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Very interesting :) everything on the planet us to bacterias viruses envolved ;)
Very interesting everything from us humans animals insects to viruses and bacterias ENVOLVED! Thankyou ALISON :)
Nice video to summarize the process
I think what is probably the most misunderstood concept in all of science and, as we all know, is now turning into one of the
most contentious concepts - may be not in science, but in our popular culture - is the idea of evolution.
And whenever we hear this word - I mean: even if we don't hear in in the biological context -,
we imagine that something is changing, it is evolving, and so when people use the word evolution in
its everyday context, they think of this notion of change
that, you know, - this is going to test my drawing ability - , but they, you know:
You see an ape, bent over, we've all seen this picture at the natural museum
and he is walking hunchback like that, and his head's bent down, and
- well, I'm doing my best - that's the ape, and may be is also wearing a hat
and then they show this picture where he slowly slowly becomes more and more upright
and eventually he turns into some dude who is just walking on his way to work, also just as happy.
And now he is walking completely upright and - you know - there is some kind of implication that walking upright
is better than not walking upright, and - oh he doesn't have a tail anymore.
Let me eliminate that. This guy does have a tail.
And let me do it in a appropriate width. You are gonna have to excuse my drawing skills.
But we've all seen this, if you have ever gone to a natural history museum.
They'll just make more and more upright apes and eventually you get to a human being.
And there is this idea that the apes somehow changed into a human being.
and I've seen this in multiple contexts and even inside of biology classes and even in the scientific community
they'll say: oh the ape evolved into the human or the ape evolved into the pre-human:
the guy that almost stood upright,
you know, the guy that was a little bit hunched back, he looked a little bit like an ape
and a little bit like a human and so on and so forth.
And I want to be very clear here:
Even though this process did happen, that you did have creatures that over time accumulated changes,
that maybe their ancestors might have looked more like this and eventually they looked more like this.
There was no active process going on, called evolution.
It was not like the ape said: Gee, I would like my kids to look more like this dude.
So somehow I'm gonna get my DNA to get enough changes to look more like this.
It is not like the DNA knew.
The DNA didn't say: Hey, it is better to be walking than to be kind of hunched back
like an ape and you know therefore I'm going to try to somehow spontaneously change into this dude.
That is not what evolution is.
It is not like - you know - some people imagine that: Maybe there was a tree.
There is a tree and on that tree there is a bunch of good fruit at the top of the tree.
There is a bunch of good fruit at the top of the tree.
Maybe they are apples. And then maybe, you know, you have some type of cow-like creature,
or maybe it is some type of horse-like creature.
It says: Gee, I would like to get to those apples.
And that - you know - just because they want to get to those apples, may be the next generation....
they keep trying to raise their neck, and then after generation after generation,
their necks get longer and longer and eventually they turn into giraffes.
That is not what evolution is and that is not what evolution implies,
although sometimes the everyday notion of the word seems to make us think that way.
What evolution is, and actually this is the word that I prefer to use, it's natural selection.
Natural selection, let me write that word down.
And literally what it means is that in any population of living organisms you're going to have some variation.
And this is an important key-word here. Variation just means: Look, there is just some change
If you look at the kids in your school, you'll see variations.
Some people are tall, some people are short, some people have blond hair, some people have black hair.
So on and so forth. There is always variation.
and what natural selection is, is this process
that sometimes environmental factors will select for certain variations.
Some variation might not matter at all, but some variations matter a lot.
One example that is given in every biology book, but it really is interesting, is
I believe they are called the peppered moth,
and this was in pre-industrial revolution England,
that these moths, that some of the moths were - let me see if I can draw a moth
to give you the idea, you know, let me draw a couple of them,
let me draw a few peppered moths.
A couple of peppered moths there. Let me draw one more.
So, most peppered moths there was just this variation, some of them were I guess
we could call them more peppered than others.
So, some of them might look like this, you know. No let me do another colour. Let's do white.
So it has spots like that, some of them might have looked more like that.
And of course they also had some black spots on them.
And then some of them might have been, you know, almost - barely have any spots.
You just have this natural variation like you would see in any population of animals.
You'll see some variation in colours .
Now they were all happy, probably for thousands of years, just this natural variation.
Just this it was a non-important trait for these peppered moths
but then all of a sudden the industrial revolution happens in England,
and all of this soot gets released from all of these factories
that are running these steam engines powered by coal, and so,
all of a sudden all of these things that once were grey or white,
for example maybe some tree trunks - let me draw some tree trunks -
may there were some tree trunks that used to look like this, you know, may be it looked like a
maybe it kept the, maybe some tree trunks looked something like this
and a peppered moth would be pretty OK,
maybe there were some tree trunks were pretty dark,
but all of a sudden the industrial revolution happened,
everything gets covered with soot from the coal being burned and then all of a sudden all
the trees look like this:
They are completely pitch black or they are a lot darker than they were before.
Now all of a sudden you have had a major change to these moths' environment, and you have to think:
What is going to select for these moths? Well, one thing that might get these moths are birds
and the ability of these birds to see the moths.
So all of a sudden if the environment became a lot blacker than it was before you can guess what is going to happen:
The birds are gonna see this dude a lot easier than they are gonna see this dude,
cause this dude on the black background is gonna be a lot harder to see.
And it is not like the birds won't catch this guy,
they'll catch all of them, but they're gonna catch this guy a lot more frequently.
So you can imagine what happens if the birds start catching these guys
before they can reproduce or may be while they are reproducing what's going to happen:
This guy, the darker dudes are going to reproduce a lot more often
and all of a sudden you're gonna have a lot more moths that look like this.
You're gonna have a lot more of these dudes. So what happened here?
Was there any design or was there any active change by any of the moths?
It looks like a really smart thing to do, to become black.
Your surroundings became black and you wait for a couple of generations of these moths
and all of a sudden the moths are black and you say: Wow, these moths are geniuses.
They all somehow decided to evolve into black moths in order to hide from the birds more easily.
But that is not what happened.
You had a bunch of them. You had a lot of variation in your peppered moth population
and what happened was that when everything turned darker and darker,
these dudes right here, and dudettes, had a lot less success in reproducing.
These guys just reproduced more and more and more and these guys got eaten up
before they were able to reproduce or may while they were reproducing
so that they couldn't produce as many offspring and then this trait became dominant.
and then the peppered moth became - you can kind of view it as a black moth.
Now you might say: OK Sal, that is one example, but I need more.
This is natural selection, this is purported to apply to everything,
it purports to explain why we evolved from basic bacteria
or maybe from self replicating RNA which I will talk about more in the future.
You know, I need more evidence of this - you know - I need to see it in real time.
and the best example of this is really the flu is really the flu.
And I'll do other videos in the future on what viruses are and how they replicate
and viruses actually are fascinating, because it is not actually clear that they are alive,
they're literally just little buckets of DNA and sometimes RNA
which we'll learn is genetic information and they're just contained in these viral...
these little protein containers that are these neat geometrical shapes
and that's all they are, they really don't have - you know - they are not like regular living organisms,
that actively move and that actively have metabolisms and all that.
What they do is they take that little DNA
and then they inject it into other things that can process it
and then they use that DNA to produce more viruses.
But anyway, I could, we could do a whole series of videos on viruses,
but the flu is a virus and what happens every year is that you have a certain type of virus
a certain type of virus and they have some variation
and I'll just make the variation by how many dots they have.
how many dots the have and they, in fact, - let's say it is a human flu, they infect humans -
and slowly our immune systems, which we could make a whole set of videos on as well,
start to recognize the virus and are able to attack them before they can do a lot of damage.
So now you can imagine what happens, if let's say this is the current flu,
let me do all of them, they all have these little two dots
and that's how and we'll talk in the future about what these dots are.
and how they can be recognized, but let's say that's how our immune system recognizes them.
they start realizing: O, any time I get this little green dude with 2 dots on it,
that is not a good thing to have around.
So I am going to attack it in some way and destroy it before he infects my immune system and DNA and all the rest.
And so you have a very strong natural selection once immune systems learn what this virus is
and we'll talk more about what learning means for an immune system.
that they'll start attacking these guys, right?
But flu , you can kind of think of them as being tricky,
but they are not really tricky, they are not sentient objects.
But what they do do: They constantly change.
so what you have in any flu population, you're always having a little bit of change,
so may be the great majority of them have those two dots, but may be every now and then
one of them has one dot, one of them has 3 dots, and maybe that is just
a random mutation, this just randomly happened, maybe one in every - I'll make up a number -
one in every million of these viruses has this only one dot instead of two dots,
but what's gonna happen as soon as the human immune system gets used to attacking
the virus with the two red dots, well then this guy isn't gonna have to compete with the other virus
capsules for infecting people he's going to have people's DNA all to himself.
He or she or what ever you want to call this virus, is then going to be more successful
so by next year's flu season
when people start sneezing and are able to spread it on door knobs and whatever else again,
This guy is going to be the new flu virus. So when you see this process of every year there
is a new flu virus, that is evolution and natural selection in real time. It is happening!
It isn't this thing that only happens over eons and eons of time. Although most of the substantial things
that we see in our lives or even in ourselves are based on these things that happened
over eons and eons of time, but it happens on a yearly basis.
Another example is if you think about antibiotics and bacteria.
Bacteria are these little cells that move around and we'll talk more about them,
they are definitely living, they have metabolisms and whatever else.
And so this is just a nice thing to know: When people talk about infections
it could either be a viral infection which are these things that go and infect your DNA
and then use your cell mechanisms to reproduce or it could be a bacterial infection
which are literally little cells and they move around
and they release toxins that make you sick and whatever else,
so bacteria these are what antibiotics kill.
Anti-biotics. Actually I don't think there is a hyphen: Antibiotics.
They attack bacteria, they kill them.
Now you've probaly, if you know a couple of doctors or whatever, and you say:
Hey I am sick, I think I have bacterial infection, give me some antibiotics,
a responsible doctor says: No I shouldn't give you antibiotics just willy nilly, because what happens
is that the more antibiotics you use, you're more likely to create versions
and I want to be very careful about the word create,
because you are not actively creating them, but let's say
- and let me finish my sentence -
you are very likely to help select for antibiotic-resistant bacteria.
Now how does that work? Now let's say this is a green
let's say that these are all bacteria and you have bazillions of them, right?
And every now and then, you get one that is slightly different.
Now in a random population of bacteria these all will make you equally sick
and this is just some random difference in the bacteria
may be on his DNA some slightly different changes happened, but whatever happened,
these all are the kind of bacteria that you don't want to get a lot of them in your system.
Your immune system can attack them and fight them off.
If you get a lot of them they might kill you or make you sick or whatever else.
Now, if everyone just starts using antibiotics when they are not sick or when they don't really need to
in a life or death situation, you might have an antibiotic that is really good at killing the green bacteria.
But what happens if you all of a sudden kill a lot of the green bacteria?
Well, now the blue bacteria have the whole ecosystem, that before it was competing
with all these green dudes to get at your - get all the good stuff inside of your body, but now he is all
alone and now he can replicate willy nilly, so now he is going to replicate willy nilly and obviously
and this is - once again - it isn't like there was any design, there was any intelligent process here that said:
Hey look, this bacteria should, - you know, I am some bacteria - said: I am going to be a little bit smarter
and design myself to resist this antibiotic threat .
No, there is just these random changes that happened and mutations in viruses and bacteria happen frequently.
And there are these random changes that happen and this might be this one in a billion change, right?
but all of a sudden if you start killing off all the people that it is competing with then this
guy can start replicating really fast and then become the dominant bacteria and then all of a sudden
that antibiotic that you had developed very carefully to destroy the green dudes is useless.
And you have this superbug. You might have heard the word superbug. That is what a superbug is.
It's not like it designed itself somehow. It is just that we got very good at killing its competition and so we allowed it
to take over and we can't kill it, because all of the drugs were just good at killing its competition.
And these bacteria just keep mutating and keep mutating
and if we use these antibiotics a little bit too heavily,
we will always be selecting for the things that won't be affected by the antibiotics.
Anyway, I think I have spoken long enough, but it is a fascinating fascinating topic
and I really wanted to make this my very first, my very first - I guess - video or lecture if you will on biology,
because if you really went to, you know: Biology is the study of life and we can talk about what life is
whether viruses are living and what not, but if you really want to study living systems,
you really can't make any assumptions other than natural selection.
We could go to another planet where the creatures don't have DNA
or may be they have some other type of hereditary information stored in their cells
or they replicate in some other way or
they are not even carbon based, may be they are silicon based
and if we went to that type of a planet in order to study the biology on that planet everything else we know
about biology and about viruses and DNA would be useless.
But if we do understand this one concept, this one concept of natural selection,
that your environment will select, and you know there is no active process here,
it is just some random stuff happened and they randomly select for random changes
and over large swats of time and these are unimaginably large swaths of time
those changes essentially accumulate, and they might accumulate for fairly fairly significant things
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