CrowdScience

It's a topic that's taboo in many cultures, yet it's also something nearly every woman experiences – on average upwards of 400 times throughout her life: menstruation.

Responding to a flood of questions from our CrowdScience listeners, Marnie Chesterton seeks to unpack how periods affect women physically, mentally and societally.

Why did humans evolve to have periods when fewer than two percent of mammals share our experience of menstrual cycles? Is it really a good use of our limited energy reserves? What can the little Egyptian spiny mouse teach us about PMS symptoms? We hear why periods may reduce the number of faulty embryos that implant and how more menstrual cycles may even increase our chances of developing certain types of cancer.

Finally, as the number of periods a woman has over the course of her life has more than quadrupled since the pre-industrial era, Marnie asks: Do we really still need to have them?

Presented by Marnie Chesterton

As millions more of us move to live in densely populated cities, we almost inevitably face living in closer proximity to our neighbours. Neighbour noise can certainly be a source of annoyance – but could it even be damaging to our health?

Contributors:

Produced by Jen Whyntie and presented by Anand Jagatia for the BBC World Service.

You are a star. Literally.

(Photo: Neutron star. Credit: Getty Images)

There are over 400,000 species of plant on earth, they’re on every continent including Antarctica. But humans only regularly eat about 200 species globally, with the vast majority of our nutrition coming from just three species. Many of the fruits, leaves and tubers that other plants grow are packed full of toxins that are poisonous to us, and would make us very ill if we ate them. But could we take out the poisons and create new, edible crops? That’s what CrowdScience listener Marija wants to know.

Crowdscience dives into this topic, and uncovers the that many crops are poisonous, and why so few plants are eaten globally. Host Anand Jagatia finds that even the modern scientific processes of crop breeding are very slow. But science can now engineer plants at the genetic level by adding, silencing or removing specific genes. This ‘genetic modification’ is hugely controversial but can be highly effective.

Anand finds a man who has spent decades making cotton seeds edible by removing the poisons they naturally produce in their seeds. This GM crop could help fend-off starvation. But sometimes introducing poisons can be as important as removing them, as we find in the genetically modified ‘BT eggplants’ in Bangladesh. The new gene makes the vegetable toxic to a major insect pest, so they are much easier to grow.

But GM crops are not the perfect solution. They have problems of gene escape, can increase the use of environmentally damaging herbicide, and can be open to monopolisation. In some countries, particularly in Europe, GM crops are hugely controversial. Anand finds out whether these concerns stand up to science and looks at the counterpoint in developing countries in Africa, South Asia and elsewhere, where local farmers like Patience Koku in Nigeria have little time for some of the concerns around GM, particularly as they see poor harvests, poverty and starvation as the more pressing problems.

Contributors:

Image: Farmer with Fruits. Credit: Arif Hossain, Farming Future Bangladesh.

Have you taken classes to learn a new sport or musical instrument or a language? It’s hard work! Why is it that as children we effortlessly absorb new skills and we don’t as adults?

[Image: Adult and Child learning Piano. Credit: Getty Images]

When eating a blackberry one day, CrowdScience listener Charles got a tiny seed stuck in his teeth. That got him wondering: why are seeds the size they are? Why does a blackberry have dozens of tiny pips, while a peach has one huge stone right in the middle?

Plant seeds have been around for hundreds of millions of years, so they’ve had plenty of time to shapeshift into wildly different forms: from dust-like orchid seeds to giant coconuts. This evolution has been a long and intricate dance with wind, water and animals; we ask how different kinds of seeds might respond to today’s environmental threats and rapidly changing ecosystems.

And we go in search of the world’s biggest seed, the coco de mer: native to just two remote islands in the Indian Ocean and weighing up to 18kg, how did this seed evolve to be so much bigger than any other?

With Professor Angela Moles, Dr Si-Chong Chen, Marc Jean-Baptiste, Dr Frauke Fleischer-Dogley and Dr Wolfgang Stuppy.

Presented by Marnie Chesterton

[Photo: Different sized fruit seeds. Credit: Getty Images]

Most of us don’t like to dwell on our toilet habits, but this week Crowdscience has gone down the drain to discover what wastewater can tell us about our health.

It’s been more than a year since scientists across the globe started to track the spread of Covid-19, with help from home test results and hospital data. Marnie Chesterton investigates the latest tool in their arsenal: sewage. Listener Kevin has heard how human waste can be monitored to check for virus levels, and wants to know if it can also be used to stop the disease in its tracks?

Although the coronavirus has been discovered in people’s poo, so far there’s little indication it’s actually being spread through the water system. But by taking regular samples from different parts of cities, authorities are now able to accurately predict a local peak weeks before the population shows signs of sickness, then take immediate measures to alert them. In Detroit we hear how environmental engineer Professor Irene Xagoraraki used this method to detect a rare strain of Herpes which doctors didn’t even know was a potential problem.

Marnie also talks to Professor Nick Thomson from the Wellcome Sanger Institute, who sequenced the genome of the bacteria that causes cholera, to understand how it has crisscrossed the globe. He discovered that the pandemic currently devastating Yemen actually originated in Asia. It’s a discovery that has changed how the WHO is thinking about this killer disease and could have important implications for vaccination programmes. But our effluent can also pose environmental problems, and Professor Andrew Johnson from the UK’s Centre for Ecology and Hydrology explains there are now as many as 300,000 chemicals that could threaten natural habitats.

While authorities try to test each one individually, he’s concerned they may have different effects when they mix in wastewater, and current monitoring systems don’t take this into account. Not only that, but some of these substances contain silver nanoparticles, which Professor Juliane Filser tells us stick around in soil for ever, threatening organisms and bacteria at the base of the food chain.

Presented by Marnie Chesterton and Produced by Marijke Peters for the BBC World Service.

[Image: Sewage outlets. Credit: Getty Images]

Grief is universal. It is something almost all of us will go through at some point. And it is something that the people we love will experience when we die.

Grief can be all consuming, it can make everyday tasks like getting out of bed, feel impossible. Which makes listener Oliver from Australia wonder - what is the point? It doesn’t bring what we lost, back.

Why have we evolved to be so affected by loss? Be it the death of a loved one, the end of a relationship or the loss of a job. Does it serve any purpose? Or perhaps it is just the price we pay for being a social species with such strong connections.

Image: Families Mourn Victims of The Tamaulipas Massacre in Tuilelén, Guatemala

Produced by Caroline Steel and presented by Marnie Chesterton for BBC World Service.

Gossip often has negative connotations, but does it get a bad rap? Might it serve a useful function and should we think of gossiping as an advanced social skill rather than a personality defect? CrowdScience listener Jayogi thinks it might be useful, and has asked CrowdScience to dig into the reasons why we find it so hard to resist salacious stories.

Presenter Datshiane Navanayagam meets a scientist who views gossip as a key evolutionary adaption - as humans started to live in bigger cooperative groups, gossiping was a way of bonding and establishing acceptable group behaviour as well as cementing reputations of trustworthiness.

Datshiane heads to the local park to catch some real gossiping in action and finds out that whilst people like to gossip they don’t consider themselves gossipers.

Datshi asks a team of scientists what information we are most keen to share and glean in these interactions and if there is such a thing as ‘good’ and ‘bad’ gossip. She hears that in some group settings – like in the workplace - gossip can enhance cooperation and limit free-riders, but that it can also have a more self-serving dark side.

Datshiane finds out if our stone-age gossipy minds are fit to operate in the world of mass communication and social media – is our fixation on celebrities related to our being hard wired to gossip?

Presenter: Datshiane Navanayagam

[Image: Gossiping people. Credit: Getty Images]

If a tree falls in a forest, and no-one is there to hear it, does it make a sound? This is an age-old debate that listener Richard and his family have been arguing about for years. Can CrowdScience settle it once and for all?

Caroline Steel speaks to experts in hearing, biology, philosophy, physics and sound design, which takes her to some unexpected places.

Professor Stefan Bleek is an expert in psychoacoustics who says that sounds only exist in our heads.

Things get truly weird as we delve into the strange implications of quantum physics. If there is such a thing as reality, doesn’t it change when we’re there to observe it? Does the tree even fall if we aren’t there?

Presenter: Caroline Steel

(Image: Fallen Tree. Credit: Getty Images)