An empire billions of years in the making
A carnival of natural wonders
Societies of cells
Simple and complex
All connected by an astonishing web of miraculous processes and global ecological systems
A web of life
These are the greatest discoveries in the history of biology
In the early sixteenth hundreds, basic microscopes were used throughout Europe.
General scientist were held spell bang by their ability to enlarge the universe of the very small
Then in 1665, an English scientist named Robert hook
observed the tiny boxed in the sliver crock and called them cells.
Because they reminded him of the small room lived in by monks.
Hook's observation set the stage for our first great discovery.
Antoine Leeuwenhoek was a Dutch merchant fascinated with science
Upon learning about hook's microscope, he decided to build one for himself
Doc. Gaul
To find out what happened next, I paved a visit to Joseph Gaul
A cell biologist at Carnegie institution in Baltimore Maryland
Antoine Leeuwenhoek, What did he discover
Leeuwenhoek discovered quite a few things. But what is his most famous for are discovering protozoa
That's small single cell animals living in pond water
How did he do that
He did use a microscope of his own construction
Then would you like to see Oh yes.
You have a Leeuwenhoek microscope
Not original. I have a replica of Leeuwenhoek microscope
It consists of two brass plates with a small piece of glass which at the lens
And when you use this, it's to put the specimen on the pin here
And then you hold your eye up very close to lens on this side
And when you do that, you can see the point of the pin
Would you like to take a look at Oh yeah
It's kind of heavy Cause it 's brass, it's brass
In 1675, then Leeuwenhoek was using his microscope to examine a bit of water
When he observed something extraordinary
A world full of creatures that no human would ever seen.
Microorganisms
So with this, with all due respect, primitive gismo, yes.
He discovered single cell animals. We take for granted yes
But he is most famous for are discovering protozoa,
bacteria
and sperm.
This thing is brilliant
It's got mechanical stage, it's got focusing device
It got all over the things that you need to look at the specimen
And it works
The day they know they were seeing. Do you what I mean like did they understand
Well I doubt that they really understood what they were seeing in the modern sense
But they were impressed that all the little things that were alive in water
And people had no idea that water was teeming with organisms
I guessed I just had no idea the thing was this small and delicate
and frankly, so elegant
Because it's upon your hand
And what you see on the tip that pin changes the world. It does, indeed
It was an enlargement of our understanding of nature, nature than natural world
That, that the world out there was not just dead things, but it was teeming with life
Our next great discovery occurred in 1831.
English naturalist Robert brown was studying the different types of plant species he collected during a voyage to Australia
Brown has an exquisite eye for detail
The cells of the plant were of particular interested in him.
On examine under the microscope, he saw something intriguing
In each cell, a similar structure, circular, opaque
He called it the nucleus
Upon learning of brown's observations
German physiologist Theodor Schwann
began looking for a similar structure in the cells of tadpoles.
And he found it.
Each in every cell of the tadpole has nucleus as well
It was a revolutionary breakthrough.
Here was evidence that all life was connected.
In this book, Schwann describes every cell type from all sorts of organisms
And identified them by the fact that they have a nucleus in them
How would you say the discovery of nucleus was a great discovery
The realization that there was a union structure to all organisms
This was a union structure not only in plant but in animals
So united both plant and animals kingdom into something that had similarities to each other
More than a century after the discovery of the cell nucleus.
It was believed that there are two fundamental types of life on earth
Bacteria and everything else
Bacteria was classified prokaryote
These were simple, single cell organism with their DNA contained not within a nucleus but by the cell wall.
All other life form were classified as eucaryon
Their cells carried their DNA enclosed within the nucleus
But this simple classification system was in for a shock
In 1977, biologist Carl Woese was studying the genetic make-up of a methane-producing microbe
When he realized it was different from any known bacteria.
Its cell wall was unique. It produced unusual enzymes
And its genetic sequence was unlike anything he'd ever seen.
It came soon apparent under within the microscope an hour
That there was something a third thing at there
This was the moment of discovery
Carl Woese had found a third form of life
A group of single cell organism that he called archaea
We used to think that there are two primary kingdoms on this earth
Now we know there are three
That was the shift, the shift
Because all of the microbiology have been structured on the idea that all bacteria are fundamentally the same not in all details
but in their essence, their ancestry and their basic cell organization
here are something that every microbiologist and biologist firmly believed in and it wasn't true
so, it does make you smile. Yeah, look I found
what he found was a life form able to live anywhere on the planet
including the most extreme environments.
Some archaea even call this home.
Hydrothermal events on the ocean floor
Temperature here fluctuated wildly within just a few inches.
Going from freezing to a scorching 760 degrees Fahrenheit
Archaea have also been found living miles inside the earth
Thriving in lakes of acid even iron minerals dissolve
Today, some biologist believe
that archaea are the common ancestor from which you carried yourself off
And that includes you and me
For Carl woese, the discovery of archaea remains a sweet memory.
It was picked up one published by the New York time first
And other newspaper and TV came in
And I could remember I walking out my house when I say,
When all this have seen, tonight, the world belongs to you.
Our next great discovery sought to answer the question at the heart of biology
How cells form new life
In the course of human events
This is all pretty recent. Right Yes.
We found nucleus, the cells around nucleus.
Animals and plants all have cells Yes
And what happened next
After a gap of some 30 years or so, people began to see cells dividing.
Cell division is the process that the cell of plant or animal go through to duplicate itself
Well scientists had known about the process for decades
German zoologist Walter Fleming was the first to describe and to publish his findings.
And his book was published in 1881
This book is momentous and extremely important in cell biology
Because Fleming described cell division in a way
which would be acceptable in modern journal
Fleming observed the process of cell division in great detail.
With the help of a powerful new microscope and a new dyed stinging techniques
With these innovations, he was able to identified structure that later was named chromosomes.
And then his great discovery
During cell division, the chromosomes undergo dynamic change.
They divide into two identical parts. One for each daughter cell.
Fleming called this process mitosis
So, that's the whole process of mitosis as he described it in 1881
And the tadpole tail yes, the tadpole tail yes
And he knew to go to the tail because the tail is growing
and the back of tadpole is going on Exactly
He knew that if you want to see the cell division in details, in details
I am sorry for the pun. Oh. I love the pun cookie for the pun.
Then, that's was one of the places to look.
The splitting of the chromosomes during mitosis was a breakthrough discovery.
It opened the door for scientists to begin understanding
How one cell can turn into a complex organism, made of many interacting cells.
Around the time that Walter Fleming was studying the cell division process.
Biologists already knew that fertilization resulted from the union of two sex cells
sperm and egg
what they didn't know was why this was the only type of cells in body capable of reproducing new life
what made them different
The first answer was provided in 1883 by Belgian zoologist Edward van Beneden
Van beneden was studying a species of roundworm
And then discovered that all of its cells contain four chromosomes
The only exceptions were the roundworm's sex cells.
The male's sperm and the female's egg, these cells had only two chromosomes.
Then beneden observed that once two of the sex cells came together
A full set of four chromosome appeared in the fertilized egg
But just why the sex cells had only the half number of the chromosomes compared to the all the other cells was still a mystery.
Then in 1887, German biologist August Weismann entered the picture.
He knew about the work of van beneden who have shown that the sperm and egg bring the an equal number of chromosomes
But van beneden's work had not really worked out the details of how the chromosomes were reduced in number.
He thought he thought them go in half and he thought them recombine
He thought the sperm and egg brought in half number of chromosomes than the body cells
But he didn't really know how they got rid of the half. They got rid of
So Weismann discussed how this might happened from a theoretical standpoint
And he said, well, what you could have would be that either one of the chromosome was just split in half and half would go off one way and half would go another way.
Or, you could have more complicated, that the chromosome could paired and then, instead of splitting, they just separated again
After years of studying the behavior chromosomes
Weismann determined that some point, a developing organism signals the sex cells
To divide their number of chromosomes in half
Weismann called this very special form of cell division meiosis
I think they would look back and see this as the golden age of biology
Because let's say 200 years between 1800-2000
We went from not knowing what distinguish the stone from a frog
Ok.
And now we know the difference between the stone and the frog
That's pretty good
So that, in a real sense, we've answered the old philosophical question, what is life
May be not to everybody's satisfaction but we are well on the way
Our next great discovery answered another question about the biology of life.
In the late 19 century,
Biologists knew that during the formation of embryo, the cells of most organisms became differentiated
That is they received their assignments for specific jobs in the adult organisms.
Arms, legs. Eyes
But when did this differentiation happened
German biologist Hans Driesch was determined to find the answer.
In the lab experiment with sea urchin
He observed that in the early stage of an embryo development.
Its cells are not yet differentiated
They can still develop into all cell types
Today, scientists called cells that can develop to all or many types, stem cells..
- Hi bill. - Hi
To find out more, I paved a visit to Helen Blau
Who was directing stem cell research at Stanford University's genetic pharmacology lab
Everybody is talking about stem cells
Cells started out their fertilized and they stated to divide
But they still haven't sort of divide into what I would think liver cell, fingernail cell, eye cell, right
That's right
And what do you call that
So that points their totipotent cell
They have a lot of plasticity and they can give rise to all cells in the organism.
And then something changes, we don't know what that something is.
But those cells are now destined to make different kind of tissues
And that's why we have organs such as the heart, and the liver, and the spleen in an adult
So then the question is how yearn reversible are these decisions
So, I wanted to challenge the idea that the cells were yearn reversible determined
That once the cell became liver that was it.
And so, we showed that they were not yearn reversible determined
And that by perturbing their environment inside the cell
You could activate genes that were usually never used.
That demonstrated the certain kind of plasticity
And this kind of plasticity that people are trying to unleash in stem cells
So, understanding the mechanism under minus may allowed us to use the fundamental principles we discovered in treating disease
What's recreating the cells, what's getting them to fuse
And what's getting them to reprogrammed. So it's even more efficient.
We might unleash that and what called regenerate medicine
We are finding that cells have more potential than we thought before.
So that a blood cell, stem cell, not only makes the blood.
But those cells came travel elsewhere through the circulation to aid and repair damage in tissues such as muscles, tissues as the brain, also liver.
And that's v been shown in several labs now.
Sound like star track or something, do you remind. Dr. Maicao the guy in 15 seconds and later it was
Ok. Well that was quiet like that. yes, we got
To gain a better understanding of the new technologies that Helen Blau was using to uncover the potential of stem cells.
She showed me an experiment being conducted with genetically-altered mice.
So, that is one unusual mouse, certainly is
It has green fluorescence protein in all of the cells of its body.
Because we have been able to introduce the jellyfish's GFP gene into these mice
Now, their tissues are glowing, particularly in the ears, the eyes, the tail.
It's But all the tissues are, are green
It's unable to take cells that glow and put them into another mouse
And see what tissue it would participated.
So, in the way you can follow what stem cells can do
It's a marker, it's a marker, yes
Just all you need is ultraviolet
That's right and it didn't exist before
And because of that we now can follow the trace of the cells
Where the cells go, what they become
And in a way it wasn't previously possible
It's fantastic
In the 1930, German biologist Hans Krebs,
the son of a Jewish physician, was forced to flee Nazi Germany
By 1937, he was doing research in the University of Cambridge in England
Determined to unraveled the mystery behind the central biology process
How did the cells in our body convert food into energy
It's our next great discovery.
To investigate this process Hans Krebs broke open a group of cells by grinding a sample of animal tissue
He collected the liquid from the broken cells
And put the content through a serious of chemical reactions
And measured the results.
Slowly, a pattern began to emerge. A pattern that led to a remarkable discovery
From his measurements, Krebs determined that sugar molecules from digested food
Go through a cycle of a various chemical reactions inside the cell
The cycle result in the production of the energy rich molecules ATP
This molecule provides us with the energy we need to make us go
And the cycle of chemical reactions is known as the Krebs' cycle
It was a milestone discovery in the development of biochemistry.
The Krebs' cycle opened the door to a deep understanding of how cells function in the human body
Just like our next great discovery.
In the mid nineteenth century, scientist using powerful microscopes,
found something never seen before.
A mysterious structure lurking inside nearly all the types of cells.
It was equipped with two membranes and had the ability to change the shape.
Over the next hundreds years, several biologists combined to uncover the secrets of this biological wonder.
They called this structures mitochondrion
Among the scientists involved the first way of discovery about mitochondrion was Britton Chance
His contribution included the invention of door waved linked spectral photometer
A device that provided scientists with a clearer picture of how mitochondrion function
Today, he is a professor of biophysics at the university of Pennsylvania
I make a gadget, this gadget would look through the turbidity of these organelles
Because they had membranes and they had cell walls
And had things with scattered light near the hold of multiplies or you can see was a fuss
Well, we made an instrument which got rid of the fuss
And found two components that linked the mitochondrion to Hans Krebs' citric acid cycle
So this sort of tied the whole things up and made links between enzyme action and the whole energy chain
So it was together
With the help of chance's invention scientists found the mitochondrion that provides the energy that enables us the cells to work and the body to function
The mitochondrion hast to be a very efficient way of using the food stuff that the whole cells gathers And this is called the phenomena of respiratory control
To a man, it means that he can exercise like hell you wants to,
and all he has to do is stop to recoup in another word, he don't have to take a pill, he don't have to take an injection
well, his mitochondrion will reconstitute the energy deficit
having done that and go to sleep
so, I think, especially in these days of Olympics sports where everybody pushing their ATP to the very limit
it has a real significance
Britton Chance appreciates that significance as a scientist and as an athlete
In 1952, he won a gold medal as a member of us Olympic sailing team
I think discovering the components, studying the mitochondrion and veval finding how they work
Showing how important respiratory control was and how it works
And of course, studying free radical generation which now is recognized as enough to dangerous but a signal process
And that was sort off kicks me of the street now, I am working more on brain and cancer.
Because of the implications of mitochondrionology there
At the end of the nineteenth century, one of the great puzzles challenging the scientists
was how the billions of nerve cells that make up of the human nervous systems communicate with each other
They knew that each nerve cell called the neuron carries electron impulses
And many believed that the connection allowed the impulses to jump from on one neuron to another was electrical as well
Until our next great discovery
In the early nineteenth hundreds, British biologist Henry Dale was conducting a serious of lab experiments
Studying the physiology of nerve impulses
In one of his experiments, he injected adrenaline into a cat
Expecting the animal's heart rate increase, but nothing happened.
Suddenly, Dale realized his mistake
It was the same cat that he already given another drug to, one that slowed the heart rate
With this mix-up Dale realized that he was under something
If a drug could interrupt the nerve impulses that governing the beating of the heart.
Then the connection between neurons must be chemical, not electrical
Dale turned his colleague, German biologist Auto Louie for help
To test Dale's hypotheses, Louie conducted an experiment using two frogs.
Louie put the first frog in a saline solution
And then he electronically stimulate its vagus nerve, the nerve that control its heart beat
The frog's heart beat slowed
Next Louie took some of the solution in applied to the heart of the second frog.
What happened next was extraordinary.
Without any electrical stimulation of its vagus nerve,
The second heart slowed as well
This was the moment of discovery
Louie realized that the vagus nerve of the first frog has released chemical
Which had directed the second frog's heart muscles to slow their contractions
Here was proof that the transmission of impulses among nerve cells and
then into the heart muscle was chemical
Louise has discovered the existence of the first known nerve chemical
Now are called neurotransmitter
Today, we know there are many neurotransmitters in the human body
And researchers are using this knowledge to learn more about how the brain works
At the chemical messages at sense
For example, low levels of serotonin have been connected with pression, alcoholism and anxiety this orders
But is our next great discovery revealed that nervous system isn't the human body's only method of communication
In 1903, two British physiologists William Bayliss and Ernest Starling were investigating the food digestion process
From their studies, they determined that the body produced digested juices that helped break down food, once it moves from the stomach to the intestine
But what caused the digested juice to flow
To find out, Bayliss and Starling conducted an experiment.
They took a blood sample from a dog that had just eaten a meal
Then injected the blood into a second dog, this one with the empty stomach
Then something astonishing happened
Without any food in his belly, the second dog began secreting digested juices from an organ called the pancreas
How was this happened
After more testing, Bayliss and Starling finally had their answers,
When the food reaches its intestine, the intestine produces a chemical substance,which then carried the blood stream to the pancreas
Here, it stimulates the pancreas to produce secretion that helps digest the food
Bayliss and Starling called this chemical secretin
The first they realized was a never before seen group of chemical substances.
They called this substances hormones
Since Bayliss and Starling's discovery, more than 50 hormones have been identified
Hormones that are produced by gland and tissues and carried in the blood stream as the human body needs them.
There are hormones which affect the body's growth, metabolism, heart rate and blood sugar.
They even help us prepare for reproduction
Estrogen, for example, is one of several female hormones it helps prepare the room for the baby and the breasts for feeding
So far, we've seen the discoveries that reveal the biology life on the microscopic level
Our next great discoveries open our eyes to the biology of the macro
Those system s on which all life on the planet depends
The year is 1771; chemist Joseph Priestley conducted a serious of experiments.
To see what happened when he hit various substances in close jars and collected the gas coming off.
In one of his experiments, he put a litten candle in the jar
but the flame quickly burned out.
In Priestley's words, the air inside the jar was injured.
Curious what affect this injured air might have on an living thing
He put a mint leaf inside the jar and left there for ten days.
When Priestley checked back, incredibly, the leaf was still green
Somehow the air inside the jar was fresh again,
Priestley speculated that the mint leaf must be responsible for the transformation.
But. How
This question remained unanswered until a Dutch scientist named Jan Ingenhousz decided to duplicate Priestley's experiment.
Using plants, Ingenhousz witnessed the same beguiling phenomena
After conducting a serious of more tests, Ingenhousz began to realize what was happening.
The ability of the plant to transform the air inside the jar only worked if the plant was exposed to the sunlight.
This was the breakthrough,
Together, Prestley and Ingenhousz had discovered photosynthesis
The biochemical process by which plants trap the energy of the sunlight and convert it into chemical energy.
Photosynthesis removes carbon dioxide from the atmosphere
And replenished it with the gas on which our survival depends, oxygen.
The same gas that Joseph Priestley would discovered 3 years later in 1774
Our next great discovery has no discoverer in a classic sense.
Many took hand in expressing and shaping the idea over the several centuries
It's the discovery of tropical diversity.
And today, it's fundamental to our understanding of the biological world and our dependence on it.
The term biodiversity refers to the variety of living things on earth and their interactions with the environment.
The tropical rainforests are the richest recourse of biodiversity on the planet
In the 15th century, Italian explorer Amerigo Vespucci visited the tropics and wrote it in his journal
What should I tell of the multitude of wild animals
So many species could not invent in Noah's Ark
Today, we continue to be odd by the biodiversity of the tropics
An estimate 50 percent of all the species in the world inhabit tropical rainforests.
An area that occupies only 2 percent of the land on the earth's surface.
The Amazonian rainforest in brazil
has nearly five hundred species of trees growing in an area of just two and half square miles.
Compared that to the total area of the unites state and Canada, which combine, have only about 700 species of trees.
But just why the discovery of tropical biodiversity consider so important
Because not only did it enable scientists to better understand the natural systems at that work here
But helped them began to harvest and extraordinary rearrange the sources which touch our life every day.
From the production of more food and better industrial products to the development of new medicines
For example, many of the most promising anti-cancer drugs come from plants found in the world tropical rainforests.
But those benefits have come up a deep price
Scientists estimate that loss of tropical biodiversity is happening at an alarming rate.
Millions of acres of habitats have been out countless species have gone distinct
It's estimated that with the current rate of deforestation
All tropical rainforests could disappear by the year 2030
That disappearance has far-reaching environmental implications
Because as our next great discovery revealed all the earth biological systems and the community of life that depended on them are connected
The dust ball of nineteen thirties
After years of drought the once fertilized America mid-west became a waste land.
Without rain, farmers continued to plow and plant
Hoping that the nutrient in the field would somehow be replenished.
But their efforts only made things worse.
The top soil turned to dust
And the wind took its avenges
For British ecologist Arthur Tensely, the dust ball was proof that scientists and the public in large
Were too narrow when they are view of the physical and biological world
They did not understand the dynamic of the environment as a whole.
A perspective that helped to explain the cause and effect of events like the dust ball
He advocated a new concept, what he called the ecosystem
The world has simplicity to its understandable by the ordinary person that can be applied effectively
Also has a scientific significance in the apt it brings together ideas form variety of sciences
To understand the impact of Tinsley's idea,
I paved a visit to Frank Golley state botanical garden in Athens Georgia
Why was this a revolutionary shift in thinking
At that time, ecological work was a strongly involved with the description in the nature
And the system approach, you are actually is going further your experimenting
You are looking for patterns
That are persistent across a variety of locations and species
And then you make statement about the way they perform that can be tested
Its moves ecology into the same value as physics and chemistry and molecule biology
So, Tensely took the word system and applied it to ecological studies.
He tried to convey the idea that ecology is part of a hierarchy physical system at the universe at one extreme
To the atom and the other
So, that's someone may be the solar system Yes
- And down blow that would be ecosystems, - Yes
Back here is something I want to show you, the quantity of silt that you see in the river right now.
Is due to the erosion of the farmland that upstream
This is a opportunity to see what we could say is a ecosystem defined physically. Bill, right here, in front of us.
So, this is a flood plain that's right
As we see the water from the Oconee river.
Periodically we get enormous rainfall and the river floods
And would then, send the water into this sort of area
Would might be we might be stemming just deep in water during a flood.
Presumable at one time, it was a forest
See the reminisce of the trees.
But because the floodingand, persistence of flooding, the tree's roots were unable to respire and the trees died
you can see if you look yourself around here
how beautiful before they recovering forest and its shape
We've study that in great detail, using an ecosystem approach
So, we are able to talk about the how to rebuild ecological systems here in this region
But manipulating the very species and the environment to speed up the process to get the…….. we want to amply size and to do it at the blast cause,
And that's a very positive step
Cause we can rebuild nature to meet certain human needs
And so it has functions and maintains itself honestly own under solar power.
Solar power yes Under solar power
Which is driving all the cycle s and everything else.
Our journey through the greatest discoveries in the history of biology
has revealed an amazing diversity of life on earth.
And it has given us an insight at that how life works
From a life cycle of a smaller cell, to the system that governs the physical environment of our entire planet
But there is one insight that …….. all above others is this.
The search for more discoveries about life is never ending. That journey goes on forever