According to the fossil record, ancient humans usually had straight teeth, complete with wisdom teeth. In fact, the dental dilemmas that fuel the demand for braces and wisdom teeth extractions today appear to be recent developments. So, what happened? While it's nearly impossible to know for sure, scientists have a hypothesis. G. Richard Scott shares the prevailing theory on crooked teeth. This TED-Ed lesson was directed by Igor Coric, Artrake Studio, narrated by Addison Anderson, music by Salil Bhayani, cAMP Studio.

Why do we have crooked teeth when our ancestors didn't? | G. Richard Scott

What does exercise do to your brain? Can psychedelics treat depression? From smart daily habits to new medical breakthroughs, welcome to TED Health, with host Dr. Shoshana Ungerleider. TED speakers answer questions you never even knew you had, and share ideas you won't hear anywhere else, all around how we can live healthier lives.

Health & Fitness

Catching cancer at its earliest stages saves lives. But in a body made up of trillions of cells, how do you spot a small group of rogue cancer cells? Biomedical researcher Hani Goodarzi discusses his lab's discovery of a new class of RNAs that, when paired with emerging AI tools, could help detect cancer earlier, more precisely and even through routine blood work — potentially transforming our understanding of the disease.

What if a simple blood test could detect cancer? | Hani Goodarzi

Since humanity’s earliest days, we’ve been plagued by countless disease-causing pathogens. Invisible and persistent, these microorganisms and the illnesses they incur have killed more humans than anything else in history. But which disease has been the deadliest? Dan Kwartler digs into how human progress and innovation throughout history exposed us to surprising new maladies. This TED-Ed lesson was directed by BASA, narrated by Addison Anderson and the music was created by Igor Figueroa, Estudio Mono.

The diseases that changed humanity forever | Dan Kwartler

Having your period is exhausting — and for many people across the world, menstruation is even more challenging because of stigmas and difficulty getting basic hygiene supplies, says social activist Ananya Grover. In this uplifting, actionable talk, she shares how "Pravahkriti," her campaign to spread period positivity, creatively engages with everyone to promote menstrual health, raise awareness and break taboos around periods. After the talk, Shoshana has a sweeping conversation with OB/GYN, activist and fellow TED Audio Collective host Dr. Jen Gunter on breaking down period myths and misconceptions.

A campaign for period positivity | Ananya Grover

Biologist Kathleen McAuliffe dives into emerging research that explores how certain gut bacteria can influence major parts of who you are, from your personality to life-changing neurological disorders. Learn more about how this ongoing clinical medical and pharmaceutical research might change how we treat disease — and discover the impact of your internal microbial makeup on your mood, weight and more.

Do gut microbes control your personality? | Kathleen McAuliffe

Have we misunderstood pain? This week we’re revisiting a talk by researcher and physician Amy Baxter as she unravels the symphony of connections that send pain from your body to your brain, explaining practical neuroscience hacks to quickly block those signals. Her groundbreaking research offers alternatives for immediate pain relief -- without the need for addictive opioids. (Followed by a Q&A with TED current affairs curator Whitney Pennington Rodgers)

Why do we have crooked teeth when our ancestors didn't? | G. Richard Scott

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