Today we're here to talk about evolution.
If you didn't know, 
evolution is a theory. The theory of evolution states a
couple of really important things. 
The first that that it states is it that modern organisms are descended and modified
from ancient organisms. The other thing that is states is
that evolution is based in DNA.
DNA and a conglomeration makes up genes.
And when we look at the theory
of evolution, what we find are that genes change
in a population, now we're not talking about
individuals, we are talking about a large
group together. That is the way that evolution exists 
is through populations. And these genes and a population
they do you change from one generation
to the next
over time in very small increments. So you don't see changes 
in evolution from one generation to the
next. Meaning that, 
you wouldn't see me, who looks like this, have offspring 
or a child that has wings. That would be a
really crazy change
or modification in evolution.  But what we might see
in thousands of generations or millions years
is that humans do evolve or change into it
a different form. So evolution does take indeed a long time. 
And it is based in DNA.
 So, you might be saying, "So what's a theory?"
A theory is very different than a hypothesis. Generally the way that we use the word "theory" every day
is totally incorrect. So if someone says, "I have a theory 
that this weekend it's going to be much
warmer that is has been 
this past two weeks." Well, that's incorrect. That's just a hypothesis or an educated guess. 
A theory is information
that is based, and usually it's a natural
phenomenon, that's
based on a lot of data by a lot of scientists 
and they all come to the same conclusion.
Now, you think about this piece of
information, we often call it a fact. It is not necessarily
completely true because we might find that
in the near future
that someone disproves this "fact." The thing is 
that technology of changes overtime so we
might find that we discover a new
piece of technology that disproves the theory
 of evolution for example.
But at this current time,  there is lots
and lots of data
by lots and lots of scientists. They all come to the
same conclusion
of those points I just talked about about
what is the theory of evolution.
And nobody at this time can disprove that.
So today, I want to give you some information
about what those facts are
or what that data is that tells the
evolution is a theory.
So we're going to look at five different
pieces
or parts of the data set that tells us that
evolution is a theory.
We are going to look at embryology, limb structure,  
fossil and transition animals, skull structure, 
and then also, biochemistry.
So let's start here with embryology. Embryology is the study of embryos.
What we mean by an embryo is that as sperm and egg come together
and they make that first cell, they go through a period of what we call cleavage, 
or that one cell goes into two, it cleaves into two, 
it cleaves into four, it cleaves into eight… And then we 
get eventually actually the amount of cells that we are in our body. 
So embryology is the study of a fertilized egg and how it develops.
Now, if we take a look at these pictures here,
I'm guessing that you all can tell the
difference between a pig and a human.
and pretty easy doppler
however let's take a look at me and we
have three different
yes we have humid we have pig and we
have
leader you tell the difference between 3
now
very good he 3 organisms they're all
vertebrates
that me user organisms that have a
backbone
so any early and rheology
worked fine that the three organisms
well very
come from a very common faster
now if we take a look at something like
a firefly
and wanna be's with the there early and
reality stages
are very different so everything will be
you might not know that this was a good
year first one 31 was okay
31 is the human their similarity
shows that of closely related
faster now let's take a look at
