Population Genetics: When Darwin Met Mendel - Crash Course Biology #18

[@TheFireflyGrave]

'Like Fast and Furious movies, there are five of them.' Come on man, you had to know this reference would be outdated within a year. 'Do not mate randomly' on the other hand, is universal advice that transcends time and culture.

[@peterdiers1966]

ya now there are 8 and making a 9

[@hannahcaplan9261]

my anthropology professor assigned us to watch this video for homework. and you explained it better than my professor whom i'm paying $20,000 + tuition for. thanks, hank.

[@bookishogre]

We might be in the same anthropology class...

[@leo-hao]

Stallkeeer....

[@seankhoyle3168]

@@bookishogre i'm in it now as well lol

[@MrJuandahero]

you and you're brother should consider making a crash course for math too, hopefully their's a third neglected brother with nothing going on.

[@littlewitchParker3]

Juan Gonzalez as long as their third brother is hot/handsome and not boring just like the other brothers.

[@maxmclean7733]

*your

[@parpzful]

Apparently you need one for english too.

[@vidSpac]

Maybe he can do the grammar crash course

[@supreetsingh987]

Dave!

[@MelanieDitmay]

I wish I could pay my university tuition to SciShow and Crash Course instead.

[@annag6400]

+Melanie Dittmer My lecturer linked us to the Natural Selection video for our Genetics paper which was pretty funny. But these videos are great and cover stuff that we have learnt in the lectures

[@BarbarosaAlexander]

"And I have good news! It's going to involve a lot of math..." Just spat my soup across the screen.

[@renegade839]

😂😂😂

[@shaymysarmstrong3278]

BarbarosaAlexander so funny 😂😂😂

[@phenomenalphysics3548]

Lol😂

[@lialo2636]

I said EWW out loud in my campus library hahahahah

[@Adam-lw6es]

Alphabet soup and Scott the Woz is the perfect combo 🥰.

[@DavidFelipe03]

I'm a biologist and I study population genetics. You explained the basis in an extremely simple and accurate way. Your video was a nice review of the general principles, thanks!

[@weaveroflaurel]

The best thing about these is your humor-it makes all the rest of it so much easier to relate to and understand. :)

[@richardxu7251]

It is amazing that you can write backwards.

[@NessieGoesWild]

They're mirrored the whole video. His mole is on the wrong side and he is wearing his wedding ring on the wrong side as well.

[@brycefergusson8573]

NessieGoesWild Whoa. You're observant. Cheers Nessie!

[@dovregubben78]

Oh, so that's _not_ a women's shirt! That doesn't explain why he wrote the percent sign backwards though.

[@EyeLean5280]

Seni, I noticed those things, too. Glad it wasn't just my imagination.

[@supreetsingh987]

@@EyeLean5280 do you sometimes imagine things reversed?

[@comfortablegrey]

I like how the video is flipped horizontally, so he didn't have to learn to write backwards or anything. Really clever!

[@Toey346]

I was wondering how that worked!

[@ethanling1576]

it is but he is writing on a glass

[@joshuathompson3258]

Thanks for dropping this here, my wife and I noticed he was flipped early on and I had to come check the comments on the vid while we were watching :)

[@PhysioAl1]

No Elijah, he is writing from his right to his left, so that it looks left to right for us. He is indeed writing on glass, as Ethan said...

[@comfortablegrey]

@@PhysioAl1 You are right that he's writing on glass, but please note that Hank Green has a birthmark on the right side of his neck in real life but on the left in this video.

[@Iksnalow2]

"Don't mate randomly" lol this made my day

[@Leonpavo]

I'm about to get my teaching certification after a year of being out of school. Your videos are a life saver. I never even learned this stuff in college.

[@b0t_papa]

Hey Hank, so I don't comment a lot, but I have a biology final tomorrow and I've had a pretty difficult time with biology. I was cramming tonight, and this video really helped me stop freaking out because you explained things so clearly. It takes a whole lot for that to happen. So I had to comment. You may never see this, but never stop what you're doing man, you're awesome. Thanks on behalf of all 121, 231 people that have watched this video.

[@ebkdoa3535]

So is no one gonna talk about the fact that there's been a board in front of Hank all this time and we only notice when he starts writing?

[@courtcourt9723]

slow down the playback to 0.5 if you wanna hear Hank teach drunk genetics

[@kritimishra387]

🤣🤣

[@andresguty]

Done!

[@sophie7704]

omg lol sounds like that drunk person at the party who just starts sprouting random knowledge and facts everywhere

[@rusiru4082]

LMAO

[@usercanalviejo2]

I heard the intro music theme at that speed and omg it cracked me up xD

[@imakevideossometimes2916]

Crash Course, the youtube channel that goes beyond time itself and is forever relevant

[@Bexahlia5933]

"Alas, earwax." - Harry Potter easter egg

[@themaskedninja763]

THANK YOU I COULDNT FIGURE OUT WHY THAT MADE ME SO HAPPY

[@leo-hao]

FBI man Thank you sherlok Oh wait, FBI

[@leo-hao]

By the way i love HP so i basiclly got every word memorized

[@peterdiers1966]

????????????????????? earwax is not a Harry Potter reference

[@Jez2600]

Thank you very much for this video. I'm at university, 2nd year, studying a module called Evolution and Genetics and the Hardy Weinburg equation. The video helped me with my revision by giving me the background knowledge again and working through the equation. Really helped, thank you :D

[@vaciladoras]

Dude you are awesome!!! I absolutely loved it. Enjoyed it. Laughed with it. And refreshed, already known concepts, with it. Wish more professors... actually high school teacher were more like you. Keep up the good work.

[@manamejeffbeezos]

"Just like fast an furious movies there are five of them." ....yeah, about that.

[@islamsaied4135]

YEAH ABOUT THAT XDDD

[@bymyspotfordreams9057]

I'm getting worried about your unhealthy fixation with earwax...

[@HendrikHenderson]

+Abhinav Das: The video was edited to be flipped. For him, he wrote normally, but when flipped, it was left to right (normal) for us.

[@dasvader90]

LoL thanks, I don't know all these fancy shmancy camera tricks these yougins use these days.

[@thingamabitch]

/holds up Darwin and Mendel fingerpuppets/ NOW KISS!!!

[@brandonkim8423]

Kinda like Sims, eh?

[@haye7475]

Kimchi Kim just with less trapping of your neighbors

[@brandonkim8423]

jacob nichols by putting them in a room and blocking the doorway with a chair?

[@haye7475]

and putting very flammable objects in there, and then putting a few lit fireplaces in there with them.

[@brandonkim8423]

jacob nichols yeah. Ugh, a neighbor. Kill it with fire.

[@trishalish13]

"Alas, earwax." Thank you, Dumbledore!

[@brandonkim8423]

When he tried out those Jelly Bean thingies :D

[@loissharpe2760]

*Moment of silence for Richard Harris*

[@shaunakiyomi]

bless your soul hank i watch these for fun but i have a genetics exam on thursday and guess who loves crash course i doooooooooooooooooooooooo

[@ShelbyGTMustang60]

I'm a maths undergraduate and totally just watched this as a simplified version of what I'm doing at the beginning of my final year project :) But alas no Punnet squares, got to love Punnet squares. It goes so well with the Hardy-Weinberg Law :)

[@paulb7824]

Thank you Hank! You've just made my genetic's exam tomorrow a lot easier!

[@winniejan5510]

You have helped me more than any tutor at my university and have saved my ass a couple times. Thank you Hank Greene

[@arshmeetkaur9600]

*Green

[@MikeJones-qn1gz]

Im doing this in my Bio class and I understand how to use the equation and work the method however I dont understand why we still use this theory when most if not all life on the planet is effected by mutations, natural selection, migration and genetic drift. How can Hardy Weinberg have any application when alot of the assumptions needed for a Weinberg application do not occur in most populations? In short can sombody explain how this method can apply to everyday populations in this day and age?

[@Anonymous-gb6ur]

Mike Jones The Hardy Weinberg Equilibrium might be impossible, but their equation is still used to guess at the allele and genotype frequencies in populations.

[@kristenemurphy814]

Mike Jones The Henry Weinburg equation is mostly just used as the null hypothesis to compare actual populations to. For example, if a rare homozygous recessive trait occurs more often in an actual population than in the Henry Weinburg equation, the population likely engages in inbreeding that increases heterozygosity.

[@MikeJones-qn1gz]

Ahhh ok so its a weird way to figure out how inbred a population is, have to tell my Teacher that.

[@puncheex2]

Mike Jones As in all such efforts, the simplified equation gives the result in the basic case, and provides a basis on how to determine the non-simple cases.You don't stop with H/W, but you use it as a starting point. Without it you haven't got a clue for approaching the hard cases. There are numerous cases of laws promulgated under unrealistic ideal conditions: the ideal gas laws, ideal springs, perfectly resistive circuits with no induction or capacitance, ideal antenna behavior, and so on. Even motion without friction (f=ma, v=d/t) are idealized.

[@amandaburger6560]

When he said “alas, earwax” I SCREAMED DUMBLEDORE we love a hp fan

[@zoedoss6639]

the hardy weinberg equation is just a punnett square thanks for coming to my TED talk

[@moviemaker1986]

Haters, yes. Some say "evolution is not real! Look to religion!" Some say "religion is not real! Look to science!" (I'm paraphrasing, of course.) But there's no need to manufacture a debate between science and religion where only one can "win." You know, there is ample room for both to coexist. So many people miss that point.

[@killerbee2562]

Unless your talking about Buddhism, science and religion can't co-op exist. Because science has proved over last 200 years how religion is wrong, it hasn't set out to that but it has done it anyway.

[@moviemaker1986]

killerbee256 I can't really respond to that statement because there's nothing to respond to that I haven't already said. Come back with actual examples of how you see science proving religion wrong, and I can respond to those. I mean, if you're actually looking for a response, trying to start a discussion. If you're not, well, don't bother and I won't either. Why do you think Buddhism is special in this regard? Why the last 200 years? Why not more or less than that timeframe?

[@killerbee2562]

Jack Eggebrecht Then you don't know much about science. Genesis is wrong, because we have fossils and genetics evidence that prove humans are just animals related to other animals. Geology proves there was no great flood and that the earth is 4.54 billion years old. Linguistics show the tower of babel story is that just. There were no 10 plagues of Egypt, because A we can read Egyptian records and B archaeologists don't find mass graves dating to that time. The wall of jeriho were not destroyed in the era the bible claims the Israelites returned. I could go on but I don't need to. And why two hundred years? Because that's about the time science broke away from religion fully, what I mean is that's about the time a scientist could propose something that countered the bible with being arrested. en.wikipedia.org/wiki/Buddhism_and_science and for more exmaples of how the bible is wrong read this en.wikipedia.org/wiki/Historicity_of_the_Bible

[@kristur1]

There is no debate between science and religion. It would be irrational to argue against a scientific theory on the basis that something you think is true for no adequate reason (i.e. faith) is contradicted by something that has been demonstrated to be true more thoroughly than anything unscientific. No reasonable person would doubt the reality of evolution by natural selection because in support there's so much evidence that it is literally the foundation of modern biology.

[@M941CheeseMan]

kristur1 Personally, I am an atheist and that is just my opinion but I think there should be a debate due to the fact that neither you, nor anyone can explain why it occurs. Not on a human level, but on a universal level. We have no idea why we exist or any of the things that science proves because no-one knows why the universe exists. For this reason, until we can find out why the universe exists or even how it was created, we can't rule out religion because in that sense, it is clear to see why people do support that side of the argument when we cannot say where it all came from or why. In what killerbee is talking about in response to the bible, I believe in the bible, not because I think a man with a stick parted the red sea, or Jesus had the uncanny ability to kill Mycobacterium Leprae. It was stories who wanted to help live their lives to good principles like helping others. They were like short stories that had a moral to live your life by and however much their reality was pushed in the centuries after it, it may have not happened, but the lessons learned are still applicable as humans today.

[@jamescarmody4713]

You explain Hardy-Weinberg better than Khan Academy. These 11 minutes made more sense to me than Sal's entire microlecture.

[@torimoss7481]

“Just like the fast and furious movies, there are five of them.” Well that didn’t age well.

[@Lady_in_Yearning]

- Hey, Hardy! - What's that, Weinberg? - How do you like these new educational shows? - I guess they're alright but why all the puppets? - Well, at least we know where all of the budget went! DO-HO-HO-HO-HOH!

[@arturosanabria8815]

When?

[@chibiprussia5574]

What

[@datherax]

Maters gonna mate, potatoes gonna potate

[@mrleiby1]

nice.....

[@lalaithan]

Taters

[@sweta_verma]

You gonna urinate

[@franklinpope7941]

Ha that was FuNnY

[@KawaiiKoalaBear]

This is really helpful! I've been having a hard time wrapping my head around this because it seems to fly in the face of everything else I've learned. Thank you!

[@erincuentas529]

Hank, I'm a high school bio teacher and really want to understand this well before I teach the connection between population genetics and evolution. As far as mutations go, how do we know helpful mutations were indeed mutations and not just less frequent alleles that became more frequent under the right environmental pressures? For example, lactose tolerance. How do we KNOW that was a mutation? Where can I learn more about the percentages of mutations that are helpful, silent, and harmful?

[@williaml872]

How did you become a teacher if you don't even know your own lesson plans

[@margaretjanowski-bell7585]

Erin, First, all genetic variation ultimately came from mutations: changes in the DNA nucleotide sequence. Some times rare alleles will become more frequent due to changing environmental conditions. The Rock Pocket Mouse is an example of this. (www.hhmi.org/biointeractive/making-fittest-natural-selection-and-adaptation). HHMI has a great set of resources addressing the genetics of lactose intolerance. It comes with a great video found here: www.hhmi.org/biointeractive/making-fittest-got-lactase-co-evolution-genes-and-culture . If you scroll down you will see the lesson plans and activities for students. The pedigree activity has students find the mutation in the DNA nucleotide sequence. Have fun with your students!

[@fluxbird]

william l Maybe this stuff wasn't yet known when they got their education?

[@mrsdiggory3211]

I'm a new teacher, struggling to explain all these equations without sounding like nonsense rambling in the class, finally know how to explain clearly now. thanks!!!!

[@Sara-pp9fm]

I absolutely love the videos. Has helped me better understand my genetics professor and you actually make it fun

[@SadeMetsavirta]

College is a great environment to observe random mating take place quite frequently

[@ItsRiya123]

"alas, earwax" honestly love everyone could use a good dumbldore quote

[@kimberlywilliams4603]

So glad you uploaded this! Easier to understand than the past few lectures I've had in genetics! Thanks so much!

[@edmondrieffer4060]

Strange that I noticed this but the image in this video is mirrored. His mole on his neck is on the right side in this one but it's on the left in all the others. And his ring is now on his right hand instead of his own left.

[@dogdemon62]

It's so you can read his writing.

[@henrypeterson211]

Yeah, Maybe, he wants people to think he doesn't have one.......?

[@sixmilllpesoman4741]

well ive gotta thank this guy he got me through my bio30-1 course

[@stephaniemcnugg9693]

You lost me at "you know math?"

[@JALong-hp6zv]

BEST helping you learn "all the stuff" videos ever! I love this guy :)

[@losthighwaygnr3685]

"Do not mate randomly !" LOL !!!! I love CrashCourse :)

[@terrygyatso3928]

Dude this was amazingly helpful, he was crystal clear in his explanations

[@Stilllife1999]

"Chucky D." Honestly, wtf.

[@spacedoughnuts]

NOBODY HAS EVER MADE ME UNDERSTAND HARDY WEINBERG UNTIL NOW THANK YOU WILLIAM HENRY GREEN

[@lollipoplilly100]

you make life in bio so much easier! I LOVE YOU!!

[@fallintomexo]

I show LITERALLY all of your videos to my students

[@dtcanxz]

"And I have good news. It involves a lot of math!"

[@Jiggelmeister]

how did he do the drawing? was their a glass surface in between him and the camera? special effects?

[@TheSpoonyFox]

So... the meaning of life is 0.42 instead? *grin*

[@colleenwindell]

Spoon Fox LOL!

[@jeffmckeown023]

Well played.

[@maxmclean7733]

Bravo m8!

[@flyingfoxes2630]

No. Why 0.42 instead of 42? It's not 42%.

[@colbyfrison9416]

*sigh r/wooosh

[@atalantaarden-miller2860]

This was a really clear, excellent explanation of population genetics. Thanks for slowing down the pace a little: all the biology videos are amazingly interesting, but sometimes the pace is so quick and the cognitive load so high it's difficult to take in all the information.

[@Zerepzerreitug]

"...and I have great news, it involves a lot of math!" that cracked me

[@Chautice]

This is exactly what I'm learning at university in my Evolution paper, so watching this is kind of like studying so thank you a lot ! It really helped hearing this from a different person as well, and TBH you actually do a better job of explaining it then my lecturers...

[@vsj2k]

hey hank! thanks for that informative video on Pop-Gen(as you call it) ...could you just make another video on the derivation of H.W Equilibrium explaining covariance etc; (since you love math). thanks once again!

[@rosiecarter6631]

In my physical anthropology class, my instructor used the example of a near sighted mountain climber who had lost their glasses, got drunk, and fell off a mountain, then got back up and climbed again to explain genetic drift....it's very odd but it makes sense when you explain evolution as a mountain climber who had lost their glasses, and can only climb the top of a mountain with the only rule being "just go up, and I will eventually get there" even though there are many peaks that could exist.

[@blancspacespeas3208]

Ugh why don't you teach physics!!

[@theplanissimple6025]

+MinYoung Han he does!

[@MagnusSkiptonLLC]

+MinYoung Han They are doing physics next now that astronomy is done.

[@blancspacespeas3208]

yea great they're doing it now once ive finished it -_-'

[@mariusmeiser8360]

+syzygy yessss, i will finally get good grades in that subject too ! XD

[@aaroneloy21]

Im from the future... be patient my child , it will come

[@Hopeyfish]

This was explained so much more clearly in 12 minutes then in the 2 hour lecture I just struggled to keep notes through.

[@jacobknighten798]

I can't mate randomly? what the hell am I supposed to do with my weekends?

[@meepmerp1562]

+Jacob Knighten you can, its not recommended

[@maxlindner2274]

+Jacob Knighten U also need someone else that is willing... but then it is not random, but then it is rape... You know what, just stay in and jerk it

[@dareen3295]

69 likes btw

[@ViiceTM]

You ought to know that I never once in class understood how that equation worked until I watched that video. My test is tomorrow morning. THANK YOU!!!!

[@Yamikaiba123]

I was taught that Mendell sent an enthusiastic letter to Darwin which the latter didn't sufficiently understand.

[@aseasyash]

Google "codominance" for more but here goes: Say A and B are two dominant alleles and c is a recessive allele (we usually label with the same letter but hopefully it will make it a bit clearer). If those with genotypes AA and Ac show a phenotype of blue and those with genotypes BB and Bc show a phenotype of red, then AB (the heterozygote) will show a phenotype of purple, displaying codominance. The blood type AB is an example. Note with 3 alleles there are 6 genotypes (AA, BB, cc, Ac, Bc, AB).

[@malavikapradeep9771]

Thank you so much

[@ashlyntheninja]

I'm sending all of these videos to my ninth grade biology teacher so that her future students can learn something. I've learned more in one of these videos than I did in an entire semester of her class.

[@laylaalshameh9961]

bruhhhhh.... I thought he said maters gonna mate because he was referring to shake it off but that was released in 2014 and this video came out in 2012 WOOOOAAAAHHH

[@TheTravisng]

You know "haters gonna hate" existed before Shake it Off right

[@lyricsoftheart]

Right, 3LW ,”players goin play.”

[@armsanal]

You are amazing, I'm studying Biology and I took a course of Genetics Population, and you explain it so well and easy.

[@vinaypolavarapu873]

DId he have to write backwards when doing that problem?

[@piercemcconvey3270]

haha no he wrote normally and they flipped the camera view like a mirror image

[@bonasaurusrexus]

Finally, someone who explains things so I don't fall asleep! :D THANK YOU!

[@MrRoboskippy]

Good News!! Math!!!

[@Gewath]

I learn biology in peace knowing that the sound group of Crash Course will slowly burn in a rotting, popping, levitation-sounding Hell.

[@aeroscience9834]

I wouldn't exactly call that "involving a lot of math". The most difficult thing was a square root.

[@velocity1146]

You have to understand though math is scary to many people and the average person doesn't need to understand square numbers/square roots.

[@puncheex2]

Aeroscience Probably the hardest thing is learning to write backwards on the glass screen. I imagine many minutes of cussing and joking around wound up on the cutting room floor during this session. Ah. I just read below where he has been genetically altered for this show by a reversal of his handedness, His facial mole switched sides. A neat trick. He should patent it.

[@aeroscience9834]

+puncheex2 True, haha

[@aeroscience9834]

+Velocity I agree, but anyone taking a bio class should be able to do that easily

[@Baesjegutten]

Aeroscience Yes, but population genetics is a lot more math than just the math you use in Hardy-Weinberg eq's.

[@SYSPLUCK]

Your ambidextrousness and ability to write backwards on thin air is quite impressive.

[@MiniMervii]

Maters gonna mate.

[@pritomdey6745]

Great Video Man! Keep it up!

[@pogostix6097]

"And I have good news! It involves a lot of math!" ... I hope you're doing the math for me Hank... :p

[@Aidiera]

I am so impressed with Hank's ability to write backwards.

[@zhuochenyuan1819]

there are 7 fast and furious movies now :|

[@scootchoong3920]

8 now bb

[@KyrstSings]

I learned this last year, Hank makes it more fun.

[@dasvader90]

he had to write all of that backwards...

[@bluejedi723]

Dear hank: Because of you, I managed a C+ in my college ecology course-the one science course required for my major. I would have gotten a F- if not for you.

[@sarahgarris938]

Did anyone else notice the Harry Potter reference?? "Alas, Earwax".

[@Napkinatorz]

Thanks for helping me study for my midterm!!

[@blueskies2u4me]

Darn those hot surfer dudes

[@tonyv7407]

Hey! I realize this videos pretty old at this point but if someone happens to be reading through comments still, I have a question! I’m having trouble figuring out why you square the equation (p + q) instead of multiply it by 2 or something. I’m sure the answers simple and I just haven’t realized it yet. Thanks!

[@lydiajoy2631]

Oh my freaking god!!!! I just found out this guy's brother is JOHN FREAKING GREEN!!!! The freaking author of TFIOS!!! The best book of all time!!! We watch these stupid crash course vids in bio all te time and I nee knew we were seeing the family of an amazing dude and occasionally THAT AMAZIG DUDE!!!! I AM DYING SO BAD!!!!!!!!!!!!!!!!!!!!

[@birds-nest]

Your show is approximately two weeks behind my bio class! Perfect for reviewing after the test! This way i know the information sticks. I am definitely rewatching all of the crash courses before finals because it is the same case with my global class! Thank you to everyone involved with this wonderful tool!

[@frankvales7860]

THATS A NECK BOIIIIIIII

[@frankvales7860]

+Vanilla Chilla YOU'RE CANCER

[@frankvales7860]

+Vanilla Chilla FAMILY PACK LIKE OK PAPITO

[@ps-uj5dm]

+Vanilla Chilla wtf

[@Zulligula]

On the Hardy Weinberg equilibrium: It is important to note that the assumptions of the equation (6:00) can act on a sub section of an organism's genome. For example, take human blood type, where there is no advantage for having one blood type over another and we do not select our sexual partners on that basis. Accordingly, the allele frequency of blood types is stable over long periods of time. Props to Dr. Haglund, highschool biology prof at Windward highschool.

[@harlowsolid]

If it weren't for random mating I'd never get laid.

[@colleendeighton3524]

As an English teacher, I've learned to write upside down. I started out thinking that that was what Hank was doing, and I was REALLY impressed. Then I realized that he was pushing up his glasses with the wrong hand, and that his mole was on the wrong side of his neck. Not quite as awesome, but better than making him learn to write mirror.

[@alishamalhotra8439]

Alas, earwax!!! omg #harrypotter connection right there like if u know what im talking about

[@laurawilder1234]

Yay!! You're helping me study for my bio final!!

[@shumpeter2]

hank, this is a pretty impressive intro on hardy-weinberg equilibrium, i loved the background on darwin-mendel..!!

[@sokra]

How do you write so perfectly backwards!? Hank never cease to amaze me...

[@b991228]

These patterns intrigued geneticist Reginald Punnett so in 1908, he consulted with his friend and colleague Godfrey Hardy, an eminent mathematician, who wrote a solution without hesitation on the nearest napkin... Voila, the Hardy Weinberg equation.

[@DreamHopeLive]

Thank You Hank, I FINALLY understand Hardy-weinburg after having it explained to me by 3 TA, my instructor and numerous students and tutors... I was beginning to think I would never understand it...