Well, we're a type of animal called primate:
monkeys, apes and lemurs and tar...siers...
[laughing]
[intro music]
Oh, what the [bleep] did I just kick?
So the places in the animal family tree where
these transitions take place...
shhh. [from back] the hell?
Something like this merganad... merganagadon.
[laughs]
This practice actually started back in the
middle ages, when educated peop...
Shut up.
Hardy-Weinberg principle.
Giffrey...
Godfrey Hardy...
God...
Godfrey Hardy and Vilhelm Weinberg...
I should stop doing the funny W's and just
be American.
Hey, look!
It's our old friend Gregor Mendel, the super-monk
who discovered the basic principles of genetics.
[gibberish]
Why are you getting naked, Darwin?
That's weird.
Oh, and here's our friend Chucky D. He lets
me call him that.
All of this information that Mendel figured
out would have been very, quite interesting,
oh f*** my... s***.
But under those "right circumstances"... [laughs]
Uh, balls... awww... [bleep] balls.
So evolutionary developmental biology, or
evo-devo for all of us cool kids, is the science
that looks deep into our genes to figure out
why the cracky knuckles?
I'm recording!
Early embryonic groundwork is laid, makes
a differ... a diff bigrence...
Which is of course total... to... totally...
totally far out...
-was the one who let us know what was up with
natural selection and how it can lead to allopatric
speciation.
Stop me if you've heard this one before, but
Darwin visited the Galac... [gibberish]
Now stop me if you've heard this one before,
but Darwin visited the Galacpagos...
Now stop me if you heard this one before,
but Darwin visited the...
Partly because some modern whales still have
vestigial remnants of a pelvis and hind bone
limbs... hind limb bones.
In fins per... ah... ah... so good.
*burp*
*belch*
*burp*
Are we... on?
Mammal!
At some point in our embryonic development,
humans actually do have gill slits like a
fish and tails like a dog or a pig or a jaguar
and webbed finger... pfff.
They have to be turned on and why aren't you
controlling it?
I!
Need!
To speed up!
-and population genetics gives it special
attention, particularly when it...
I'm too slow.
-particularly when it's come... particular...
Go faster, bunny rabbit, where are you?
Bunny rabbit?
Oh god.
Did that work?
Things get more...
Things get more...
Things get more.
Things get more.
They are also pseudo-coelomates like nematodes,
and although they have [gibberish]
One, they all have a visceral mass, which
is a true coelom, a body cavity completely
was in the [gibberish]
We each use our forelimbs for totally different
purposes; the bat flies, the whale swims,
women... women?
and they got a spinal cord running down their
backs protected by discs b...
protected by vertebrae and discs in between
them, and they got a tail, which doesn't...
have a... mmm.
all of the life that you think of as life
and quite a lot of that you d... [gibberish]
which contains stinging cells called... whoa.
The poss... [gibberish]
Just, stop at all but's.
Here's where you put the leg.
Here's where you put the tail.
The leg is over here, the tail is over here,
I don't know what animal this is.
What does it... is that what it says?
In addition to an endoderm and an ectoderm,
the embreyns... embreyns?
That's not a word.
I hate you.
And you...
now you... you n... pfff.
The same sort of crazy throwback features
have been observed in snakes with legs born...
born with... what?
Fossil remnants of another cedation... cetation
[sp?]...
Rode... why didn't I do a pronunciation guide
on that?
Rode... ah...
Rodocitus... anybody?
For instance because they're the simplest
of the tripo... triploblasts
How regu...
How reg... [gibberish]
Now you probably noticed I mentioned an explosion
a minute ago.
Well, I'm not going to taunt you with explosion
talk without giving...
But in addi...
But in addit...
But in a...
But in additio... in addition...
These guys are pseudo-coelomates, meaning
that they have incomplete... eh.
meaning that they have an incomplete body
cavity, unlike a true coelomate, the body
cavity is contained within the mesoderm...
what?
and the foot of a cephalopod has been modified
into a really powerful muscle that shoots
out water to help it steer and move... balls.
And next time, we'll talk about even more
complex animals... [gibberish]
Thank...
Thank you fo...
Thank you fo...
Thank you for bein...
Thank you for becoming smarter with us here
at Crash Course Biology.
If you are thought... furger...
And there's a table of contents over there
that you can click on and it'll take you to
the bits of the video, uh, that you...
want to see.
[laughing]
Thank you for watching this episode of Crash
Course Biography anus.
If you were confused about anything that we
covered today anus, you can go back and look
at that anus right now anus. [laughs]
