Around the world, at dawn, something magical happens. As the sun rises, nature seems to wake up, and different species break into a chorus of song and call. These “dawn choruses” are one way we experience the rich tapestry of life all around us. But that tapestry is wearing thin, as species disappear from our planet at an increasingly fast rate.

On this episode, we take a look at biodiversity — the variety of life on earth. We talk about why it matters, how it’s being threatened, and what people are doing to better understand and protect it. We explore the legacy of the late biologist E.O. Wilson, who popularized the term “biodiversity,” and speak to conservation scientists about their efforts to protect “biodiversity hotspots.” Also, the challenges affecting natural history museum collections, and the fight against the growing threat of species extinction.

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When you hear the word fungi, chances are mushrooms come to mind: button mushrooms, maybe portobellos, or chanterelles. But so much of the fungi kingdom is invisible — underground — and many say underappreciated. Fungi are vital to life on the planet, but scientists are just beginning to understand their many functions and possibilities. On this episode, we explore the role of fungi in nature, in medicine, and in our lives. We’ll talk about sustainable design that utilizes mycelium, discuss how fungi form networks that communicate information, and look at an experimental and unapproved fungi-based treatment people are using to regain their sense of smell.

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Jessie Flynn decided she’d had enough. For years, multiple sclerosis had taken more and more away from her life — her ability to move, her freedom, the job she loved, even her marriage. Now it seemed like medical treatments and physical therapy were no longer halting the illness’ progression — it seemed like she was on a rapid slide toward immobility. She wanted hope, and she wanted options. So she decided to try an experimental treatment called HSCT, which is not yet approved in the U.S. It came with great risks and a staggering price tag — which Jessie was willing to take on against her medical team’s advice.

Many patients find themselves in a similar place; a new treatment promises results, some experts call it a breakthrough — others caution that it’s not as good as it seems, or worse yet, a scam that takes advantage of vulnerable people.

On this episode, we examine the crossroads where desperate patients and experimental treatments meet.

Learning how to be a parent can feel overwhelming, and advice is everywhere. There are the things you’re learning from other parents, the things you’re reading in books, the things you hear from your pediatrician, from influencers, from your great aunt Margaret … and in the meantime, you’re trying to develop your own instincts as a parent.

So who do you listen to? Who’s the real expert? And how much do these decisions ultimately matter to the health and well-being of your kid?

On this episode — navigating parenting advice, and what science can tell us about raising kids. We dig into advice about sleep, food allergies, how much influence parents actually have on their children, and how to raise kids who aren’t a**holes.

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Getting the right diagnosis can be life-changing. It can mean the end of pain and the beginning of answers; it can mean treatment, a cure — or at least a path forward; or it can just mean validation for everything a patient has been through.

Diagnosis is at the heart of medicine — and yet it seems like it often goes wrong. Patients sometimes wait months or even years for answers. They suffer through endless tests, ineffective treatments, overlooked issues — or straight-up misdiagnoses. And for some patients, answers never come at all.

On today’s episode, we travel down the long and winding road to diagnosis. We get an inside look at how diagnoses are made, what they mean to and for patients, and the challenges doctors face in getting them right.

We hear about the dangers of too much testing, the debate over “gaming disorder,” and a medical mystery from The New York Times columnist Lisa Sanders.

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When it comes to generosity, there’s a wide spectrum in terms of how far we’ll go for others. There’s buy-your-friends-dinner generosity, donate-to-charities generosity — and then there’s give-your-organ-to-a-perfect-stranger generosity. There’s generosity that makes us feel good, generosity that happens anonymously, generosity that goes viral on social media, generosity that changes someone’s mood, and generosity that changes someone’s life.

On this episode, we explore generosity — what it is, where it comes from, and how it spreads. We talk with Georgetown psychologist and neuroscientist Abigail Marsh, who studies everything from psychopaths to extraordinary altruists. We hear stories about the role of an altruistic family structure in the Black community and find out how the TV show “Buffy the Vampire Slayer” is inspiring random acts of kindness.

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On a technical level, noise and sound are the same thing: vibrating molecules that travel in waves straight to our ears. But when sound is annoying, we tend to call it noise. From garbage trucks to car alarms, shrieking babies to nails on a chalkboard, noise can be really grating and irritating. In fact, some noises are so annoying, so loud, so obnoxious that they can take a toll on our well-being and health.

On this episode — part two of our exploration of sound — we take a look at noise, how it affects us, and what we can do to reduce it. We listen to stories about a phantom beep in Brooklyn that had everybody on edge, the quest to quiet hospital alarms, and a day in the life of a noise detective.

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The soundscape of our lives changes depending on where we are — the murmuring of voices, birdsong in trees, the beeps and dings of technology, and the cacophony of traffic.

Our worlds are dense with sound. Often, it all blends together to the point that we barely notice it. But every sound has its own distinct profile — providing information, bringing joy or irritation, causing us to snap to attention or zone out.

In this episode, we explore the world of sound, how we interact with it, and the people who compose the sounds that define our lives.

We hear stories about the teams designing the hum of electric cars, how the sounds of a rainforest inspired the pings and dings coming from your computer, and a disorder that makes ordinary noises almost unbearable.

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It’s when a dark alleyway makes the hairs stand up on the back of our neck; when a mother just knows that something’s wrong with her kid; when you meet someone, and can tell they’ll either be your best friend — or your worst nightmare.

On the surface, intuition can seem a bit like magic — this unexplainable knowledge that pops in our heads, based on nothing but a feeling. But scientists say there’s more to intuition than just gut instinct. It’s about how our brains use years of accrued information to make predictions about what’s going to happen next — all on a subconscious level. But if we don’t know exactly how intuition works, how can we trust it — and should we trust it?

On this episode, we explore intuition — what it is, how we can harness it, and when to avoid it. We hear stories about the edge that human doctors have over AI, one woman’s incredible feat of motherly intuition, and why some people call intuitive eating the antidote to diet culture.

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The human brain has an incredible capacity for processing information, from sensory data, to casual conversations, to everything we hear and read — in fractions of seconds. Not only that, our brains make sense of it all, allowing us to learn, work, form relationships, and navigate the world. On this episode, we take a closer look at how this all works — and why it sometimes doesn’t. We hear stories about listening instead of reading — and test the limits of speed listening; we’ll find out why reading comprehension tests in schools may be misguided; and why some people who think they’re hard of hearing might actually have a different issue going on.

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