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 people...

Shut up.

Hardy-Weinberg principle. Giffrey... Godfrey Hardy... God... Godfrey Hardy and Wilhelm 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 biggerence...

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 embranes... embranes? 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 cetacean... cetacean [sp?]... Rode... why didn't I do a pronunciation guide on that? Rode... ah... Rodhocetus... 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 addition... 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 being... 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]