topics: Determining people's biological age; Factors that boost life expectancy; Collective intelligence; Flying scarecrows; Why is the sea salty? the first before we even see the light of day our biological clock has already started ticking. we grow older and birthdays pass by year after year but how and why do we age scientists are trying to understand more about the process so they can slow it down or even make it stop. this mission might want to drive me the most is finding out why we age the iota. and. are in desperate to find out how it works. and how we can intervene through treatments and medications to slow the aging process for long. biostatistician steve harvey what's for the you. versity of california in los good genes are a top draw a gift from your parents. people who survive well into old age are more likely to have children who also have long lives. the reason is in your genetic makeup. british researchers have discovered genes in seven regions of the brain that are directly linked to life expectancy. one of these genes for example plays an important role in the immune system. them. on camera such extend our longevity. wild life style an environmental factors obviously play a big part thirty suggests that twenty to thirty percent of the variation in lifespan is genetic. a person's gender also plays a vital role when it comes to life expectancy. women live longer than men globally on average of four years. when the two genders lead near identical lives however that difference is not so pronounced. nuns and monks live under similar conditions. here to the women outlive the men. but by an average of only two and a half years. our genes could be a factor here. women have two identical x. chromosomes men have one x. and one y. chromosome if the x. chromosome is damaged they cannot be corrected by the other as is the case in women so men are more prone to genetic defects one hypothesis is that to start to run might also play a role in the prevalence of cardiovascular disease in men. nutrition also affects our life expectancy. a good diet is crucial to overall health and can help us live longer. a mediterranean diet one that includes lots of fresh fruit and vegetables and refined cereals and all of oil is another factor associated with increased life expectancy. swedish researches back to the theory with statistical evidence. calorie consumption also affects life expectancy. maintaining a normal weight boosts the likelihood of a long and healthy life. outlook on the world is another significant factor. in the one nine hundred seventy s. researchers in the us found people who are optimistic about getting older live longer. back in the one nine hundred twenty s. american psychologist lewis terman began a long term study eighty years on the research project made some unexpected contribute to a long life include our genes in our gender but also ones that we can influence a good diet a positive approach to life on plenty of exercise. living longer and staying young it's something many people dream of we asked our viewers on facebook what they think keeps people young. up obeid own was a car things you need to find a good place to live so that you can rid yourself of bad feelings. callously minister viruses inclement mexico lots of people swear by coconut oil. and in italy olive oil is the recipe for a long life says sell paradise. maxime you share it says happiness love and joy are the key to looking young so be happy and love each other. also swears by positive attitude it gets rid of negative thoughts and worries and makes you feel free. suffers dimitri wrote to us from the greek capital athens to say partying is how people there stay young with lots of traditional dancing. and david earnings recipe for youth is to make music. maybe he's on to something mick jagger is after all seventy five years old. we humans spend a lot of time probably our entire lives learning new things one way or another in schools if we have the opportunity but also in everyday life knowledge is. skills strategies to negotiate the world. different species develop their own clever methods for survival. we visited now where bunch of small fish show what they can do together. in cousin has had a big pool built here. today it's reserved for a school of sticklebacks. the pool has some regions that are lit up and some in the shade. the tiny fish always manage to stay in the dark areas avoiding the areas in the light that's a matter of survival for sticklebacks sunlight reflects off their skin making them visible to predators but when your cousin puts a single fish in the pool it fails to locate the shadowy parts it seems but sticklebacks can only do better as a swarm one of the most frustrating things worse was exhibit collective intelligence the group can often solve problems no individual within the group. where does that collective intelligence come from how does the swarm develop capabilities that individual fish don't have. that something that's puzzled researchers for a long time. they watched the swimming fish over and over again. but they found the decisive clue in an old russian book there was some great britain work in the fifty's and sixty's in russia with a guy called dmitri ruddock of who was the first person to actually realize that the interactions among these individuals could produce emergent properties and he tracks the motion of fifths by projecting city fall on a wall and tracking with each individual goes with a pencil and he speculated that in future this is going to become increasingly important. on the sound how and why this form schools. in carson and his colleagues took on the idea and refined it with the help of modern technology. they've created bar codes to attach to the fishes dorsal fin. each fish gets one of these individual markers so they can be clearly identified at any time. when they're released into the big pool. as expected the fish moved from shadow to shadow. the camera footage of the swarms movement is then analyzed using software that can show the path of each individual fish. straight away the scientists notice at the fish swim more slowly when they reach a dark area. in cousins studies how the changes in speed affect the swarms overall behavior. we've tried the most and we can look at the accelerations that the individuals exert influence the social influence that exists between these different individuals and we can visualize these as connections almost like springs or elastic connections between the individuals and this allows us to understand how the collective how this network of communication helps the the group solve problems. what we find is that the social interactions almost like a spring and invisible spring between the individuals and sort of two individuals are moving together and one hits a dark region and slows down the other means going fast the spring is titled the last it gets tighter and tighter begins to start exerts a force that turns the cinder good will towards the dark region even though it doesn't know it's that. the spring represents one of the swarms of ground rules always keep the same distance from your nearest neighbors. when one fish slows down and lags behind initially the distance grows the spring stretches the restoring force makes the fish swim to the shadow. the amazing thing here is that evolution has flown very very simple rules the rules of the simplest possible that the organisms could use and even though the individuals are not aware that they're solving the problem as a collective they are. it's not just sticklebacks that solve problems together lots of species seem to demonstrate collective intelligence. one thing salt water fish don't need to learn is how to deal with all the sultan the water they live in whenever they drink lots of salt enters their blood luckily they have specialised cells and they kill as they're transported back into the water. which brings us to an interesting question that our viewer francisco known for in mexico has posed. why is the ocean so salty if someone can't see that they pouring salt into it just the opposite farmers harvest the mineral from the sea so we can later sprinkle it on our food. the ocean so begins its journey when it rains in the mountains for example. as the water flows through soil and over rocks it picks up sodium chloride a mineral formed when the metal sodium reacts with chlorine gas. you don't detect the salt and fresh water lakes and rivers because the concentration there is too low. but as rivers transport the water into the oceans the salt accumulates over time along with more released from benson the ocean bottom. as a result one leader of sea water contains about three tablespoons of salt on average. that's one good reason why you really don't want to drink ocean water. but why doesn't the sea continue to get salty or that's probably because some of the dissolved salt is constantly being removed from seawater to form new minerals deep down on the sea bed. when sea water seeps into the shore along the coast it also leaves salt deposits there. the water evaporates into the atmosphere only to fall again as rain. in rivers washing more salt into the sea. because it is red white i mean latin even. do you have a science question that you've always wanted on thing that we're happy to help out send it to us as a video text over smell if we answer it on the show we'll send you a little surprise as a thank you cannot just honest. you'll find as i did on the dot com slash science drop us a line at d.f.w. undisclosed site tech on facebook d w dot science. in the sky pretty crowded with countless birds flying around and lots of plane sitting over the place. in fact. there are about two hundred thousand flights every day we see them pull speeded up. planes and beds do not mix it's extremely important to keep birds away from escorts but that's not easy the dutch company called clear flight solutions has come up with an interesting answer to the problem. it looks like a bad approach. but this is very bad and it hasn't quite mastered london yet. and this clumsy machine is supposed to frighten off real boats everyone knows that birds are dangerous for airplanes but birds are also annoying for farmers because they eat their crops and birds in history are not a really good match because for the oil and gas side it is not wanted the birds can nest there so there's a lot of various sides where birds are. on one side so you want to keep them out of the area and that's where we can. come back at port windy weather isn't the only factor hampering a smooth landing marcus most keeps a close eye on flying objects on the runway. a number of pose a safety risk but once you're in hamburg they include seagulls and crows. and we're seeing increasing numbers of grey herons ducks oh i'm also great peace. and so guns ingrid is a real falcon truly fear in choosing falcon ahead but boca takes us to the airport to scare off other bads he's heard of the brave falcon but he thinks his flesh and blood but can do the job much better. simply as it did seem to be at the end cross contact very quickly i felt but of praising him. so if it's really a danger or not they know. stinks of me now and then you see the whole flying around here on its way somewhere on the crows don't react the bird of prey needs to be actively hunting as. a feat. in contrast to the real falcon the robot can be controlled and that's an advantage. for the nearest prey so you can't make it go off to a specific but as soon as it's flown off you can't control it. once it's taken off a real falcon pulte whatever takes its fancy. a robotic one is a lot more user friendly so long as other bats a convinced by. a real bird of prey it's dangerous to them sort it will try to stay away from it and since they don't see the difference between the row birds and a real bird of prey there will also be afraid of the rober. in designing their grandma you control the crate with the realistic appearance and white of its living counterpart robots developers have succeeded where many others have failed by doing it straight forward because it doesn't require their wings to me at craft engineering uses the same principle. of the movement a much harder to emulate but it's propel themselves forward by pushing at backwards with the wing tip following an elliptical path. when the bird flaps its wings up its angles them slightly and opens it sound to feathers this minimizes the average distance as the wings meet up with. when the bird flaps its wings down it spreads them and the feathers are efficiently pushing arrow away. trucking provides both forward on to lift. the very bad doesn't have any feathers but it's. movements emulate the use of real bad what kind of make to cities and where the position is the engine is closely guarded secret. bird fly basically is based on two different motions so it's like a rowing boat so what you have is you don't only have the motion of a lot of people think the bird's dude like the up and down movement but you also have the movement that's like a rowing boat so a little bit like this and so what we really want is that the wing. can make a flexible motion so it should be able to really move like this so those motions are really needed for flapping wings light. the engine is soon found out that attempting to copy nature brings its own challenges for an airplane for example it is very easy to make a small scale model and the put it in the wind tunnel and then to calculate everything this related to the aerodynamics before bird this is difficult because you cannot put a real bird in the wind so i know you're going to do these measurements so you really have to learn from how to do this in nature. they also copied the shape of the body from nature that's how the buts' recognize members of the species so they can distinguish between friend and five sim a word that's really important. and with that it is very important that it flies by flapping its wings so if it doesn't flap its wings. other birds know that it is not active for you hugs but if the bird of prey starts flapping its wings then it starts to spend energy and it wants something in return so it would really wants to get something back for the effort that is making so that's when it starts hunting so they know to the moment that the good grace starts moving its wings that they need to get out of. the groove just already deployed on runways in england and come into but in germany it's constantly drawing and trends about an apple. next time on tomorrow and today we're going policy for many people posses mean alcohol but how does a social behavior change under the influence that is a serious academic question studies show we get smiley and others look friendly of course to get the wrong impression we're not saying go out and get wasted on down sides want to hear more cheney next week bye for now. your story t.v. smarter than g.w. bush knows. what you want when you want to up to date extraordinary. into decide what song plays more that come smartly. his creations or interests his brand understandable calm that icon of the fiction. book what do we really know about the man behind the dark shades what motivates him how does he think and feel good moments in the life of a great fashion designer. sun smart. start september ninth to w. looking kind of thing you know i think the evidence very clear and clear the everyday person to the question is what can they do about it so it's very oldest me walk with their beauty and don't take little or elevators i do i do that every time i think about an elevator or lived and this is still way to about i take the stairs . and i try and walk wherever i can instead of going in a car or even in public transport it's just you know doing things that i think would be very common and we just got out of the habit as of becoming museums to take automobiles but actually it's not very hard to change this very easy car individuals to i think you know people you meet with me making a difference. to