layers of tissue formed in early stages of development morula: bunch of zygotes (after mitosis) blastula: hollow sphere of cell, round hollow ball of cells gastrulation: blastula starts to invaginate (fold in on itself) "blastopore" gastrula: 2 layer thick, outer layer (ectoderm), endoderm diploblastic: have two germ layers. same mouth n anus. we are triploblasts: mesoderm blastopore forms mouth: protostome blastopore forms anus: deutrostome
At what point were we just assholes? Because as far as my med school embryology goes, we have a cloaca which is later on, during the urogenital development, separated into the anus and urinary tract. So, afaik, we were never "just assholes"
Also, the primitive intestine and the allantois (whose remnant is the urachus) come together in the cloaca. This video is educational, but human embryonic development is much more complex than this. Unlike animals such as sea urchins, after being the morula mammals don't become a blastula, they become a blastocyst, and after a process called compation, where outer and inner cells are differentiated, water follows ions into the intercellular spaces, and thus a blastocel is formed. The outer cells become the trophoblast, which is divided into the inner cytotrophoblast and the outer syntitiotrophoblast, which grows into the decidua of the uterus and later on becomes the placenta. The cytotrophoblast contains the embryoblast, which is comprised out of the epiblast, inside of which the amniotic cavity is formed, and the hypoblast, which creates the Heuser membrane, creating the wall of the primary yolk sac. Then it gets even more complicated with the extraembryonic mesoderm (or, due to historical reasons, mesenchyme), which divides into parietal and visceral parts and then combination of this and trophoblast forms the chorion, etc, etc. Gastrulation occurs in the epiblast, where the epiblast cells migrate towards the primitive streak, and in the process called invagination they are twisted inside, creating the three germ layers in humans - the ectoderm, mesoderm and endoderm. And then you have the prechordal and notochordal plates, but that's even more complicated so I won't go into that much detail. It's interesting, but quite complex to understand.
+aaaaammmmmyyyyyy There's an art installation created by a Belgian artist that is a poop tube. It's a machine that literally produces crap. It's pretty hilarious: www.amusingplanet.com/2012/05/poo-machine-by-wim-delvoye.html Talk about art imitating life imitating art!
Actually, this is incorrect (despite the best efforts of wikipedia to support the view). The invagination in the blastocyst forms our navel, not our butthole. The human butthole forms from the cloacal plate, while the human mouth forms from the prechordal plate. Both open up separately into the by-that-time already formed "inner tube".
May I just say THANK YOU SO MUCH HANK! I have my biology final exam this afternoon and you're helping me to remember all the terminology. You are one of my favorite people, buddy.
If Hank and John merged Bio and History... oh god... "So this goes to prove that you have a mouth, an anus, and cannot conquer Afghanistan unless you are... wait for it... a MONGOL SEA SPONGE!"
"...we were once just a butt hole attached to a little wad of cells." I want this on a t-shirt. Do you catch my hint (it's literally a demand but whatever).
That was the first Crash Course that was all about things I didn't know :) it was awesome! I'm glad I got to feel clever so far, and even happier to feel that I'm learning new things now.
Wow this is a great video. I'm a college student currently enrolled in Bio 211 ( an Intro class) and we're learning about Protsomes, deuterosomes (of course its more in depth). But my point is, this video is great! It has all the main ideas that are great to know!
it never fails to ease my mind when humbled by such perspectives, i like the idea of being a tube, i can manage that. Get ready universe! im gonna be a greatly simple and perfectly efficient element in your life!
Hey there Hank... do you, just maybe you know... as an hypothetical question, have any advice... on how to dispose a blenderized cat... without leaving any hint or proof of the cause of death?
MARAUDING SEA-SPONGE HORDES! This reminds me of that time I played SimEarth and (somehow) ended up with a starfish civilization? They made it to the Bronze Age--not bad for creatures that had to keep going back into the water. Maybe the Mongol-Sponges could be what invades their empire...
Though the main focus is on the content, I can't help but think, "wow, they're really good with the animations and illustrations." It really makes things easier to understand.
That whole thing about Haeckel, I heard from my high school teacher. Only problem was it portrayed it as fact. I'm a senior in college and this is the first time sense that sophomore year in high school that I heard anyone mention it or even dispute it. Thus, until I saw this video, I thought it was fact.
you and your tumblr hank XD i told my friend the thing about "we all were once just little butt holes" and my friend and i died laughing for a few minutes, then i ended up making his next phrase my tagline on deviantart "we're all just glorified assholes". fucking beautiful, lmao~
Thanks so much for this, I've forgotten a lot of this and it's a very helpful review both for my sister in high school (Biology, covering biodiversity!) and for me in college!
I finally decided to start watching the biology courses, and clicked on this one to start... Hank you in a hippie getup has got me convinced. Okay, I'll watch these. :) [Seriously though, way better than I expected...]
Being British, I cringed at the 'kind of a spaz' comment - here it's a really offensive term. Still a really interesting video though! And 'dude... no edge' - I love Hank! :)
My professor didn't deliver the lesson as hilariously as this. When it was mentioned that we started off as 'arse-holes' I couldn't contain myself, my inner 12 year old boy took over in a giggle-fit down front. This left me to explain to my professor, and 100 other students, that I know a few people that never really made it beyond that stage, clearly, they are still just one big butt hole. Hank, this was delivered the way all doctors and professors should teach it to their students, bravo! I nearly peed a little.
Were I an educator, I would encourage my students to study from these. And it would only make me glad that he was covering the same material as me in a format that the students love and feel like is just screwing around on the computer. As a student who had an exam with questions that could range from anything in text books that tend to have 48 chapters, I couldn't study the whole thing over the past few days, but this would have been more helpful. If it were posted yesterday.
It's amazing how the back of your book is the same is your green screen back drop, what a coincidence. Also, I totally dig CrashCourse:Bio way more than History. Thanks Hank.
It seems you've alligned these videos in accordance to my Adv Bio class so that they are posted just after I am quized on it in school. Not cool, Hank. That's totally forgetting to be awesome.
i love this i told my little brother "everyone starts out as an asshole a lucky few grow out of it" turns out i wasn't just calming him down, i was giving him a biology lesson ^^
Can someone please draw that? I want to see pictures of stomach-like tubes with anus's on one side and a mouth (with teeth) on the other, preferably crawling around.
By the way, Hank, "spaz" is an ableist slur, it might not be that good of an idea to use it in an educational series... Or, ever. Sorry if I'm not the first one who pointed that out and you already apologized for it.
"If there's anything harder than teaching people something, it's unteaching them something."
Well said.
layers of tissue formed in early stages of development
morula: bunch of zygotes (after mitosis)
blastula: hollow sphere of cell, round hollow ball of cells
gastrulation: blastula starts to invaginate (fold in on itself) "blastopore"
gastrula: 2 layer thick, outer layer (ectoderm), endoderm
diploblastic: have two germ layers. same mouth n anus.
we are triploblasts: mesoderm
blastopore forms mouth: protostome
blastopore forms anus: deutrostome
We all share one thing in common
In our mothers womb we all were once
assholes
Simply assholes
Isn't that beautiful
At what point were we just assholes? Because as far as my med school embryology goes, we have a cloaca which is later on, during the urogenital development, separated into the anus and urinary tract. So, afaik, we were never "just assholes"
Also, the primitive intestine and the allantois (whose remnant is the urachus) come together in the cloaca. This video is educational, but human embryonic development is much more complex than this. Unlike animals such as sea urchins, after being the morula mammals don't become a blastula, they become a blastocyst, and after a process called compation, where outer and inner cells are differentiated, water follows ions into the intercellular spaces, and thus a blastocel is formed. The outer cells become the trophoblast, which is divided into the inner cytotrophoblast and the outer syntitiotrophoblast, which grows into the decidua of the uterus and later on becomes the placenta. The cytotrophoblast contains the embryoblast, which is comprised out of the epiblast, inside of which the amniotic cavity is formed, and the hypoblast, which creates the Heuser membrane, creating the wall of the primary yolk sac. Then it gets even more complicated with the extraembryonic mesoderm (or, due to historical reasons, mesenchyme), which divides into parietal and visceral parts and then combination of this and trophoblast forms the chorion, etc, etc. Gastrulation occurs in the epiblast, where the epiblast cells migrate towards the primitive streak, and in the process called invagination they are twisted inside, creating the three germ layers in humans - the ectoderm, mesoderm and endoderm. And then you have the prechordal and notochordal plates, but that's even more complicated so I won't go into that much detail. It's interesting, but quite complex to understand.
Nightraven26 medical school education FOR THE WIN
randomtrucks And some people have stayed assholes.
randomtrucks And some people have stayed assholes.
We started from the bottom, now we are here.
LOL
+Gayatri Puthran hummmmmm
This is going to help me remember what deuterostome means on my coming bio exam and for that, I thank you.
no god why
Wasn't expecting the start of this video, hilarious stuff Hank
You = Tube
Oh boy
I laughed so hard
WOahhh... mind blowwwn...
U killed it breee 👉🏻👌🏻
IQ of 500 man right here right here
I can die peacefully now, knowing that we were all once buttholes.
hahaha
+aaaaammmmmyyyyyy There's an art installation created by a Belgian artist that is a poop tube. It's a machine that literally produces crap. It's pretty hilarious: www.amusingplanet.com/2012/05/poo-machine-by-wim-delvoye.html
Talk about art imitating life imitating art!
+aaaaammmmmyyyyyy It really puts into context calling someone an asshole now doesn't it? lol
omg my friend said that yesterday
Actually, this is incorrect (despite the best efforts of wikipedia to support the view). The invagination in the blastocyst forms our navel, not our butthole.
The human butthole forms from the cloacal plate, while the human mouth forms from the prechordal plate. Both open up separately into the by-that-time already formed "inner tube".
That intro tho
Samdara I know right like WHAT IS THIS
Really puts the Green in Hank Green
Oh the horror
May I just say THANK YOU SO MUCH HANK! I have my biology final exam this afternoon and you're helping me to remember all the terminology. You are one of my favorite people, buddy.
Who figured out the thing about the sea sponges and the blender? Some scientist was like hmm I wonder... bzzzzzz
Probably the "Will it blend?" guy.
life42theuniverse He probably wanted some sea sponge smoothie!
I can't thank you enough. You've helped me in my history exam reviews and now sciences throughout his school, and I just want to say thank you.
If Hank and John merged Bio and History... oh god...
"So this goes to prove that you have a mouth, an anus, and cannot conquer Afghanistan unless you are... wait for it... a MONGOL SEA SPONGE!"
>cue awesome montage of mongol sea sponges
Hank and John thank you so much for both this Channel and SciShow. I've learned so much since you started them. I really appreciate it.
When you said 'AAANUS' I just couldn't keep down my laughter.
"...we were once just a butt hole attached to a little wad of cells."
I want this on a t-shirt. Do you catch my hint (it's literally a demand but whatever).
I love this opening!
+InsideLauren'sWorld I was seriously questioning what exactly I was watching when I first clicked on this video. But it was pretty awesome.
Overall it was a grand opening
Dank Green returns!
I didn't like it.
"dude, no edge" *Whisper* "I know"
I laughed throughout this episode. Sooooo funny! Keep up the good work Hank :)
Hank u are an amazing teacher to me and other pupils that watch crash course so thanks for the help
CaptainClark thats one good comment
"If there is anything harder than teaching people something is unteaching people something." One of the best sentences ever.
We're just like, tubes, man. Dude. The internet? Tubes, bro. The government.
You-tube. Us-tube. We-tube.
I'm like, mega tubular.
Dude, no edge.
'Mmm... juicy....morula pie... Oh God! They are gonna ban us from schools...' 😂😂😂
@ 3:54
Sea Sponges: "We're the exception!"
*dramatic music
I think you've finally dumbed it down enough that I'm able to understand a whole episode the first time through. Well done.
"We were once just a butthole attached to a wad of cells"
This single sentence has made my day.
That was the first Crash Course that was all about things I didn't know :) it was awesome! I'm glad I got to feel clever so far, and even happier to feel that I'm learning new things now.
Wow this is a great video. I'm a college student currently enrolled in Bio 211 ( an Intro class) and we're learning about Protsomes, deuterosomes (of course its more in depth). But my point is, this video is great! It has all the main ideas that are great to know!
it never fails to ease my mind when humbled by such perspectives,
i like the idea of being a tube, i can manage that.
Get ready universe! im gonna be a greatly simple and perfectly efficient element in your life!
Hey there Hank... do you, just maybe you know... as an hypothetical question, have any advice... on how to dispose a blenderized cat... without leaving any hint or proof of the cause of death?
place in a container full of HCl :)
Darryl Villar 2 months too late, but thanks!
Eat it.
lye
bathtub
an hour of time
drain
flush it down the toilet, but im 5yrs l8
I didn't expect the video to start this way
A protostome?
Well, I was wrong, and ended up feeling like an ass.
Ahhhh you son of a bitch you 😂😂😂😂😂
I could just watch John Green's videos and understand the major concepts. His videos is such a great resource. Thanks.
so are sea sponges like the mongols? THEYRE THE EXCEPTION
Lol, was thinking the same thing.
+Daniel Body +change_your_fate
I demand a SeaSponge-gol-tage. :P
Cue the mongoltage
MARAUDING SEA-SPONGE HORDES! This reminds me of that time I played SimEarth and (somehow) ended up with a starfish civilization? They made it to the Bronze Age--not bad for creatures that had to keep going back into the water. Maybe the Mongol-Sponges could be what invades their empire...
I thought he was gonna say the mongols didn't have anuses of mouths.
Again, a wonderful You Tube presentation by Hank.
3:55 "Most animals have a mouth and an anus, wait for it, unless you are" a politician!!!
Though the main focus is on the content, I can't help but think, "wow, they're really good with the animations and illustrations." It really makes things easier to understand.
this is by far the best video of the handful I have watched, I couldn't stop laughing! P.S. crash course helped me get an A+ on my exam, thanks!:-)
you have a knack for teaching my guy, love your vids. Best around, keep it up!
We all start as buttholes, and some stay that way.
-my mom
U mean...assholes?
QueenSahara Eyes No, that's how she said it
best intro ever i cant stop crying :3 crystal hank for president lol
2:12 that's exactly what I said when he said that
Your videos on Biology have helped me finish up my studying for my exam tomorrow, thanks for all the edjyamacation
That whole thing about Haeckel, I heard from my high school teacher. Only problem was it portrayed it as fact. I'm a senior in college and this is the first time sense that sophomore year in high school that I heard anyone mention it or even dispute it. Thus, until I saw this video, I thought it was fact.
Yes, we also learned it as a fact in high school :/ (I'm from Europe)
I had those drawings he made in all my textbooks as a kid
It's nice to come across Crash Course videos that cover topics your high school (and university *shhh!*) biology classes preferred to skip.
Like here for sea sponge rights
Are they even animals?
@Someone404 no
Only video that actually shows you a good cut and view of the archenteron
"Dude, no edge"
"I know"
XD It's been a while since I laughed that hard!
If I were a high school biology teacher I would so use these videos. Entertaining and extremely educational.
Man, I got so scared CrashCourse will never be the same. (I'm not that stupid, by the way)
SOOOO awesome how you guys post this video right after the AP Bio exam when an essay question was exactly about this stuff
Hipster Hank is his new nickname
best intro to a biology course ever !! lol
you and your tumblr hank XD i told my friend the thing about "we all were once just little butt holes" and my friend and i died laughing for a few minutes, then i ended up making his next phrase my tagline on deviantart "we're all just glorified assholes". fucking beautiful, lmao~
Hank wearing a blond wig and trying to sound like a hipster fortune teller totally made my day
Dammit, your vids are awesome.
Thanks so much for this, I've forgotten a lot of this and it's a very helpful review both for my sister in high school (Biology, covering biodiversity!) and for me in college!
I need a nerd boyfriend like Hank, ASAP!!
Karley Spriggs Or we could clone him...
That would be great! Then everyone can the nerdy cute boyfriend they want!!
Karley Spriggs Ikr!!!
+Karley Spriggs If only every girl thought like you.
Lol, nerd power!
Hank is the dreamboat of science
"Dude, no edge!" Good times.
You got the plural of Phylum right! My HONOURS biology teacher does not. Thank you hank!
CAN YOU BE MY BIO TEACHER PLEASE
Loved the way you started this one
I’m developing a crush on Hank
Thank you for the Table of Contents! It's super easy to find what I'm looking for!
0:00 MY LIFE IS COMPLETE! XD
I finally decided to start watching the biology courses, and clicked on this one to start... Hank you in a hippie getup has got me convinced. Okay, I'll watch these. :) [Seriously though, way better than I expected...]
I'm always high in biology same
Hank is the only reason I have hopes of passing my AP Bio exam on Monday. Thanks man :)
wait for it, the sea sponges
*cue the sea sponge-gol-tage*
Favorite opening to a video ever
Being British, I cringed at the 'kind of a spaz' comment - here it's a really offensive term. Still a really interesting video though! And 'dude... no edge' - I love Hank! :)
Yeah I hope he's apologised since
My professor didn't deliver the lesson as hilariously as this. When it was mentioned that we started off as 'arse-holes' I couldn't contain myself, my inner 12 year old boy took over in a giggle-fit down front. This left me to explain to my professor, and 100 other students, that I know a few people that never really made it beyond that stage, clearly, they are still just one big butt hole. Hank, this was delivered the way all doctors and professors should teach it to their students, bravo! I nearly peed a little.
How many times had you said the word "anus" in this video?
hank's face at 3:51 is legendary. that coupled with the fact that he is about to say anus in a very strange way just made my day
Sea sponges are the new Mongols
Were I an educator, I would encourage my students to study from these. And it would only make me glad that he was covering the same material as me in a format that the students love and feel like is just screwing around on the computer.
As a student who had an exam with questions that could range from anything in text books that tend to have 48 chapters, I couldn't study the whole thing over the past few days, but this would have been more helpful. If it were posted yesterday.
Brb, buying a blender and catching a squirrel....
still my favorite biology video ever
"Ban us from schools?" They show these in schools!??? My high school was never that awesome.
Hank Green makes me love bio even more.
Me looking at these comments 8-11 years later
It's amazing how the back of your book is the same is your green screen back drop, what a coincidence. Also, I totally dig CrashCourse:Bio way more than History. Thanks Hank.
Deuterostome. I was once only an asshole.
1:50 damn it was going to try that experiment on my little brother.
But if they are such simple creatures, how can the sea sponge live in a pineapple under the sea?
Who lives in a pineapple under the sea?
Tyler Snow he means spongebob
SPONGEBOB SQUAREPANTS
It seems you've alligned these videos in accordance to my Adv Bio class so that they are posted just after I am quized on it in school. Not cool, Hank. That's totally forgetting to be awesome.
You-tube?
I just took my bio 102 final....this video was a huge chunk of it! i plan on sending this video to my teacher to help her future students!
heyyy.....dduuuudee....
i love this i told my little brother "everyone starts out as an asshole a lucky few grow out of it"
turns out i wasn't just calming him down, i was giving him a biology lesson ^^
lol the hair
Sea sponges are the Mongols of Hank's videos
Can someone please draw that? I want to see pictures of stomach-like tubes with anus's on one side and a mouth (with teeth) on the other, preferably crawling around.
thankyou so much hank. you helped me pull through just enough to pass my bio exam after not paying attention all year
dude... no edge
I wish I could explain to people why your digestive system is so freakin' awesome like you do.
He is cute by the way
HOW HAVE NOT MORE PEOPLE WATCHED THIS, YO THE AP EXAM IS IN A WEEK ISH
By the way, Hank, "spaz" is an ableist slur, it might not be that good of an idea to use it in an educational series... Or, ever. Sorry if I'm not the first one who pointed that out and you already apologized for it.
Love the 'no edge' at the beginning.