A Brief History of Naming
Taxonomy, in its purest form, is simply a system of naming. It’s a scientific card catalog that says what everything is from the blue whale to the bumblebee. It begins with the broadest of categories—whether a thing is a plant, an animal, or something else—and narrows it down from there.
The trouble with taxonomy is that it’s a very complex concept dressed as a very simple idea. The simple idea is as follows: humans like to name things. We’re very good at it, so good in fact that we do it without even realizing. We do it to make sense of our world and organize our experiences. In doing so, we typically create hierarchies of complexity.
According to my high school biology textbook, we use 7 categories to describe a living thing. They start with the very general and proceed down to the very specific: Kingdom, Phylum, Class, Order, Family, Genus, and Species. Those final two, the genus and species, make what we call a binomial, or the scientific name for an organism.
You’re probably familiar with a few of these even if you don’t know it. The most famous is the binomial we use to describe ourselves, Homo sapiens. We can often get away with referring solely to the binomial because so many of the higher categories are broad enough to be assumed. Thus instead of saying that human beings are-
We get away with simply, Homo sapiens (this is similar to how you can say “the point guard for the Warriors” rather than, “the point guard for the Golden State Warriors, Western Conference Pacific Division, National Basketball Association”).
Taxonomy in Evolution. Evolution in Taxonomy
The problem of taxonomy comes about because nature doesn’t work in categories but in continuums. Over the centuries, we have developed numerous methods to categorize species; each with their individual strengths and weaknesses.
In earlier times, humans would rely on what we could see to classify one species from another. If a group of plants looked like one another and distinct from all the rest, they would be described, named, and categorized as a distinct species.
This would later evolve into the most well-known of our many classifying schemes; the biological species concept. This concept operates on the idea that it’s not necessary for the members of a species to look the same, so long as they can interbreed successfully. If you take a rattlesnake and place it in a habitat with a cobra, they will not breed, and what’s more, even if they did, they couldn’t produce little rattle-cobras as a result.
This system, popular and functional though it is, has its share of problems. Not all species that don’t interbreed, can’t. Lions and tigers, for instance, don’t interbreed under natural conditions, yet they can produce a viable hybrid. Does this make them the same species? Most biologists would argue no. And what about asexually producing life? It doesn’t breed at all, so how do we go about defining it?
In recent years, advances in genomic sequencing have added further complications to the field. It’s become more and more common to come across headlines about genetics demonstrating that what we thought was a singular species is actually two or more in disguise. How are we doing this? What does the genetics actually tell us?
Simply put, genetics tell us whether or not different populations are interbreeding. Consider the giraffe. Giraffes have long been considered a monolithic species. They can be found scattered across Africa and whether in Namibia or Niger, Zimbabwe or Zambia, the animals are relatively indistinguishable. We can isolate some general differences in coat color and patterning but overall, they appear highly similar and are more than capable of interbreeding.
But do they?
Recent research into giraffe genetics indicates that the total population is not only geographically fragmented but reproductively so as well. According to research conducted in partnership with the Giraffe Conservation Foundation, there appear to be four distinct groups of giraffe that haven’t interbred for a good long while. This has led to a push to have the giraffe reclassified from one species to four.
But debate continues. The populations may not be interbreeding, and apparently not for generations, but does that really make them separate species? If they weren’t living so far from one another, would they interbreed? Are they breeding at all where populations overlap? These are but a few of the questions demanding answers.
A Conspiracy of Lemurs
The possible re-categorization of giraffe sounds revolutionary, but in truth, this kind of thing happens all the time. Safari West recently became home to three red ruffed lemurs (Varecia rubra) and has long been home to black-and-white ruffed lemurs (Varecia variegata). These two species are closely related, occupy similar and geographically overlapping habitats, and differ only in physical appearance and vocalization.
Until very recently, both black-and-white ruffed and red ruffed lemurs were considered to be the same species. A recent study determined that the two lemur types don’t regularly hybridize. Further, it appears that a large river in Northeastern Madagascar completely separates reds from black-and-whites restricting them from possible interbreeding. Thus, they have been reclassified as distinct species (and the only living examples of the genus Varecia).
Let’s Get Political
What on Earth does this nuanced and complex branch of science have to do with conservation?
Two primary forces granting legal protection to many vulnerable and endangered species are the Convention on International Trade in Endangered Species (CITES) and of course, the Endangered Species Act (ESA). Both the CITES treaty and the ESA have proven immensely valuable in conservation work not only here at home but across the globe. These twin policies have had broad reach and deep impact but their success has also led to a sometimes problematic focus on the species.
You see, if a species is in danger of extinction across its range it then becomes relatively easy to achieve protective measures. If however, it’s only endangered in some places, that becomes less true.
The recent downgrading of giraffes from a species of least concern to one vulnerable to extinction came about because of data showing a decrease in their population of over 40%. However, if the scientific community agrees that there are in fact four distinct species of giraffe, then the numbers change. The reticulated giraffe population, for example, has plummeted by over 80% making them far more endangered than the current classification implies.
A Newer (Better?) Way of Thinking
If this has inspired in you a deep curiosity about the convoluted happenings in the world of taxonomy, great. There’s a whole, wide world of life out there that we need to better understand and identification is a huge first step. If you’re just wondering what my point might be, here it is: our reliance on identifying endangered species when planning conservation strategies is problematic.
Not only are species little more than cogs in the overall clockwork of an ecosystem, but on occasion, they’re not even clearly-defined cogs. It may be less important how any one categorized species is doing on a global scale and more important to consider ecological stability on a local level.
If we had all the giraffe we ever needed in South Africa, but they were to disappear from all the other countries in their current range, that would be a problem. The ecosystems in Kenya, or Botswana, or Zambia, would suffer major changes with the loss of such a large and charismatic species. And like falling dominos, those shifting ecosystems would impact neighboring systems.
The lines between species are vague and malleable just like the lines between ecosystems and they’re all interconnected. The trouble with taxonomy is that it encourages categorical thinking. We can plan conservation tactics categorically, but conservation in action must be holistic.