CrowdScience

Sex is responsible for the large variety of life on earth. Without the two sexes there is no sexual reproduction which means no shuffling of the genetic make-up – and no survival in a changing environment. But why do we have two sexes in the first place and does nature determine your sex? It’s with these questions and more that listener Du from Singapore persuaded the CrowdScience team to investigate the weird and wonderful world of sex. You might think that Nature would have standardised something as important as ensuring the continuation of the species. Far from it – species do sex in many different ways – some stranger than others.

Presenter Marnie Chesterton unpicks the zoological oddities of sex and along the way learns about her own sex chromosomes. We also meet an unlikely bird keeper, who is the proud owner of a female duck that is morphing into a male. Will her boyfriend, a male mandarin duck, mind the change?

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Presenter: Marnie Chesterton

(Image: Male and female mandarin ducks. Credit: Getty Images)

Biometrics are being used everywhere to recognise us. On this edition of CrowdScience we try out the tech that tells us apart. We find out just how unique our irises are and meet a man who can pick people out from a crowd of thousands just by analysing the way they walk.

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Presenter: Anand Jagatia

(Image: Fingerprints being looked at under a magnifying glass. Credit: Getty Images)

Our planet is getting rather cosy. In just over 200 years, the global population has grown from 1 billion to almost 7.5 billion – and the best estimates suggest it’s going to keep on increasing. But just how far can it go? When will we reach ‘peak human’? That’s what CrowdScience listeners Alan Donaldson and Francoise Brindle want to know: what’s the latest estimate for how many people the Earth can support?

It’s a question that’s been bothering some of the world’s greatest thinkers for hundreds of years, and now presenter Marnie Chesterton goes on her own quest for answers. Her journey takes her through the technology and innovation that keeps our growing population alive, and she looks to Dhaka, Bangladesh, to find out what a more densely populated world might feel like. But are there signs that things are already levelling off? And could improving photosynthesis allow populations to grow without destroying the environment?

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Presenter: Marnie Chesterton

(Image: People on busy street. Credit: Getty Images)

Mining asteroids, moons or even other planets has remained firmly within the realm of science fiction. But as certain elements become increasingly scarce on Earth, private companies and even nation states are looking to make extra-terrestrial mining a reality. Presenter Marnie Chesterton heads to an Earth-based mine in Scotland to see just how tricky space mining could be, and what possibilities it holds. On the way she discovers what laws govern this new far frontier, and hears from a space prospector who already has designs on key sites for exploration. Could our solar system's asteroids really become self-fuelling gas stations for spaceships?

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Presenter: Marnie Chesterton

(Image: Double the Rubble Artist Concept. Credit: NASA)

For most people the idea of chewing on a caterpillar or tucking into a tarantula is pretty unpalatable. Yet according to the United Nations, some two billion people around the world consume insects regularly. This prompted World Service listener Saman from Pakistan to ask the BBC CrowdScience team “are insects a serious food source?”

To tackle this question, we head to Burkina Faso in West Africa where shea caterpillars are an important part of the local diet in a place where food security is low and malnutrition is high.

Here we follow scientist Charlotte Payne as she tries to crack the tricky science behind the caterpillar’s life cycle and see how local entrepreneur Kahitouo Hien is trying to change lives and reduce malnutrition with edible caterpillars.

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Presenter: Anand Jagatia

(Image: Bowl of cooked Caterpillars. Credit: BBC/Anand Jagatia)

Why do we have so many accents - even when we’re speaking the same language? What's happening in our brains and mouths to make us sound so different from each other? This week’s question from listener Amanda takes CrowdScience to Glasgow in Scotland: home to one of the most studied - and distinctive - accents of English.

Along the way we visit a voice coach to try and learn a Texan accent, use ultrasound to see what different sounds look like inside our mouths and find out how a brand new dialect was formed when many accents collided in New Zealand.

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Presenter: Nastaran Tavakoli-Far

New Zealand Mobile Unit recordings courtesy of Ngā Taonga Sound & Vision

(Image: A mouth screaming white letters. Credit: Thinkstock)

Do your joints ache when it's raining? Are you blighted with headaches when the wind picks up? If the answer’s yes then you're definitely not alone. People have been linking their heath to the weather since the time of the Ancient Greeks - but is the effect real?

CrowdScience heads for the hills and gets closer to the clouds to have a go at answering this 2,500 year old question.

People who believe they’re sensitive to the weather aren’t always taken seriously. But presenter Datshiane Navanayagam hears about the latest ground-breaking experiments that show there's a lot more to it than folklore. And if you've ever wondered why you're particularly prone to aches and pains in the winter, the answer could all be in your genes.

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Presenter: Datshiane Navanayagam

(Image: Man looking up to grey clouds. Credit: Thinkstock)

Can we really live on Mars? Or exist in a virtual world? And why does movie science sometimes have us shouting at the screen? Our panel of scientists and sci-fi experts reveal all in this special edition of CrowdScience recorded live at the South by Southwest Conference & Festivals in Austin, Texas, USA. To tackle all of our listeners’ questions about science in film, presenter Marnie Chesterton is joined by a team of specialists.

Prof Polina Anikeeva is an MIT materials scientist and engineer whose research focuses on developing devices that work directly with the human nervous system. A sci-fi fan, Prof Anikeeva knows just how realistic brain-computer interface movies such as Avatar and The Matrix are.

Former NASA astronaut Dr Mae Jemison is a medical doctor, engineer, educator and entrepreneur, and the first African-American woman to go into space aboard the shuttle Endeavour in 1992. She is leading the 100 Year Starship Project, which aims to take humans beyond our solar system by 2112.

Prof Clifford Johnson is a theoretical physicist at USC whose work leads him to think about space-time, black holes, and extra dimensions, making him a regular contributor to documentaries about science and sci-fi films.

Rick Loverd is Program Director of The Science & Entertainment Exchange at the National Academy of Sciences, which inspires better science in Hollywood by introducing entertainment professionals to scientists and engineers. The Exchange has consulted on movies including Star Trek: Into Darkness, Iron Man 2 and Thor.

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Presenter: Marnie Chesterton

Audio clip from Gravity

Audio clip from Interstellar

(Image: Matt Damon in The Martian. Credit: Getty Images)

The human race is getting fatter. But is it our fault? There are a whole host of factors influencing our weight - how many of them can we control?

CrowdScience discovers how factors like our environment and our genes can tip the scales in the wrong direction.

We visit an apartment complex originally designed for Olympic athletes, to see if people can get fitter just by living there. And from a brand new menu plan for overweight Mumbai police, to hormone injections that stop you getting hungry, CrowdScience asks the experts what we can do if we’ve been dealt a bad hand when it comes to our weight.

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Presenter: Marnie Chesterton

(Image: Women and a Man standing next to each other holding hands. Credit: ThinkStock.)

Trees take in carbon dioxide but they also convert some of the toxic gases in our air. How much help can trees give us in fighting air pollution and could where we plant them make an even bigger difference? Crowdscience reports from the side of some busy roads on how canopy coverage may be part of the answer. At a lab in Louisiana one scientist is putting oak leaves through their paces to find out how effective they are at cleaning our air.

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Presenter: Marnie Chesterton

(Image: Trees in a forest Credit: Julian Stratenschulte/Getty Images)