And it's even harder to answer after you've had a few.
Intrepid science journalist Charles Q. Choi takes inspiration from both the Drunk History series of videos and a really awful lot of whiskey to try and help you better understand a scientific concept (and also the finer points of orc biology). This was an idea I had, which came together with the help of several science journalist friends during the Science Online conference back in January. I'm still impressed with how accurate Charles was on the science while in that state. I can't speak to the Tolkien mythology.
Video Link (Note: This seems to play softly on some computers. If you're having trouble hearing it, plug in headphones or turn up your speakers.)
Thanks to Rose Eveleth, Colin Schultz, and Jennifer Honn — whose work on editing and producing this video was invaluable. Also thanks to John Rennie, Steve Ashley, Olivia Koski, Maki Naro, and Stephen Granade — whose input and assistance made this possible. And, of course, special thanks to Charles, who really was fully recovered by the next morning.
This is the second story in a four-part, weekly series on taxonomy and speciation. It's meant to help you as you participate in Armchair Taxonomist — a challenge from the Encyclopedia of Life to bring scientific descriptions of animals, plants, and other living things out from behind paywalls and onto the Internet. Participants can earn cool prizes, so be sure to check it out!
On the sixth floor of New York's American Museum of Natural History — far away from the throngs of tourists and packs of schoolkids — there is a cold, white room, filled with white, metal cabinets.
The cabinets are full of dead things; leeches, sea anemones, lobsters ... any kind of invertebrate you can imagine. Even a giant squid. All of them have been carefully preserved. Each soaks in its own, luxuriant ethanol bath. Here they sit, some for a hundred years or more, waiting for scientists to pull them out into the light.
It's a bit like the final scene of Raiders of the Lost Ark, but for slimy, crawly, spineless things. There are collections like this all over the world, containing every species of animal, plant, and microscopic organism. Together, they serve as a record of Earth's biodiversity, a library of life. In them, you'll find more than just random specimens. Some of the individuals are special. Called "type specimens", they serve as ambassadors for their species, real-world models that define what each species is. For instance, the leech species Myxobdella maculata is both a group of leeches and exactly one leech — A leech that I got to meet on a behind-the-scenes tour with invertebrate curators Estefania Rodriguez and Mark Siddall.
It's a small squid world, after all. A recent study shows that giant squid from all around the globe have remarkably low levels of genetic diversity — essentially, writes Tina Hesman Saey, they're all more closely related than scientists previously thought. Giant squid, as it turns out, are a single species, traveling, living, and breeding all around the planet.
The Australian blacktip shark lives in tropical waters. The common blacktip shark prefers its water subtropical and temperate. Because of the difference in habitat, these two animals have become separate subspecies with distinct physical differences.
However, there are some places where their habitats overlap. And here, along the eastern coast of Australia, there is interspecies nookie. And hybrid baby sharks.
Now, none of that is particularly shocking. Hybrid zones, where the habitats of two genetically compatible species overlap, aren't ridiculously common, but scientists have documented quite a few. What makes this finding interesting is that the two species and their hybrid have been genetically documented. Hybrid zones can be fuzzy places. What happens there calls into question how sure we can be that that what we call species really are all that different from one another.
What makes this study interesting is that researchers actually performed genetic testing on sharks caught in the hybrid zone. They found distinct genetic differences between the blacktip and Australian blacktip sharks, especially in their mitochondrial DNA. And the hybrids were identified based on genetics as well. That's something that's a lot more rare in the study of wild hybrids. The information gathered here could end up having a lot to teach us about how evolution happens and what speciation really means.