It's the Taxonomy, Stupid!

My recent post about sorting a purple fork is a parable about taxonomy. Taxonomy is the scientific word for sorting things. And while it sounds simple, sorting can get complicated quickly, and is sometimes subjective. Which is why scientists try to define a taxonomic system, a universal way of sorting things.
You're probably familiar with this system, at least in terms of biologic taxonomy. For example, plants and animals are part of different kingdoms. Delving deeper into taxonomy, cats and dogs are sorted into different families. If you want to break that down further, everyone can see that a chihuahua has some things in common with a Great Dane, but they definitely aren't the same thing.
In order to get a better grip on taxonomy, and taxonomic changes, I called my friend Dr. Paul Valentich-Scott, curator of malacology at the Santa Barbara Museum of Natural History. He knows more about clams than just about anyone on Earth. When I asked him about taxonomy, he said, "It changes. All the time." He doesn't mean that different species of clams are evolving into something new all the time; he simply means that scientists sort them differently as they get new information.
One example of this he gave me was the Pacific littleneck clam. He told me that in doing some research into the history of scientists who had described this clam, the name was changed at the genus level. Before this research had been done, the scientific name was given by the person thought to have described it first. However, it turns out that it had been described by someone earlier, and precedence was given to the original classifier.
Another example he cited was a type of clam he is working on in the order pandora. As malacologists have made new discoveries about this clam, they have found that it makes more sense to change what was a single species into four different species. Again, the clam didn't change; scientists are just relabeling it. Paul told me that as we are doing more and more DNA research, this type of taxonomic splintering is more and more common.
I know this seems like a lot of biology for an astronomy blog, but by now I think you've figured it out. Today marks the 79th anniversary of the discovery of Pluto by Clyde Tombaugh. Although it was celebrated as a planet then, it has infamously been "de-classified" as a planet. I could make this long post longer by telling you all about it, but I did myself a favor three years ago and made a movie about it. So watch the clip below and please remember that the movie is 3 years old. Since then, 2003UB313 has been named Eris; Pluto has been reclassified as a dwarf planet (and even more recently as a plutoid); and two more larger-than-Pluto objects have been discovered in the Kuiper Belt (Haumea and Makemake).


Pluto: Planet or Not? from Krissie Cook on Vimeo.