Evolutionary Development: Chicken Teeth - Crash Course Biology #17

[@christaylor8271]

So let's just recap here; Old genes, like the teeth in the chickens, can be "turned back on". They had that gene because they evolved from dinosaurs. Scientists can interact with gene regulators, like putting an extra eye on the fruit fly. ... Do I have to spell it out? Where the hell is my Dinosaur theme park?

[@belindachong7474]

There's an entire series of movies why that's a very bad idea

[@doppelhelixes]

Just go to an austrich or emu park

[@guairefernandezamil4084]

Chris Taylor there are birds parks, and birds are dinosaurs

[@orion8829]

oh, I thought you were leading up to the point that scientists need to put teeth on chickens because that would have been way more interesting.

[@Jim90117]

Don't be so preoccupied with whether you could, that you don't stop to think if you should.

[@anoli2759]

McGinnis is a molecular biologist and professor of biology at the University of California, and he studies the evolutionary changes in transcription factors by looking at the Hox genes.

[@RedMinorFilms]

You can't not tell us the story of how that blood got there!

[@johns3929]

Amazing facts about Hox genes: 1. Sequence analysis showed that the homeodomain of one of the mouse Hox genes differs from Antp gene of drosophila by only one amino acid. 2. Similar mechanisms for segmentation occur in flies and mammals even though they are separated by some 600 million years of evolution. 3. Everything else about hox genes.

[@glowhazel]

1:41 "Shut up" "No I won't shut up!" You tell em Hank

[@CatzEyz66]

I am so glad Hank exists. There needs to be someone to show the proper level of enthusiasm for this stuff.

[@Jim90117]

I wonder what would happen if we turned on all the regulatory genes in a human, i like to imagine we'd have superpowers but i'm guessing we'd look like something out of a horror movie.

[@MeshachMalley]

+Ulrich Purath I disagree. I think that humans evolving quickly could be a success to the sustaining of the human race.

[@AnimaRytak]

+Dragonaut111 Tumor. You would be a tumor.

[@rachelallen8241]

and messing with the human genome like that is pretty illegal.....

[@karigrandii]

Dragonaut111 GREAT MOVIE IDEA

[@sandman7883]

we would look like cronenberg monsters

[@fred321cba]

There seems to be a contradiction between physics and biology. According to physics, nothing travels faster than the speed of light. However in KZbin comments, creationists have their arguments shot down in flames in what appears to be faster-than-light speed.

[@GermaphobeMusic]

This isn't just regular evolution. This is... _advanced evolution._

[@Yamikaiba123]

*Goes to comments section to see if there's anything interesting.* "Who else is watching this for their AP class test they have tomorrow?" *Nope...*

[@alaaalhalabi3773]

Yamikaiba123 I am watching it for philosophy

[@silaskuemmerle2505]

what about an IB MYP test?

[@boldanabrasevic3020]

Curiosity?

[@brianvu764]

I was looking for some insightful discussion but apparently, everyone else is studying for their tests

[@insanity1505]

Im in college our professor just uses these videos instead of lectures. Literally that is it nothing else just a link to the video a discussion about the video and a weekly 25 question test that is word for word pulled from quizlet. 4,000 a semester well spent(sarcasm). Also this is not some low level community college this is a tenured professor at a D-1 school, and people wonder why our generation complains about the education system.

[@NeonsStyleHD]

Another question: When they did this messed up experiment and the fruit fly grew an eye on it's leg, did they test to see if the fruit fly could see from this new eye? ie did it have an optic nerve connecting to its brain? I assume not, since that would require more instructions to be sent to make the optic nerve also. Fascinating subject, I must know more.

[@grinleef295]

And does that mean that we could maybe eventually create "super beings" that have features that enhance their function? like actual functioning eyes on the back of your head; or lots of mini brains that we have forced to grow inside of your thorax that will enhance your psychological abilities?

[@NeonsStyleHD]

@@grinleef295 5 years later, the science is in. Theoretically yes. Though no one has done this on humans for obvious reasons.

[@forzee42]

@@grinleef295 Oh god! That's like.. If I.. I can't even form this question. Right, so let's say we somehow make a human with an eyball(s) on the back of it's head, even if it's connected with the brain; how would it see if our brains aren't accustomed to 360 field of view? Or are they?? Would it be a 360deg view with blurred spots near ~160-200deg? Or would the image overlap in the front if you've got all your eyes open? Lets not even talk about the eyes on limbs...

[@littlebelleblue]

This is absolutely what I want to do with my life. I always have the hardest time trying to explain it to people, now I'll just show them this. I love being a scientist.

[@Zhmenka]

This guy is truly amazing! I've never thought that someone can combine science and humor and make it really interesting to listen the stuff which is normally boring to read about

[@nataliebernstein926]

In my Advanced Biology course at my college, he has us watching your videos every week! Thanks for making such great content!

[@XhanAnimations]

-astonished- "Shut up!" -sassy- "No, I will not shut up" xD

[@VicariousGamer]

As usual it's a great video but the major mistake is listing homeobox and Hox genes as the same things. All Hox genes are homeobox genes, but not all homeobox genes are Hox genes. It isn't just a misuse of brackets, later in the video Hank says we have several hundred Hox genes in our genome, which is entirely wrong. If you Google "difference between Hox and homeobox" it'll be explained. I love Crash Course!

[@jazzyjake6503]

i cant entirely blame critics of evolution as i doubt any person is equipped to truly grasp the length of time involved in such a process. and you wouldnt be entirely wrong either to say "its just a theory." but the fact remains that evolution is one of the best supported scientific theories in ever. there are absolutely heaps of evidence to support it and to say something like "call me when you see it happen" is to say: if two men go into an empty room with one door and no windows, one comes out with a hot gun, and the other is found recently dead of a gunshot wound from that same gun, no one can be found guilty since it wasnt observed.

[@Artesian_Turkey]

I don't normally add something to my favorites list, but this video had me fascinated enough just with the potential for new discoveries that I had to do so. Thanks!

[@BeaChapman]

This is my favorite Crash Course video.

[@andrej_capko]

I started watching Crash Course in order to pass the final high-school examination. I still use it to revise for the uni exam, but man, I would watch this as a TV show before going to bed!! Thanks everyone who makes this possible, whether it be for us who need to pass the exams, or us who enjoy geeking out on stuff like this :)

[@314rft]

+andrewcapko Or in my case, it's actually PART of my biology homeworl. Biology just got 10x more interesting.

[@GarbageDevon]

This was one of the coolest crash course biology episodes yet! Thanks for the comprehensive overview of such a cool field! The part about chicken teeth made my brain esplode!

[@angelinafiera3998]

This video did terrible things for what was a mild fear of birds.

[@doppelhelixes]

Don't think abput them as Bords, think about them as avian dinosauriers, after all they are closely related to velocyraptors

[@Mad_S]

My cockatoo is just a bird version of a 5 year old. If you hold it she wants it, and if you aren't looking at her she is mad. But give her 5 seconds and she will crawl up into your sweatshirt and cuddle with you.

[@surisurisuri29]

BLOOD STAIN ON THE CEILING! Jesus.

[@zarkarimi]

As someone in CS, evo-devo makes me very happy! It's kind of like computation is the last major paradigm shift in human understanding. After that, understanding new things becomes a recursive call to that paradigm itself.

[@vildantoran644]

When we watched some of these videos in class after taking notes about the topic, I was tripping over his words because he talked too fast. Now that the Bio exam is coming up, I'm binge watching all these videos, and it's absolutely amazing. These videos tie up everything I learned, and I am able to catch up with his pace very quickly since I know everything. I wish luck to those who are taking the Bio Exam in 2017!

[@coolcatho13]

Liking, just for the "SHUT UP!!" comment in the background.

[@talakemaiva7297]

"Shut up!" Was also my reaction. Hank Sassy reply was not expected. I love this, made my day. #BioLover

[@lauraenever6634]

I'm not studying any of this for uni and have legitimately no reason for watching this. But god damn it was fascinating.

[@dwood2001]

Fantastic video. These are getting much easier for me to follow now and much more distinctive. Doesn't seem like as much of a mad rush. I understood the earlier videos, but I was never going to retain any of it.

[@WolfieJoeyGirl]

Hoemobox genes are something I'm gonna start studying in A-Level Bio soon, so I thought I'd give this a rewatch. Thank you for making A-Level seem easier!

[@nataliebernstein926]

"Shut up..!" "No, I will not shut up" Haha, hilarious

[@PatrickSmith104]

This is officially the coolest thing I've ever learned!!

[@KenLaSalle]

Hank et al, Love your shows! Love 'em! But I am blown away by the amount of (let's call them crazy people) your videos attract, the kind who get offended by science because it doesn't support their religious teachings. I just wanted to let you know they're not the only ones watching. (What? They're not watching? They're just posting comments? ... oh.)

[@FlyingCowRabbit]

That's a bit disrespectful, and not really funny. It amuses me how both: -Some religious people (particularly monotheists) think they're so right about science (well, evolution) being all a load of tish-tosh. -Some atheists think they're so right about religion being flat-out wrong, and science being right. And they smugly like to point out that those of the above criteria are ignorant, uninformed and old-fashioned. Look, perhaps there're faults in both things (i.e. banking solely on religious scripture or scientific evidence). So can't we just be respectful (i.e. omit the "crazy kind" and the prejudices of the so-called 'eager' and 'stupid' religious believers who allegedly skim through scientific videos simply to post comments about science being wrong), and not infuriatingly smug? We all know the saying: "Pride comes before a fall." That being said, I agree that this show is awesome. Have a good day.

[@servals2384]

I've already read about a lot of this a while ago in the book "How to Hatch a Dinosaur", but this video does a great job at summing it all up and making it seem really cool.

[@silversyntax]

i am a Computer Engineering student(i love science! if you're asking why i am here) and this topic is pretty interesting. Those instructions, those genes triggering a chain reaction is like a computer microprocessor. It is made of bunch of transistors which are basically switches, different configuration of switches will make different logic gates, arrange them and triggering a single switch will trigger other gates and switches in a nanosec chain reaction that will eventually get the work done.

[@beef.9316]

"Shut up!" "No, i won't shut up"

[@suhanahussain7]

1:58 xD

[@ratatat12356]

I love CC but Idk why they say at the end of their videos "if you have any questions ask us in the comments." I've never seen them in the comments whatsoever

[@utopia196]

_I have, frequently._

[@ratatat12356]

can you point me to where you seen it?

[@utopia196]

_There are plenty in the newer courses._

[@crisrobles3425]

Probably to get ideas for future videos

[@4571police]

"How about 85% similar?" *background* "Shut up!" *Hank looks backwards* "No, I won't shut up!" Lol

[@4571police]

Funny, the asterisks I put in my comment disappeared.

[@RedChaosScrungle]

4571police It's cause of youtube's new google + comment format.

[@4571police]

Huh.

[@fglogs6821]

hands down, the best educational channel on youtube!

[@lcorinth]

These videos are like TED talks. In that they're educational, entertaining, and awesome.

[@iamjacquie]

"How about 85% similar?" *"SHUT UP"*

[@U_F_N_M]

Why is this so infrequently mentioned during debates on evolution?

[@murdoc80]

Good point, i think it will be an great argument and also hard to counter too :)

[@proton8689]

it's new

[@veganchris1933]

Who actually googled up Bill McGinnis?

[@sarahwagner5413]

***** ....me.

[@veganchris1933]

Lol me too

[@shourishmukherjee1510]

me

[@denisegrapes9041]

me

[@ardijan706]

Me!

[@trekgirl100]

I struggle with all of science and have been watching these videos to try and better myself and i have to say this was definitely interesting, and really thought evoking thanks

[@XCrystalXMoonX]

The story about the fruit fly actually made me cry. We still have so much to learn about ourselves.

[@Quetzalcoatl_Feathered_Serpent]

So technically if cloning doesn't pan out we can still have dinosaurs in our future?? I want a pet Raptor!!

[@ethanbravin894]

eaglerocks123 we will never have any exact dinosaurs. If we genetically modify a chicken it will be a chickenasaur.

[@rjch0173]

Who would have thought - biology adopted object-oriented programming. :)

[@TonyTigerTonyTiger]

More like the other way around. Inheritance was a term in biology long before it was in OOP. Same with polymorphism.

[@MenwithHill]

DNAunion It's a rugged, well though-off and effective model with its own detailed terms and concepts that bases itself on the principle that explains the progress of life from basic to complex... would have been a waste not to take it.

[@PrimusProductions]

You know that software engineers taken a note from nature, look up genetic programming, genetic algorithms and evolutionary algorithms, one can use these heuristics (techniques) to optimise programs and search for solutions to problems. Some, such as NASA, have also be used GA/GP in conjunction with Computer Aided Design to create machinery too.

[@taurus_says_hi8404]

F A N T A C I N A T I N G

[@sazarod]

Best episode of Crash Course Biology so far. Well done, Hank & Co.

[@tincre10]

Took a break from my biochemistry research project in a medical school lab to watch this video! Keep it up!

[@SigniaDesign]

Wait wait wait. So through manipulation of these regulatory genes, you can easily - relatively speaking - control where body parts are positioned. So we could, for example, genetically engineer humans with lots of legs that should actually function as human legs by, say, using a regulatory gene(s) from, say, a spider?

[@thatotherguy27]

Well, number 1, that would be super unethical, and number 2, legs require a lot of other stuff to work like legs - a pelvis to plug into, a bit of backbone to tie the pelvis into the rest of the skeleton... In short, you could probably do it, but it would take a lot of very messy experimentation and a knowledge of genetics greater than what we currently know. You couldn't have settled for a 6th digit on the hand, could you?

[@jimisquirrell6262]

Absolutely, but I'd like to just point out that you wouldn't need to take the hox genes from a spider to give a human more legs, you could just have multiple iterations of our own hox gene for legs! Like Hank said, the regulatory genes don't actually say anything other than "make leg here" - and lots of animals make legs with the *exact* same regulatory hox gene. Like mentioned, however, human legs need a pelvis and a pelvis is a pretty complicated structure. We could put lots and lots of legs on somebody but those legs would be very limited in movement and would serve no purpose other than to make life really, really difficult.

[@jangwoo24]

You could but it's not as easy as putting them in a fruit fly or something since humans are _waaaaaaaaaaaaaaaaaaay_ more complicated than flies, and no one would want the extra legs, and such

[@natattacc99]

Dear Crash Course, Can you easily explain genetic drift?

[@SunnyDays9]

So could you take a "grow a tail here" hox from another animal, put it in a human, and make them grow a tail?

[@reigngage]

Hackers show more respect for the coders than these guys! Amazing how they can't see the Truth staring them in the face. Too bad that Bush-appointed fed judge OUTLAWED EINSTEIN's views..."I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; the rest are details." OR "Every one who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe-a spirit vastly superior to that of man, and one in the face of which we with our modest powers must feel humble." Its good to see they're backtracking on "junk DNA" though...quietly.

[@driveslow2010]

I believe they mention (maybe this video or a previous one) that we begin our development with a tail and, I suppose, have genes that say "no tail at this point" for humans. It appears that all the embryos have a little tail when they start developing... and I'm pretty sure there are people that have longer spines that protrude like a tail.

[@SunnyDays9]

antoinette laforce So.. yes. (: I wonder if it would be unethical since its something that can be removed without causing deformity.

[@driveslow2010]

Kendra Desmone​ I don't know about unethical but I'm sure there wouldn't be too many folks lining up for a tail... or, could be big business for the cosplayers at comicons. Lol! But, yea, we could possibly have tails :)

[@SunnyDays9]

antoinette laforce Too bad wings aren't possible :( I'd rather have those than a tail

[@skyblazer7]

Fantascinating...love it. One thing to note is that humans are also sometimes born with prehensile tails, an the snake is born with vestigial legs, or the chicken embryo has vestigial teeth.

[@BasBleu02]

Yes, you blew my mind! WOW! The beginnings of answers to questions I asked as a kid in school ... so many years ago that your parents might not have been born yet. :-) Not a lot of things make me want to be young again, but evo-devo makes me want to be a little nerd-kidlet again in today's era of scientific discovery. Thanks, Hank.

[@Mucksauce]

Snakes with legs? No thank you.

[@killerbee2562]

Boas have remnants of rear legs en.wikipedia.org/wiki/Pelvic_spur

[@oscarestrada3926]

killerbee256 Good ole vestigial traits :)

[@Mad_S]

I could see them tripping all the time.

[@TheAlocam]

so can we activate all dinosaur genes and then make something as dinosaur resembling as possible. also would that mean that chicken tastes like dinosaur?

[@killerbee2562]

Or you could just make a chicken grow a full tail, teeth and fix it's arms. www.creativereview.co.uk/images/uploads/2012/10/convenience_food_1.jpg www.inspirefusion.com/featherless-chicken/

[@NeonsStyleHD]

A really cool thing to do until it eats you

[@ChaneloAdventures]

omg now i understand why birds are considered reptiles

[@ssosafiscella]

These CraschCourse videos are just brilliant! In behalf of all your fans, thanks a lot, Green brothers!

[@FlorianFahrenberger]

I think this is the first episode that told me something really new. And it was awesome! Don't get me wrong, the others are great, too, to help me not forget all that stuff I read a long time ago... Keep spreading the awesome, guys!

[@reallyCaden]

Damn, Our lord and Savior works in mysterious ways... I PRAY TO YOU EVERY NIGHT FLYING SPAGHETTI MONSTER LET YOUR NOODLEY APPENDAGES BLESS ME WITH HOPE

[@thatotherguy27]

When you walked in the sand and saw no sets of tracks, that's where the FSM cradled you in his noodley apendages as he hovered along.

[@FuseBit]

"Not gonna lie, they had us in the first part"

[@Anemoiaspaceghoul]

Nice to meet u my fellow atheist. 💖 Glad to meet another atheist like me.😘 U got me good with the first part. Lol.

[@kathyxie6061]

Wait does that mean we can make dinosaurs from birds

[@blueNet101]

In theory, yes.

[@zhongliangcai602]

0:03 watch this in 0.25 times speed

[@valentinsarmagal]

The best one of the series so far. You made me a fan. Go evo devo!!!

[@ThatSoddingGamer]

This was a great episode IMO. Probably the most exciting of the lot. In part, I think the dood's excitement rubbed off on me XD

[@TonyTigerTonyTiger]

+Charlie Peterson: Um, what? Humans didn't evolve from reptiles, and spiders are not reptiles. In response to your, "So if you can turn on old regulatory genes that have been repressed through mutation... does that mean humans could redevelop reptilian traits? The Amazing Spiderman all makes sense now."

[@Kronimiciad]

Reptiles came before mammals. Yes, we evolved from reptiles.

[@TonyTigerTonyTiger]

Kronimiciad No, mammals did not evolve from reptiles. There are two clades of amniotes: synapsids and sauropsida. Mammals evolved from the former whereas reptiles evolved from the latter.

[@queergeologist8207]

DNAunion In other words we were all fish. If I remember correctly, and I am probably wrong, fish evolved into amphibians, then MAMMAL LIKE REPTILES so in a way Kronimiciad was right, but I said they were Mammal like Reptiles.

[@haye7475]

Hannah Glenn well were did those fish come from.

[@TonyTigerTonyTiger]

jacob nichols en.wikipedia.org/wiki/Pikaia (may be an ancestor of fish, or at least anatomically close to an ancestor of fish) en.wikipedia.org/wiki/Haikouichthys (may be an early fish)

[@napoleon_bonaparte2462]

I'm... going to become a biologist? I'm just a curious physicist/chemist/mathematician, pls don't hurt me T_T

[@Doc_Loc]

BLOODMOONNNNNNNNNNNNNNNNN! *gets out knife*

[@silaskuemmerle2505]

*swiftly disarms KnightCraft 130* not today scumbag, not today Bonus points if you know where that quote is from

[@Doc_Loc]

jokes on you sucker i got like 10 mil knifes *pulls out Knife-seption

[@silaskuemmerle2505]

KnightCraft 130 I hate to do this, but... *pulls out the mother of all machine guns*

[@Doc_Loc]

bruh you can't beat Knife-seption it's just not done *pulls out Knife-seption machine gun*

[@swimkid526]

This just saved me about an hour of searching the internet for AP Biology. Thanks Hank

[@WayFinder42]

@crashcourse Thank you everyone who works on these! So awesome!

[@macmarty2025]

Really great video. You did an awesome job of explaining these new ideas and thoughts in biology. Not an easy task, new ideas are so often tumbled and tangled up in such a way that makes it especially difficult to sort, teasing the meaning of them out of them. Thank you very much.

[@stacieheck2649]

"Fantastisizing!" Nice one. As a nursing student who is miserable in microbiology class, I'd like to thank you for making it more exciting, interesting and relevant. Please keep it up. DFTBA

[@sehmio]

This is my favourite CrashCourse Bio video so far! Love your enthusiasm Hank :)

[@weshard1]

Brilliant stuff! Evo-Devo has been a fascination of mine, ever since i learned of evolutionary biology. Thanks!

[@lili011]

It's possible for chickens to have teeth? Sir Hank Green, you have accomplished your goal. You have BLOWN my mind.

[@TheNellehFox]

I just watch this for fun, this was a very fun one! Such awesomeness! I watched a programme recently where a guy was looking at chicken embryos, and showing how they could basically make tiny chicken dinosaurs by re-surfacing those old features that begin in the development but aren't kept for hatching.

[@ClockworkGriffin]

When I was a kid and I said I wanted to be a scientist, I specified Archaeologist and that I wanted to dig in the ground looking for lost pieces of our past. And I did, I am, and it's awesome.

[@MysticMD]

thanks so much hank!!!! your videos are the best introductory learning tools! always keeping it interesting and i have to admit i cant help but smiled a few times throughout the video at your nerdiness haha! cheers!

[@lightandarklove]

Favorite crash course bio so far. Great job Hank

[@MrEgrave]

fantasinating. you evolved that word to better express evo-devo's awesomeness

[@aliensuit1495]

Great episode! Learned something new from it However, I'd like to do some further reading on evo-devo It would be nice if you guys could provide us with some sources in the description.

[@NavaneethMurthy]

This was the coolest episode so far!

[@ohthatsclever]

There's some dripping water in the background of the video (intentionally). It's not annoying; I just noticed it and thought it was worth pointing out. Also I'm just as blown away by instantly giving chicken teeth as Hank seemingly was. That's incredible.

[@ccubed215]

I love how Hank said "you PROBABLY haven't thanked your mom" because ya know Nerdfighteria and some people probably have actually thanked their mom for that

[@michaelrch]

The point that the mouse version of the “make-an-eye-here” gene works for flies is amazing. That means that this is a gene that has been in the DNA of these animals’ ancestors, unchanged, since at least as far back as when they had a common ancestor, which is at least (guesstimating here) 300+ million years ago. The fact that it’s the same gene is amazing evidence FOR what creationists deny as “macro evolution”. It makes it obvious that flies and mice have a common ancestor.

[@Kitt0Katt]

This is an awesome video! Evolution and mutations are incredible and fascinating. Fantascinating indeed :D

[@vimalramachandran]

Chicken growing teeth is super awesome. What a vindication of the theory of evolution.

[@RebelAngel474]

Always nice to see someone who actually knows about the halo universe for a change :D

[@LeahMarkum]

"Fantascinating" is now part of my vocabulary. I needed a word to properly express my excitement when learning cool stuff.

[@killerbee2562]

+Leah Markum Never watched star trek did you?

[@K9Negative]

one of the best videos yet! fantascinating

[@mrosters]

4:21 Now you don't have to google it: Bill McGinnis is a molecular biologist at the University of California, San Diego. McGinnis studies the evolutionary changes in transcription factors by looking at the Hox genes. His main research has been comparing Hox genes between species to see if they are kept intact during evolution. One long term objective of the research in his lab is to understand the molecular interactions that underlie functional specificity in the Hox patterning system.

[@isardiv08]

Science is absolutely amazing. I can't even express how i feel about it. Thank you so much for you videos

[@jemanjii]

For once i can honestly say history is more fun... I love Hank but John is my favourite teacher.

[@ms_dlou]

Homeotic genes also known a homebox genes are not the same as HOX genes as u stated at 2:54. They are different. A homeobox is a sequence of DNA within a gene. The protein that results from the gene will will include a small number of amino acids that are dictated by the homeobox sequence. This part of the protein is known as the homeobox domain (or just homeodomain). The importance of the homeodomain is that this is the part of a protein that can interact directly with DNA (or RNA). So, proteins that contain a homeodomain can act as transcription factors. Equivalently, genes that contain a homeobox sequence can be regulatory genes. Hox genes are simply one group of genes that contain a homeobox sequence, and which are very important in body plan development. However, there are plenty of other genes that are not hox genes and also contain a homeobox sequence.

[@velositee]

I love you Hank

[@mishmashmixofstuff]

Awesome episode. Also I got the answer right about the eyeball on the fruitfly's leg before Hank said the answer.

[@hanyuukawaiinanodesu]

so far Hank you have made the entirety of biology fantacinating for me OwO

[@theWACKIIRAQI]

Please make a video elaborating more on the relationship between regulatory genes and macroevolution. Thanks anyway and keep up the good work

[@yuridisaroamado9562]

This one was the most revealing enlightening amazing content of an youtube video ever!

[@googoosmd]

To answer the second part of the question, the removal of earlier traits alongside new ones is enough to account for the speed of bird evolution. Additionally, many of those traits were already developing in raptors and their relatives. For example, they had strong legs for jumping. Feathers are first shown from the early Jurassic, millions of years before birds hit the scene.

[@EtherealToxin]

This is the sort of thing I've always wondered about. And now I know, and actually understand it. Thanks!