Unnatural Selection - How Humans Are Changing Evolution | Free Documentary Nature

a colony of Cliff swallows in Nebraska they look familiar but something strange is happening here the wings of these birds are getting shorter Park a world away in Australia snakes are evolving smaller heads in North America's Chesapeake Bay Turtles are getting larger [Music] Europe are getting smaller all these changes are happening without standing speed [Music] and on the Galapagos Islands Evolution has even gone backwards what has happened to evolution there's a very simple answer us for billions of years species evolved by a process called natural selection but now we've added a new dimension the process of unnatural selection [Music] life arose on planet Earth three and a half billion years ago [Music] and over that time it evolved into a dazzling variety of shapes and forms foreign [Music] but the process driving that Evolution wasn't understood until 1859 when Charles Darwin Pub you show that life is continually changing and evolving through the process he called natural selection when animals or plants reproduce by sex all their offspring are slightly different foreign [Music] variations in their genetic men purely by chance some are better adapted to their environment than others [Music] those less well adapted are more likely to die the fitter ones survive selected by nature to breed and pass on their successful genes to the Next Generation and so the slow driving force of evolution continues this is natural selection a thousand years ago one species arose that changed all that our own ancestors evolved on the plains of East Africa and quickly spread across the globe [Music] in the blink of an eye on the time scale we turned grasslands and forests into fields and cities we polluted air and water we transformed the planet beyond recognition and in doing so changed the course of evolution just as the natural world shaped Evolution for billions of years so now does our unnatural world ah that world began ten thousand years ago at that time people living in the Middle East survived by hunting game and by collecting the seeds of wild grasses including the ancestors of our Familia wheat [Music] to this ancient wheat weren't easy to gather try to harvest The Ripe seed heads and they shatter scattering the seeds among the dirt making them hard to collect [Music] at the National Institute of agricultural botany in Cambridge in the UK Phil Howell still grows these ancient forms of wheat [Music] as these plants grow towards maturity the seeds that are forming on them fall to the ground it's a seed dispersal mechanism so these early farmers were probably having to sweep grains off the floor with all the dirt and stones and so on before they could bring them back and pound them with a pestle of mortar and and make flour and make bread and then one day one of the farmers spotted a plant like this where the seeds didn't fall on the floor they stayed there on the plant itself and obviously that's much better you can harvest the whole plant bring all the seeds back much much more efficient and instead of just taking all of these seeds and pounding them and getting the flour out they kept a few seeds back and planted them for the next season's crop until eventually everything they grew kept hold of its seeds at Harvest time they weren't having to pick them up off the floor and that's kind of the birth of agriculture by selecting those varieties of grass that were most useful to them the people of the Middle East created a completely new plant domesticated wheat and this laid the foundations for Humanity's success thanks to agriculture human populations exploded [Music] but even before we became Farmers we had already started our first experiments in unnatural selection around 30 000 years ago we brought wild animals to our fire sites a wolf pup it's packed might have been killed to protect the tribe or as competitors when hunting but reared amongst humans from an early age some wolves became tame their Keen senses are perfect early warning for their human companions or to help them track gang the most tame and the most useful were then bred together and the Wolf began its Journey from wild animal to domestic dog [Music] from this one species we created breeds that look nothing like a wolf and look nothing like each other [Music] how is this possible how can the Wolves behavior and appearance change so radically [Music] in the 1950s an experiment with foxes showed how quickly the first stages can happen the most tame and friendly Cubs from each litter were selected and bred together and this was repeated over several Generations [Music] in just a few Generations the foxes became tame but they also began to look different with flatter faces and floppy ears these were all features of young cubs breeding for tameness arrests the fox's development and their fur group patches of white they soon looked less like foxes and more like domestic dogs [Music] the same thing happened to wolves as our ancestors selected them for tameless creating domestic dogs that we recognize today [Music] more recently we've been selecting random traits for spots or short legs for large sizes or Shaggy coats to create today's familiar dog breeds what began as accidental selection around 30 000 years ago is now very deliberate but holy unnatural [Music] deliberate our natural selection doesn't just change the course of evolution it can be made to run Evolution backwards we can now create a long-lost wild creature cattle descended from the European wild ox called the hour rocks around 10 000 years ago our rocks were huge and big herds of them grazing and browsing helped us shake the nature of the Wild Wood that covered much of Europe but by the mid-1600s they were extinct now a project in the Netherlands is beginning to bring back the our rocks not just as a prehistoric curiosity but to use them on nature reserves to recreate their role as grazers and browsers that once shaped the Ecology of Europe some scientists now think that Europe's original Wildwood wasn't a vast Tangled Forest but a mosaic of forest and open grasslands maintained by big grazing animals like our rocks but before we can recreate the hour rocks we need its genetic code the makeup of its DNA at wageningham University in the Netherlands Richard kroymons is collecting the remains of our rocks from all over Europe trying to piece together is genetic code if you want to rebuild the arcs first of all you need material from the aerox your bone material we just cut out Parts in there and therefore we have to extract that DNA and we have to analyze that difficult but feasible [Music] thank you but once they have the code from fossils how will the scientists recreate a living creature much of the arrox genetic code is still with us fragments of it scattered across various primitive breeds of domestic cows and that's where Ronald hodary and a natural selection come in Ronald is part of the Taurus project which brought primitive breeds from across Europe together on this polder in the Netherlands these roots all have in themselves different aspects of our rocks none of them has a has it all because otherwise the animal would have not been accent the plan is to cross breed these cattle to try and reunite as many our rocks genes as possible they have old descriptions of our rocks to help them and the genetic blueprint created at the wagon Indian University which tells them how close their animals are to the original [Music] the project has already taken its first steps towards an hourox-like Beast first blue maybe it was a lucky shot but uh by mixing the right Bridge fairly fast you can you'll be uh like 70 80 up to what you expect all the calves in this herd are now crossbreeds each a step closer to the ultimate goal the project can't recreate the whole original Arrow rocks genome but the animals called turos will look and behave like the our rocks [Music] and tour us together with ponies like these that closely resemble the original Wild Horses of Europe can begin to take Europe's ecology back in time on a few key reserves across Europe they will recreate the Mosaic of grassland and Forest that cloaked most of Europe at the end of the last ice age [Music] [Applause] [Music] thank you foreign [Music] s have changed animals and plants ever since the dawn of farming farming Darwin knew about this process and called it artificial selection [Music] he also understood that this worked in the same way as Natural Evolution Darwin knew that understanding artificial selection was key to convincing the world that natural selection really create [Music] he worked with domesticated pigeons making detailed notes on how selective breeding could generate new forms he visited the best Pigeon breeders of the day and held long discussions with them about how they created new breeds [Music] fascinated by the world of pigeon breeding that it became something [Music] foreign [Music] if artificial selection can produce creatures as different as these pigeon breeds in just a few hundred years then surely a similar process could easily produce a rich diversity of natural species over hundreds of millions of years [Music] Darwin was convinced that Evolution needed such vast spans of time he wrote natural selection can never take a great and sudden leap but must Advance by short and sure though slow steps but he underestimated the speed of evolution examples of unnatural selection suggest Evolution can happen far quicker than Darwin could ever have believed [Music] in the wild predation is one of the greatest forces driving Evolution for prey and predators [Music] they're both locked in and evolutionary arms race as prey gets better at escaping predators respond by becoming better Killers but we humans are now super predators we don't just hunt for food sometimes we hunt for pleasure [Music] technology turned us into the most deadly killers on the planet and this and exerts a new massive force on [Music] natural Predators usually Target the weak or sick but human predators Trophy Hunters aim for the biggest and fittest the best specimens to display [Music] when hunted by humans animals with smaller bodies and smaller less desirable horns or antlers usually don't get shot they survive and breed and this has changed the course of evolution in just a few Generations deer evolved smaller antlers and their bodies became smaller too so when hunted by humans it's better for the deer to be smaller for another creature opposite [Music] [Music] a diamondback terrapin Diamondbacks live in estuaries and bays in North America such as here a Chesapeake Bay they share these Waters with crabs that are a valuable commercial catch the greedy crabs are easily drawn by the bait in the mesh cages 14.9 foreign packs are just as greedy and they're curious the smaller ones easily find their way into the Trap they can't get out they'll drown long before the Trap is recovered by the fishermen but biologist Randy chambers of William and Mary University in the U.S has discovered that unnatural selection is at work here too the world record for the most number of turtles caught in a single commercial crab pot and drowned is 90. so you can wipe out a large portion of the population just in one single day of trapping yeah 5.0 in response to this the turtles are evolving or at least the females are unfortunately the male turtles never get larger than this particular size they stay fairly small the female turtles on the other hand tend to get large and there is a wonderful sexual dimorphism associated with this particular species the small males find it all too easy to enter the Trap but not the large females a female Turtle if she gets large enough is no longer able to fit in these commercial crab traps the female turtles that don't die because they don't fit into the traps breed and pass on their genes for large size to their offspring when the team compared Diamondbacks from areas with and without crab traps they found that the females in trapped areas grew much bigger and grew more quickly becoming too big to get trapped to the much earlier age than the others so females get large females get large quickly and that seems to be a selection force that is being generated by the commercial style crab crops all these changes happened in a very short time in roughly 75 years or something on the order of seven to eight Generations the female turtles have changed their size by roughly 15 percent they are 15 percent larger now than they were 75 years ago and that degree of change in size over just a finite number of generations is incredibly rapid and you know most darwinian biologists would say oh you can't have that sort of thing happen over such a short time frame over so few generations and yet we're seeing it [Music] natural selection can happen just as fast demonstrated by animals which now bear Dar Darwin's name thank you the Galapagos Islands off the coast of Ecuador famous for their links to the study of evolution the animals collected on his visit here gave Darwin new insights into the process behind Evolution there are many different birds scattered across the islands among them Darwin's finches Andrew Henry from Montreal university has studied these ordinary looking birds for many years Darwin's finches are an amazing example of what natural selection can do indeed the one that inspired Darwin's research in the first place they show how when you have a single group of birds from a single species that colonize a new environment they are exposed to a whole bunch of different resources in this case different food types so from insects to fruit to to plant matter to seeds and because those things require different specializations particularly in terms of the shape of the beak you have the diversification the splitting of that one initial species to become specialized into different species incredible difference in big size all from a single ancestor that colonized Galapagos Islands only a few million years ago this process of natural selection is still happening today on some of the islands you have one particular species that seems to be in the midst of splitting into two species and that's the medium ground finch at one location you have large and small seeds you have a large number of small beaked ones and then you have a large number of very large beaked ones with almost nothing in the middle so you have the the beginnings of the emergence of new species it seems to be splitting in the same way that we think the the radiation occurred the the diversification occurred in the first place but the Darwin's Finch story doesn't end there these birds are now also affected by unnatural selection we also study another site where humans have a much larger influence from the 1960s to the present you used to have these nicely distinctive two forms that might have been splitting but in the present now that has disappeared and it's because seemingly the humans were providing all sorts of food resources for Darwin's finches things that they wouldn't normally get like like rice and potato chips and fruit and things like that [Music] for those types of foods it doesn't really matter what your beak size is so what happened was this beginnings of a split into two species they're fusing back together again it's a speciation reversal or a or a collapse so reversing the process of evolution and uh I think it's kind of ironic because it's occurring at the very place that was so inspirational for Darwin in the first place on the Galapagos something as simple as humans throwing away food is turning back The evolutionary clock reversing the formation of new species yet in many places we deliberately encourage Birds by providing lots of easy food no one has studied the effects we're having but it's possible these birds could already be evolving into something new studies on other birds are already showing that Evolution can respond with Incredible speed to human influences foreign [Music] birds in the U.S are killed by traffic [Music] Cliff swallows have taken to nesting on freeway Bridges which puts them in serious danger of being hit by a car truck the perfect situation for unnatural selection to begin its work [Music] Charles Brown of Tulsa University has been collecting dead Cliff swallows for over 30 years and looking back through his data he saw something very strange over time we began to to notice that we were seeing fewer and fewer of these dead birds on the road and we found that the the birds that had been killed by by cars had significantly longer Wings than the than the other birds in the population it seems that in this population Cliff swallows have evolved shorter winds in the 30 years since Charles began his studies the wing length in this in this population has declined by uh by between five and seven millimeters over the 30 years now that may not sound like a lot but a five to seven millimeter change is really quite a bit for a bird of this size and probably confers fairly substantial maneuverability advantages shorter Wings even by a few millimeters make a difference to the bird's aerodynamics they're more agile which means a quicker vertical takeoff and a better chance of avoiding oncoming vehicles evolutionary biologists have always sort of considered the measurement of a of a bird's Wing to to be a good characteristic for that particular species but it turns out it's very changeable as our study shows 29 and a half [Music] so Evolution has responded to our increasingly busy roads with swallows that are more agile in flight with the biggest challenge to life is the jumble of Concrete and brick we now call home [Music] foreign [Music] two-thirds of the human population will be living in cities [Music] already some creatures have made this alien world to their own peregrine falcons peregrines Nest on Moorland or Coastal cracks so for them these city blocks are nothing more than a concrete cliff and there's plenty of food here pigeons lots of pigeons the pigeons wild ancestor The Rock Dove also lives on Coastal Cliffs but these birds are more at home on the city streets they have to stay alert City peregrines are just StreetWise [Music] foreign climbs high above the city streets [Music] [Music] and when it's spotted to prey it Dives on it from the bath in a stoop that can reach over 300 kilometers per hour a male has caught a pigeon but it's not for himself his mate has been brooding their eggs and now she's hungry and the female finds a quiet spot to enjoy her lunch [Music] for peregrines a city provides more opportunities than a natural sea cliff night falls but it doesn't get the city lights up the night sky with an orange glow foreign birds migrate at night to avoid the Keen eyes of daytime Hunters like peregrines [Music] but flying over a city they're lit up from beneath so the peregrines can still hunt at night but they need to change their hunting technique they fly underneath the migrating birds to see them lit by the city lights then attack from yeah so far this is just a change in Behavior a good City Life bring evolutionary changes to Urban peregrines perhaps in time even a new species of Falcon it's not as far-fetched as it sounds [Music] a city is not just a Concrete Jungle it's broken up by small patches of real Greenery parks and greens to relieve the gray monotony and scientists are finding that these green patches act like Islands [Music] in New York City these oacs hide creatures that normally live in rural landscapes a white-footed mouse Jason munchie south from Fordham University in New York is live trapping these mice to study their genetics wait for the mice seem to be thriving in urban Forest fragments their population densities are actually unusually high unlike the familiar house mouse brought by European settlers these mice can't live in the buildings of the city itself only in these green sanctuaries white-footed mice in each Park are cut off from each other by a sea of concrete as if they were on real islands like the Galapagos [Music] and just like the finches on the Galapagos each population of mice is starting to change genetically when we're collecting genetic information we usually punch out a piece of the ear and in the lab we extract DNA and then we analyze how similar or different mice in different parks are to each other and we're actually fairly surprised that it turned out that each major Park basically had a distinct population of mice and we didn't expect that amount of Divergence over what's really only 120 years or so of of urban history in much of New York City so given enough time each Park in New York City could evolve its own species of mouse just as dozens of different species of Darwin's finches evolved in the Galapagos [Music] [Applause] City Life is a powerful driving force for unnatural selection [Music] began with a birth of large cities in the middle of the 18th century with the Industrial Revolution cities grew from expanding Factory towns smoke belched out over the countryside blackening it with soot and this brought about one of the first known cases of unnatural selection the story can still be traced deep in the vaults of museums [Music] the peppered moth exists in two distinct forms a light one and a dark brown one before the Industrial Revolution the dark form was very scarce the much commoner light form has a pattern that makes it almost invisible on the bark of lichen covered trees in these conditions the dark ones stand out and are quickly eaten by Hungry Birds in early collections the dark form of the moth was a valuable Rarity but pollution killed the lichens an industrial soot blackened the trees now the situation was reversed the light form was easily seen by predators and eaten so it didn't take long for the dark form to become the more common today with strict controls on Industrial smoke the situation is reversed again and the dark form is once more a rarity [Music] but other forms of pollution still affect the planet we fill our world with all kinds of chemicals and they are a driving force of evolution blue chemicals called pcbs are nasty byproducts of many industrial processes in the past they were dumped into lakes and rivers where they reached havoc on the local fish in just 30 years two factories alone dumped half a billion kilograms of pcbs into the Hudson River in New York state [Music] Isaac wergin from New York university has been studying the effects of pollution in the Hudson over most of that period you know two plants have polluted almost 200 miles a river and affected the ecosystem and have affected a lot of human lives [Music] the big problem with pcbs and related compounds is how persistent they are but they discovered that one type of fish has responded to these lethal chemicals in a way that they didn't expect [Music] they're highly exposed they live on the bottom and that's where all these types of contaminants end up the only way you could survive in this soup of contaminants is to develop some kind of resistance and that's exactly what these tomcard have done usually if you're talking about a lot of genes involved and maybe a lot of genetic variants but in this case it's one Gene and there's one form of the variation is a lethal because they react with one kind of molecule in the cell membrane which is fatal so all it took was a tiny change in that molecule [Music] that molecule is slightly altered in time card from the Hudson River such that they no longer respond to pcbs and dioxins because they don't bind them if you compare Tomcat from the Hudson to Tomcat from other populations they are a hundred times less sensitive to PCB toxicity than tomcard from elsewhere foreign [Music] shows how unnatural selection can overcome even the most [Music] so what happens if we want to poison animals deliberately [Music] New York City Nightfall brings a new breed of animal onto the streets [Music] that these are no ordinary rats these are super rats brown rats are very comfortable living in our cities too comfortable they're smart and seem to thrive on a diet of fast food for more than 60 years we controlled rats by poisoning them with a chemical called Warfarin and up till now it worked [Music] oh [Music] but rats breed quickly and evolution doesn't stand still when a few rats were born that weren't affected by Warfarin it didn't take long for them to breed and create a new population of super rats Rats the confessed on Warfarin with knowing effects it's now much harder to kill these rats and many are concerned that plagues of super rats will overrun cities sooner than we expected [Music] today rats were at home in every large city on this planet carried there by our ever-increasing Global Transport Systems ships and planes turned the natural slow trickle of species spreading to new islands and continents into a raging torrent [Applause] today huge numbers of species thrive in places where they shouldn't be they often cause problems for local wildlife even changing the evolution of native creatures one famous Invader has already done just that meet the cane toad in the 1930s just a hundred cane toads were brought to Australia to control pests feeding on sugarcane the Toads didn't like the sugarcane pests but happily ate many Native Australian creatures they bred and spread out rapidly a double disaster for the native woman's life cane toads release a powerful poison from the glands on their back so anything that tries to eat one will probably die an Australian Wildlife doesn't know any better some would be Predators revolving resistance to the cane toads poison but others are changing in a very different way as Ben Phillips from James Cook University in Australia has discovered this is a um red belly black snake from North Queensland these guys have a remarkable story to tell when it comes to cane toads when toads first arrived in the area many populations of these of these snakes went extinct but small toads are less toxic than big ones so snakes that only eat small toads are more likely to survive a snake with a larger head can eat a larger toad a snake with a small head can only eat a small toe and so what we found is that the snakes that were left over tended to be the ones with smaller heads and so one of the consequences one of the evolutionary consequences of the arrival of toads has been that snakes heads have shrunk over time [Music] but it's not only the snakes that are changing toads themselves are also evolving as they spread all over the country the ones at the front of the invasion find themselves in Rich new territory free from competition and getting there first gives them an advantage what happened as toads are spread across Northern Australia is that their their legs have got longer their tibia has increased their length relative to their body size so toads on The Invasion front have noticeably longer legs yeah where a toad might have displaced a few kilometers in the course of a wet season they'll now move in excess of 55 kilometers and so the the rate at which toads invade new areas has increased from about 10 kilometers a year to closer to 60 kilometers a year now across Northern Australia so they really have evolved very rapidly over the course of 70 years to become you know even more formidable Invaders than they already were toes are having devastating effects on Native species some like the snake are changing and Will Survive but others beasts can't adapt many species across the globe are struggling to survive in the modern world [Music] like the common Crane in Europe its Wetland habitats were drained and it was hunted for food its numbers fell dramatically and in places like Britain it disappeared entirely [Music] now the wild fowl and wetlands trust are trying to re-establish a world population on the somerset levels in Southwestern England eggs from Germany are hatched to the trust's headquarters at slimbridge but it's not that simple as we've seen whatever we do has some sort of effect on nature creating changes often unwanted changes rearing the cranes it would be easy to make them tame but as with the fox experiment being tame might have other effects so Nigel Jarrett and the crane team must go to extreme lengths to ensure that the cranes don't imprint on us as human beings we actually disguise our body shape by wearing this unusual costume and the reason why we wear the costume is because we know that young Crane's imprint and the first moving thing they see which in nature happens to be mum or dad crane so it's very important that the birds don't say us as people when they let the babies grow up believing that they're cranes so that when they were released they can actually survive as wild birds the business end of the costume is this artificial head and neck painted to look just like Mom and Dad Crane and then unlike mum and dad crane we've got a spoon on the end of the beef and every time they do something positive like follow us we give them some food so it's really important that we imprint them on this head so that the birds will grow up thinking their cranes and not people and so far the project has worked back in the wild the cranes show no signs of Tamers towards humans and form pair bombs with other cranes just like birds born and raised in the wild this year we had a pair build a nest lay at at least one egg and hatch a chick in That Nest so it delighted with the success of the project the wildfowl and wetlands trust have avoided the problems of our natural selection in recreating a wild population of birds that's the effects of unnatural selection are only going to get more common [Music] we're starting to change the whole planet scientists now predict that the Earth will warm by several degrees of The Next Century changing environments the world over and evolution will respond [Music] climate change raises worries about more severe droughts or hurricanes crop failures or rising sea levels but all this recent work on a natural selection has shown that climate change would also bring unknown and unpredictable effects on the evolution of plants and animals everywhere on our planet [Music] Darwin thought that Evolution was a slow process played out over vast geological time scales yet he also understood that breeders could change animals or plants in just a few Generations [Music] so perhaps he wouldn't be surprised after all to see how quickly life can evolve [Music] we can even watch it happening in front of us by the process of unnatural selection yes

Channel: Free Documentary - Nature

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Keywords: Free Documentary, Documentaries, Full documentary, HD documentary, documentary - topic, documentary (tv genre), nature documentary, Free Documentary Nature, Nature, Wildlife Documentary, Wildlife, Animals Docuentary, Animals, Evolution, Evolution Documentary, On the Origin of Species, Charles Darwin, Charles Darwin Theory of Evolution, Natural Selection, Unnatural Selection

Id: x4ruDIkRets

Length: 53min 6sec (3186 seconds)

Published: Wed Jan 10 2024