MUSINGS ON DISAPPEARING DINOSAURS, AND OTHER STRANGE PHENOMENA

    Dinosaurs seem to be taking over the earth again--not the animal ones, but the kind that are printed on t-shins, lunch boxes, notebooks and stickers. Kids are fascinated by dinosaurs these days, and so are adults. For instance, three news articles in the January 11, 1991 edition of Science Magazine discuss theories of--what happened to make the dinosaur extinct.
     The new theory is that dinosaurs and many other forms of life may have really been snuffed out when an asteroid hit the earth 66 million years ago. The evidence of this impact is a thin layer of rock which is rich in iridium, an element found more in asteroids coming from outer space than in most rocks here on earth. So it seems that when that iridium rich asteroid hit the earth, it made a dust cloud around the earth that blotted out the sun for months and which settled down to make a black layer on the ocean floor and on the bottom of lakes and seas. Ordinary rock was later laid down on top of it. Dinosaur fossils are never found above that iridium layer.

Can you figure out how many dinosaur fossils each one found on the average?

   The volunteers found that the dinosaurs there did not die out gradually, but the number remained evenly distributed throughout the last million years of rock layers below the meteor impact.
    In Italy, David Bice found grains of quartz. These grains were just above the mark of the asteroid. He found that below that mark were many forms of life never found above it. Right above the impact were fossil fern spores, and ferns are one of the first forms of life that come out after a volcanic eruption or other life-destroying disaster. In western North America half the members of the major plant groups disappeared forever at the same marker and were replaced by ferns.
    In Tunisia scientists are analyzing data about extinctions. Jan Smit of Amsterdam finds all the foraminifera (microscopic animals in the sea) became extinct at the time of the impact. Gerta Keller of Princeton finds them dying out as much as 30,000 years before and up to thousands of years after the impact. They are going to Tunisia in May for a field trip to El Kef where these microscopic marine fossils are found--unless the Gulf war is still going on.-JE

    Biosphere II is a huge greenhouse structure constructed in the Sonora desert outside of Tucson, Arizona. The designers of Biosphere II, who call the earth Biosphere I, were charged with taking components of the earth and isolating them in an enclosed system. Researchers plan to use the complex to study the interrelationship of life systems that have maintained the ecology of the earth over the centuries. The Biosphere II project was conceived at the Institute of Ecotechnics, an international ecological development firm based in the United Kingdom.
 
  Biosphere II will contain seven biomes. (A biome is a well-defined ecosystem or piece of earth, air, and water.) The biomes included in Biosphere II are (1) a tropical Savannah, (2) a tropical rainforest, (3) a marsh, (4) a twenty-five foot deep ocean with a coral reef, waves and tides, (S) a coastal desert, (6) an agricultural farm and (7) a human habitat with apartments, laboratories, a library, a gymnasium and an amphitheater. The five wilderness biomes are contained in one 675-foot-long building that is connected to the agricultural area and human habitat by a sealed walkway that keeps the animals in the wilderness. When the Biosphere is sealed, the ecological systems inside will control the water, air and nutrients that keep 3,800 plant and animal species alive.

    Biosphere II was designed by Sarbid, a London architectural firm, and construction of the project has been charged to a California firm, Pearce Structures. Peter Pearce says that he feels the project is more lice building a space shuttle than constructing a building. The biomes are enclosed by an airtight space frame structure, and no exchange of air with the outside is allowed. A normal building exchanges air completely with the outside at least three times a day. Biosphere II will make this only once in its expected 100 year lifetime.

    Eight humans or biospherians will live in Biosphere II for cycles of two years. They will not be allowed to leave during that time except in an emergency. Their only contact with the outside world will be through television, telephone and computer.

    I wish I were teaching right now, because my students would have a field day with the Biosphere II concept. I think that I'd begin with "sketch problems" where teams of children would be charged with designing the Biosphere project. I would give them the criteria, listing the biomes and then have them draw a plan for the relationships of the biomes. I would use large 5' x 4' butcher paper for their presentations and then let them present their designs to the class.

    I imagine the next activity I'd undertake would be to have the children begin writing about being a Biospherian chosen for the project. I'd have the students imagine they were about to be sealed into the Biosphere II and keep a log of what was going on.

    In class, we would group ourselves into different areas of the room--five groups for the five wilderness biomes. and each group would be responsible for bringing in things that would make their area of the room look like their chosen biome.

    In order to design their assigned biomes, research groups would have to use the resources of the library for information, and I would ask them to chart their data to share with the class. Photos of the blame would be displayed. Then I'd let them use tri-wall cardboard, boxes, fabric and paint to create their biome.

    Mark wanted to know what the moon is made of--Jack answered, moon rocks, moon sand, and moon dust, which are a little bit different from earth rocks, sand and dust--not a whole lot different from a volcano on earth.
Sarah wanted to know what lightning was made of, and Raymond asked about the composition of the Sun. Sarah and Raymond sent Jack and me on quite a quest.

    We submitted Jack Easley's description of the composition of lightning and the sun to our guest scientist, Jack Paxton. Jack Easley wrote that both the sun and lightning are made of plasma. Jack Paxton disagreed. (For those of us who don't even know what the two Jack's are talking about, I offer Jack Easley's definition).
Plasma is not a solid, a liquid, or a gas, because those kinds of matter are made of whole atoms or molecules. Plasma is often called "hot gases" or just "gas," but it is rather different from air or the gas in gas stoves. The littlest pieces of a gas are atoms or molecules, but the littlest pieces of a plasma are only parts of atoms.

    Jack Easley says that plasma is what lights up when someone turns on a fluorescent light, a neon sign, a mercury vapor (bluish) street light, or a sodium vapor (yellow) street light.

    In a regular light bulb, what is lighted is a very hot wire. More heat than light comes out of these hot wire bulbs. A plasma light gives out more light than heat. For the same amount of electricity you get a lot more light from a plasma than from a hot wire.
 

Fluorescent, plasma tube

    For example, a fluorescent tube in the ceiling of your school room may use 40 watts of electricity but it makes much more light than a regular 40 watt bulb.  The fluorescent tube stays pretty cool when it is turned on, but the regular 40 watt light bulb gets too hot to touch when it is turned on, and it is not nearly so bright. That is because most of the 40 watts of electricity are being turned into heat and only a little is turned into light. Fluorescent lights are more expensive to buy than regular, hot wire bulbs, but they last a lot longer and use a lot less electricity.

    So, if you use a plasma light every day for several years you save a lot of money, and the power plant saves some of the oil that is burned to make C02 and electricity. Besides, if you heat up your house with regular electric light bulbs in the summer, you may want to use even more electricity for electric fans or air conditioners to cool it off again.

    Plasmas can get very hot like they do in the Sun and in lightning, but those things are using enormous amounts of energy. The energy of the lightning is made by the wind blowing raindrops way up high in a storm cloud. That's the same friction process, but much much faster, that makes people get charged up when they slide across the carpet and make a tiny plasma spark by touching a door knob. The energy of the sun comes from hydrogen atoms fusing together to make helium atoms. That makes an enormous amount of energy, because the Sun is so big and the atoms are changed so much in the Sun.

    Now Jack Paxton, our guest scientist did not agree with the theory that lightning is made of plasma. Jack Paxton defines plasma as a gas composed of electrically charged molecules. He sees plasma as a much more powerful charge than that involved in fluorescent lighting or the sparks created in static electricity. Jack Paxton would prefer that we stick to saying that lightning is a huge electrical discharge between clouds or clouds and the earth.

    Jack Easley decided that this whole issue of lightning needed further investigation, so he called Bob Rauber, assistant professor of Meteorology and Atmospheric Sciences at the University of Illinois. Bob said that while it's true that a lightning strolce is a gas heated to 50,000 degrees and is therefore a plasma, the important thing about lightning is that it is created by electrons flowing from cloud to cloud or cloud to earth. He also said that sometimes there are balls of plasma generated by a lightning stroke that float around in the air awhile after the stroke.

    So, Bob agrees with Jack Paxton, but then Bob also agreed with Jack Easley that the sparks created when you rub your feet on the carpet and then touch a metal surface are exactly the same thing as lightning, only much smaller.
We conclude that probably these two scientists agree that the important thing about lightning is how it is produced, rather than what material that brief flash is made of. So, to Sarah and Raymond, our kindergartners who ignited this great discussion we say that two scientists agree that lightening is a huge electrical discharge between clouds or clouds and the earth, and one agrees with J.E. that it is made of plasma for a split second.
-MO

Q1. HOW DO ANIMALS HIBERNATE?

 Students in Rebecca Bisselle's class at Taft School in Kankakee, Illinois wanted to know! Which animals are true hibernators? Jack Easley writes:

A1.    I am going to describe some of the different ways animals spend the winter that are sometimes called hibernation. Then I will give some different definitions of hibernation that are used in English.

    Bears usually have a den, a kind of cave to sleep in during the winter. The mother bear usually has baby bears in the den and nurses them until spring time, when they come out to eat berries or catch fish. Although bears in the den sleep a lot and use up most of their body fat, they stay pretty warm inside their fur coats--about 88 degrees Fahrenheit or warmer. One definition of "hibernate" is living on body fat during the winter at a lower temperature and sleeping a lot.

    Arctic ground squirrels live up north where it is often 20 to 40 degrees below zero for a month or more at a time. They spend at least six months burrowed in the ground, curled up in a ball. Unlike bears, their bodies get ice cold, 30-34 degrees. That's warmer than the below zero weather outdoors, but it's really not warm enough to melt ice. They breathe only once every few minutes, and their hearts beat so weakly it is very hard to feel. They do wake up briefly every few weeks and warm up just long enough to eat some of their stored food. Then they curl up again into a ball like before.

    When the weather outside gets above freezing in the spring, most of the hibernating ground squirrels gradually warm up, but some never awake. Perhaps the cold was too much for them, or they didn't have enough stored food to last all winter: Waking up is a remarkable recovery because, in the six months of hibernation, the ground squirrels lose nearly half of their body weight and their bones and teeth get very weak. But in just one day, their bones and teeth are back to normal, and in a few weeks of eating fresh food, they make up the weight they have lost. The females have babies in the spring, and the babies grow big enough in time to hibernate when it gets really cold again. So another definition of "hibernate" is almost stopping body functions in the winter with the body temperature near freezing.

    The poorwill is a bird who gets into a tight place, perhaps under a rock, and spends the winter there. Like the ground squirrel, it's body temperature goes down near freezing, and it loses a lot of weight, so it fits the same definition.

    Some frogs, turtles, and fish burrow into the mud to spend the winter. The ponds and mud may freeze, but when spring melts everything, most of these animals come out of the mud and start moving around, raising a family, and finding food. Some scientists consider this to be hibernation, but others say it is not. The new definition they disagree about is that "hibernation" is changing from being "warm blooded" to being "cold-blooded" which means that their body is the same temperature as the environment they are in. Since "cold blooded" animals are usually not warm unless they are sitting in the sun, or it is a hot day in the puddle, they don't have to stop their normal habit of being just as hot or cold as the outside when they spend the winter. Bears don't stop staying warm in the winter. So some scientists would say that the poorwill and the ground squirrel are the only "true" hibernators we have written about.

    The Encyclopedia Britannica, 1989, has two different articles by different scientists which give two different lists of "true" hibernators. One list includes many fish, amphibians, reptiles, one bird, and a few mammals like bats, hedgehogs, ground squirrels, marmots, and bears. The other article does not list fish, amphibians, reptiles, or bears as "true" hibernators, but does include hedgehogs, bats, hamsters, the dormouse, and the arctic ground squirrel. If you look up the word "hibernate" in a dictionary, you may find a definition that is different from the ones 1 gave.
Most dictionaries give more than one definition of most words. Look up the word "car" and see if it surprises you. Some of you might want to say that just one of the definitions is a "true" car, but other people could well disagree with you. Scientists use evidence to back up their theories, but they have to choose definitions just like the rest of us. [Jack Paxton adds that science is the process of discovering. ] -J.E.

    Dioxin is found in some weed killers and in malting many other chemicals. The chemical has become quite controversial because of its potential health hazard, and because it was found in Agent Orange used to kill the rainforest plants in the Vietnam War. Three articles in the February 8th issue of Scorner summarize recent opinion on the use of dioxin:

    "For two decades now a debate has been raging about whether dioxin causes cancer in humane.. one form of dioxin, TCDD, [is]... the most powerful [cancer producer! ever tested. earning it a reputation u ...the Danh Vader of chemicals." However. not every scientist, farmer, industrialist. or military officer, believed it. ~Now, a new study by federal scientists presents what many consider the strongest evidence yet that dioxin is indeed a human [cancer producer]--but ... only at high doses."

    [Jack Paxton adds: High is in the mind of the beholder. Daily background exposure is now estimated by scientists to be about 1 pictogram. [This is 10-12 grams, one trillionth of a gram.] The newly established limits of 10-1° or 100 pictograms per kilogram per day doesn't leave much margin for additional exposure! In fact this is equivalent to less than 1/3 of a drop for the whole U.S. population each day!]

    "In the exhaustive study, which tools nearly 13 years to complete, Marilyn Ftugerhut and her colleagues at the National Institute for Occupational Safety and Health (NIOSH) [studied] all the US chemical workers exposed to dioxin on the job from 1942 to 1984; a total of S,172 men at 12 chemical plants." They measured the TCDD in the blood of these men and found out whether or not they got cancer and died from it. For men who were exposed to dioxin less than a year, there was no increased risk of cancer. For those who received S00 times more dioxin in their blood than the people outside the factories, the risk of dying of cancer was 50% more than in the people outside.
In St. Louis, the Monsanto Chemical Plant is being sued for exposing workers to dioxin in an accident with a tank car of dioxin, and the Environmental Protection Agency of the Federal Government is investigating.

    Optimist, KEPT scientist Linda Birnbaum, director of the environmental toxicology division. says the [Marilyn] Fingerhut study gives a new way to figure out who is at risk," and Michael Gallo and Robert Scheuplein, at a recent meeting on dioxin, said the Fingerhut study shows dioxin is "safer than we thought." Everyone at the meeting agreed that no cancer has been found unless a chemical receptor is activated.

    The graph on the next page shows that when there is one part of dioxin in a billion parts of blood, one third of the receptors are activated. Linda Bimbaum concluded, "The Icey point is that there is a dose of dioxin [one part in a trillion] below which the receptor does not function, and if it is not activated, there can be no effect." But George Lucier and Ellen Silbergeld are two scientists who think the optimists are all "dead wrong."

How would you determine if a compound is safe for your friends and family to use? After you have arrived at an answer, see Risk Assessment by Jack Paxton.

    Biological magnification
    The common process whereby organisms accumulate compounds from the environment and thereby concentrate them to much higher levels than found in the environment at large.

    A good example of this is the accumulation of radioactive strontium in milk by dairy cows grazing on contaminated pasture, and the ultimate deposition of this radioactive strontium [which chemically resembles calcium] in the growing tips of young children's bones, where it can do severe damage.

    DDT in lake water and its concentration up the food chain is another of several examples where very low levels in the environment do not necessarily have benign consequences.

Establishing the maximum Permissible level of a material to which people should be exposed.
    In all natural populations there is a rather wide range of sensitivity in individuals to a given compound. Are we willing to establish what the most sensitive person can tolerate? If not, how many of the most sensitive individuals are we willing to 'sacrifice' in order that the rest of the population can 'enjoy the benefits' of a given compound or organism?

    How do we establish this maximum permissible exposure? Since at the present time we do not tolerate lining up people and dosing them with materials or organisms to establish what the maximum 'safe' dose is, we use animals as representatives of humans.

    How close is the fit between a mouse's tolerance to aflatoxin and that of a human? How long should that dose be applied? Since we can't wait the average person's lifetime for an answer, how long is long enough to determine the effects of chronic [long term] as opposed to acute [brief] exposure?

    How do we establish what is an 'acceptable' effect on an organism? Biopsies after feeding trials may or may not detect subtle but important effects and certainly would not, for example establish psychotic effects.
As an example, should we establish whether materials that go into the manufacture of window shades are toxic to humans? Before you answer this, consider that breathing a compound is the quickest and most sure route to the blood stream. [I thought about this when I woke up after a night's rest in a room reeking of something being 'cooked' out of window shades by the sun. ] --Jack Paxton

ANSWERS:
Each volunteer found 125 fossils, on the average.

A clock with hands not pointing to 12 o'clock or to 6 o'clock is not symmetrical.

 Director lack Easley
 Editor Michele Olsen