Modern Biology: An Introduction


Biologists at Work is a program designed to help you make sense of an exciting, but sometimes confusing field of study known as modern biology. This program has two parts. Part One will give you a brief tour of the history of biology. Part Two will introduce you to some working biologists of the 21st century.

Part 1: A Brief History of Biology

Biology is the study of life, of living things. In a sense all living things are themselves biologists. The bee studies how best to find the nectar. The lion studies how to find a prey. The lowliest fern studies how to spread its leaflets to find the sun.

Plants and animals, of course, do not study the way we do, but they do behave in ways that enhance their own survival. Humans, too, from time immemorial have found ways to find and kiIl the deer, ways to make the corn grow, ways to cure human sickness and ways to increase human fertity.

In ancient times humans used a mixture of magic, myth, common sense and luck to find ways to survive and prosper in aworld they shared with so many other living creatures. This is the same living world we that today call the biosphere.

And today we rely still on these same methods of pluck and luck, but we have also added a more reliable aid, the knowledge that working biologists provide. Let's take a short look at how that last method, biological science, has come to be and has grown to such overwhelming importance today.

One of the first steps toward a modern science of biology was taken here on the island of Kos in the eastern Mediterranean about 2300 years ago. A Greek physician named Hippocrates set up a kind of combination resort-hospital health spa here. It was dedicated to finding cures for human diseases.

True, there had been physicians before and healing before. The unique thing about Hippocrates and his center was the scientific approach it took. Instead of relying on magical or religious theories, Hippocrates stated boldly, "Diseases have natural causes and therefore have natural cures." Thus, while medical men and women in nearby and far off places were trying to appease the gods or drive out the demons by nailing human heads onto poles or sprinkling bat dung over doorsteps, Hippocrates was calmly prescribing rest, exercise, herbs and healthy habits as more effective remedies.

Like a true scientist, as Hippocrates looked for natural causes and cures he did so by considering "What can be learned from sight, touch, hearing, smell and taste." And as all working biologists know only too well today, he cautioned that "It is valuable to know what attempts have failed, and why they have failed."

Hippocrates had the right approach, but further progress in biology and medicine had to wait until the more basic sciences of physics and chemistry could provide tools for biology to work with. This would not happen for another thousand years.

Most attempts at scientific understanding of living things were concentrated in those early days on the human being. A Roman physician, Galen, wrote one of the first scientific treatises describing the anatomy and the physiology of the human body. Unfortunately it was based mainly on dissection of pigs and apes, and though extremely influential, it was also extremely inaccurate.

Progress was made in agriculture in China, in India, South America and North Africa. New crops like rice, corn, citrus fruits, cotton, potatoes, sugar cane, plums and apricots were domesticated and selectively bred from wild beginnings. New ways of making cheese, beer and wine. Selective breeding of goats, sheep and cattle. Irrigation was developed and improved, especially in China and in all of the great Islamic Empire that ruled for over six hundred years from Spain in the west to India in the East.

Muslim doctors in Baghdad, across North Africa, and in Cordoba Spain worked in over 30 fully functioning hospitals founded and run on some of the same scientific principles Hippocrates first promoted.. Diseases like smallpox, measles, bladder stones and kidney stones were diagnosed and described in scientific detail. New medical techniques using surgery and anaesthesia were developed. Cures for most of these diseases were still hard to come by but a Muslim physician echoed Hippocrates when he pointed out that “eating sparingly, walking often and briskly, putting your cares away when going to sleep, will make our doctors poor and idle.”

While Europe was struggling through the Dark Ages and Medieval times, Muslim scholars and scientists were also advancing our knowledge of the details of the natural world. Hundreds of new plants and animals were discovered and described in encyclopedias. To Muslim scientists the earth was not something to be overcome, but a garden to be observed and to be loved.

Real progress in biology in the western world began during the Renaissance here at the University of Padua in Italy. This was the same time and the same place that Galileo was laying the foundations for modern physics and astronomy. Here in this dissecting theater a man named Vesalius was demonstrating how wrong the authority Galen was.

Together with an artist, Jan Stephen van Calcar, Vesalius made some of the first visual aids in biology, beautiful drawings that accurately showed the bones, muscles and organs of the human body. Earlier artlsts did not try to be precise or accurate in their rendition of particular parts. Their work was intended, instead, to symbolize the prevailing astrological, magical, herbal or scientific theory of the author Vesalius wanted to get the facts straight. The theory could come later.

Another milestone in human biology came about the same time in England where another physician, William Harvey, worked through a careful set of experiments to show conclusively that contrary to what was always believed before, the blood circulated around the body in one continuous loop.

Around the time the new world of America was first being visited by and then settled by European immigrants, a janitor in this town hall of Delft, Holland, was discovering another new world. His was a revolutionary new world of living things so small no one in the world .had ever before seen them or even dreamed they existed. Anton van Leeuwenhoek worked secretively long through the day and night perfecting his .microscopes. Then he worked equally long to discover and describe the 'little beasties" that he found swimming through the drops of rain water when he looked through his lens.

Leeuwenhoek and other early microscopists also saw and described another level of all living things--cells. This invention and perfection of the microscope in the 17th and 18th centuries (along with the invention of new methods of dyeing and staining cells) probably helped more . than any other single thing to bring biology into existence as a genuine science. For now biologists could see and experiment not just with the whole organism, but with the building blocks of all living creatures, cells and tissues.

Biologists could learn about bacteria, about parasites and about the many complicated and critically important relationships between the invisible- to-the-naked eye microscopic world and the more obvious-to-the-naked- eye macroscopic world of living things.

In the 19th century great pioneer doctors, biologists and chemists like Edward Jenner, Louis Pasteur, Robert Koch and Ignaz Semmelweis were able to connect these two worlds in exciting new revolutionary ways. By so connecting the microscopic world to the macroscopic world they were able to make genuine progress in curing many of the terrible scourges that had afflicted humankind for centuries. Within a few decades terrible diseases like smallpox, malaria, typhoid fever, cholera, tuberculosis and bubonic plague--diseases that had .periodically wiped out a third to a half the people in many countries of Asia, Africa, Europe and America--were conquered. As the crusty cynic H. L. Mencken once wrote, "It was the . noblest chapter in the history of mankind."

So far we have talked mainly of progress in understanding the human living system. Early investigators of the living world were also interested in other living things. In fact, a great deal of practical knowledge about plants and animals was found and passed on from generation to generation by early farmers, hunters, fishermen and food gatherers.

While Leeuwenhoek and his fellow explorers were finding new living worlds under the microscope, other explorers were rapidly expanding humankind's knowledge of the immense variety of plants and animals that shared this planet with us. Until the great ages of exploration in the 15th, 16th and 17th centuries people had no idea how incredibly large that variety was.

Aristotle, the first scientist to attempt a scientific classification, found room for about six hundred species of animals. As late as 1600 only six . thousand species of plants were known. By contrast, today over two million species of living things have been described.

For biology, one of the most important of these early explorers was a poor Swedish boy named Carl Linnaeus. Linnaeus hated school but he loved plants. As a young university student he left on a field trip to Lapland to collect plant and animal specimens. The 4600 mile trip cost him only one hundred dollars and the knowledge gained on the trip paid off handsomely for himself and for mankind.

A few years later Linnaeus published his first book, Systema Naturae. It was so popular he .became a great celebrity. In this book he proposed a classification system for plants and animals that is still in use today.

All living things, he suggested, should be grouped into species, genus, family, order, class, and kingdom. Later he invented the binomial nomenclature system as well. Each kind of living thing would be assigned a double name in internationally accepted Latin. Genus first, species second. For the first time, system and order were being brought into the study of the living world.

As more and more plants and animals and microscopic creatures were discovered, the question .was: why? Why are there so many different kinds of living thlngs? And how are they all related to one another? With the discovery of more and more fossils in the 18th and 19th centuries, new questions were added. Why did so many creatures that used to live on earth no longer live here? What relation is there between these animals and plants that left their bones and imprints with present day animals and plants?

The biologist generally credited with providing the most satisfactory answers to these questions lived here in Down, England in the mid 19th century. His name was Charles Darwin. As a young man Darwin was not considered very promising. His father once said to him, "You are interested in nothing but shooting, dogs and rat-catching, and you will be a disgrace to yourself and your family."

When he got the opportunity to travel on a ship of exploration around the world, Darwin snapped it up. His trip aboard HMS Beagle lasted five long years. Over and over again he would land in remote spots in South America and the Pacific Islands and find new marvels. As he himself wrote of his first experience with the plants and animals of South America, "It was like giving a blind man eyes."

When he returned to England he married, raised a family and worked here at his study in Down. Every noon he strolled down this path overlooking the quiet English countryside. Perhaps it was on these walks that he pieced together his theory of evolution by natural selection that is in broad outline still accepted today as one of the bedrocks of modern biology.

At the same time Darwin was creating a theory of evolution by natural selection to explain the immense diversity of life on this planet, another man in central Europe was discovering some basic laws of heredity. That is, a way to explain the incredible stability and sameness of life on this planet. How it was that life always passed on life just like itself, with so few mistakes.

Gregor Mendel was a Catholic monk who lived in a monastery in Brunn, Czechoslovakia, about the time of the Civil War in our country. Mendel was a busy man. Besides smoking twenty cigars a day, he kept fifty hives of bees, many cages of mice, was regional weather correspondent for the Austrian empire, was elected abbot of his monastery and carefully raised . and studied thousands of garden pea plants. It was for this last task that the world is in his debt.

By working with his garden peas, Mendel discovered some laws of heredity, laws that told just how traits were passed on from parent to offspring. These laws of heredity in pea plants turned out to be equally valid for corn plants and trees, for ants and elephants, for bacteria and for human beings.

His work showed that inheritance was carried not by body cells but some kind of special amazingly reliable something that was hidden in the sexual cells of organisms, the .egg and sperm cells. These special somethings were later found and given the name of genes.

In our own twentieth century the most important biological breakthrough was also about genes, and it happened about fifty years ago in the 1950s. While strolling along the Cam River, having long luncheons here at the Eagle Pub and longer sessions at their small office here at Cambridge University in England, two young working biologists are given credit for this giant step forward in biology.

It was here that James Watson from Chicago, USA and Francis Crick from Cambridge, England together solved the mystery of how the central molecule of life, DNA, deoxyribonucleic acid, is constructed.

DNA, you see, is the actual physical molecule that carries the codes of life itself. DNA is the physical molecule in the nucleus of all cells that governs the way cells behave. And since all living things are made of cells, the way geraniums and goats, pea plants and people behave.

DNA is the actual physical molecule that Mendel worked with but could never see. DNA is the molecule that determines whether you have blue eyes or brown, whether you are a man or a woman, whether you are short or tall, athletic or sedentary, vivacious or shy.

Since that discovery of DNA structure, biologists all over the world have developed more and more sophisticated techniques to work with life at this basic molecular level-moving genes from one organism to another, custom building new forms of life to improve agriculture, cure . disease, stop pollution and enhance life.

Which brings us to biology today. One way to picture working biology today is as a complex tapestry woven of different colored threads.

One thread-the oldest-is the study of whole living organisms, especially the human one.

Another thread is the study of the microscopic world of living things pioneered by the Dutch lensmaker, Anton von Leeuwenhoek. .

A third is the broader field of relationships between living creatures and their environment pioneered by the English gentleman, Charles Darwin, and in a broad sense today called ecology.

Thread four is the study of life on the molecular level, pioneered by men like Gregor Mendel, Francis Crick and James Watson. This was the last to be developed, but is today leading world-wide revolutions in biotechnology to the delight of many and the worry of some. .

But in fact, all four of these threads are vibrant with progress today. So much so that when a recent poll of college professors asked which department on campus generates the most exciting overall development, the top choice was biology, the science you are studylng today.

Part 2: Working Biologists Today

Richard Burgess: ... Director of Biotechnology Institute

"This is probably the most exciting time in the history of the world to be a biologist. The tools . that we have available allow us to do things in weeks that we couldn't have even thought of doing five years ago.."

Brenda Faison: Microbiologist

"You start tinkering with it. What is tinkering? You add a little bit of this, take away a little of that. See what happens."

Howard Odum: Ecologist

"An ecosystem forms a kind of hierarchy with a lot of peons at the bottom and a few plutocrats at the top. So there is an organization to maximize production and recycle the natural materials and do all the things our society is only now learning to do."

Thomas Lovejoy .. Rainforest Researcher

"There are two or three reasons to be concerned with what's happening with the tropical rain forests. First and foremost is that somewhere between 50 and 90 percent of plant and animal life occurs in those forests.

Anna Marie Nuitilla .... Botanist and Genetic Engineer

“What we do is take a small seed here ... And dissect the embryo .. Right here and we transfer the gene that we want into the little embryo with the help of a gene gun.

Neal First ... Pioneer in Cloning

“Now what cloning does is provide the opportunity to multiply these cells, engineer the cells in transplantation ....”

Regina Murphy: .... Alzheimer’s Disease Research

"Alzheimer's disease is diagnosed by the presence of deposits in the brain called amyloid plaques.... So one of the things we're looking for is how these plaques form. And why.."

Lloyd Smith .... Human Genome Project

“...basically the sequence of all the genes encodes the structure of all the proteins, sort of the minimal fundamental building blocks.”

Timothy Mulcahy ... Stem Cell Research

“Stem cells are such that their biology allows them to continue to grow as far as we can tell indefinitely.”

Robin Alta .... Ethical Concerns

“The very people who were most adamantly opposed to cloning, are beginning to separate their opinions into an opposition to reproductive cloning and a tolerance of research cloning.”

Biology today is a mansion with many rooms. Let’s briefly visit a few of these rooms to get some idea of what it is like to be a working biologist in the 21st century.

We'll start with Richard Burgess, a specialist in genetics and presently the Director of the Biotechnology Center at the University of Wisconsin in Madison. I asked him to explain just what is biotechnology.

Richard Burgess.

"It's using the knowledge that's been gained by basic research In biology for practical purposes. Of course, that means it's not new. People have been domesticating animals, domesticating plants, breeding plants for improved food .production for thousands of years. They've been making wine and cheese and beer by fermenting and using microorganisms to convert in food processing for thousands of years.

“So applied biology is not new. What's new is the power that's been developed through research breakthroughs in the last ten, twenty years."

What is it about biotechnology that makes it so powerful today?

“One is genetic engineering, the ability to cut-and-splice DNA. One of them is cell biology and .the ability do tissue culture, to grow cells from an organism in a tissue culture. Finally, I think the development of computers and analytical instrumentation has allowed us to analyze protein and DNA much more sensitively and accurately than we couId ever have done in the past."

Your lab, I understand, is working on a number of environmental projects using biotechnology tools. Can you give us an example?

"How do you make paper? Paper is typically made by taking wood which is made simplistically of cellulose which is what you want for paper and lignin, which is the glue that holds it .together. The typical way to make paper pulp is to dissolve the lignin in chemicals. This requires a great number of harsh chemicals and leads to a loss of fifty percent of the mass of the wood which is the lignin. And this becomes a waste in itself.... Alternatively you can do mechanical pulping, breaking apart the fibers, but this requires .a lot of energy and produces weak paper. What researchers here have done is to demonstrate that we can treat wood chips with a .biological treatment. In this case treating them with fungus. Fungi grow on dead trees. These . fungi will degrade lignin. With the right kind of fungi and the right kind of conditions we .found we could tenderize the chips and now you can do mechanical pulping with very large savings of energy-fifty percent-and produce longer fibers leading to better, stronger paper and avoiding the use of chemicals in the process."

Many specialists in biotechnology like Dr Burgess are also leaders today in environmental studies and solutions. The branch of biology that is closest to environmental studies and solutions is ecology.

Shortly before they both died last year I talked to Eugene and Howard Odum, the two brothers many consider the founders of modern ecology, Eugene Odum was then a professor emeritus at the University of Georgia. I asked him about the differences between ecology and other branches of biology.

"It's a top-down approach. The average science approach is reductionism. Looking at the smallest thing and thinking the answers are there. But we know reductionism won't always help .us with real world problems like pollution. We can study organism cancer with that kind of work, but not environmental cancer.... It's an integrative science, not reductionist, and there's an important difference."

I understand some of your first studies were done with your brother, Howard Odum. Could you give us an example of how you personally worked at this integrative level and what implications it might have for solving some of our real world problems today.

"We went out to Eniwietok in the Pacific, and none of us knew anything about coral reefs so we were about to study it as a whole without looking at all the fishes and things separately. We .looked at the metabolism of the reef. We picked a reef where the water flows only one way-that's between the islands. That way you can measure what's in the water when it comes .into the reef and when it gets back, and you can do night and day studies to see what was used. ... We made a new theory that the reef was a system that evolved to be prosperous with limited resources. The water around the reef out there is so poor, but because of the intimate relationship between producers and consumers, plants and animals, and the recycling and retention mechanisms out there, they were able to do with very little input.

“We all know we live in a world of limited resources, and simply because of growing population there is going to be less per capita around. The coral reef teaches us-the first chapter in my new little book is called How to Prosper in a World of Limited Resources- and uses the coral reef, the tropical rain forest as examples of systems that have cooperation and not competition. That's another theory, that when systems get tight and things are used up and things get complicated, cooperation pays."

I asked Eugene's brother, Howard Odum, a professor at the University of Florida for a more recent example of the use of ecological studies for human benefit.

Howard Odum

"Our wetlands center started in 1973 and we had national workshops. I think we were responsible for setting off the whole furor worldwide of consciously using the wetlands as nature's kidneys.... We've learned more and more how it binds heavy metals and even toxins and immobilizes all sorts of organic poisons. If you give the waters we have coming off our streets and treat them somewhat coming out of the sewers and put them back in the wetlands, then you have a use and an economic excuse to keep the wetlands and save your greenbelts. You save nature. You take care of our cost of taxes that normally would go to into very expensive treatments. .... Now they're out of wetlands because people drained them, so they're putting them back. That's another thing our center is learning, how to put a ecosystem back after it's gone. If you adjust the water right and .seed it, the secret is to put back a lot of species and let nature give you the right combination... We call this business letting nature design for us, ecological engineering."

Some biologists today devote their time and energy to studying and saving ecosystems before they are destroyed by human actions. And to saving endangered species before they become extinct. One of the most important of these ancient ecosystems are the tropical rain forests of the world.

I talked to one of the biologists who is a leader in the fight to save the rainforests, Thomas Lovejoy of the Smithsonian Institute. I asked him to give us an example of how his field studies in the tropical rain forest could help in the effort to save species and to keep ecosystems healthy.

"I'm looking at isolated remnants of forests of different sizes. What they, in the end, can support in terms of biological diversity. There is an inverse relationship. The smaller the plot, the more species are lost. What that says is that you need very large areas to protect biological diversity. When a forest is fragmented, you end up with isolated pieces of forest. What happens as a consequence is that they lose species. They become impoverished over time. By studying the rates of impoverishment in different sizes of forest remnants and studying the pattern by which species are lost, we in the end will be able to say what the ideal minimum size for national park should be. The answer is that it's got to be quite large, in the order of hundreds or thousands of hectares."

What about human designed and maintained ecosystems today. Agricultural ones that is. Again biologists are leaders in improving our ability to grow food efficiently and safely and to protect our crops from harmful parasites and other environmental disasters.

Anna Marie Nuutilla uses genetic engineering to develop new strains of barley that will be resistant to a harmful fungus. To do this she uses a new tool of biotechnology, a gene gun. Let’s take small peek at a few of the details of how a gene gun works.

“What we do is take a small seed here .. And dissect the embryo .. Right here and we transfer the gene that we want into the little embryo with the help of a gene gun.

“This a gene gun. This is the chamber where the actual bombardment is done and we start getting it ready for the bombardment. This is a pressure disc here which we use to choose the pressure we will use in the bombardment. We are using 1100 psi. Put it into there and tighten it a little. This is the macro carrier on which the little gold particles have been precipitated and the little gold particles contain the DNA we want to bombard into our cells and then we turn it upside down so the little gold particles are on the bottom side now. The next thing we do is put in this stopper screen which stops the macrocarrier particles but lets the little gold particle go through to hit the actual target.

“We close the chamber and we start taking the vacuum in. This tells us what the vacuum is in the chamber Put the vacuum on hold and now we bombard as you see how the pressure goes up and then we let the air back into the chamber and take your embryos out and can put it now to grow”

As you can see biology today is a crossroads for many sciences. It includes chemistry, economics, technology, toxicology, agriculture and much more. Dr. Regina Murphy is by training and degree a chemical engineer. She once worked in a large oil refinery. Today her research is directed to .understanding more about the role of proteins in the human body, especially in the case of Alzheimers disease, a dread affliction of old people, and Down's syndrome, a genetic defect in newborn babies. I asked Dr. Murphy to explain her approach to Alzheimer's and Down's syndrome.

Regina Murphy.

"Alzheimers disease is diagnosed by the presence of deposits in the brain called amyloid .plaques. They're extracellular, outside of the main cells, abnormal. It's not proven yet but a lot of people think that the plaques are an early stage of the disease. In fact, maybe the cause of the dementia, of all the problems patients have later. So one .of the things we're looking for is how these plaques form and why. Cause if you can figure that out you can figure out how to stop it potentially or at least how to develop an earlier diagnosis so you can intervene with treatment sooner”

Could you briefly describe a typical day for you?

"I have a number of graduate students working in my lab. What I do in a typical day might be to work in my lab, do actual experiments. Now a big piece of my job is to work with my grad students and plan what kind of experiments we want to do. Then you have to figure out once we've done it, what does it all mean. So in fact the actual experiments don't take most of the time. It's figuring out what you're doing, how you're going to do it, then what does it all mean .when you're done. That might involve some time in the library looking up various articles so I understand better what's been done before."

How did you get into this field?

"I fell into it. When I was in high school I wanted to be either a writer or a journalist. Then talking to a friend she said you're really good at chemistry and math. I thought, well, maybe I am. No one had told me I was but actually I was probably better at that than English. So when applying to college I got lots of brochures from different colleges sent to me. I got one from MIT which I'd never thought of going to. I thought, well, I'Il apply there but I won't get in. But then I got in and said, OK, I'II go for a year and flunk out and go some other school. But I didn't flunk out. .... I was kind of interested in chemistry. ... I took a class my freshman year in chemical engineering and I loved it. Really fun and I saw it as something practical, useful that also involved a lot of the skills I like, the chemistry, physics, math, the whole combination. It wasn't esoteric, so far removed from anything that was part of daily life. It really was all about real things that people use every day."

Probably the most controversial of the new fields in modern biology are the recent advances in biology at the molecular level. Here again you notice that biology crosses the line and becomes intertwined with chemistry, physics and especially with social and ethical issues.

Lloyd Smith is by profession a chemist but most of his work today has centered on the Human Genome Project, the most ambitious biological study of all time that has just been successfully completed.

“If you want to understand biology at a really comprehensive level at a systematic level you pretty quickly know that you’d want to know at a minimum the information as to what biology is made of. And basically the sequence of all the genes encodes the structure of all the proteins, sort of the minimal fundamental building blocks. There was a lot of resistance to this concept when the genome project started. That resistance has pretty much gone away, because the power and utility of this information has become so obvious no one can overlook it.”

Like many researchers in molecular genetics Dr. Smith has also played a major role in founding biotechnology companies that are trying to produce new drugs and new techniques to help conquer pollution, advance agriculture, and cure disease. I asked him to give us an example of his work in that area.

"Some good examples of that ... another company I work with, Visible Genetics, has been doing sequencing of the retino blastoma gene. That is a gene that is involved in the generation of cancer of the eye and it turns out that if you’re in a family that has that gene and you don’t do any genetic testing then you don't know which of your children have that gene and which don't. And it turns out since you don't know what you have to do is end up having to do these examinations of the eye under general anaesthesia which are pretty expensive and they have to do them every six months on young children to detect if there is going to be an early occurrence of eye cancer.

“Visible Genetics put out this test that allows them to go in and rapidly sequence those genes from the affected members of the family. Once they do that they can find out what the mutation is in the gene that's causing the problem and that allows them to go and very quickly and easily test the children and find out which children have the bad gene and which don’t. The ones that don’t are right away free and clear. They're out of it. No test, no general anaesthesia, no anxiety. And the ones that do, you can also begin building up a data base to look at what the prognosis is based on different types of mutations and also try to tailor treatment that is specific for those mutations."

In 1997 the first mammal was cloned in Roslin Scotland. She was named Dolly. She lived a normal life, had a baby and died a natural death in 2003. Since that first cloning many hundreds of other mammals have been cloned and there have even been reports, probably false ones, of human beings being cloned.

Dr. Neal First at the University of Wisconsin Agricultural School was the first biologist to clone a cow. He explains some of the details of how it is done.

"What we are doing is super-ovulating a donor cow. This might be a 40,000 pound cow we’re talking about. And so we would cause her to have not just one egg shed, but ten eggs shed and these eggs would be harvested at about the 30-cell stage. Sort of like this.

"And so we'd flush them actually from the uterus with physiological saline ... flush them into a vessel and retrieve them by looking into the bottom of the vessel with a microscope and finding the eggs.

"Then we would take a single cell from the embryo of 30 cells and we would transfer this into the enucleated oocyte. Now where did the oocyte come from? "For us the oocycte came from the carcasses of slaughtered cattle. ... And then with a pipette we aspirate the chromatin material in the nucleus from this oocyte we do not push the needle actually into the plasma of the egg. That’s important. You kill eggs if you do that.

"Then with electro fusion we will fuse this cell that we took over here from the 40,000 pound cow. We will fuse it into the ooplasm of the egg and then we expect the ooplasm to develop them now like it would a brand new embryo back to the 30-cell stage when we could do this all over again. “

Cloning a whole sheep or a cow from a single cell is one thing. More often cloning techniques are used to clone cells alone. The most startling, potentially revolutionary and controversial way this is done today is the special case of embryonic human stem cells.

All human embryos begin with a male sperm uniting with a female egg. This fertilization usually happens inside the mother's body. In modern in vitro fertilization clinics, however, couples who for one reason or another cannot conceive normally, allow their sperm and egg cells to unite in a laboratory petri dish. The fertilized eggs in the laboratory are given the right nutrients and allowed to grow to a very early stage (10 to 15 cells) and then implanted in the uterus of a potential mother where they grow to term and are born as healthy babies. In vitro fertilization there are usually far more embryos formed than the couple can or want to use, and the unused ones are typically discarded.

Today, instead of being discarded, some of these unused embryos are being made available, with the consent of the donors, to scientists who want to study stem cells.

Dr. Timothy Mulcahy explains why stem cells are so potentially useful in treating human disease.

"Well, I think the simplest way to explain that is to think of stem cells as a pretty much a blank cell. It is a cell that has the potential to do anything that any cell in the body does, but it hasn't received specific instructions yet as to which particular program to follow. So the beauty of stem cells is in the potential they offer for medicine, for example, is if we can understand the signals that will tell the cells which programs to follow we could then develop cells to replace cells that are injured in heart attacks, or we could make neural cells that could replace deficits that people suffer in Parkinson's disease and others."

The use of human embryos for such research is controversial. Dr. Robin Alta is an example of a biologist who later obtained a law degree and is now is a recognized international expert on legal and ethical issues of stem cell and other research involved in reproductive studies. She recently worked on a national commission appointed by the President to look into these questions. Here she explains the problem and possible solutions.

"I think that what constitutes a morally significant form of life is one that has gone on for centuries and is not likely to be resolved anytime in our lifetime. At face it touches on things that cannot be proved, on things that cannot be explored through experimentation. For example, if you believe that the real potential to develop under the right circumstances into a baby means that this form of life must be protected, in other words the acorn should be protected as if it were already an oak, then you are making this value judgement based upon a vision of the world that could transcend time in which we see life as part of a continuum across time.

"On the other hand, there are people for whom that is not a relevant factor and they ask only do we have an entity that can experience itself and can feel disappointment and pain, in other words, can be harmed. And they look at an embryo and say no, it doesn't even have the biological substrate to be self aware and to have formed a desire to continue to exist, and so it is in no way wrong to harm it. These are very different views about moral significance and they can't be brought together."

How can we as a society then decide such irreconcilable differences? Should we simply put them up to a vote, and let the majority rule?

"Well, I personally think there is a lot of guidance within the philosophy of our Constitution. The United States is not governed by pure popular majority. Instead we have a mix. On topics of rather ordinary concern we allow the popular will to prevail.

“On the other hand there are areas of life that we have said are so central to a personal identity that even when popular sentiment would suggest that things be restricted, we will permit them until the most compelling arguments have been made for restriction.

"Those are things that are listed in the Bill of Rights, the freedom of association, of speech, of practicing your own religion, and it is also a set of things that have been identified by the Supreme Court as implicit within the Constitution and Bill of Rights . Now one of the areas that we need to examine is the freedom of scientific inquiry. Just as free speech insures the long term stability of a civic society by providing an outlet for dissent, so we don't have violent revolution, so scientific inquiry insures the continued development of new knowledge which helps to stabilize society. ... something that needs to be protected even if it is against the popular will."

As you can see, every biological challenge has many sides. For those about to begin their biological studies the challenges may at times seem insurmountable. We conclude this program on working biologists today with a scientist, Dr. Brenda Faison, working on a modern pollution problem. A scientist able to explain both the challenge and the joy of the quest.

Brenda Faison.

"Hire an organism to do that work for you. What I have growing is a fungus that is involved in .wood degradation in nature. I've got it growing in a test tube. You start tinkering with it. What is tinkering? You add a little bit of this, take away a little of that. Try shaking, incubating at a . different temperature. See what happens. That's what I did. Then when I discovered certain trends I stopped tinkering and began to work in a more controlled fashion.

"My organism is going to do whatever it wants to do. I just have to understand how to coax it . to reveal to me how it does it. There will be a moment sometime six to twelve months before you finish, when you'll be in the lab doing a calculation and you'll say--Hey! you know what that is! You get all excited. You tell everybody about it. They say, prove it. You go back to the laboratory. You do your damndest to prove it. You get an answer, yes or no. You were right .or wrong. Doesn't matter what your was answer was. You got an answer, and that answer becomes part of the scientific literature."

I asked Dr. Faison if she had any advice to give to a beginner in biology today.

"Believe in yourself. It sounds corny. Don't give up. The most important thing is to remember you wouldn't have gotten this far if you weren't any good. This includes having made it out of the third grade. I think what is important for youth in general and girls in particular and black people especially is to realize that you can do anything that occurs to you. If I can do it, anybody else can. There's nothing unusual about me. I'm just a little colored girl from outside Cleveland. But I'm a microbiologist. And a good one. And I'll be a better one."