Big Picture Science · Big Picture Science

Flower Power

March 30, 2026·54 min·2 clips

Ruby Stevens explains how flowers invented sex-based genetic diversity and why that made them dominate the planet.

The episode opens with a visit to a flower stand called Millefiori in the United Arab Emirates, establishing flowers as both culturally beloved and biologically remarkable. Host Molly Bentley notes that flowering plants appeared only about 140 million years ago yet now make up roughly 90% of all living land plants. The first scientific segment features Eva-Maria Sadowski, a paleobotanist at the Natural History Museum in Berlin, who specializes in amber-preserved specimens. She describes the largest flower ever found in amber, dating to 38–34 million years ago and about an inch wide, preserved along the ancient Baltic coast. Sadowski explains that pollen is made of sporopollenin, one of the most biologically resistant polymers known, allowing grains to survive 400 million years. Using a scanning electron microscope, she analyzed the pollen morphology of a flower that had been misidentified as Stuartia coloesci when collected 150 years ago, reclassifying it as Symplochos coloesci, a species whose closest living relatives now grow in East and Southeast Asia. The second segment moves to the La Brea Tar Pits in Los Angeles, where assistant curator Regan Dunn studies the last 50,000 years of plant life preserved in naturally occurring asphalt. Dunn explains that while flowers are too delicate to survive the abrasive sand in the tar, pollen, seeds, wood, and tree rings are well preserved. She describes how 50,000 years ago Los Angeles had a cooler, wetter ecosystem supporting mammoths, mastodons, saber-toothed cats, and American lions, and that a roughly 10-degree Celsius warming coincided with their extinction. Dunn draws a bottom-up food web argument: declining plant productivity under heat and drought reduces herbivore populations, which in turn collapses carnivore populations, and she warns the current warming event could be faster and more dramatic. The third segment introduces Ruby E. Stevens, a PhD candidate at Macquarie University in Sydney and member of the international eFlower project. Stevens explains that all modern flowering plants — angiosperms — descended from a single ancestor, evidenced by genetic data and the fossil record. The key innovation of angiosperms was the covered ovule, or carpel, which allowed flowers to selectively accept or reject pollen, enabling outcrossing and greater genetic diversity. The eFlower project's current model suggests the first flower had combined sepals and petals, stamens, and possibly multiple pistils. Stevens notes that insect pollination predated flowering plants and was critical to their success, with pollinators providing genetic specificity that wind pollination cannot. A brief interlude features Royal Krieger, an American Rose Society consulting rosarian at the Morcom Rose Garden in Oakland, who explains that all roses are native to the Northern Hemisphere, trace back about 40 million years, and have been cultivated since at least 2000 B.C. The final segment features Stephen Long, professor of plant biology and crop sciences at the University of Illinois Urbana-Champaign, who explains that photosynthesis theoretically could be 10% efficient but that the best crops achieve only about 2%. Long's team built a digital twin of the photosynthesis process to identify bottlenecks and has engineered three changes that produced roughly a 20% improvement in crop yield in greenhouse tests. He frames the motivation as both scientific and humanitarian, noting that one in ten people globally face food insecurity and that the UN Food and Agriculture Organization predicts the situation could become catastrophic by mid-century. The episode closes with the implication that understanding the origins and mechanisms of plant life — from the first flower to the chemistry of photosynthesis — has direct relevance to humanity's ability to adapt to a changing climate.

As heard by us

A bouquet opens into a lively tour of flowering plants, rose history, pollination, and the puzzle of the first bloom.

Flower Power starts with a familiar sight, roses and daffodils in bloom, then opens onto one of botany's durable puzzles: why flowering plants appear so suddenly in the fossil record that Darwin called them an "abominable mystery." Molly Bentley keeps the scale moving, from the…

Read the full review in PlayNext →

Why you'd press play

For when you want flowers, ancient blooms, and a smart look at how plants turn sunlight into stored energy.

Read the full recommendation in PlayNext →

Listen to the show on

Apple Podcasts Spotify

Play clips from this episode More from Big Picture Science