Midtopia

Midtopia

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

Friday, January 11, 2008

Blind fish, sighted offspring

From researchers in New York:

Researchers crossed four populations of blind fish from caves in northeast Mexico. Sightless for at least half a million years, the fish evolved from sighted surface fish.

By creating hybrids of the different cave fish populations, researchers found that nearly 40 per cent of some hybrid crosses could see.

The farther apart the caves of the hybrids' parents were, the more likely it was that their offspring could see.

The reason? Sight arises from a combination of genes. Different populations of cave fish had different sets of genes knocked out. One group might have a functioning Gene Set A but a nonfunctioning Gene Set B; another group might have the reverse. Both were blind, but for different reasons.

So when the populations were crossbred, some of the offspring inherited working versions of the full gene set.

From an evolutionary perspective, this illustrates the huge size of the genetic toolbox -- one of the things that makes evolution work, by providing a large number of variables and mechanisms to effect change in an organism. It also highlights one mechanism whereby a major shift -- from sightless to sighted -- could occur in a single generation. It provides a logical basis for rapid evolution in the face of rapid environmental change.

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Monday, December 10, 2007

The problem with Creationists....

.... is that many of them are stunningly ignorant.

Which is why Mike Huckabee's professed support for creationism, however cautiously expressed and however carefully separated from his political policies, is going to keep causing him political trouble. It might not be totally fair, but such a position makes it hard not to wonder about his judgment in other matters.

Meanwhile, click on the link above and enjoy the stupidity.

And if you want more, follow author John Scalzi on his tour of the Creationism Museum. The essay is okay; the pictures are the real ticket.

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Thursday, June 28, 2007

Lucy on tour


This is way cool:

The State Department gave final approval Wednesday for one of the world's most famous fossils — the 3.2 million-year-old Lucy skeleton unearthed in Ethiopia in 1974 — to tour the U.S. on exhibit for the first time.

Okay, the actual experience promises to be quite a bit less impressive than the idea -- a partial skeleton arranged in a box. But to actually get a chance to view real 3-million-year-old bones -- instead of a replica -- has my inner science geek excited. The fact that Lucy is thought to be one of the oldest human ancestors yet discovered is simply icing on the cake.

Lucy's first stop is Houston, where she'll stay until April 2008. Then it's on to other cities, including Washington, New York, Denver and Chicago. We've been meaning to take a family vacation to Chicago anyway, and if that's the closest Lucy comes to Minnesota it provides a good excuse to go.

LUCY RESOURCES
1. A primer on Lucy from Arizona State University. The info is pretty good, even if the Web designer was unable to spell "institute."

2. A fairly extensive review from Washington State University of what is known about her species, Australopithicus afarensis.

3. A Scientific American piece on "Lucy's baby," (a baby A. afarenis), that includes a discussion of some of the questions and controversies surrounding Lucy and her species.

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Friday, June 08, 2007

Monday, May 28, 2007

A small step backward

It's open!

The Creation Museum I wrote about back in August is finally opening its doors.

The Christian creators of the sprawling museum, unveiled on Saturday, hope to draw as many as half a million people each year to their state-of-the-art project, which depicts the Bible's first book, Genesis, as literal truth.

While the $27 million museum near Cincinnati has drawn snickers from media and condemnation from U.S. scientists, those who believe God created the heavens and the Earth in six days about 6,000 years ago say their views are finally being represented.

The funny thing is that their views have always been represented -- they just lose, because not only is there zero evidence to support a 6,000-year-old Earth, but there's mounds of evidence to refute it.

People are free to believe in anything they like. But it's not too smart to believe in easily disprovable things.

I personally think opponents are overreacting:

Scientists, secularists and moderate Christians have pledged to protest the museum's public opening on Monday. An airplane trailing a "Thou Shalt Not Lie" banner buzzed overhead during the museum's opening news conference.

This is like getting worked up about flat-earth theorists. It's just not worth the effort.

Then again:

A Gallup poll last year showed almost half of Americans believe that humans did not evolve but were created by God in their present form within the last 10,000 years.

Three of 10 Republican presidential candidates said in a recent debate that they did not believe in evolution.

We can only hope that the museum loses its shirt, or exists as little more than a kitschy oddity.

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Tuesday, March 06, 2007

The evolution of religion

As a follow-up of sorts to my genetics of altruism post, The New York Times magazine had a fascinating, thought-provoking piece on the evolutionary advantages of belief.

Turns out that some scientists have been studying religion from an evolutionary perspective, trying to figure out why religion is universal when it is seemingly maladaptive to survival: usually, believing in nonexistent things and expending energy on nonproductive pursuits will make it harder to survive, not easier.

First the science, then my two cents.

The science is split into two camps. There's the "byproduct" school, which says religion is not in itself an evolutionary advantage, but is a byproduct of a complex and imaginative brain that is. Then there's the "adaptionist" school, which argues that religious belief is in fact advantageous by promoting trust and cooperation within a group.

The byproduct folks have some fascinating bits of data to work with. Their main ones are three recognized human traits:

Agent detection: The ability to infer the presence of organisms that intend to harm us. If we see motion out of the corner of our eye, our mind tends to assume it is a potential hostile organism and react accordingly. We assume the motion is guided by a mind rather than assuming benign causes like wind blowing leaves around. This makes evolutionary sense: If we're wrong about it being hostile, we're still alive. If we're wrong about it being benign, we're dead or injured. But it predisposes us to see intelligent agents behind every observed phenomenon.

Causal reasoning: The ability to "impose a narrative" on seemingly unrelated events. I tend to describe this as "pattern detection", the ability to see patterns even where none exists. Again, this is evolutionarily advantageous: it helps us solve puzzles and figure out cause and effect even with scant evidence, and is largely harmless when applied incorrectly. But it, too, predisposes us to see order and causation where there is none.

Theory of mind: This is simply the recognition that other people have their own viewpoint and do not know everything we know; it's the ability to imagine yourself in other people's heads. It lets us anticipate the actions of other people based on our knowledge of their knowledge. The survival advantage is obvious. The link to religion is a little more complex. Experiments show that children do not develop "theory of mind" until they are 4 years old or so. Until then, they believe others -- and especially their parents -- are omniscient. In other words, we are born believing in omniscient, invisible minds, which paves the way for a belief in God.

Then come the adaptationists. They argue that while the byproduct school might help explain some of the biochemistry of belief, belief itself is also favored by evolution. Some of my thoughts on altruism closely reflect adaptationist arguments. Religion can make people feel better by worrying less about death, letting them focus on living and the future. By reinforcing desirable behavior, it helps them attract better mates. It makes groups more cohesive, allowing them to outcompete nonreligious groups. It makes individuals more willing to sacrifice themselves, again increasing the survivability of the group. Such advantages outweigh the evolutionary costs of religion, which is measured in the time and resources devoted to ritual.

Adaptationists also note that this doesn't have to be an either-or thing. All species contain a range of various traits: height, strength, speed, disease resistance, etc. Why should belief be any different? In that view, theists and atheists aren't enemies; they represent a socially healthy mix. "What seems to be an adversarial relationship between theists and atheists within a community is really a division of cognitive labor that keeps social groups as a whole on an even keel," to quote the article's paraphrase of David Sloan Wilson.

Me, I don't see the two schools as necessarily being in conflict. Humans are social creatures by design, and the idea that we're wired to view the world in a certain way makes sense. Further, anything that promotes social cooperation is evolutionarily advantageous. Religion is an effective tool to that end, so it's easy to see why it would be so ubiquitous.

I would add that belief is advantageous for a reason not cited in the article: because it gives us a sense of control. Early humans were surrounded by deadly things they didn't understand. That could be debilitating to a mind imaginative enough to envision all the horrible things that could happen. But if we think we know why lightning strikes or earthquakes happen or people die, then we can develop rituals and practices to control or appease them. If we think we know what the stars are, we can use them to store our hopes and dreams. Belief is just one more tool to help us order our surroundings, giving us a framework that lets us live our lives more successfully by explaining away the unexplainable.

Believers may be offended by this whole discussion, as if God can be reduced to a particular brain structure or random chance. But that's not necessarily the case. Knowing the mechanism by which humans experience God does not prove God doesn't actually exist. To quote Justin Barrett, a prominent member of the byproduct school and a practicing Christian:

"Christian theology teaches that people were crafted by God to be in a loving relationship with him and other people. Why wouldn’t God, then, design us in such a way as to find belief in divinity quite natural?”

This is a variation of "evolution is the tool by which God created humans" argument. And it works just as well. We believe because God gave us the ability to believe when He created us.

Anyway, it's a fascinating article, far more interesting than I can do justice to here. Give it a read before it disappears behind the Times Select wall.

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Tuesday, February 20, 2007

The genetics of altruism

Are humans innately good, or innately selfish?

That's a fundamental question when it comes to discussing morality, law and society. If humans are innately selfish, then the only way society functions is by the majority forcing everyone to behave, through tools of social control like government, religion and culture. Without such control, the argument goes, society would disintegrate into a Darwinian anarchy where the strongest reigned through force and cruelty.

In addition, this worldview lends weight to the idea that only an extrahuman authority -- such as God -- can effectively impart a moral code, for if humans are naturally immoral or amoral they simply would not bother to develop one. In such a view, religion is not merely a tool for enforcing whatever society defines as morality; it is an essential source of morality that transcends society.

If humans are generally good, however -- if they are hardwired for altruism, for example, or if our social nature makes us seek approval, and render cooperation and compromise common and successful survival strategies -- then the importance of religion and tradition and government all shrink. They are still useful as founts of distilled wisdom and as a way to enable or compel group behavior. But they are not in and of themselves a necessary component of virtue.

The reality, of course, is as variable as the human experience. Like any other distribution, human behavior follows the bell curve. So even if most humans are innately good, there will be some that misbehave. And if our natural state is despotic anarchy, there would still be a few selfless saps trying to help others. Throw in other considerations, like love of family or economic ties, and the picture becomes more muddied still.

That said, a couple of recent developments shed some interesting light on the subject.

Last year, molecular researchers identified what they called an altruism gene that is present in almost all living things. It's not a gene that makes people give to charity; it's a gene that appears to explain why some cells in a multicellular organism give up their ability to reproduce -- and thus commit genetic suicide -- in order to help the organism as a whole function better. Their conclusion? The function arose for a separate purpose -- letting cells shut off temporarily useless processes to conserve energy -- and was then co-opted by evolution in multicell organisms, in something of a biological bait-and-switch. The resulting combination was so successful that all later organisms retained it.

Another study around the same time found that altering a single gene in a species of bacteria turned resource "cheaters" into cooperative organisms. Further, the genetic change occurred naturally in response to environmental stress. In other words, the stress apparently promoted a genetic change that favored cooperation.

Couple that with demonstrated examples of altruism in the animal kingdom, and it's clear that altruism is compatible with evolution.

If altruism can arise spontaneously on the cellular level and among lower animals, it seems obvious that it can arise naturally at the behavioral level of intelligent species, which have an advantage that bacteria do not: the ability to calculate the costs and benefits of cooperation.

It could start out as loyalty to a family group, wherein a parent, for example, sacrifices itself to save its mate or offspring and thus protect its genetic legacy. As populations grow that definition could be expanded to include clan or tribe, based on a reciprocal economic calculation: I'll come to your defense if you come to mine, increasing our overall chances of survival.

Society would eventually develop ideals and traditions that enforce such altruism, allowing it to apply to larger and larger groups. It would confer approval, admiration and reproductive success on those who are generous or take risks in its defense. As social creatures we are especially susceptible to "doing what is expected" and seeking the approval of our fellows.

And that, in fact, appears to be the case, as a more recent experiment shows.

The experiment hooked up college students to MRIs and had them make decisions about whether or not to give money to various charities. What they found was that deciding to give money produced activity in two different areas of the brain: the part responsible for social attachment, and the same pleasure centers stimulated by food, drugs, money and sex. In other words, acting altruistic made them feel good, as well as involving a bit of social calculation.

Such altruism may be learned rather than innate; the study doesn't attempt to establish a root cause. But it demonstrates that good behavior does not necessarily need ongoing external enforcement. People do not have to be coerced or scared into doing good; they simply need to be attached to a society or family group that prizes such behavior.

This also demonstrates that altruism can in fact be quite selfish. Altruistic acts can lead to very real individual benefits, such as increased reproductive success, enhanced social stature or simply feeling good about oneself.

But such benefits must be weighed against the potential cost. At the extreme, altruism is detrimental: the warrior who is killed in combat never gets a chance to enjoy the fruits of his sacrifice. He may still consider the risk worth it, but how can we explain the person who deliberately sacrifices himself to save others, like the soldier who throws himself on a grenade?

In some cases, even such extreme decisions can be selfish, genetically speaking. A suicide bomber, for instance, knows that his family will probably be taken care of. A soldier's family gets a government pension and the thanks of a grateful nation.

But absent those scenarios, I think such examples demonstrate the power of societal expectations. People raised in a given society often internalize that society's values. The stronger their attachment to the society, the stronger the internalization. Further, people who live when others die often experience "survivor's guilt." Many people talk about how they "couldn't live with themselves" if they behaved in a way society disapproves of. The cost-benefit analysis is different for every individual, of course, but many people would apparently prefer to risk near-certain death than live with the knowledge that they chickened out, or let others die so that they could live.

So it turns out the question I posed at the beginning of this article is a bit misleading, because in many cases being good and being selfish are the same thing. But overall I think the evidence points to morality and altruism being biologically based but socially defined. Religion is a part of society, and thus contributes to defining society's morality just like any other philosophical system. Religion is also a singularly powerful social tool for enforcing that morality -- though like any tool it can also be used for ill. But morality can flourish absent religion, just like religion can flourish absent morality.

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Friday, February 16, 2007

A threefer: Creationist Jew-bashing Republicans

It started in Georgia....

The Anti-Defamation League is calling on state Rep. Ben Bridges to apologize for a memo distributed under his name that says the teaching of evolution should be banned in public schools because it is a religious deception stemming from an ancient Jewish sect.

Bridges (R-Cleveland) denies having anything to do with the memo. But one of his constituents said he wrote the memo with Bridges’ approval before it was recently distributed to lawmakers in several states, including Texas, California, New York, Illinois, Pennsylvania and Ohio.

“Indisputable evidence — long hidden but now available to everyone — demonstrates conclusively that so-called ‘secular evolution science’ is the Big-Bang 15-billion-year alternate ‘creation scenario’ of the Pharisee Religion,” the memo says. “This scenario is derived concept-for-concept from Rabbinic writings in the mystic ‘holy book’ Kabbala dating back at least two millennia.”

The memo calls on lawmakers to introduce legislation that would end the teaching of evolution in public schools because it is “a deception that is causing incalculable harm to every student and every truth-loving citizen.”

It gets better.

It also directs readers to a Web site www.fixedearth.com, which includes model legislation that calls the Kabbala “a mystic, anti-Christ ‘holy book’ of the Pharisee Sect of Judaism.” The Web site also declares “the earth is not rotating … nor is it going around the sun.”

It gets better.

The letter was written to Texas lawmakers, and one of them -- House Appropriations Chairman Warren Chisum -- distributed it to colleagues.

In his apology, Chisum (like Bridges) says he didn't bother to read the memo distributed under his name.

That should play well. "I'm not anti-Semitic; I'm just stupid!"

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Thursday, April 27, 2006

Bird language

A researcher has found that birds understand complex linguistic structures. If the findings hold up, it demolishes yet another ability that supposedly is unique to humans, joining "tool use" and "abstract thinking".

Researchers trained starlings to differentiate between a regular birdsong ''sentence" and one that was embedded with a warbled clause, according to research in today's issue of the journal Nature.

This ''recursive grammar" is what linguists have long believed separated man from beast.

(snip)

While many animals can roar, sing, grunt, or otherwise make noise, linguists have contended for years that the key to distinguishing language skills goes back to our elementary school teachers and basic grammar. Recursive grammar -- inserting an explanatory clause like this one into a sentence -- is something that humans can recognize, but not animals, researchers figured.

This news will probably present some conservatives with a cognitive problem. On the one hand, it directly attacks the notion that humans and animals are somehow separate. On the other hand, it debunks a major linguistic assertion by many conservatives' favorite punching bag, Noam Chomsky. So do they accept the former in order to jump on the latter, or defend the latter in order to attack the former?

As an aside, while in Chicago we visited the Field Museum. They have an outstanding exhibit on the evolution of life, which I urge everyone to go see if you have the chance; it's a hugely informative and multilayered explanation of what scientists know, how we know it, and the conclusions drawn from that knowledge.

But what struck me most was the exhibit on Sue, the almost complete T Rex skeleton that is the centerpiece of the Field's collection. The skull was in such good shape that they were able to do a scan of her braincase and build a picture of her brain structure, showing the sinuses, olfactory bulbs and other regions. Judging from the scan, Sue had an excellent sense of smell.

One of the things you can examine is Sue's wishbone. It's a lot bigger and cruder than the one you pull apart after Thanksgiving dinner. But the exhibit notes that there are only two groups of animals that have wishbones: birds and meat-eating dinosaurs. And that is one of the reasons we think birds are the only living descendants of dinosaurs.

Likewise, humans are clearly descended from earlier animals. I don't see why people think this somehow lessens our humanity, disproves God or makes us less amazing. No other species has accomplished what we have in our short existence. And our having emerged from earlier species is far more wondrous than the idea that we were created as is.

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