Hi everybody and welcome to another Storytime.
My name is teacher Bia and I'm going to be your storyteller for today.
We're continuing our series called Stories in STEAM
where we tell the stories of different scientists throughout history
and today i'm telling the story of a scientist called Lynn Margulis
and we're gonna have to explore a little bit
about what work contributions to the
world of science.
But before we get started,
I want to invite everyone to please subscribe to our channel,
give this video a like
so you stay tuned to other videos that we might post.
Alright, shall we get started with today's story?
Let's do it!
Alright, so here is our scientist for today.
Her name is Lynn Margulis
and she was a biologist
to help us understand how life is connected
and we're going to learn a little more about what this means.
So let's tell her story. Shall we?
Alright, so Lynn Petra Alexander was
born in March 5th 1938
in Chicago, Illinois, in the
United States.
She was a self-proclaimed biophiliac,
that means someone who has a natural affinity for nature.
Maybe you at home might be a biophiliac too
and you just didn't know that there was a word for it!
But there it is.
And like a great scientist,
she wouldn't believe everything she was told.
She always looked for evidence.
So she really enjoyed nature,
both big scale nature — like we see in this picture
with landscapes and plants and animals —
but also the parts of nature that we can't see.
Parts that are microscopic.
Things that you need a microscope to look at,
just like what this scientist is doing on this picture over here.
And she, as a good scientist, always looks for evidence-based knowledge.
So that's an interesting word here. "Evidence."
Do you know what "evidence" means? Hmm..
What does evidence mean in a scientific sense? Hm.
Think about that for a moment.
Well, evidence in science is something that can be used
to prove a theory or tell a story.
Evidence are facts that are discovered and proven
through experimentation or observation.
When Lynn was 15,
she enrolled at the University of
Chicago Laboratory School.
Later she tells that, that was a very good
decision.
Before she went to Chicago Laboratory school, she said she was not a very good student.
That she was always put in the corner and
punished and she was not doing very well in school.
But in that new school, she was able to learn from both scientific experimentation
and reading original science texts.
That really gave her a solid strong background in scientific knowledge
as well as scientific practices.
After, she graduated with a Bachelor's degree at the age of 19
and went on to earn her Master's in genetics and zoology.
That's the study of genes
and the study of animals at the University of Wisconsin.
After she got her Master's, she continued her studies with a PhD program at UC Berkeley,
where the Lawrence Hall of Science is,
and in 1966, she joined Boston University,
where she taught biology for 22 years.
So she would also become an educator.
She would teach science and biology to other students at Boston University.
While she was in the beginning of her career at Boston University,
she wrote a paper called
"On the Origin of Mitosing Cells."
Those are very big words but we're going to get into it in just a moment.
In that paper, she brought together ideas from many scientists before her
to tell the story of the origin of
eukaryotic cells.
All right, so we just use a lot of new words here.
First, let's talk about what are
eukaryotic cells, shall we?
Over here, we have pictures of two types of cells.
Actually, let's back it up a bit.
What are cells to begin with?
Well, cells are the building blocks of living things.
So every living thing is made up
of many cells put together.
Cells are microscopic, meaning they are very very small.
We can't really see individual cells
but if we look at any parts of our body,
we'll know that they are made up of cells.
And there are two different types of cells.
Over here, we have eukaryotic cells
and you can notice that there's lots of things inside.
We don't have to worry about the name of
those things but they're there in case you're curious
and you can notice on this picture, how there's a lot of things inside of the cell,
including this middle part over here, that has a blue circle
with green things inside.
That is the nucleus of the cell.
But before there were eukaryotic cells around Earth,
there were already prokaryotic cells,
which is this kind of cell that we see underneath here.
Prokaryotic cells are cells that make up bacteria.
And bacteria are microorganisms that
are made up only of one cell.
You notice that there are things inside of prokaryotic cells,
but they are not surrounded by something called a "membrane."
All the things inside the eukaryotic cell are covered with a layer
that protects them and makes them their own thing.
On the prokaryotic cells, all the things
that are inside are just floating around.
So bacterias are prokaryotic beings and at one point, in the history of the Earth,
the only living things on Earth were bacteria or prokaryotic cells
until eukaryotic cells appeared.
And Lynn helps tell the story of how that came to be.
So let's take a look about what her theory means.
So in this paper, she proposes the theory of endosymbiosis.
That's another big word, right?
Well, let's break down this word in parts and
see what it means.
"Endo," the beginning of the words, means inside.
And symbiosis means living together.
So this theory proposes that eukaryotic cells,
those are the cells that have things inside,
came to be when they took other cells inside
and instead of eating them,
they just started working together.
So let's look at this diagram and see if
we can understand this a little better.
On this side over here, we have an
ancestral host cell,
which is the cell that they propose would give origin
to all new eukaryotic cells.
And this host cell, engulfed, took inside other bacteria.
But these were not just any kind of bacteria.
They were bacteria that could perform very important functions
like processing oxygen in order to get energy —
it's a process that we call respiration —
and other types of cells that can use
sunlight and other substances in order to make sugar.
In other words, food.
So these two functions are very useful:
getting energy from oxygen and getting food from sunlight.
So instead of eating these cells that it just took inside,
the ancestral cell ends up keeping them.
And having those one cells, now
organelles, perform these functions for the cell,
giving origin to the eukaryotic cell
that has structures inside of it that perform certain functions.
So let's recap.
The endosymbiosis theory says that eukaryotic cells came to be
when ancestral cells engulfed or took in bacteria cells
and instead of digesting them,
it kept them in order to perform functions
together.
At the time this theory was proposed,
no one knew about that yet
and it was an idea that was very new
and a lot of people had a hard time
wrapping their heads around it.
Her paper was criticized and it was actually
rejected 15 times before it was published
So when scientists do research,
they spend a lot of time in a lab
and gathering data and running experiments
and writing papers with their findings.
But in order for these findings to be accepted, they need to be published
in a scientific journal.
What happened to Lynn was that her ideas were so new
that other folks were having a hard time accepting them as true
even though her study was definitely based on evidence.
But she bravely kept pushing her idea
and using this evidence to back it up.
Today, scientists are in agreement that the theory
indeed tells the story of the origin of eukaryotic cells
and new experimental methods in the field of genetics
that we have today, that we didn't have back then,
help prove this idea.
So Lynn's ideas have been studied further with new techniques
and scientists have found out that indeed that is most likely
the way that eukaryotic cells came to be.
So it's very fortunate that even though her paper was rejected many times,
she kept pushing those ideas forward so
that we can know more about
our cells and how they came to exist.
Lynn Margulis was able to perceive how
the relationship between organisms are
crucial for their survival and a major
driving force in evolution,
more so than natural selection.
So before, Lynn proposed these ideas,
a majority of scientists agreed
that something called "natural selection"
was what drew evolution.
It's what would drive the origin
and establishment of new species and new life.
But Lynn proposed something different:
that symbiosis — the way organisms live together and help each other
and interact with each other —
are a much bigger driving force on generating new kinds of life,
and therefore, a major driving force in evolution.
Later in her career, she also collaborated with James Lovelock
in writing the paper that formulated the Gaia Hypothesis.
This hypothesis proposes that the entire earth
is a self-regulating system.
Let's talk about what that means for a moment.
So in order for life to exist,
we need certain conditions to be met.
Right? If you think about what are the
things that we need in order to survive.
Well, see if you can come up with a few ideas.
If you're watching this with someone,
maybe share your ideas with them.
I can think of a few things myself!
I know that as I'm standing here, I am
[inhales and exhales]
breathing and I'm using that oxygen for energy.
So in order for some life to exist,
there needs to be oxygen in the atmosphere.
But do you think that has always been there
from the beginning of the earth?
Hmmm..
As scientists started studying about the
origins of the Earth,
we know that the earth is not the same place it is now
millions or billions of years ago.
The atmosphere on the earth
actually did not have enough oxygen to
sustain the life that it has now.
But some organisms, in the very early
story of Earth, like bacteria
are able to produce oxygen by processing
other gases like carbon dioxide.
So that tells us
that some life have to do some work
and perform some functions
in order for other life to be able to exist.
And if we look at all the specific
environments on Earth and all the specific conditions
that some life need in order to survive,
we know that life factors
are helping regulate each other.
So some organisms are creating the conditions necessary for other organisms to exist
and the Gaia hypothesis doesn't really just stop there.
It also talks about non-living factors
like climate and minerals.
So all of these factors that are in the Earth,
both living and non-living,
work together as a system
in order for all life on the planet
and the planet itself
to survive and keep existing.
So this theory really puts things into perspective and
helps us understand how connected everything is
and how all organisms are dependent on one another
and on the planet itself
in order for life to survive and thrive.
Although in many occasions, Lynn
Margulis' ideas were criticized,
she did not let that stop her and she became an outstanding scientist
and gained a lot of recognition.
She has won many awards and was part of many very
renowned organizations.
And I want to end the story today with a quote from her.
The quote says,
"Life did not take over the world by combat,
but by networking."
So let's talk about what that means.
Before Lynn Margulis presented her ideas to the world,
a large part of the scientific community was focused
on natural selection and competition
as a principal driving source of evolution.
What she was able to bring to light is that
although these forces do shape evolution,
other forces that are additive, that support each other,
also drive evolution, even more so.
I think that's a rather beautiful way to
look at the natural world
and that her ideas can remind us about the power of networking and collaboration.
We can see that being reflected on the science
but also in the practices of her work
seeing that she also seemed to
understand the importance
of collaborating with other scientists
and colleagues.
This quote is from her book
called "Microcosmos: Four Billion Years of
Microbial Evolution."
She has published many books
including a coloring book of microorganisms
that you might want to check out if you
enjoy coloring.
All right my friends,
that is the end of our story for today.
What did you think of her story?
Can you imagine what would you do if you
were a scientist
trying to bring your ideas forward and
those ideas keep being rejected?
Do you think that would bring you down
or do you think that will motivate you to keep going?
I hope you enjoyed learning more about Lynn Margulis
and her theories including endosymbiosis
and the Gaia Hypothesis.
If you want to see more story time
 or other science videos,
make sure to subscribe to our channel
and give this video a like.
And I'll see you next time on Storytime!
Thank you for watching!
Bye bye!
