In 1832, less than a year into the first voyage of the Beagle, Charles Darwin found a beetle in Argentina. Turns out, discovering new species in the depths of museum archives is not so uncommon. 180 years later, an entomologist who happened to specialize in rove beetles requested an assortment of samples from London’s Natural History Museum. There, among 24 pinned beetle specimens, was Darwin’s rove beetle. Dozens of such tales of are told by biologist and author Christopher Kemp in his new book The Lost Species. He describes the treasure hunts and serendipitous finding of species like the ruby seadragon and the olinguito, and why there may be many more discoveries waiting in the backlogged shelves of museums around the world. And Regina Wetzer, associate curator and director of marine biodiversity at the Natural History Museum of Los Angeles, explains how combining centuries-old museum specimens with modern techniques may help turn up new clues in understanding the past, present, and future of Earth’s biodiversity. This week, scientists published a study in the journal Science that described organic molecules—building blocks for life—in mudstone near Gale Crater, a 3.5 billion-year-old dry lakebed. Another study measured methane in the Martian atmosphere that varied with the seasons.  Astrobiologist Jennifer Eigenbrode, who is an author on those studies, discusses what this reveals about how ancient water and rock processes may have worked on the planet, and what the findings tells us about the possibility of life on the Red Planet. Plus: While it has been a tradition in many Asian cultures for centuries, kelp farming only reached U.S. shores in recent decades—and in part due to its environmental benefits. Ira is joined by Science Friday video editor Luke Groskin and Suzie Flores, a kelp farmer featured in our latest Macroscope video, to discuss the new wave of kelp farming.