritance of acquired traits—will be the skunk at the party.
NEWSWEEK
Sharon Begley
Published Jan 17, 2009
From the magazine issue dated Jan 26, 2009

Alas, poor Darwin. By all rights, 2009 should be his year, as books, museums and scholarly conclaves celebrate his 200th birthday (Feb. 12) and the 150th anniversary of "On the Origin of Species" (Nov. 24), the book that changed forever how man views himself and the creation. Teamed with genetics, Darwin's explanation of how species change through time has become the rock on which biology stands. Which makes the water flea quite the skunk at this party.

Some water fleas sport a spiny helmet that deters predators; others, with identical DNA sequences, have bare heads. What differs between the two is not their genes but their mothers' experiences. If mom had a run-in with predators, her offspring have helmets, an effect one wag called "bite the mother, fight the daughter." If mom lived her life unthreatened, her offspring have no helmets. Same DNA, different traits. Somehow, the experience of the mother, not only her DNA sequences, has been transmitted to her offspring.

That gives strict Darwinians heart palpitations, for it reeks of the discredited theory of Jean-Baptiste Lamarck (1744–1829). The French naturalist argued that the reason giraffes have long necks, for instance, is that their parents stretched their (shorter) necks to reach the treetops. Offspring, Lamarck said, inherit traits their parents acquired. With the success of Darwin's theory of random variation and natural selection, Lamarck was left on the ash heap of history. But new discoveries of what looks like the inheritance of traits acquired by parents—lab animals as well as people—are forcing biologists to reconsider Lamarckism.

The lab mice, of course, came first. Since 1999 scientists in several labs have shown that an experience a mouse mother has while she is pregnant can leave a physical mark on the DNA in her eggs. Just to emphasize, this is not a mutation, the only way new traits are supposedly transmitted to children. Instead, if mother mouse eats a diet rich in vitamin B12, folic acid or genistein (found in soy), her offspring are slim, healthy and brown—even though they carry a gene that makes them fat, at risk of diabetes and cancer, and yellow. It turns out that the vitamins slap a molecular "off" switch on the obesity/diabetes/yellow-fur gene. (Don't try this at home: no one knows which human genes soy, B12 and folic acid might silence.) This was the first evidence, now confirmed multiple times, that an experience of the mother (what she eats) can reach into the DNA in her eggs and alter the genes her pups inherit. "There can be a molecular memory of the parent's experience, in this case diet," says Emma Whitelaw of Queensland Institute of Medical Research, who did the first of these mouse studies. "It fits with Lamarck because it's the inheritance of a trait the parent acquired. There is even some evidence that the diet of a pregnant mouse can affect not only her offspring's coat color, but that of later generations."

Inheriting a DNA-silencing mark that your mom acquired is not as dramatic as giraffes passing on elongated necks to their kids. And the new Lamarckism doesn't mean that human moms who work out will pass along toned abs to their children, or that human dads who dye their hair red will have red-haired children. But preliminary evidence suggests that Lamarckism acts in people, too. In 2005, scientists in London found that the grandsons of men who had abundant food when they were boys (the study was done on men in a small town in northern Sweden) were much more likely to have diabetes and to die an early death than were the grandsons of men who suffered food shortages as boys. A 2006 study by the same scientists found that when fathers smoked as young boys, their sons tended to be more obese than did the sons of men who did not smoke as boys. Similar to the lab mice, the experience of the parents is visited upon the children and even the grandchildren. If the results hold up, says Whitelaw, "it would signal a paradigm shift in the way we think about the inheritance" of traits.

The existence of this parallel means of inheritance, in which something a parent experiences alters the DNA he or she passes on to children, suggests that evolution might happen much faster than the Darwinian model implies. "Darwinian evolution is quite slow," says Whitelaw. But if children can inherit DNA that bears the physical marks of their parents' experiences, they are likely to be much better adapted to the world they're born into, all in a single generation. Water fleas pop out helmets immediately if mom lived in a world of predators; by Darwin's lights, a population of helmeted fleas would take many generations to emerge through random variation and natural selection. The new Lamarckism promises to "reveal how the environment affects the genome to determine the ultimate traits of an individual," says Whitelaw.

Some of these studies will not hold up, as is typical with revolutionary new science. And resistance to what is being dubbed "the renaissance of heresy" is firm; one scientist called a paper on this stuff "a misguided attempt at scientific humor." But evidence for the new Lamarckism is strong enough to say the last word on inheritance and evolution has not been written.


A water flea without a helmut, from bioBlog at University of Waikato, New Zealand.

In some circumstances (water temperature, presence of predators), rather than having that sharp little point on their heads (top of the picture, above the eyespot) some Daphnia will have a longer, spikier 'helmet'. And this is where it gets interesting: it depends on the mother. If a 'helmet-less' female Daphnia is in an environment where there are also predators, her offspring will sport helmets. If not, they won't.

Saturday, February 07, 2009

Christians who are pro-science and pro-Darwin meet in Oxford

Charles Darwin, age 51, just after publishing Origin of Species

Churches hold Darwin conference
7 February 2009
BBC

A group of churches in Oxford is hosting a conference to mark the 200th anniversary of the birth of scientist Charles Darwin.

The event also commemorates the 150th anniversary of the publication of his seminal book the Origin of Species, on the theory of evolution.

Organiser reverend Tim Stead said it wanted to explore the relationship between science and religion.

He said evolution was one of the "most influential scientific ideas ever".

The conference is aimed at "exploring Darwin's contribution to our world view".

Reverend Tim Stead said: "It impacts on our entire understanding of the world.

"One of our aims in holding this conference is to go some way towards redressing the impression that some of the general public have that Christians are anti-science and anti-Darwin."

Mr Stead said many Christians wanted to celebrate Darwin's huge contribution to their world view.

"This is a chance to set the record straight and to explore how it is possible for faith to sit alongside Darwin's views," he said.

"Darwin's theory of evolution by natural selection is one of the most influential scientific ideas ever conceived."

Wednesday, January 07, 2009

Evolution is making some animals weaker


Theodore Roosevelt and another hunter hold the heads of kudus they killed on an African safari in the 1910s

It’s Survival of the Weak and Scrawny
By Lily Huang
NEWSWEEK
Jan 3, 2009

Researchers see 'evolution in reverse' as hunters kill off prized animals with the biggest antlers and pelts.


... The phenomenon has been most apparent in harvested fish: since fishing nets began capturing only fish of sufficient size in the 1980s, the Atlantic cod and salmon, several flounders and the northern pike have all propagated in miniature.

If being smaller is safer, this might be a successful adaptation for a hunted species. After all, " 'fitness' is relative and transitory," says Columbia University biologist Don Melnick, meaning that Darwinian natural selection has nothing to do with what's good or bad, or the way things should be.

Tusks used to make elephants fitter, as a weapon or a tool in foraging—until ivory became a precious commodity and having tusks got you killed. Then tuskless elephants, products of a genetic fluke, became the more consistent breeders and grew from around 2 percent among African elephants to more than 38 percent in one Zambian population, and 98 percent in a South African one. In Asia, where female elephants don't have tusks to begin with, the proportion of tuskless elephants has more than doubled, to more than 90 percent in Sri Lanka. But there's a cost to not having tusks. Tusked elephants, like the old dominant males on Ram Mountain, were "genetically 'better' individuals," says Festa-Bianchet. "When you take them systematically out of the population for several years, you end up leaving essentially a bunch of losers doing the breeding."

Thursday, August 14, 2008

Evolution is happening in your local forest and fishpond

From the New York Times:

"Evolution should be taught — indeed, it should be central to beginning biology classes — for at least three reasons.

"First, it provides a powerful framework for investigating the world we live in. Without evolution, biology is merely a collection of disconnected facts, a set of descriptions. The astonishing variety of nature, from the tree shrew that guzzles vast quantities of alcohol every night to the lichens that grow in the Antarctic wastes, cannot be probed and understood...

The second reason for teaching evolution is that the subject is immediately relevant here and now. The impact we are having on the planet is causing other organisms to evolve — and fast. And I’m not talking just about the obvious examples: widespread resistance to pesticides among insects; the evolution of drug resistance in the agents of disease, from malaria to tuberculosis; the possibility that, say, the virus that causes bird flu will evolve into a form that spreads easily from person to person. The impact we are having is much broader.

For instance, we are causing animals to evolve just by hunting them. The North Atlantic cod fishery has caused the evolution of cod that mature smaller and younger than they did 40 years ago. Fishing for grayling in Norwegian lakes has caused a similar pattern in these fish. Human trophy hunting for bighorn rams has caused the population to evolve into one of smaller-horn rams. (All of which, incidentally, is in line with evolutionary predictions.)

Conversely, hunting animals to extinction may cause evolution in their former prey species. Experiments on guppies have shown that, without predators, these fish evolve more brightly colored scales, mature later, bunch together in shoals less and lose their ability to suddenly swim away from something. Such changes can happen in fewer than five generations. If you then reintroduce some predators, the population typically goes extinct...

The third reason to teach evolution ... concerns the development of an attitude toward evidence. In his book, “The Republican War on Science,” the journalist Chris Mooney argues persuasively that a contempt for scientific evidence — or indeed, evidence of any kind — has permeated the Bush administration’s policies, from climate change to sex education, from drilling for oil to the war in Iraq. A dismissal of evolution is an integral part of this general attitude.

Moreover, since the science classroom is where a contempt for evidence is often first encountered, it is also arguably where it first begins to be cultivated...