For years, we've been asking, "Which came first: the chicken or the egg?" Maybe what we should have been asking is, "Which came first: the frog or the tadpole?" A new paper in the journal Nature details the oldest known tadpole fossil. Ringing in 20 million years earlier than scientists previously had evidence of, this fossil might get us closer to an answer. Have another scientific discovery you want us to cover on a future episode? Email us at shortwave@npr.org — we might feature your idea on a future episode!

Conservative influencer Charlie Kirk has focused his political organization on winning Trump another turn. But many longtime Republicans are concerned about the group's effectiveness.

Every American red wolf alive right now is descended from only 14 canids. In the 1970s, humans drove the red wolf to the brink of extinction. Because of that, red wolves today have low genetic diversity. But what if we could recover that diversity ... using "ghost genes"? That's right, today's episode is a ghost story. Along the way, we get into gene dictionaries, the possibilities of poo and how a photo of a common Texas coyote started it all. Have another animal you want us to dig into for a future episode? Email us at shortwave@npr.org!

Some clinics will now check your breast scan for arterial calcification, which can be a sign of heart disease risk. But questions remain about the approach.

In human history, fear kept us safe when running from predators and anxiety kept us from going back to that lion-infested area. But what happens when these feelings get out of hand in humans today? And why do some of us crave that feeling from scary movies or haunted houses? For answers, we turn to Arash Javanbakht, a psychiatrist from Wayne State University. He likes studying fear so much, he wrote a whole book called Afraid. This episode, he gets into the difference between fear and anxiety, many of the reasons people feel afraid and why things like scary movies could even be therapeutic. Want to know more about the science behind what keeps you up at night? Email us at shortwave@npr.org — we might cover it on a future episode!

Years ago, astronomy professors started noticing something that troubled them: Many of their students didn't understand climate change and the science supporting it. So a small group of professors decided to do something about it — teach climate change in their introductory astronomy courses. Want to hear more stories about climate change? Email us at shortwave@npr.org — we'd love to hear from you!

Patrick Anderson is widely recognized as the greatest wheelchair basketball player of all time. He's represented Canada at the Paralympics six times and led his team to win three gold — and one silver — medals. But since he first started playing in the 1990s, the sport has changed dramatically. He says that's due in part to the technological innovations in wheelchair athletics. In this episode, guest host Andrew Mambo chats with Patrick about the reasons for these changes. They also cover the origin of the sport, how the innovations that have changed gameplay and the rising popularity of wheelchair basketball around the world. Plus, the commonality between sport wheelchairs and stance cars. Interested in hearing more about the science behind sports? Email us at shortwave@npr.org — we'd love to hear your feedback!

Hurricane season is heating up: Hurricane Francine hit Louisiana last week and dumped rain across the South, and forecasters expect more stormy activity in the Atlantic in the next few weeks. A big factor in this stormy weather is our extremely warm oceans. Scientists know climate change is the main culprit, but NPR climate correspondent Rebecca Hersher has been following the quest to figure out the other reasons. Hint: They may involve volcanoes and the sun. Read more of Rebecca's reporting on this topic. Questions about hurricanes or other weather disasters? Email us at shortwave@npr.org – we'd love to hear your ideas!

Climate change is contributing to erratic weather where cocoa beans are grown and threatening the global chocolate supply. Record rainfall last year led to fungal infections among cacao trees and dwindled supply of cocoa beans. Heat is also making it more difficult for cocoa beans to thrive. So, for day three of Climate Solutions Week, we look at one innovation in the food industry: chocolate substitutes. As big chocolate manufacturers rush to stockpile cocoa beans, some companies like Planet A Foods are looking for a more sustainable solution: an alternative that looks like chocolate, tastes like chocolate and feels like chocolate... without chocolate. You can read more of international correspondent Rob Schmitz's reporting here. Interested in hearing more climate solutions? Email us at shortwave@npr.org – we'd love to hear your ideas!

Jeff Goldblum has a special brand of charisma — the kind that seeps its way into all of his roles. Whether it's in The Fly or Independence Day or Jurassic Park — or his newest show KAOS — every character feels like a version of Jeff Goldblum himself. He also brings that Goldblumian charisma to Wild Card, breaking into song as he reflects with Rachel about his life. To listen sponsor-free, access bonus episodes and support the show, sign up for Wild Card+ at plus.npr.org/wildcard