How Humans Domesticated Just About Everything | Compilation

thanks for the note for supporting this scishow compilation video for all things lenode you can go to lenod.com scishow that link gives you a 100 60 day credit on a new lenode account [Music] you have domestication to thank for some of your favorite foods furry friends even a mode of transportation Apple's domesticated cats domesticated zebras well we tried it's such a huge part of your daily life that you might not know just how much of your world is domesticated that's probably because of the broad effect that domestication can have domestication can mean that we're selecting for one specific trait narrowing the species diversity but it can also mean introducing new diversity take for example how we have domesticated our food domestication made wild cabbage into many of the distinct greens we know today like broccoli kale and Brussels sprouts here is why those foods are actually all the same species one of the most extraordinary things about dogs is how different they all are like we took one wolfy species and made over 200 breeds from adorable wrinkly pugs to lanky powerful Greyhounds we didn't just do this kind of whole body tinkering with dogs we've done it with plants too just about all the fruits and veggies you can buy at the supermarket have been shaped by human breeding most look totally different from their wild ancestors but there is one plant species that has produced so many different varieties that it's known to biologists as the dog of the Plant World you probably know it as kale and broccoli and cabbage and Brussels sprouts that's right those are all the same species of plants foodie favorites like kale and cauliflower are just a couple of the cultivars or human modified and grown varieties of Brassica oracia and there are dozens more from the logarithmic spiral of Romanesco broccoli did this distinct pointed shape of caraflex cabbage and you might think that tons of variety is just what happens when humans selectively breed something for Generations but that's not entirely true after all we've been growing and breeding lettuce for about the same amount of time and yet all lettuce varieties look you know pretty lettucey it turns out that be olarasia is kind of a special plant it was so transformable because it underwent some massive genomic events during its Evolution the story of why we have such a variety of this kind of plant starts millions of years ago back then an ancient Brassica ancestor did something quite remarkable it tripled its genome that massive genome was whittled back down to a more reasonable size by the time wild cabbage emerged as its own species around 4 million years ago still it meant that wild cabbage ended up with a lot more genetic variation than your average Garden plant you see broccoli and kale at Brussels sprouts don't just look different they're very genetically just stinked too and we're not just talking about little tweaks to genes in a 2016 paper researchers sequenced the Genome of nine different cultivars to construct the plant's pan genome the total genetic variation that exists in the species and they found that nearly 20 percent of the genes in that pan genome are only present in some varieties so not only do cultivars have a lot of mutational difference they also have whole genes that are not present in other members of their own species even though they all came from the same wild cabbage that plant as far as we can tell originated in the coastal areas of southern and western Europe we don't know exactly when our species first grew and domesticated it but genetic evidence suggests it may have been around 2000 BCE the earliest written records come from ancient Greece and they suggest the first cultivars were leafy veggies like kale and collard greens and the Greeks weren't the only ancient people who tinkered with wild cabbage scientists are pretty sure that the plant was domesticated many times in several locations some of these domesticated varieties found their way back into the wild became feral and then were redomesticated adding to the genetic diversity of the species and all that genetic diversity eventually allowed people to magnify different structural parts of the plant the variety We Now call cabbage for example seems to have Arisen sometime before the 10th century when people bred a kale-like plant to have larger buds on the tips of its stems brussels sprouts are also enlarged buds the buds that grow all around the length of the stem and scientists aren't quite sure when that cultivar emerged but it was definitely being grown in Belgium by the end of the 18th century and then there's Kohlrabi which literally means cabbage turnip in German presumably referring to its bull Blake enlargement at the base of the stem it's not clear when it first came about either but historical literature suggests it was grown throughout Europe by the 1500s then there's broccoli and cauliflower both get their unique florets the yummy parts we eat from Utah rotations to the flowering genes and broccoli those mutations lead to a lot of flower buds packed tightly together cauliflower has a lot of tightly packed flowering structures too but most of them never actually flower instead the white pre-bud flour tissue replicates itself as it grows leading to The Familiar curd-like head since both have modified flowers it's thought that one came from the other but it's not totally clear which came first as of 2018 genetic research seemed to be leaning toward team broccoli in fact scientists are still trying to piece together how we got all of these amazingly different versions of Brassica oracia and in what order trouble is the same genomic shuffling events which gave this species so much genetic diversity also make it challenging to figure out a precise timeline for these cultivars and the relationships to each other and researchers are eager to figure out as much of this as they can not just because it's fascinating but because it will also help them better understand how the different varieties tolerate different environments resist different diseases and produce different nutrients so I better understanding these nutritious delicious and fascinating dogs of the Plant World scientists just might figure out how to make our favorite crops more hearty sustainable and nutritious so we could turn one green into many different veggies using the tool of domestication but that same tool can keep apples weird without turning them into new fruits that's how we ended up with varieties like red delicious and Golden Delicious here's Olivia to explain why domesticated apples went in a completely different direction from other Foods if you went to school in North America you were likely introduced to Tales of Johnny Appleseed a well-intentioned if slightly odd gentleman who traveled the continent planting apple seeds everywhere he went which if you know anything about Apple genetics might come across as a colossal waste of time after all every time you grow an apple from seed you're actually rolling the dice you don't know what's going to grow so it's not like Johnny was spreading tasty apples across the U.S of a just crabby gross ones but it turns out growing all those not so yummy apples was kind of a good thing because it ensured that Apple Growers have tools to continue to cultivate delicious varieties today Jonathan Chapman traveled hundreds of thousands of miles across what is now the American Midwest in the 19th century toting the fruit seeds that would earn him his nickname Johnny Appleseed he made a living selling the trees that sprouted from those seeds but here's the weird thing he had no way of knowing what apples would come from those seeds and a modern Apple grower couldn't tell you much better suppose you go to the grocery store and buy yourself some nice Fuji's or Pink Ladies you say to yourself gosh this is the best apple I've ever eaten so you plant the seeds in your backyard in hopes that once the tree matures you can experience that delicious apple all over again but you wait about a decade until the tree finally produces fruit and surprise your apples are small or sour or kind of just ugly looking or maybe all of the above well if you talk to an Apple grower first you would have expected that unlike planting seeds from your favorite store-bought Tomatoes the fruit of any apple tree you grow from seed will never look like the fruit it came from they don't grow true to type as gardeners say and that's because genes in those seeds are always from two genetically distinct trees see we can't just inbreed the trees to preserve the traits we like like we do in dogs apples and other species like pears and sweet cherries won't let us do that these species have a system called self-incompatibility where they're capable of recognizing genetically similar individuals and then not breeding with them generally for flowering plants the process of seed production starts when a pollen grain Falls onto an organ within the flower called a pistol that pollen grain then grows a long tube down to the flower's ovaries and delivers its genetic material plants are a bit Oddball so there's more to it than that but that's the gist many flowering plants produce both male and female reproductive organs on the same flower and if that's the case they can often fertilize themselves like the reason Mendel's pea plants were so great for studying genetics was because they're self-fertilizing if he'd been studying apples he never would have gotten as far as he did but even though apples do have the necessary Parts in place for self-fertilization they also have a really robust ways of telling their own pollen from that of a genetically distinct tree the female reproductive organ produces an enzyme called an srnas that enzyme's job is to chop up RNA which would be bad for a future seed since cells need RNA to make proteins and by extension live still these enzymes are transported into the growing pollen tube luckily it has a defense it can degrade the srnas before the enzyme can do any degrading of its own but it will only do that if its genes and the rnas are a mismatch if it recognizes the rnas as being from genetic stocks similar to its own the rnas gets to do its work unencumbered and fertilization is stopped this means apple blossoms won't pollinate themselves or other blossoms on their tree even if the pollen happens to land in the right place it even reduces the odds that parent or sibling trees can breed with them most of the time pollen from a totally different strain has to be carried by bees or the wind for a flower to produce fruit that's good for the plant because inbreeding can lead to a loss of resistance from pests and disease as well as just being less healthy overall but it's bad for us because it means we can't pick a tree we like and force it to produce Offspring with very similar genes instead Growers have to find another type of apple tree that blooms at the same time produces compatible pollen and Carries desirable genes in order to breed new trees what that all means is that we've essentially been rolling the dice for literally thousands of years hoping that two trees will mate and produce a nice apple and it's not even like a six-sided die it's more like a handful of d20s that's because apples have remained almost as genetically diverse as their wild ancestors starting from when they were first cultivated around 4 000 years ago normally domestication really hurts the genetic diversity of a population as humans select for desirable traits Gene variants get left behind creating what's referred to as a domestication bottleneck and more modern methods of cultivation can narrow the gene pool even further creating a second Improvement bottleneck estimates vary but Improvement bottlenecks can remove as much as 25 of the wild genetic diversity but that's not the case with apples a 2014 paper surveyed the genetic diversity of modern cultivated apples and found it's basically equal to the very oldest varieties that means that any genes that contribute to sweetness or color or pest resistance or ability to grow in cold climates are mixed in with all sorts of other genes throughout the Apple's gene pool and that means that once Apple Growers find an Apple they like they just can't risk letting it breed with other apple trees so if they hit the genetic jackpot they usually propagate that tree by cloning not modern molecular cloning but a growing technique called grafting where you take the fruit bearing part of One Tree and fuse it with the root of another creating a new hybrid tree that produces genetically identical fruit it's a process so ancient we've had it about as long as we've had cultivated apples and it means that we can keep growing what's effectively the same tree for Generations like Golden Delicious apples go back to 1890. there is still some room for genetic changes even when you're cloning trees in this fashion though like sometimes a new Branch will turn up with a Chance mutation that makes the apples on it a little different a Deeper Shade of red perhaps Growers might select for that more appealing color propagating the mutant branches over the older variety even if the deeper color comes at the expense of flavor you might see where I'm going with this yes the reason red delicious apples taste like misery incarnate is probably for the selection for color at least According to some food scientists by all accounts they used to taste pretty good of course good tasting apples have only really been the goal of Apple Growers for the last century or two your honey crisps and your Galas are what the trade calls dessert apples they're sweeter than cider apples and we tend to want them to be more consistent apples that go into hard cider don't have to be sweet or perfectly firm or well good really they basically just have to have enough sugar to ferment which in the end is why our buddy Johnny probably wasn't wasting his time sure he didn't know what would grow from his seeds exactly but at the time most apples ended up as hard cider so pretty much any Apple worked and the genetic studies suggested he or people like him may actually have helped apples maintain their genetic diversity up to to the present day the apples you see in the grocery store originate from the tianshan mountains in Central Asia they travel to Europe along the silk route where they further interbred with European crab apples to produce the modern domesticated Apple malice domestica in fact they've interbred so much that domesticated apples have more genetic material in common with the European Apple than the Asian ones and only modern genetic Studies have been able to establish for certain where they came from then those European domesticated strains were introduced to North America and somehow they stayed super diverse some have suggested that that's because malice domestica interbred with North American species to adapt to a new climate but others think it had more to do with our dear pal Johnny and others like him because even though different Apple varieties were often kept apart in their European Orchards with people running around planting them all over North America some were bound to go wild that let them get together and they were different enough from one another to overcome self-incompatibility so they made new varieties of trees called chance seedlings that turned out to be a pretty good thing for us because we've gotten more than a few delicious apples through these new Offspring literally red delicious and Golden Delicious apples were both chance seedlings and the Macintosh and Apple's so popular it's got a certain type of computer named after it was also a chance seedling that was discovered all the way back in 1811. so there's a lot to be said for planting apple seeds when you don't know what will Sprout from them genetic diversity isn't just valuable for its own sake Apple breeders rely on that huge gene pool to create new varieties though these days we're lucky enough to have genetic sequencing to cut down on the guesswork and apple Growers aren't just looking for things that improve flavor hiding amongst those jeans are also the keys to resisting pests and disease growing in different climates or making apples that are heartier and easier to transport or soap breeders hope in fact there's some evidence that a gene for disease resistance made the jump from Wild to domestic apples as recently as the 1970s and the need for resistance isn't just theoretical both pests and a changing climate have been making life harder for North American apples in recent years that's why efforts are ongoing to preserve Apple diversity see apples as a whole are diverse but as of 2008 90 of apples produced in the U.S consisted of just 15 varieties and if we want to keep creating new tasty Apple varieties that can survive whatever gets thrown at them will need to do better than that fortunately researchers are on it much like Johnny once did they're planting all sorts of seeds and by doing so they're ensuring that apples stay wonderfully diverse the rest of us will just have to wait for the fruits of their labor all this domestication might seem pretty high-tech but it's nothing compared to today's cloud computing technology cloud computing allows you to stream videos like this one create websites and run analytics on them store important information and generally exist in the modern online world and lenode cloud computing from Akamai keeps it all running with servers across the physical world they're already a cloud computing Powerhouse but they're still working to improve your access to Cloud technology by adding at least a dozen more servers by the end of 2023 to hit the ground running this year with those brand new servers you can click on the link in the description down below or go to lenode.com scishow for a 100 60 day credit on a new lenode account thanks to lenode for supporting the scishow compilation now back to the episode and we're not just talking about domesticated food because the domestication of our food may have led to the domestication of cats here's how cats we know that they like to chase lasers and lick their own butts but there is a lot that we don't know about cute little whiskers like where her cuddly domestic ancestors came from and when she evolved from wild animals we used to think that the earliest historical evidence for domestic cats was from ancient Egypt like art and mummified remains from around 4 000 years ago but now some Clues are pointing to domestic kitties older than that from separate places across the globe the oldest probably domestic cat skeleton we've found was in 2001 on the island of Cyprus in the Mediterranean Sea scientists guessed that this cat lived around 9 500 years ago which makes sense historically that's after people started farming in the Fertile Crescent that not totally desert region in parts of Western Asia and Northern Africa farming means you have to store extra crops somewhere and piles of tasty grain attract rodents and for hungry cats that's an all-you-can-eat buffet so one hypothesis is that feral cats might have started snagging some meals and getting cozy with humans humans were happy to have them too because they took care of the pests and were fluffy and cute by this time we think humans had domesticated other animals like dogs cattle and sheep so adding another furry friend wouldn't seem all that unusual and we think this cat from Cyprus was a pet for a couple of reasons first of all Cyprus is an island with no native cats so someone must have brought them over on a boat and if they weren't a little tame that would have been a scratchy panicky animal mess like you might know how hard it can be to get an uncontrollable Kitty just to the vet back plus the cat was buried with a person presumably its owner and surrounded with carved seashells wild animals wouldn't get this special treatment and if the cat was a meal its bones would have been separate and probably scattered all of this evidence lines up with a study published in the journal science in 2007 which looked at the genetic origins of domestic cats those researchers found that our feline friends are most closely related to the Wildcat felis Sylvester's specifically the near Eastern subspecies your eyes also if you look at this cat will back this evidence up because they look a lot like domestic cats lots of signs point to domestic cats splitting off from their Wildcat cousins in the Fertile Crescent but hold on some other scientists discovered probably domestic cat bones in 2001 in an ancient Millet farming Village in central China a close computer analysis of Jawbone shapes showed that these cats weren't related to the Wildcat at all instead they were a kind of leopard cat which is in an entirely different genus from small animal tunnels throughout the excavation site and ceramic containers that looked like they stored grain the researchers were pretty sure that this Village had a rodent problem and by looking at the carbon Isotopes in cats bones it was clear that they ate lots of small animals that ate lots of human-grown millets this was the first convincing evidence to support the domestic cats eat pests that eat grain hypothesis but this domestication happened in different kinds of cats around 5300 years ago on the other side of this huge landmass so what's the real story The Middle Eastern or the Chinese domestication of cats well there's no reason to think that domestication couldn't have happened twice in in two separate places with two separate cat species when people started farming grain but remember genetically all of our Modern Cats seem to be descended from the Wildcat not the leopard cat maybe the domestic wild cats were just snugglier and had a leg up to win our favor see domestication leaves its fingerprints in an animal's genome so even though any cat person will joke that their cats are too independent to really be considered domesticated we can look at these genetic fingerprints a 2014 collaboration between a bunch of American universities took a close look at the domestic cat genome using 22 different breeds from different places the study found recent changes in genes that controlled the development of the cat's nervous system these genes could play a role in how domestic cats for example behave less defensively in new situations and can change their behavior in response to rewards in other words compared to a wild cat fluffy is genetically more likely to walk up to you with a friendly headbutt and beg for treats this could explain why our cats are extra Snuggly the ones that got along best with humans could take advantage of our rodent pests and table scraps and survived to pass on their genes so in a way cats did domesticate themselves and it seems like they did it more than one time which kind of means that the rise of cat videos was practically inevitable the most cat thing a cat could do was probably domesticate themselves but in the end cats and dogs might not be so different because dogs may have been domesticated for the same reason to eat our leftovers and we played a bigger role in their domestication here's Michael's list of the three weird things we did to dogs like accidentally giving them floppy ears a world without dogs sounds like no fun at all but many of the hundreds of dog breeds we know today are only a few centuries old and according to current research if you go back in time at most 34 000 years dogs as we know them didn't even exist even though we know that modern dogs and modern wolves share a wolf ancestor no one's exactly sure how dogs were first domesticated or even when but we do know that at some point dogs evolved from Mostly ignoring humans to wanting to be best friends with us that process of domestication came with consequences some of them you'd expect like dogs becoming Tamer over time and others are just strange for instance there's a trait that dogs share with other domesticated animals that even Darwin thought was weird lots of dog breeds have floppy ears evolutionarily this doesn't make much sense it's the result of deformed ear cartilage and it can actually make it harder for a dog to hear so why would we breed dogs to have deformed ears well we didn't at first at least not on purpose instead floppy ears seem to have a lot to do with other traits that domesticated animals have like patches of white fur and adorable little faces that retain their juvenile features into adulthood according to a new hypothesis it turns out that in the process of domesticating dogs we might have actually been affecting some of their stem cells in a dog embryo there's a group of stem cells called the neural crest and these cells are responsible for forming a specific set of physical features like the dog's coat the structure of its face and its adrenal glands and according to this new research a lot of the features that we associate with tameness may actually come from changes that have been made to this neural crest the earliest dogs may have been less aggressive because they had smaller adrenal glands so when early humans bred for tameness the dogs probably also ended up with changes to other traits that are controlled by the neural crest like floppy ears in the faces with more juvenile features such as smaller Jaws so basically by domesticating dogs we may have ended up selecting for mutations in their stem cells that made them less like wolves and more like the animal that's probably sleeping in your living room right now but domesticating dogs has had other useful side effects too for example dogs are a whole lot better than their wild cousins at digesting starch a study published in 2013 analyzed the genomes of 12 wolves and 60 dogs of different breeds the researchers were looking for genetic differences that showed up in all of the dogs but none of them wolves they found changes in 36 regions of all of the dog's DNA some of the results were somewhat predictable like changes to genes that were involved in brain development which account for how friendly and tame dogs could be but they also found something they didn't expect the dogs had three genetic variations that helped them digest starch and this fits with a theory that dogs first started to be domesticated when humans settled down to agrarian life at some point hungry wolves might have started venturing into human settlements and eating their leftover starchy food something that a lot of modern dogs seem to be into as well the wolves that were best able to digest the starch were better Fed so they survived to reproduce and speaking of things that dogs are really into you know how dogs really like chewing on bones but it seems to take them forever to actually finish eating one well that has a lot to do with their ancestry too wolves eat meat and they're really into this stuff it doesn't matter how delicious you think your pie is a wolf is going to pick the steak any day so they've got really sharp teeth that are perfect for tearing flesh apart and powerful jaws that polish off a bone pretty quickly especially if they're looking to get to the marrow inside but even though dogs inherited wolves desire to gnaw on Bones they have smaller jaws and a less powerful bite which means that it takes them a whole lot longer to finish a bone if they can even make a dent in it at all but if you've ever seen a dog chewing on a bone it doesn't seem like they mind how long it takes to finish while we made dogs more tame our interactions with zebras went in the other direction I mean we've managed to domesticate horses for writing but we pretty much totally failed with zebras here is how we tried to domesticate them for transportation I don't know if you've noticed but zebra's looking awful lot like horses they're even part of the same equine family and you can crossbreed them into an animal called a source but no matter how similar they look don't be fooled thanks to their biology and evolution you just can't ride a zebra it's a beautiful stripy Majestic trap according to archaeological evidence humans have been taming horses for at least 5500 years but our relationship with zebras goes back much further humans and zebras have spent millions of years together because both species evolved alongside each other in Africa and that's actually where the problems with zebra riding start because even though we've spent Millennia together it's not like humans and zebras were best buddies for quite a while early humans saw zebras as food and not much else there's even evidence that we hunted them so our striped neighbors kind of grew up knowing that people were bad news According to some researchers that means they could be predisposed to fear us horses meanwhile didn't encounter people until much later and we likely didn't hunt them long enough for them to pick up the same fear but even though we totally started our relationship off on the wrong foot there's actually an even bigger problem with zebras their evolutionary history has made them just plain nasty they spend their whole lives surrounded by large Predators like lions cheetahs and hyenas so they have a really well developed fight and flight response this means that zebras are flightier than horses and a lot more aggressive Corner a zebra and it will bite and kick and in general try to end you because those are the kind of skills it needs to survive in the wild and a zebra's kick is Serious Business an adult zebra can kick hard enough to break a lion's jaw and zebras injure more American zookeepers than any other zoo animal this aggressiveness is such a big deal that some researchers have even looked for a genetic component to it although they haven't found anything conclusive yet either way trying to convince a zebra to let you ride it is just asking to get hurt and I don't know about you but I would rather walk somewhere than deal with that finally temperament aside zebras aren't built for writing even though they're from the same family they're smaller than domestic horses and their backs aren't as strong so they're not able to comfortably carry as much weight eight they also have thick necks so it's not easy to direct them with reins and because they're so ill-tempered they're a lot more prone to getting fed up when they're tired and that's likely to end with your Swift introduction to the hard ground this isn't just a hypothesis either during the Victorian era when Europeans were attempting to colonize parts of Africa taming zebras was a popular idea their horses weren't that useful because in sub-Saharan Africa they were susceptible to a fatal disease commonly called animal sleeping sickness which is carried by setsy flies zebras meanwhile almost never catch this disease because they're only rarely bitten by setsi flies possibly because the Flies are put off by all those stripes or maybe because they have natural fly repellent in their skin whatever the reason Europeans took note of this and famously attempted to domesticate the horse's striped cousin and while there were a few individual successes this was for the most part an abysmal failure today most people have given up on writing zebras partly because we've come to our senses and mostly because we have Jeeps now still it goes to show that no matter what we Mighty humans do nature can still sometimes get the upper hand and that's probably okay so we don't successfully domesticate everything we touch but we sure do give it the old College try now aside from food friends and transportation there's one big group that we have not talked about yet us here is the totally not creepy way we accidentally domesticated ourselves Evolution has given us some useful abilities over the past millions of years we've evolved to stand on two legs use tools and develop language and as recently as a few thousand years ago humans were still evolving part of what drives evolution is natural selection where those with traits that make them better adapted to their environment tend to survive long enough to pass on those traits to their offspring modern medicine can sometimes interfere with that process since it keeps people alive who maybe otherwise wouldn't be but that doesn't mean humans are done evolving one recent example of human evolution is the fact that 35 percent of adult humans can digest milk seven thousand years ago not nearly as many people could do that instead mainly babies drank and digested milk so they could get energy from the lactose in their mother's breast milk once they grew up though the gene that allowed them to digest milk was switched off but when we domesticated cattle the mutation that allowed certain people to digest milk as adults became something that helped them survive since they had an extra source of nutrition a few thousand years later being able to digest lactose is pretty normal so humans were still evolving in the not so distant past and a lot of scientists think that we still are and we might even be able to predict what future humans will be like for one thing it's possible that in the future women will be shorter and slightly heavier than they are now researchers figure this out using the data from the Framingham heart study which tracks the medical histories of more than 14 000 people who live in Framingham Massachusetts the team wanted to know what traits gave women higher reproductive success they found that shorter slightly heavier women tended to have more children and that those traits were passed on to their children if this trend continues in 10 Generations the average woman might be about two centimeters shorter and a kilogram heavier another possible difference between us and future humans is that their brains might be a bit smaller which is weird because for most of human history brain sizes tended to get bigger over time but over the last 20 000 years the brain size of homo sapiens has decreased during that time the average volume of the male brain has shrunk from about 1500 cubic centimeters to about 1350. about a tennis ball size difference a similar decrease in brain size happened for women too but why the chain one possibility is that our brains are smaller thanks to the emergence of more complex societies as population density increased and there was more division of labor humans didn't have to be as smart to stay alive so their brains didn't have to be as big other scientists think our brains have been shrinking because we've become more tame see domesticated animals have smaller brains than their wild counterparts probably because if a wild animal isn't smart enough it won't survive too long so like domesticated animals maybe our brains have gotten smaller because we aren't constantly worried about things like being attacked by Predators but a shrinking brain might not mean the human species is getting Dumber instead our brains might just be getting more efficient having a big brain uses up a lot of energy so if it's a little smaller and more efficient we don't need as much energy to stay alive that said a recent study of the skulls of Americans showed that they've actually been getting bigger since the mid-1800s but that's probably because of better nutrition and not an evolutionary change so if we factor out the effect of better nutrition it's possible that the shrinking Trend will continue into the future even if natural selection isn't what drives the future evolution of our species we might artificially evolve ourselves through genetic engineering as we learn more about what all of our genes do and how to modify them we'll be able to eliminate certain genetic disorders and maybe even diseases related to getting older and eventually we might be able to design people like we design avatars in video games altering things like height intelligence athleticism or any other trait so whether the changes are natural or artificial humans of the future might be very different so we have domesticated plants like cauliflower and animals like dogs on purpose we tried to domesticate zebras but couldn't quite pull it off and some animals like cats and people were accidentally domesticated we haven't domesticated everything in the world but we sure do seem to do it more than most people consider and that's not even the full list to learn about the first mammal to be domesticated for scientific research you can watch our video about the lab rat thanks for watching this scishow compilation foreign [Music]

Channel: SciShow

Views: 565,350

Keywords: SciShow, science, Hank, Green, education, learn, complexly, domestication, genetic diversity, kale, cauliflower, broccoli, johnny appleseed, domestic cats, domestic dogs, zebra, human evolution

Id: DmjXPj51Hdg

Length: 32min 39sec (1959 seconds)

Published: Wed Feb 15 2023