ah, in blue, no da vinci's, mysterious masterpiece. oh, that is perhaps the greatest leonardo masterpiece in the collection of the louvre and no, it is not the mona lisa. it is the virgin of the rocks. was there another symbolic meaning to this beautiful painting that perhaps we just don't understand? the search for answers stuart's july summons on d. w. o. the flora and fauna on earth have developed over millions of years, driven by the process of evolution. and by the survival of the fittest, take answer, for example. they exist almost all over the world. so

what's their secret? but 1st olive oil is one of the most counterfeited food products. how can this be exposed? these topics and more coming up on to morrow to day, the d. w. science show he college grow on these trees. they're mainly native to the mediterranean region and have been cultivated since ancient times. most farmers still largely harvest their olives by hand. one reason why olive oil is so valuable, but it's also one of the most frequently tampered with food products, fake and adulterated. oil can be found everywhere. a research group now wants to get to the bottom of olive oil fraud. we're at the university of by white northern barbarian and m r. center chemist

stefan. chancing a heads a research team bent on tracking down from fraudsters. the c s i food it's latest. tests are aimed at olive oil forgers. the lie about origins, spike olive oil with green code, sunflower oil, or use an array of tricks to turn spoiled oil into something they can sell must done casias. what happens then is that oils which have been stored awhile a frequently pepto using various processes which involves heat treating them. but then they don't qualify as extra virgin olive oil. those kinds of oils are often mixed with virgin or extra virgin oils and make their way on to retail shelves against on killing and so be that and, and handle a professional olive oil mafia is skill that evading the numerous checks already in place and getting sub standard oil into the stores. now a new chest produced that this german research center offers instant results. it's

about to even the playing field by analyzing 4 aspects of oil samples with one single test. firstly, is it really olive oil? the analysis has to clearly differentiate which oil or oils are in the sample, rapes doyle, hemp or sunflower oil, not oil. or is it genuinely pure olive oil? something for a magnetic residents or m r analysis in this unit here. inside the temperature is kept at an optimum 23 degrees celsius for the m r spectrometer. in it, the oil samples are exposed to extremely powerful magnetic fields, with differing make up the substances contained in the samples respond differently to the energy each returning to its own characteristic signal. yes is looking at the fatty acids. you can see the different oils are highly distinctive and stylish talk. a sunflower oil returns a strong signal olive oil has

a very weak warnock. as many as if i now combine the reading from a single measurement which was confirmed another independent evaluations, i can obtain a very characteristic fingerprint of the various oil types with the common. then 2nd, where does it originate from? does it really come from with of late says 70 percent of the world's olive oil production comes from europe, primarily from spain at around $1600000.00 tons. as well as italy in greece had some quarter of a 1000000 tons, each with italian oil commanding premium prices of swift, swamp of labels can be lucrative for years, a considerable amount of greek olive oil has turned up at italian exporters who then mislabeled it as italian extra virgin olive oil, the new magnetic resonance test, quickly lift the lid on this kind of fraud. the analysis shows that greek italian and spanish olive oil each returns their own individual signal. thirdly,

chemical quality control. a check is usually made by the producer, but quality changes over time. incorrect storage exposure to air light and warmth, all oxidizing oil. it becomes rancid in his hand, thinking if it's rancid in this area, i'd see a very large cluster of signals. it can be difficult to get a real deal and discount supermarket when they get to the shelves, they've still only just acceptable quality. but olive oil ages fast. that severely affects taste rather than fresh, bitter, sharp, fruity oil, the tastes off dog shower, or even mouldy can magnetic resonance measure that so last but not least, the chased the censorship. quit at the moment. no amount of analytical

technology can replace and soil testing by a trained panel of tases. but in magnetic resonance spectroscopy, we can also see signals from taste related compounds such as the shop and the bitter taste residential food because english mock. so it's actually quite possible that these 2 sensory impressions are very much in line with the tasting panels, results make them panel to a hydrogen. the re, jaylen goods industry is especially enthusiastic about the new technology. commercial labs expect to be offering the chests within the next few months. but even if the fraudsters find it harder to cheat in the future, if you want good quality in anything, it's best to develop a chaste for it. oh, you also need good taste buds and a good sense of smell to test chocolate. chemical analyses have found that the chocolate

a taste is actually comprised of many other surprising flavors and aromas such as peach, cucumber and potato chips. but a good chocolate is much more than the sum of its aromas. how farm is it? how well does it melt? that's where another mysterious component comes in. the shape of the chocolate crystals, shanklin contains cocoa butter, which as a solid has a rigid crystalline structure. when chocolate melts the crystals break um and the lattice shape dissolves when the mass cools the cocoa butter crystallizes again, much because it's holly morphic, it can crystallize into several forms with different physical characteristics. here's a simplified illustration. chocolate researchers have divided them into 5 groups. only one of these shapes is desirable and that can be challenging. the shape of the crystals influences the glazed, the texture,

and the appearance of the chocolate. if mainly crystals from these groups form, the chocolate will become dull, gooey, and robbery when you bend it, and it will have specs and whitish streaks. the lattice structure won't be stable with only when the ideal crystal structure comp beat of 5 predominates. will the chocolate get its proper shine and snap and melt pleasantly in your mouth? so how can you influence that? and important thing to know. different crystal forms have different melting phases . and that's what you need to keep in mind. set aside a 3rd of the chocolate melt the rest in a water bath pot, but not boiling. with at 40 to 50 degrees celsius, the fat molecules are receptive to every crystal form. if you now add the rest of

the chocolate finally graded than this will happen next, the mass cools to the perfect temperature for the desired beta 5 crystals. the melted fat molecules magically assume the right crystal form. that's not only due to the right temperature. it's also because they prefer to take the form of the crystals in their vicinity. so they take their queue from the good grated chocolate . ah, sweet treats like chocolate, don't only tempt us humans. and so swiftly on the scene when they get a whiff of something delicious and may pass that information onto their bodies. so the whole colony can please in no time at all lively traffic routes

formed right to the goodies. but believe it or not, ants are picky too. oh, oh, this aunt is about to be duped. it's on the way to feeding spot for the 4th time in rapid succession. the food is a sugary solution with rosemary. what are and doesn't know, biologist, felix ober houser has changed the recipe. this time is a, took a new some we've put lemon into the sugar solution. so it tastes of lemon. be suit horner. but how will the angry act to that the sugar content is just the same, so it's just as nourishing when the sugar contained rosemary don't was certainly cain felix over how's a mock the young yellow for easy recognition. it'll clean the marking of itself later on the way back to its nest, the insect dragged its way,

ran along the surface, leaving an invisible scent. trail is a battle oak mocked and blue with this leaf caught her aunt the almost the aunt put down st. on the substrate here, the paper to tell her nest made hey over here there's something good to eat ticket of this. that's how and communicate with each other in the wild. an ant initially set out on its own when searching for food. if it finds a good source, it runs back and forth between the nest and food marking a trail for the others. but what does it do when the food suddenly tastes different? when it finds lemon or not rosemary, sugar water? it's been rejected. shame, but it seems the and had a certain expectation and when the expectation wasn't fulfilled,

it regarded the food source as less valuable than previously thought that's also evident in its st. trail. this time hardly left any trial for the others to follow . ah, we asked felix ober houser for more insights into the world of ants. i. yeah. magazine amazon thing we saw and don't seem to like lemon water as much as rosemary, water, ninty. i creatures of habit the only consume was familiar to them. oh connoisseurs, he don't like lemon water movements. it will assign bonnie so gonna like if magnus took as long as we speak of in this case the taste of the sugar, rosemary or lemon wasn't really so important. see what we actually wanted to see was if the aunts had developed expectations related to the taste. what we've known for a while is that answer quite adept at recognizing good food sources to capacity when in and goes to the sugar water in nature, they feed on honey,

do they notice its quality? is the sugar water? very sweet or less sweet eda. if they return on the sugar water is watered down and as less sugar, they often don't want it anymore. that reaction has previously been considered logical from an evolutionary perspective. that ants would switch food sources when they're no longer worthwhile. however, what we found in our experiment was that the energy contained in the food is not necessarily what's decisive, and that ants have expectations about food on the whole. that means the answer didn't just identify it as a good source of food, but also that it tastes like lemon or rosemary to corn. what it was 1000000 when that lighted on that guides on searching for food. the how do they find a new source? has an assessment and if nigel does hank, that's a very interesting question. it really depends on the species of and when we observe the black garden and for our experiment, we found that it relies heavily on its sense of smell on the hunt for food. often

a pheromone trail has been laid by another end and they are known for doing that laying centrals that can be detected by others. with the help of a camera, we observe them do it on these centrals are very important. sensory impressions of sight is also important for the answer, just as much as it is for humans. they noticed distinctive points on the ground, and use those as a guide. yeah. usually when young ants leave the nist, they 1st follow a pheromone trail because they know it'll lead somewhere interesting probably to food. and when they visit this food source, often many times they've got the chance to learn the route while getting a visual impression too high. that means that even if the entire centro were removed, they could still find their way. yeah, good customer, no. can i? maybe i'll head back to individual lance could also just enjoy gobbling up the sugar bowl to drops all to themselves without informing other am. thank you. in

fact, why didn't develop into these altruistic little creatures now shine by listing titian and picket assessment. also very interesting. there are actually an stake don't do that. there are ancient species that only forage and search for food alone and returned to the nest alone to his nest. alina was like, it is all oh, worker, female aunts often battle for power over who gets to reproduce. so to lay eggs myself as ants began to form larger societies, customs were created, such as one and being responsible for laying eggs. she usually also lives a lot longer than the others, and the other female worker and complete other tasks in the at collin o. oscar now is amazon, not this, and that certainly advantageous in terms of food sources like sugar water, which isn't the most natural example but, and still march towards it. you have to put the camilla and the more ads from its

own colony at the source, the better chance to successfully defended a formula of hiding. it's also possible that when an ant leaves the nest, another insect will try to steal it spawns. but this can be prevented by other and still present value. i don't need to explain the building of their nests. an obvious example of what ants can accomplish in groups. all these things together explain why the insects of thrive just some of the amazon formulas. gemma, they're on fascinating. thank you. thank you. you're welcome and have been able to spread far and wide thanks to their ability to adapt to different environments like ants. we humans to are constantly adapting our jaws and teeth have become smaller over time, adjusting to cooked food long. we also seem to be developing a new artery in our forearm. normally it recedes in the embryo, but some people still have it. it's called our terry. a med yana. evolution just

keeps on going. our viewer a little more you while barbara windsor wanted to know more is the theory of evolution true? or humans, descendants of apes. with countless species of plants and animals, live on earth and water on land, and even in the air. this diversity was not created by one being all at once. british naturalists, charles darwin put forward a radical and shocking new hypothesis in the mid 19th century. his theory of evolution provided scientific evidence that all life forms evolved gradually over long periods of time. evolution never stops on life is program to reproduce. but it's not an equal playing field. only the fittest have

a chance. those best adapted to their environment. this adaptation can cause populations of one species to evolve in such different ways that new species emerge . darwin explained how all life evolved from different primordial forms. the horses that inhabit our earth to day have a common ancestor. this properly, a theory hm was about the size of a fox, had told was rather than hoofs, and lived in humid forests in the thicket. scientists know this from fossil bones around 50000000 years old. preserved phones of our ancestors have also been found, helping to deduce our origins and the development of our unique features, such as the upright gate were not direct descendants of apes. but we have a common ancestor who lived about 6000000 years ago. dna analysis shows how closely

our genes match those of 8 we share around 99 percent with chimpanzees. so with this level of similarity, can we still consider ourselves a crown of creation? ah, here they live on the streets. there are abandoned unwanted and rome wild while here they go to the hairdresser. there, groaned, brushed, combed, and spoilt. still the dogs have a lot in common. they can so resources and like us humans in high numbers, they can be harmful to the environment. for many having a canine companion is one of the joys of life. but pet dogs can cause environmental

problems which ones geo ecologist mathias fink bye know from berlin's technical university. wanted to find out. first he calculated the impact of the average german dog. 15 kilograms in weight, 13 years, life expectancy. he then examined the key aspect of a pet dog's environmental impact. it's food. but he is faint by now took measurements across 15 categories, including climate change, soil, a certification, and water pollution. dog food production rated poorly in almost all categories, but one area was especially alarming. the amount of climate damaging gases, the average german pet dog, generates 630 kilograms of c o. 2 emissions per year quite a lot. then as he forced and us, the intergovernmental panel on climate change recommends that we only him, it 2 tons per person per year in the future. so it's 630 kilograms. you've already

used up about a 3rd of your personal c o 2 budget for the dog. and if you've got a big dog, it's more than half done. it's from malice. you have the main culprit for this high c o, 2 footprint or pop rent the meat in dog food, especially beef that buys hate at us. we all know that cows is ruminants, emit me thing up, which causes climate change to bite on. and then the cow is also fed partly with concentrated feed, which contains saw for example, which is also partly grown outside germany in brazil. well, and has been cleared, it is in plain deflation, get ordered. well, we have to include all these factors. when examining the environmental impact of dog food in this, when, if with i get home, as people no longer eat as much awful as they used to slaughtered animals, organs end up in dog, food, mostly from factory farming. this is part of the reason why the average dog

generates such high climate damaging c o 2 emissions. when was he bullied that endorsement failure on given that 10000000 dogs live in germany with? if you then extrapolate that it adds up to 6000000 tons of c o 2 emissions each year from dogs alone to inquire dog food also affects the environment. once it comes out, the other end, over the average, 13 year lifespan, a dog excrete 2000 leaders of urine and 1000 kilograms of feces. these contain heavy metals and nitrogen mathias fink by nurse discovered that urine and feces are a significant cause of the over fertilization of water bodies. excrement also plays a role in water pollution because if the sun goes cuz you can't blame the dog alone for damaging a lake or a body of water or the soil, kashodi is the total impact of all kinds of other products and emissions. look good m a c o another. the pet dog does add to all of these categories and he was anti

the 2 by the average person doesn't generally notice if the condition of soils in plants is deteriorated. pito, who to man wants to change that. she's out taking a stroll in munich with her dog. anton, ma'am happens over that. now sometimes i worry it am i wonder about the full impact of what anton leaves behind and what other docs do? take you all because i have no idea how it all affects plants or nature in general . what else? we cannot why naked biologist ta cielo franklin and wanted to show her the impact canine hearing of fluid with highly concentrated nitrogen has on plants here talking about if you can see it clearly here and there to these a stinging nettles, many people know they grow mainly in nitrogen, rich soil, which gets that way mostly due to animal excrement, especially urine in cities. it's generally dog urine, him to the doctor building houses and so it's assigned. there are lots of dogs round her bar where the nettles grow. there are usually a lot of dogs out and about in the city or doing bugs of twist. these are who do

the high dog population, wherein i verdant, the encouraging lee's very plants and that's what it means. we don't have bio diverse green spaces in urban areas. so in cities we only see plants that thrive on nitrogen. and now he shows her a sloping strip of greenery. many dogs do their business there too. nevertheless plans that do not tolerate nitrogen grow their rare to loose: toma meadow, mushrooms and mouse ear hawk weed. their savior, the slope, this means nitrogen flows out of the soil quickly to speaking how that's why we have much more biodiversity here in the plants and the soil itself. ports of the microorganisms in the soil, the fun guy, bacteria might do much better here than in the flat areas and talk, thought is in even inflation. that's why it is so important to at least always dispose of your dogs excrement. this relieves the soil and water. however,

the bags are made of plastic just plastic. the plastic bag has an environmental impact of coal salvo, but being able to avoid the damage from the droppings definitely makes up for it. dog owners can do even more for the environment, cook the food yourself, and use more sustainable product. and when choosing a breed for your bread, it's best to get of smaller ones. this is because smaller dogs cause fewer problems for the environment, then larger ones. but dogs do have a lot to offer, they can help the blind and they can even sniff out corona virus infections. but for many people, dogs are simply a companion or helper. if our let is read, why are they bottom with? do you have a science question, then send it to us as a video, text or voice mail? if we answer it on the show, we'll send you a little surprise as

a thank you. come on. just ask if you can find us on the web at d, w dot com slash science and on twitter, that's all for this week on to morrow to day. thanks for watching, enjoying this again next week. until then. stay curious. ah ah, ah. ah

. with you so much frustration and so few fish, british fishermen are furious. many of them supported bread and believe to the promises of their government. but instead of more fishing rights,

they now have less income troubled waters. british fishermen in brags it close up in 30 minutes on d, w. o and german, which d w at any time, any place. a video, nevada. they have like a bit of sons to sing along to download a t from soup with a varied courses put into active exercises that are available at d. w dot com slash don't plan on facebook all in the land gym and for free

with the w. good morning speaking, how can this passionate hatred of a will be explained? a colt on where does it come from? come also, that the history of anti semitism is a history of stigmatization and exclusion of religious and political power struggles. interest in christianity wants to convey that is why christianity you like the figure of the jew as the parent plum hope is flat. it's a history of slender, of hatred and violence. is the bodies? well then on the jews were considered servants of evil. we simply told you the most atrocious chapter under, within 6 years, a 3rd of our people were exterminating 6000000 jews, like microbes to be annihilated. even 77 years after the

holocaust hatred towards jews is still pervasive. a history of anti semitism starts july, 2nd on d, w with ah, this is dw news life from berlin, ukraine's president rules act talks with moscow anytime soon. as russia pours resources into it's don boss, offensive follow de mer zalinski coles russian aggression and evil. a can only be contained on the.