Rainforest Trust’s work to protect habitats for threatened species is grounded in cutting-edge conservation science. But in this series, we explore the basics of conservation science and how they inform Rainforest Trust’s scientists.
Our species loves to categorize things. Categories can be simple to understand, such as spotting the distinction between red and blue. Categories can be complex, such as identifying the distinctions between Impressionist and Fauvist paintings. Categories can also confound, such as trying to understand the distinctions between grunge metal, prog metal and thrash metal; each style should be in one category of “fork in the garbage disposal.” (Opinions of the author on the musical quality of any style of music are not reflective of the opinions of Rainforest Trust on the musical quality of any style of music.)
Inevitably, we ended up categorizing our fellow inhabitants of this fine planet. Early in our recorded history we figured there were different species; we could see that a crab differed from a turtle. But species were classified on an ad hoc basis solely based on visual evidence. Hence, we often got things wrong. We figured out that birds and lizards and mammals were different, but we sometimes mis-categorized bats as birds and dolphins as fish. We had the beginnings of taxonomy, but no way to move forward. Until, in the 18th century, came Carl Linnaeus.
Linnaeus was a Swedish botanist with an idea. He decided on a rigid, hierarchical classification in which every species’ description fits into the same number of ranked levels. Let me break that down. Linnaeus decided on six levels of categorization: kingdom, class, order, family, genus and species. We later added phylum between kingdom and class. Kingdom is the broadest category and species is the most specific. (We’re going to ignore an even broader category, “domain,” for the sake of this blog post.)
Much like a forced game of 20 Questions, Linnaeus used the three kingdoms of animal, mineral or vegetable. Minerals are, of course, not alive and no longer classified like living things. Each kingdom is divided into phyla, which are divided into classes. Classes are divided into orders, orders are divided into families, families are divided into genera (plural of “genus”) and genera are divided into species.
Get all that? No? Yeah, I didn’t think so. Stay with me, I promise I’ll get you there.
The first thing to remember is the order of the ranked levels. While Linnaeus may not have created a simple way to remember these levels and their sequence, many since have attempted to do so with mnemonics, often involving King Philip. The most common: “King Philip comes over for good spaghetti.” Sometimes, King Philip comes over for great spaghetti. For others, King Philip is gluten intolerant and comes over for good soup. Some even beg of him, “King Philip, come out for goodness sake!” I do not know why King Philip has entrenched himself but I can only imagine the stress of having to go places to eat mediocre spaghetti has taken its toll on the poor monarch.
The best taxonomy mnemonic I’ve found is, “King Penguins congregate on frozen ground sometimes.” This is true, King Penguins will (sometimes) congregate on frozen ground. Sometimes, King Penguins congregate on other types of ground, including ground that isn’t frozen. Not only is this taxonomically relevant, it’s ecologically thoughtful.
Now that we can remember the order, the next thing to understand is how the ranked levels work. Let’s follow the King Penguin from kingdom to species.
At the broadest category, King Penguins are in the kingdom “Animalia,” the Animal kingdom. This is the same category as humans, lobsters, cockroaches, coral (yes, coral), tuna and worms. Not in the animal kingdom: plants, fungi, bacteria or algae, to name a few. Most species on earth, by a wide margin, are not in the animal kingdom.
Within the Animal kingdom, King Penguins reside in the phylum “Chordata.” Often confused with vertebrates, Chordata includes the sub-phylum “Vertebrata,” the vertebrates, but also includes some species that aren’t quite vertebrates. (The actual distinctions are complicated.)
Within Chordata, King Penguins fall into class “Aves,” the birds. All birds are Aves, all things not in Aves are not birds. Within Aves, we classify King Penguins into the order “Sphenisciformes,” or penguins. All penguins are Sphenisciformes, all things not in Sphenisciformes are not penguins.
Now, in the case of penguins, there is only one family, “Spheniscidae.” This happens sometimes. Other bird orders, like Passeriformes, the passerines (perching birds), have many families such as Troglodytidae, the wrens, or Emberizidae, the buntings. But penguins have only one.
Within the family Spheniscidae, King Penguins are in the genus “Aptenodytes.” (Genera and species are always written in italics.) The only other species in Aptenodytes are the Emperor Penguins. The other living penguin species are in other genera, but only King Penguins and Emperor Penguins are in Aptenodytes.
Finally, the species name of the King Penguin is “patagonicus,” which bring us to Linnaeus’ seminal legacy: good spaghetti. This is the so-called “binomial nomenclature,” whereby we refer to a species by its genus and species names. For example, the King Penguin’s scientific name is Aptenodytes patagonicus. The Emperor Penguin is called Aptenodytes forsteri, with the same genus name but a different species name. There are other species named patagonicus, such as Lyncodon patagonicus, the Patagonian weasel. (The only relation between the Patagonian weasel and the King Penguin are that they are found in the Western Southern Hemisphere.) But only one species has the name combination Aptenodytes patagonicus. That’s great spaghetti.
We still eat some of Linnaeus’s spaghetti. While many of his rules and categorizations have changed, the principles have stayed the same. We still use binomial nomenclature. Other sublevels (subspecies, subphylum, subfamily, etc.) were added to further classify differences within levels but every species still fits into the same rigid hierarchy. We still even use some of Linnaeus’s names for species, such as Panthera leo, his name for lions.
For conservation, taxonomy is king. (See footnote #1) The concept of species is just one color in the tapestry of biodiversity, but a dominant color. If we thought a Hirola (Beatragus hunteri, classified as Critically Endangered on the International Union for Conservation of Nature Red List) was the same as a Hartebeest (Alcelaphus buselaphus, Least Concern), there wouldn’t be a serious effort to save the Hirola. Cue: Extinction.
While not always clear-cut, taxonomy is a useful, and (pun intended) evolving tool. There are programs to save entire classes and programs to save subspecies. But to conserve wildlife, we don’t need to understand every facet of taxonomy. We only need to see it as a useful, fluid organization filled with good spaghetti.