Hey again! Today we're going to begin delving into the
theory of evolution. Since most people don't really know much about it other than the most
absolute basics, we're going to go through it pretty much from scratch. There's a looooot
to cover though, so this's going to take a few episodes. By the time we're done though,
you'll have a pretty good working knowledge of how evolution actually works, and how you
can apply it to your world to make it that much more interesting!
This first episode devoted evolution is going to cover the most basic concepts, and then
we'll go through the evolutionary process over time and cover some more nuanced stuff later.
Soooo, why cover this at all? I mean, evolution's
only a theory, right? Well, it's also the single theory with the
most evidence we have of any theory that exists. Yeah, gravity's only a theory, but you don't
worry about randomly flying off into space, do you? The heliocentric theory is that the
earth revolves around the sun, yet you can see that if you just look up in the sky...
so what's a theory? I've covered theories before, but let's review
this - a scientific definition of a theory isn't the same as what most people call a
theory. Generally speaking, most people use the term "theory" as scientists do "hypothesis"
and a hypothesis is only the start of a theory. Your hypothesis is basically saying you have
an idea of what might be the case. In our example of evolution, that means we have a
hypothesis that plants and animals, and all living things really, follow a specific process
by which they adapt and change over time. Note that at this point, we're not even questioning
whether life adapts and changes over time - that's already a fact. Evolution, in the
sense that most people understand it, isn't a theory - it's flat out fact. It's *MORE*
than on par with the idea that if you jump up in the air, you'll come back down again.
That things are pulled down to the earth's surface isn't in question either - that's
also a fact. We know it happens. We know exactly how fast it happens as well; at 9.80 meters
per second squared at the earth's surface, with minor variations based upon the density
and placement of mass within the earth and how far from sea level you are and such.
The point there is, the hypothesis for how gravity works has nothing to do with whether
you're going to fall back down if you jump. The hypothesis is detailing things like warping
space-time in 11-dimensional space with the graviton being the carrier particle for the
force of gravity. The previous theory of gravity was newtonian physics' version, which said
that objects just pulled each other together, which was proven to be false; objects don't
directly interact with each other, but rather warp the space that other objects are situated in.
So yeah, basically "gravity" as a hypothesis,
was proven wrong. That doesn't mean that people randomly start flying off into space by jumping.
So back to what a hypothesis is - it's just the defined guess at what people think is
happening. To go from a hypothesis into a theory, a theory
needs a hypothesis to start with, but it also needs a few more things to qualify as an actual theory.
First off, it needs to be falsifiable. Meaning
if you make a claim that's impossible to prove one way or the other, or to disprove it, it
can't be a theory. A theory absolutely must be able to be defined in such a way that you
can say "If we ran a given test, then if A happens, the hypothesis may be true, but if
B happens, then it's guaranteed false because B can't happen if it's true."
Note that the phrasing there says if A happens, it doesn't guarantee the hypothesis is true,
it only says IF the hypothesis is correct, then A would happen. You could have several
different things which could cause A to occur, so it doesn't guarantee that the hypothesis
is actually correct. And this is why theories are "only theories" - no theory can ever be
100% proven as actual fact, as that would require 100% of absolutely all information,
all circumstances, every shred of data in the entire universe to be certain of it as fact.
All a theory can ever do is be challenged repeatedly by saying "it would be false if
X happens" and finding out that X never happens. As soon as X happens, even once, and can't
be explained by any other means, the theory is falsified and is no longer a theory anymore.
So, that's one major reason why evolution is only a theory - it's not possible to ever
be anything more than a theory. The next part that's required to make a theory...
well, a theory... is that is has to have a predictive model of some sort. Meaning you
have to be able to say "if the hypothesis is correct, then it predicts that X will happen."
In the theory of gravity, this meant that there were several predictions made, such
as what the orbit of newly discovered planets should be, and in fact, predictive models
that said "according to the hypothesis that this is how gravity actually works, there
should be a planet found exactly HERE based upon the way other planets act nearby, and
specifically, that the previous theory of gravity can't account for this planet's existence
and/or location." This's how we discovered Pluto, and it's how
we proved that the planet Vulcan didn't exist inside of Mercury's orbit.
So you need some pretty good evidence to even be considered for theory status. Remember,
gravity's also only a theory and we use it to predict all sorts of stuff with amazing
accuracy on a regular basis. And evolution is vastly better defined than gravity is.
We'll go into examples of such later on, but you kinda need a very good grasp of a lot
of different stuff before most of the examples make much sense, so we'll be getting into
that later on. For now, we know that a theory needs an initial
hypothesis, a predictive model, and it has to be falsifiable.
In addition to such, a theory needs to have loooots of evidence, many different data points
from many different fields of study. Evolution has an absurd amount of evidence pointing
towards its validity from everything from geology to archeology to genetics to molecular
biology, just to name a few different fields which support it. We're pretty much constantly
getting bombarded with more and more evidence that the theory of evolution is correct, even
when we're not even looking for it. We just constantly stumble across it all the time
in what may have even seemed to be completely unrelated fields of study previously.
Anyway, the final major part of a theory is
that its predictions have to be at least as accurate as the predictions of all other (competing) theories
which already have predictions in place, and any experiments which have ever been run,
it must be 100% accurate with predicting the results.
Meaning if anyone has ever run any experiment before, the theory absolutely must agree with
the results. If the experiment would have disproven the theory, then it's not a theory.
If another theory which already exists does a better job of predicting outcomes than the
new theory, it's also not a theory. So yeah. "Evolution is only a theory" isn't
really a criticism of evolution - being classified as a theory is pretty bloody hard to do! And
for evolution to be the single, best-defined theory with by far the most evidence towards
it compared to any other theory in the history of humanity... yeah, that's saying something.
So again, the basic concept that creatures change over time and turn from one species
into many different new species, is not a theory - that part's fact. We already know
it to be true. What the theory of evolution is, is exactly how evolution actually works.
There's no question that we get from point A to point B, it's just a question of exactly
HOW we're getting to point B. Yeah, I know, this's kinda repetitive and
annoying, but we seriously need to clear that stuff up before we even get into what evolution
is because it's so commonly misunderstood what evolution even is, or what a theory is
for that matter. So... you may be asking how can we evolve
from monkies if monkies still exist?
Erm... well, yeah, that's a common question, but it's the wrong question to ask and shows
that you don't know what evolution is. So let's get into that right now, shall we?
The basic concept here, is that if you have an isolated group of living stuff, then it
will randomly mutate and change. The vast majority of these mutations will be detrimental
and wind up getting the creature or plant or whatever which developed them killed off.
For brevity's sake (yeah, like that's ever mattered to me before...) I'll just focus
on creatures here. Sooo if a mutation is negative, it'll wind up with fewer creatures being able
to breed and produce offspring. If you die before you have kids, it doesn't matter what
the mutation is, it won't get reproduced. If the mutation happens to be beneficial towards
the end of producing more children, no matter how that may present itself, then the chances
are good that the mutation will start to show up more frequently in the population, until
it becomes pretty much universal. Now this's pretty important to understand
- this is only an averaging effect over a long period of time. Stuff which is beneficial
tends to stick around for a long period of time. Stuff which is detrimental tends to
get weeded out after awhile. Small, tiny changes may take a very long time and many, many different
generations to produce a noticible effect. For a case study, if we look at something
like lizards in deep, underground caves where there's no light... they originally had eyes.
You can even pick through their DNA and see, oh, hey, there's genes in here that describe
how to make eyes... but those genes are dormant and don't work anymore. What happened is that
the lizards which had eyes had to expend energy and nutrients on building those eyes. It took
more food to grow eyes than lizards which didn't grow them, or which grew deformed,
smaller eyes or ones which lacked important parts to make the eyes work. This meant that,
on average, over a long period of time, a lizard which produced eyes which sucked as
eyes, but which cost less food to create, was less likely to starve and more likely
to be healthy and strong in other ways because the lizards with working eyes didn't get any
benefit out of them. As these lizards were deep underground and
isolated from other lizards above ground, they were able to independantly adapt to their
specific environmental conditions. The lizards above ground still have eyes. They have use
for their eyes, and can benefit from them, and the benefit gained from having eyes leads
to them being better fed on average and surviving longer to produce offspring than those lizards
which don't have eyes. The ones below ground in deep caves are entirely separated from
breeding with those above ground - they're two separate groups in two separate conditions,
and as such, it's possible for them to diverge into two separate species.
As such... just because a new species of lizards without eyes evolved, it doesn't magically
make the previous species of lizard with eyes disappear.
Yeah, if there were only one small breeding group, where the genes would be transferred
universally amongst those present, then yeah, that entire group would tend to change over
time and the previous species would go extinct usually. If the only lizards in the world
existed in that underground cave, then the lizards with eyes would no longer exist. But
that's the thing about evolution, as long as you separate the breeding groups from one
another somehow, they can diverge into new species.
So yeah, humans didn't evolve from apes nor monkies anyway, we share a common ancestor
in the distant past which is now extinct and happened to branch out in several different
directions because there were several different groups which were isolated from each other
and found themselves in different conditions which allowed their various random mutations
to proliferate. So the question of "how can we evolve from
monkies if monkies still exist?" isn't really a valid question in the first place because... well...
we didn't evolve from monkies in the first place, but even if we did, there's no reason
that monkies would have gone extinct anyway, just extirpated, meaning one region of monkies
would have disappeared as they changed into a different species, but any other monkies
that existed in the world that weren't in breeding contact with them, would still exist
unless they also were locally extirpated. A local extinction, rather than a global extinction, if you will.
Anyway! So uh... to go back to that thing
we covered earlier... the genes which produce more offspring consistently over time tend
to carry on is described rather clearly by Richard Dawkins in his book, The Selfish Gene.
This was a revolutionary concept at the time it was introduced, and involved a lot of backlash
at the time, but it makes a lot of sense. Basically, he describes all living creatures
as merely being gene replicators. If a creature fails to replicate its genes, it gets discontinued.
Those which replicate the genes become very good at doing so.
What this means, is that if you had a really weird random mutation that... oh I dunno...
let you live to be a thousand years old, that'd be pretty good for you as an individual! Buuuut
if that same gene also made you sterile so you physically couldn't have kids... it would
die with you as well. It wouldn't enter into the gene pool, you'd never produce offspring
which also share that gene, so it wouldn't become something that happens to show up within
the species over time. It doesn't matter how good your genes are
- if they don't increase your chances of making copies of the genes, they're a genetic dead
end. As such, the "selfish gene" is one which only cares (in an anthropomorphized manner),
about itself. If the gene doesn't benefit via replication of that gene, it doesn't matter
how beneficial it is to the creature that has that gene, it won't have any effect on
increasing the liklihood that the benefits will be carried on.
Now... that doesn't mean that it can't happen. Like let's take that same example - a gene
where you basically live to a thousand years old, but nothing changes otherwise. (As in you don't go sterile from it.) Women
and men both basically "run dry" in humans after awhile and no longer are capable of
producing offspring anymore. So this immortality gene, as we'll call it, doesn't naturally
produce more children than it would otherwise. It doesn't see a wide distribution within
the population because people with this immortality gene don't have more kids than anyone else.
However...! Just because it doesn't have any immediate benefit, doesn't mean it gets removed,
either. It isn't really harming anyone... so it just kinda sticks around within that
very small percentage of the population. No big deal.
This means it has time to wait around until it can piggyback off other genes. Let's say
that one of the small number of people with this immortality gene, also just haaaappens
to also mutate a gene that lets them produce twins every time they have kids. They basically
produce about twice as many children as anyone else (well, sorta. About 1 in 8 births are
twins actually in humans, but usually one twin absorbs the other in the womb, but for
this example we'll say both twins are born every time.), and what that means is that
the one individual with both the immortality gene and the twins gene, will now make more
kids than other people... meaning their kids will become more numerous and also have that
immortality gene. In this manner, the gene proliferates because
it piggybacked onto another gene along the way.
We see this happening with negative genes as well - there's only a few ways to do something
right, but an infinite number of ways to do something wrong. As such, most genes are going
to suck. You know that kid who was deadly allergic to peanuts? Yeah, that seems a lot
more common these days, doesn't it? That's because it's a lot more common these days.
The fact of the matter is, severe allergies to commonly occuring triggers tended to kill
those people off before they lived long enough to have kids. You didn't get many people who
passed on the peanut allergy genes because well... they were dead before they were old
enough to have kids. Nowadays, we have much better medical technology
and a lot of these people who would have otherwise died, now live long, full, healthy lives and
can have lots of children! Which's great for them as individuals, so yay! Buuut uhm, it
also means there's now more children being born with deadly peanut allergies because
their parents didn't die - they lived long enough to have a child who also inherited
this bad gene. Or, yanno, any of a number of other negative genes.
To put it bluntly, nature runs a eugenics program. It doesn't matter if you like it
or not, it simply is what it is. And what it is, is a program which weeds out negative
genes. By bypassing this rather heartless, cruel eugenics program with medical technology,
we've literally weakened the human race. Our immune systems aren't remotely as good as
what they were even a few centuries ago. That thing about, oh a kid in king arthur's court
or other such tales of going back in time? Yeah, they would have realistically died in
about a month just because of the conditions they would have been exposed to back then.
We are getting taller, we're getting stronger, we're getting smarter... not by much, but
we are getting smarter, but we're also getting fatter with weaker immune systems and all
sorts of genetic diseases are being carried through which wouldn't have existed a few
thousand years ago because they would've been weeded out by natural selection and the evolutionary
process. We've basically got a gardener who thinks
weeds are beautiful, and has actively been planting dandilions, which are sucking up
all the nutrients the other flowers need to survive, and the gardener's "fixing" the problem
by just adding more nutrients to the soil. The problem there, is that more nutrients
to the soil go predominately to the weeds, not the flowers, which grow even bigger and
stronger than before, while the other flowers only barely survive, and eventually this is
going to turn around and bite us in the collective genetic butt.
Basically, we're talking a plague which will wipe out like 50% or more of the population
before we find a cure to it. It's not even a matter of if, but a matter of when. Sooner
or later, we're screwed, and a looooot of people are gonna die.
Yeah, that "survival of the fittest" thing isn't a joke, but quite much so a reality.
The thing is, what defines the term "fittest" anyway?
Well, the dinosaurs were the fittest creatures at the time for the conditions they were in...
but then those conditions rapidly changed with a rather large meteor impact. The meteor
kicked up huge amounts of dust into the air and blotted out the sun for quite a few months
to possibly years... the oxygen content in the atmosphere decreased, a bunch of other
effects all took place in a chain reaction and, well, the dinosaurs were only the fittest
in the previous conditions of the world. In the new conditions... they kinda sucked.
And then they went extinct because they weren't the fittest anymore. In fact, they weren't
particularly fit at all in these new conditions. The term "survival of the fittest" is reliant
heavily upon what the definition of "fittest" means, and the fittest is only the most fit
for that particular set of conditions. Being the "fittest" for a given set of conditions
tends to make that creature exceptionally good in that one, narrow situation,
but as soon as the situation changes, they're not so good anymore. Hence why some scientists
have started trying to use the term "survival of the fitter" instead, the implication being
that the creature which is "fitter" isn't necessarily one which is the best for that
situation, but instead is the most adaptable to new circumstances.
For example, raccoons and coyotes have adapted amazingly to city life and there's been an
enormous population explosion within the big cities because of such. Raccoons in particular
aren't exceptionally fit at any one particular environment, but they do very well in many
different ones and can adapt very quickly. As such, where other species die off when
the situation changes, that just leaves behind the raccoons who are perfectly capable of
surviving in the new situation, and... because they're the only ones left alive, they "win"
by default as the "fittest" creature around. Anyway, there's a tooooooooooon more stuff
to cover about evolution! Like we've only ever so barely scraped the surface, and yet
this's a pretty lengthy video! I tried to warn you, this's going to take
awhile. Don't worry though, it'll be worth it, because the principles you're going to
learn over the coming months (or hours, I suppose if you're just viewing this like a
few years from now and watch the evolution series back to back), these principles will
allow you to create vastly more interesting flora and fauna for the worlds you create,
and the same principles also apply to culture in a lot of ways, so it's important to understand
this before we get into culture generation for your world.
For the moment, I could give you homework, but this's been long enough of a video already so
I'm not going to. Just think about what's been covered and how you could make use of it for now.
Anyway, with that, I'm out. I'll see you next time!
I kinda want to toss a bone into the air...
see it turn into a spaceship...
then have another bone fall down on top of it and create a giant explosion...
and yell "YOU MANIACS! YOU BLEW IT UP!"
and then look up into your dead, lifeless eyes and wave, just like this.
Can you and your associates arrange this for me, Mr. Morden?
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