Rafael
Madrid, Spain

Two ironing women, by Edgar Degas. Musée d'Orsay

Well, it depends. What kind of “tired” are you talking about? If you’ve been exercising, the answer’s pretty clear, says James Krueger, a sleep researcher here at WSU. The tiredness is in your muscles. What’s not so clear, though, is how that tiredness relates to sleep.

This is an excellent example of the trouble that being scientific gets you into. If you don’t worry about the details, no big deal. You work hard. You get tired. You go to sleep. You wake up ready to go again.

But of course, the body isn’t quite that simple. Like everything else, the body is full of causes and effects. Connecting those causes and effects is the hard part. If you exercise heavily, says Professor Krueger, the number of white blood cells in your blood goes way up. White blood cells are the front line of your immune system. Also, your body produces all sorts of cytokines. These proteins regulate your immune system.

What’s interesting is that some of these cytokines are also involved in regulating sleep. And they’re also what give you that achy feeling when you’ve exercised a lot. Interestingly, even if you don’t exercise, but don’t get any sleep, your muscles will ache.

Now, if our science were perfect, at this point we’d put the pieces together and say AHA, this is what “tired” is all about. But all we can actually say is that some chemical signal is generated in your muscles, that signal is sent to your brain, and your brain interprets it as “tired.”

Speaking of your brain, that’s another story. Even though you feel tired when you don’t get enough sleep, your brain itself doesn’t really feel “tired.” In fact, according to some recent experiments, it seems that when you’re asleep, your brain is actually going over things from when you were awake. Some birds, for example, seem to rehearse their songs while they’re asleep!

So if your brain isn’t tired, why does it have to sleep? And how much of the brain goes to sleep when you’re asleep?

It doesn’t seem like single cells go to sleep, says Professor Krueger. On the other hand, we know that the whole brain doesn’t need to go to sleep for you to be “asleep.” Some animals, for example, go to sleep half a brain at a time. Some researchers recently found that when a flock of ducks goes to sleep, the ducks on the outer edge will sleep with one eye open and half their brain awake while the other eye and brain-half are asleep! Whales and dolphins also sleep a half-brain at a time. That’s how they keep from drowning while they sleep.

But back to “tired.” What IS that tired, groggy feeling you feel when you haven’t had enough sleep? “We really don’t know,” says Professor Krueger. You lose the ability to focus and concentrate. You don’t think clearly. You get uncoordinated. But what exactly does it mean? That’s part of what sleep researchers are trying to figure out. That – and why exactly we need to sleep.

Most of that tired feeling you get in your muscles can be cured by just resting. So why do we need to be unconscious for eight hours every night?

Professor Krueger believes that sleep helps the brain save its “synaptic superstructure.” What this means is that your genes gave your brain a certain pattern of synapses, or connections between neurons. During the day, your brain is constantly rearranging itself and reforming patterns and talking to itself in different ways. What sleep does, thinks Professor Kmeger, is shift these synaptic patterns back to their original design!

Matthew
Hubbell, Michigan

Young chimpanzees from Jane Goodall sanctuary of Tchimpounga (Congo Brazzaville). by Delphine Bruyere, Wikimedia

Well, I might as well admit right up front – we don’t know. But that doesn’t mean there aren’t some great arguments about who invented language. I got an earful about all this from Nancy McKee, who is a linguist and anthropologist here at WSU. That means she studies language and people.

It’s hard to say who invented language, says Professor McKee, because words don’t leave fossils. The only absolute evidence of language is writing. But think about this: As recently as the last century, the majority of the world’s population did not write. Of course that doesn’t mean they didn’t have language.

The oldest example of writing that we’ve found is a kind of writing called cuneiform, which was used by the Sumerians, people who lived in western Asia. The oldest examples of cuneiform are about 5,000 years old. Of course, language is much older than that.

But how do you figure out who invented language if there isn’t any written record?

First, says Professor McKee, you can look at the STRUCTURE of the brain. In other words, you can look at the brains of human ancestors to figure out whether they talked or not. The only problem with this is that brains don’t leave fossils either. All that lasts are the skulls, which are often broken, so you have to piece them together. Even so, scientists can tell quite a lot not only about how big the brain of the ancestor was, but how it was organized.

Another way to study when language came about is to study humans’ closest relatives, chimpanzees and the other great apes. First of all, they can’t talk, says Professor McKee. They COMMUNICATE. Slime molds communicate, she says. But slime molds don’t TALK.

When chimpanzees see food, they go UH! HUH! EEEE! HUH! HUH! Or something like that. Of course that lets the other chimps know about the food. But the chimp doesn’t necessarily WANT the others to know. In other words, they don’t MEAN to say UH! HUH! and so on. What controls these sounds is a really old area of the brain called the “limbic area.” You know when you step on a tack and yell? That sound comes from the limbic area. It isn’t something that you SAY or mean to say.

In other words, says Professor McKee, much of what chimps say is involuntary. As Noam Chomsky, another linguist, has said, saying a chimpanzee can talk is like saying a man who jumps off the Empire State Building can fly!

Now, Professor McKee’s opinion isn’t quite so extreme. She thinks that chimps really are pretty smart. It’s just that they’re really dumb compared to humans. For example, they do not talk about the nature of evil. However, when they learn sign language and tell the human studying them that they want some food, they mean they want some food. It’s not just a “conditioned response.”

So what does this have to do with the invention of language? Chimpanzee brains are about one-third the size of modem human brains. If chimps can “say” through sign language simple things like “I want dinner,” then human ancestors with much larger brains probably could do just as well and probably better.

So what ancestors are we talking about here? Professor McKee thinks it was these folks called “Homo erectus,” who had brains twice as large as chimps and who seem to have evolved about 2 million years ago from an earlier earlier ancestor called Australopithecus. (Just sound it out and say it loudly.)

The scientists who think about language are basically divided into two camps. Some think that language just happened all at once. SOMETHING very remarkable happened somewhere along the line. Maybe it was some kind of evolutionary adaptation. For whatever reason, these scientists believe there’s a BIG BREAK between humans and other animals that communicate.

Professor McKee belongs to the second camp. She believes that language is just the endpoint of a gradual evolutionary process-beginning with slime mold-that simply became more and more elaborate.

But still, when did it become “language”?

Somewhere between 2 million and 200,000 years ago, she says. Well, that certainly narrows it down!

Still, she doesn’t think that Homo erectus perfected language. It might have taken until about 40,000 years ago before there was anything like modern language.

Please, we need your help!!! We want to know what makes people ticklish? Why do we laugh when we are tickled? And why are we sometimes ticklish and sometimes not?

Michelle, Sarah, Jacob, Micah, Jeremy, Austin and Taylor
Phoenix, Arizona

Laughter from tickling. David Shankbone, Wikimedia

“Tickle” might just be a side effect of some other effect way back in our evolutionary history, says Patrick Carter, who studies the evolution of physiology here at WSU. That means he studies how and why we came to look and operate the way we do.

Professor Carter admits that thinking about tickle can be a lot of fun, and a lot of scientists and philosophers have even thought pretty seriously about it. Socrates, Plato, Francis Bacon; Galileo, and Charles Darwin all thought and wrote about tickle. Because none of them figured it out, though, we’re still working on it.

First, let’s think about types of tickles. I’m sure you’ve thought about how a little tickle, say with a feather under the chin, is different from a serious tickle, like when your buddies tickle torture you.

Scientists call the light tickle KNISMESIS and the heavy tickle GARGALESIS.

Great words, huh? Hey, how about a little gargalesis?

So anyway, where did tickle come from? Depending on who you talk to, the knismesis variety is pretty clear. It probably has to do with the feeling when a tick or other insect is crawling on your body. It tickles, and you brush it away or squash it.

That’s probably too neat an explanation, but what can I say?

Gargalesis is definitely more complicated. WHY would we start laughing hysterically when somebody digs her fingertips into our sides? It seems pretty ridiculous.

Charles Darwin thought that the tickler’s and the ticklee’s relationship had something to do with whether gargalesis was pleasurable or not. Even though a child might enjoy being tickled by a parent, being tickled by a stranger would be frightening.

To test this, psychologist Christine Harris at the University of California, San Diego, built a tickle machine. She figured that if Darwin was right, people would at LEAST need to think they were being tickled by a person, not a machine.

What she found out, however, was that it didn’t make any difference what the subjects thought they were being tickled by.

Another thing that Professor Harris has found is that tickling and humor are not related. She had a bunch of students watch a funny video and then tickled them. Others watched a not-so-funny video and then got tickled. This relied on the “warm-up effect” – if you think something’s funny, the next funny thing that happens is even funnier, and so on.

The result of the experiment? No effect. Tickling does not create a pleasurable feeling, says Professor Harris, just the outward appearance.

So where does that leave us? What IS gargalesis?

Maybe it’s just a reflex, like your leg jerking up when you tap yourself on the knee. But if so, why can’t you tickle yourself? Well, why can’t you say BOO! in the mirror and scare youself?

Actually, some scientists at the Institute ofNeurology in London decided to figure this one out. They used an MRI machine to look at a person’s brain when the person was subjected to knismesis. MRI stands for magnetic resonance imaging. It uses a very powerful magnet to look inside the body. Problem is, you have to lie very still for it to work, so studying gargalesis was out.

However, what they found was when someone else was doing the tickling, there was a lot of activity in the somatosensory cortex, the part of the brain that handles touch.

When the person tickled herself, the cerebellum lit up. So what? Well, the cerebellum handles planning. What the scientists reasoned from this is that the cerebellum knew that its person was going to tickle herself, so it WARNED the somatosensory cortex!

Okay, that’s pretty cool – but still, WHY?

Well, maybe tickling helps establish a good feeling between parent and baby – mom tickles baby, baby laughs, mother smiles and tickles some more …

Or MAYBE, says Professor Harris, gargalesis has to do with developing fighting skills. HUH? Well, your buddy tries to tickle you, and you fight her off and tickle her back and you wrestle, like kittens fighting.

You know that tickling ISN’T all that pleasant, even though you laugh. Maybe the laugh is a signal that you’re not mad. Jaak Panksepp, a scientist at Bowling Green State University, has found that rats give off a real high-pitched chirp when they’re tickled. He thinks this is like rat laughter and helps distinguish play from threat.

ON THE OTHER HAND, says Professor Carter, maybe none of this is correct.

Not everything is an obvious result of something that happened in evolution. Maybe tickle is just a side effect of something we haven’t a clue about.

In other words, we may never know for sure why we tickle. Sorry.

Soldiers from the Division cross the Rhine River in assault boats, 1945. Wikipedia

I’ve got good news and bad news. First the bad news. Humans, especially men, are violent by nature. It makes them feel important. And the good news? Humans are a lot less violent than they used to be!

I tracked down John Patton, who is an anthropologist here at Washington State University. He studies the influence of human evolution on politics, violence and warfare.

Needless to say, you can’t very well study a subject like this in a laboratory. So Professor Patton went to live with the Achuar people in the Ecuadorian Amazon. The Achuar are related to the Shuar, who live in the same valley.

Have you ever seen a shrunken head in a museum? They were shrunk by the Shuar. In the recent past, when Shuar boys were ready to become men, in a “rite of passage” they took hallucinogens, traveled to a sacred waterfall and met an animal spirit. After this, they went off to find the head of an enemy to shrink.

Unfortunately for the Achuar, most of these heads belonged to them.

Even without the headshrinking, the Shuar and Achuar are pretty violent. Traditionally, an Achuar male had a 50 percent chance of being killed by another.

As you probably have figured, these are pretty intense people!

They also make very interesting subjects for Professor Patton to study.

From what anthropologists can tell, the homicide rate for men living in tribal societies is generally about 30 percent. This was before they were affected by outside influences. So the Achuar’s homicide rate is higher than most. So much the better for studying WHY they are so violent.

Let’s think about a few basic ideas about evolution and violence. What seems to make all living things tick is the desire to reproduce and pass on their genes. Whether you’re a flower or a salamander or a human, you are driven by your wish to pass along your genetic traits to the next generation. You think you’ve got something special, and you’d like that to continue after you die.

So—our goal is to pass along our genes. Simple enough. But if that’s the case, why would a soldier go to war and be willing to die for his country? It’s pretty hard to pass along your genes if you’re dead.

And there you have it—one of the main contradictions of human evolution and behavior. How does this make sense?

Professor Patton believes that young men will risk getting killed in order to gain status, to be important in the society and to have more kids to give his genes to! He bases this idea both on his research and on earlier studies.

For example, his adviser, Napoleon Chagnon, found that among the Yanomamo of Venezuela, certain men who are very accomplished killers have on average two and a half times more wives and more than three times as many children as do their more pacifist brothers.

In other societies, we can also see that high status leads to more wives (and mistresses) and more children. In other words, according to Professor Patton’s hypothesis, being a great warrior (being willing to kill and risk your own life) gains you high status, which in our evolutionary past brought males more wives and kids, which fits right in with evolution!

So according to this thinking, humans kill each other for status. You’ve got to realize I’ve really simplified things here. Regardless, that’s not a very cheery thought, is it?

But think about this. As violent as we think our society is, tribal societies (which we came from a long time ago) have homicide rates about 50 times higher than ours. This comparison doesn’t distinguish between homicide and warfare. After all, says Professor Patton, war is just killing okayed by your country. So this rate includes all our wars and atomic bombings and so on. Even including these things, still it seems like maybe we’ve made some progress.

Even though humans can still be pretty awful toward each other, MAYBE—with the help of government and culture—they are getting a little better at keeping from killing each other. I think that’s pretty good news!

Now keep in mind that not every scientist agrees with Professor Patton. There are other ideas for why people are the way they are. But these arguments, backed up by serious research, are what science is all about.

Dozy autumn bee. By John Spooner/Flickr

That crud is their food, Elliott. That’s what I learned from Steve Sheppard. He studies bees here at WSU.

In fact, these hairs (which are branched, kind of like feathers) are one of the main characteristics of bees. They use the hairs to gather plant pollen. As they crawl in and out of flowers to gather the sweet nectar that flowers produce, the flower pollen gets caught on the hairs. The bees use their legs to comb the pollen down and pack it in little pollen baskets on their legs so they can carry more.

Bees are vegetarians. Of course, they make that nectar they gather from flowers into honey, which is their food supply for the winter. But even vegetarians need protein, and that’s what the pollen provides. They use the protein they get from eating pollen to produce “brood food” in special glands in their heads. You can think of flowers as a bee supermarket—a place where they can get all their groceries!

And this brings us to another question I got, from someone who didn’t include her name: “…I would like to know why bees are important to apples.”

Great question, says Professor Sheppard. Bees love apple blossoms. And that’s lucky for the apple trees—and lucky for us. This pollen that bees collect is the “sperm” of plant reproduction. Some plants can reproduce without outside help. (We’ll get to this in the next column.) But apples produce best if they get pollen from other apple trees.

Well, someone needs to move the pollen from a blossom on one tree to a blossom on another tree so the blossom can turn into an apple. That someone, more often than not, is the honey bee!

A single full-grown apple tree can have as many as 100,000 blossoms on it. Only a fraction of those will actually develop into apples. But still, it’s fortunate for the apple tree that they have the busy little bee.

One bee will visit 10 to 15 blossoms a minute and up to 5,000 a day! In order to produce one pound of honey, says Professor Sheppard, bees have to fly about 75,000 miles, about three times around the Earth!

But here’s the key point of all this. When the bee crawls in and out of the blossom, pollen from that blossom collects on the bee’s hairs—and one bee can carry around as many as 100,000 grains of pollen. And some of the pollen already on the bee from other blossoms gets rubbed off, so the blossom gets pollinated. The bee collects nectar and pollen, the blossom gets pollinated, we get apples and honey, and everybody wins!

And it’s not just apples. Professor Sheppard says that as far as what bees do, the pollination is actually more important to us than the honey–if you can imagine. About 15 percent of what we eat—both fruits and vegetables—depends completely on insect, mostly bee, pollination. Also, a lot of things we eat depend PARTLY on bee pollination. For example, the alfalfa that cows and other animals eat is pollinated by bees.

As important as honey bees are, they are not native to North America. They were actually brought here by European settlers. Even “wild” honey bees are bees that decided to go out on their own.

So before honey bees got here, who pollinated everything? Professor Sheppard says that before the settlers and their bees got here, all sorts of pollinating insects were doing the job, including thousands of species of “solitary bees,” bees that do not gather in hives.

But at least a couple of things have changed. Much of our farming today is in “monoculture,” huge fields in one crop. This does not provide a very good place for all these other pollinators to live. Also, even if they did hang around, huge areas of one tree or crop are just too much for these insects to handle by themselves. So be kind to those honey bees!

One more thing. Professor Sheppard is very interested in how honey bees evolved and where they came from originally. In a couple of weeks, he is going to Kazakstan. He believes there might be an undiscovered species of bee that lives there that would help answer some of these questions. I’ll keep you posted.

Tup Wanders/Flickr

Phylogenetic inertia, that’s why.

Though I guess that’s not really WHY. So another way of answering your question is “because their ancestors had eight legs.” That’s about all I could squeeze out of Pat Carter, who studies evolutionary physiology here at Washington State University. That means he studies how animals came to work the ways they do.

Spiders belong to a large group of animals called the Chelicerata (kuh-LIH-suh-RAH-da), says Professor Carter. They are named for the snappers on their heads, their jaws, their chelicera. Some chelicera snap up and down, and some snap sideways.

The other thing that animals in the Chelicerata group have in common is four pairs of legs.

Though that doesn’t explain WHY they have four pairs of legs, does it?

Well, let’s think about horseshoe crabs, which also belong to the Chelicerata group and are actually more closely related to spiders than crabs. They also have four pairs of legs. But they also have other leg-like appendages on their abdomens. (Appendages are things that stick out from the body.) Horseshoe crabs, which haven’t changed much for hundreds of millions of years, and spiders probably developed from the same ancient relatives.

But spiders lost those extra appendages. Spiders DO, however, have a pair of appendages surrounding their chelicera. These PEDIPALPS help the spider grab food and shove it in her mouth. PEDI means foot, by the way. Get my drift?

Clearly, says Professor Carter, the Arachnids (spiders, scorpions, mites and ticks, all of which are Chelicerates) are pretty successful. They’ve been around for millions of years and show no sign of disappearing. But the same could be said for insects. In other words, six legs seem to work pretty well for insects, and eight legs seem to work pretty for spiders and their relatives.

No, I’m NOT dodging your question, though it must seem like it. It’s just, says Professor Carter, that maybe there really isn’t any REASON that spiders have eight legs. They just do. And maybe different appendages that different relatives developed came to be used differently. Just as a reminder, this process took place over millions and millions of years.

SO—for some random genetic reason, some ancient relative of the spider developed eight legs. Or maybe he developed ten legs, two of which eventually developed in a later relative into pedipalps.

People tend to think about evolution in terms of adaptation, says Professor Carter. Adaptations are features that organisms develop through genetic mutations that happen to help them adapt to their environment.

It’s NOT that these adaptations develop in ORDER to help these guys survive. Rather, these chance mutations help them survive better than similar organisms that didn’t develop the adaptations. This is part of what is called NATURAL SELECTION. Those best adapted for survival survive. Got it?

But lots of traits are NOT adaptive, says Professor Carter. They just happen. Neither are they NON-adaptive, which means the trait would make the organism LESS able to survive and reproduce.

The reason we don’t know more about spider evolution in general is that fossils of spiders are relatively rare. The first spider probably appeared around 400 million years ago. But finding a fossil that old is rare.

Scientists HAVE found many less ancient spider fossils, many of them preserved in amber, which is hardened tree sap. More than 300 species of spiders have been described from about 40 million years ago.

However, these so closely resemble modern spiders that they really don’t tell us much about spider evolution.

But back to your question. We don’t know WHY spiders have eight legs, says Professor Carter. They just do. There is no WHY. That’s part of what “phylogenetic inertia” is all about. And a big part of how evolution works.

Peter Cruickshank/Flickr

Thank you, Charleen, for asking one of THE big questions that everyone wonders about. Of course, in spite of everyone’s wondering, this is another one of those questions whose answer no one is absolutely sure about.

I called ornithologist Richard Johnson here at WSU. He didn’t know the answer, but he dug out an article from 1965 in which a scientist from California named Frank Heppner reported the results of his worm-finding experiments with robins. After a series of experiments, Professor Heppner decided that robins find earthworms by sight.

That makes sense. Have you noticed how robins cock their heads from side to side? Their eyes are on the sides of their heads, so they have to turn their heads to see straight ahead.

However, says Professor Johnson, their EARS are also on the sides of their heads. You can’t see them, but they’re there, covered up by feathers.

So for 30 years, scientists tended to believe that robins find their food by sight.

Then we found an article that came out just last year, in a magazine called “Animal Behaviour.” Two Canadian scientists, Robert Montgomerie and Patrick Weatherhead, came up with a different conclusion.

They’d watched robins catch worms in fairly long grass, and it seemed to them that maybe they used another sense to find them. So they decided to do their own experiments.

For each experiment, they buried a bunch of mealworms in a tray of soil and let the robins go at it—but under different conditions. First, they buried two live mealworms and two that were frozen to death. The robins found the live ones, but not the dead ones. Since all the worms seemed to smell the same, the scientists concluded the robins probably don’t use their sense of smell to find them.

Another possibility was that robins sense worm vibrations in the soil. So the scientists rigged up the tray so the robins could not feel the vibrations through their feet. The robins had no problem finding worms. So vibrations are at least NOT NECESSARY for finding worms.

Next, the scientists buried the mealworms not quite an inch deep, laid a sheet of thin cardboard over the tray and put more soil on top of it. This would eliminate any visual cues, such as particles of soil moving around above the mealworm.

The result? No problem. They pecked right through the cardboard!

So where does this leave us? Besides taste, the only sense left is hearing. Do they HEAR the worms?

Professors Montgomerie and Weatherhead buried a little speaker in the soil with the worms and played “white noise” through it to block out any possible worm noise. White noise sounds like static on your radio.

Although the results were not completely clear-cut, the noise did cut down on the robins’ success rate. In fact, they didn’t even strike the ground as many times as they did in the other experiments.

So it seems that they DO hear the worms. Professors Montgomerie and Weatherhead figure the robins could hear some worms even through the white noise. Robins must have pretty sharp hearing!

By the way, what do worms moving in soil sound like? The scientists say that, when amplified, they sound like a person walking on gravel.

In the beginning was the quark.

Actually, it was NEAR the beginning, and it was actually a very hot quark-electron soup, says Phil Deutchman, a theoretical physicist at the University of Idaho. He says that, according to current theory, the quarks in this early Universal soup condensed to form the nuclei of hydrogen, helium and lithium around 100 seconds after the Big Bang.

You realize that with a history like this we can’t cover everything about quarks in a newspaper column. But you’ll get a pretty neat glimpse. So, just to get us started,

Three quarks for Muster Mark!

Sure he hasn’t got much of a bark

And sure any he has it’s all beside the mark.

That’s a passage from James Joyce’s 1939 novel Finnegan’s Wake. It so happens that Murray Gell-Mann, the physicist who proposed the idea of the quark in 1964, is also one of the few people who actually RE-read Finnegan’s Wake. Though it is about language and dreams and mankind, I suspect that if you understand Finnegan’s Wake, you might also have a real knack for particle physics!

Regardless, says Professor Deutchman, you have to understand quarks historically. Even though they couldn’t see them, Greek philosophers, such as Democritus 2,400 years ago, figured everything was probably made of atoms—and that’s as small as things got. In fact, “atom” is from the Greek word for “indivisible.” However, it took over 2,200 years for someone to prove that these atoms existed.

Once that happened, though, other scientists joined in to completely screw up the idea of atoms being “fundamental,” or indivisible. In 1911, Ernest Rutherford and two of his students managed to reveal the existence of the atomic nucleus. So for a while it was just the nucleus and electrons. Then someone figured out the nucleus was made up of protons and neutrons, so THESE became “fundamental.” But, of course, that wasn’t the end of it.

Accelators are machines that hurl atoms and parts of atoms at each other at such high speeds that they break up. As the accelerators got stronger, scientists discovered more kinds of particles. Pretty soon it got out of control. There were suddenly so many fundamental particles (pions, kaons, lambdas, about 200 of them) that some people wondered, well what’s so FUNDAMENTAL about that?

So some of these people, including Gell-Mann, started suspecting there must be something MORE fundamental than fundamental particles. Maybe, just maybe, there was something smaller inside those neutrons and protons. Maybe there was a pattern.

The problem with trying to figure this out, says Professor Deutchman, is that there was no periodic chart for these particles, no family tree with which to relate them. And the abstract quantum numbers used to describe things at the subatomic level don’t exactly connect to your everyday experience.

In spite of this serious weirdness, however, Gell-Mann finally saw a pattern. He proposed that at least 200 of these particles could be reduced to fundamental(!) particles called quarks.

Well, okay, it wasn’t QUITE that simple. The quarks come in different varieties, or flavors, and combine in different ways. The first three quarks were named “up,” “down” and “strange.” This is not the world as you previously knew it.

Then the “charm” quark was discovered. Then the “bottom” quark, bringing the total to five. However, calculations showed there had to be a sixth quark. According to “The Standard Model,” everything in nature is made up of different combinations of six types of quarks and six of “leptons,” which include electrons and neutrinos.

Sure enough, scientists at the Fermilab, a huge accelerator in Illinois, found the “top” quark in 1995.

So is that it? Have we explained things? Is the quark truly fundamental?

No, says Professor Deutchman. It’s the first step inside. And it looks like maybe quarks have a structure, which means there’s something smaller!

One possibility for the smaller things inside the quark is “strings,” the core of Superstring Theory, yet another take on HOW THINGS WORK.

Superstring Theory holds that everything is made up of tiny (about one millionth of a billionth of a billionth of a billionth of a centimeter!) one-dimensional strings, and that particles as we know them are determined by how the strings vibrate. You may be glad to know that one thing Superstring Theory does away with is the idea of the infinitely divisible particle. The string is as small as it gets. Sound familiar?

Actually, it’s not, but that’s another story.

Alexis Bellido/Flickr

That’s right. At night, they breathe in oxygen and breathe out carbon dioxide, a process called respiration. Basically, at night they act like animals, says Gerry Edwards, a botanist here at Washington State University.

But wait a minute! Don’t plants provide us with oxygen and take in carbon dioxide?

Yes, of course. That’s photosynthesis.

So what’s going on here? Well, let’s think this through. Photosynthesis, as you probably know, is the process by which plants absorb light energy from the Sun through their leaves to make food from carbon dioxide that they absorb from the atmosphere.

Act like animals at night? Well, not quite, says Professor Edwards. Of course, plants don’t have the lungs that enable animals to breathe in oxygen and then transport it throughout their bodies via hemoglobin in their blood. Plants just suck it in as best they can.

Actually, oxygen diffuses into the plant tissue through membranes and air spaces around their cells. Plants also exchange, or “inhale” and “exhale,” carbon dioxide, oxygen and water through STOMATA, openings on the “skin” of their leaves that they can close to prevent water loss.

Lungs or not, the process of respiration is basically the same in plants and animals. Sugars break down through a process called GLYCOLYSIS and carbon enters the very tiny mitochondria within the cells, which help convert food to energy.

But photosynthesis MAKES the food in the first place. And how do plants get food to parts other than their leaves? They transport sugar through their veins to parts of the plant that do not photosynthesize, such as roots and seeds, which need energy to grow. Also, if you think about it long enough, you realize that this transfer of energy itself requires energy.

And back to your question, the whole plant also needs energy at night so it can keep on growing. Without sunlight, it has no energy source—except what it has stored during the day in the form of carbohydrates, which can be converted to sugar.

Respiration also does a lot more than just provide energy. Respiration involves at least 50 different steps. Each step in the break-up of sugars results in different compounds. Some of these compounds lead to other compounds used by the plant. Fats, oils and hormones are produced indirectly by respiration. So are compounds such as caffeine and nicotine. And rubber. And amino acids, which are needed for proteins, and nucleotides, which are building blocks for making DNA and RNA.

In spite of the surprising fact that plants produce carbon dioxide by respiration—and in spite of us animals pumping it out constantly—the proportion of carbon dioxide in the atmosphere is actually very small. Seventy-eight percent of the air is nitrogen. Twenty-one percent is oxygen. Carbon dioxide makes up only a fraction of the atmosphere, about .035 percent!

However, even a slight change in that proportion not only can lead to global climate change, but it can affect photosynthesis. More carbon dioxide doesn’t necessarily mean more photosynthesis. Some plants will sense the increase in carbon dioxide and figure they’ve had enough and, through a process called “negative feedback,” slow down their photosynthesis.

Professor Edwards is very interested in how the increase of carbon dioxide in the atmosphere will affect plant growth. Many scientists are worried that some plants may not be able to adjust on their own to the different makeup of the warmer atmosphere caused by increased carbon dioxide and other “greenhouse gases,” at least quickly enough to keep us in food.

So Professor Edwards and others are particularly interested in helping plants, through genetic modifications, adjust. The breakfast cereal you eat 50 years from now could very well be the result of work they are doing right now. But that’s another story. So stay tuned.

Sorghum, a C4 plant that's very good at photosynthesis under adverse conditions. Robert Hubner (Read more about C4 plants in in Washington State Magazine)

How do plants get their food? Out of thin air, says Ernest Uribe, a plant physiologist here at Washington State University. A plant physiologist studies how plants work.

All living things, you realize, need energy. Animals get their energy and the materials they need to grow their bodies through the food they eat, which generally includes plants. Since plants have no mouths or digestive systems, how do they get their energy and nutrition?

Plants make themselves out of carbon dioxide from the air and water and a few minerals from the soil. They do this with the aid of sunlight, in a process called PHOTOSYNTHESIS, which means “putting together with light.”

This process was not always obvious to people. In fact, up until about 350 years ago, everybody basically agreed with Aristotle’s idea that plants just sucked their food up out of the soil as a pure “nutrient fluid.”

That’s really not a bad guess. After all, most plants do grow out of the ground. But think about it. Think about the trees in your yard. Every year the leaves fall, and you and your parents rake them up and haul them away. If that tree got its food from the soil, eventually it would suck itself a big hole, right?

This was what Jan Baptista van Helmont finally realized in the 17th century. In one of the first recorded experiments, he weighed a young willow tree, then grew it in a pot for five years. When he weighed it again, he found that it had gained 165 pounds. However, the soil in the pot had lost only a few ounces.

Van Helmont decided that it must be water that led to the tree’s weight gain and growth. Although he was wrong about the water, he was right about the tree’s food not coming from the soil—and he managed to completely change the way we think about plant nutrition.

What other scientists after van Helmont discovered is that plants use the energy of the sun to capture carbon dioxide from the air. Plants use carbon dioxide as a building block to make sugars and other carbohydrates.

How do they do this? Well, here’s where things start getting complicated, says Professor Uribe. And pretty neat.

Pigments in the leaves of plants absorb sunlight. The most important pigment is chlorophyll. Sunlight, as you might know, is actually different “wavelengths” of different colors of light. Chlorophyll absorbs blue and red light. The wavelengths of light that not absorbed are reflected—as green.

The energy absorbed from the sunlight dislodges electrons from the pigment molecules. The electrons then organize within the leaf cells into tiny electric currents. THIS is the energy that powers a series of very complicated chemical reactions. The first thing that happens is the plant splits water molecules into hydrogen and oxygen. Then it transfers hydrogen and electrons to carbon dioxide molecules.

This results in two things that are very important to us. First is the release of oxygen into the atmosphere. Second, sugar (glucose) forms from the combination of carbon dioxide, hydrogen and electrons. Here’s how chemists describe this sugar: C6H12O6. In other words, the glucose molecule is made up of 6 atoms of carbon, 12 atoms of hydrogen and 6 atoms of oxygen.

The glucose that the plant does not use immediately for food is used to make other kinds of storage carbohydrates and CELLULOSE fibers for plant structure.

However, even plants can’t live on air alone. Even though they do not suck nutrient fluid out of the soil, they do need some nutrients contained in soil. The main one is nitrogen. Nitrogen is necessary for making protein and nucleic acids. Nucleic acids are the main ingredient of DNA, the material that holds genetic information in every cell.

Plants also need phosphorus, potassium, sulfur, calcium, iron and magnesium, and a list of “micronutrients”: molybdenum, copper, zinc, manganese, boron, chlorine and nickel. And probably others in amounts too small for use to detect.

But mainly, plants get their food from the air, which is a lot more than the nothing it seems!