Monthly Archives: June 2020

To be specific…

One of the most common questions I get asked by people on social media and in person is: “What is this [insect|bug|spider]?” And, that’s a fair question–we humans really like assigning names and putting labels on things.

But what is the “what is this?” question really asking? Or, as the Bard put it: “What’s in a name?” Surprisingly, often merely being told a name is sufficient. I say “surprisingly” because knowing a name usually tells us absolutely nothing. What it does do is to afford a means of subsequently learning something about the organism at hand (and yes, that very same question is asked about plants, fungi, etc.).

But here’s another question that needs to be addressed: What is a species? If you look up the biological definition, you’ll find a lot of wiggle room and/or weasel words. Generally speaking, though, a “species” is defined as a population of organisms that breeds within itself.

Unfortunately for classification systems though, living things almost never read the books about definitions and taxonomic rules*, and instead form a very broad spectrum that is not at all clear-cut. Thus, the observation that “dogs don’t interbreed with cats” is a good one, and does uphold the “interbreeding population” definition. There are, however, myriads of examples where the definition fails and isolated populations..considered to have been distinct species..are found to interbreed when seasonal, geographical, or even morphological barriers are removed.

“But” I hear you ask, “what about our knowledge about DNA? Doesn’t that settle things?” Nope. DNA helps to identify relatives, but even among members one species there is genetic variation. In fact, DNA analysis has recently suggested that Neanderthals (once considered a separate species, viz. Homo neanderthalensis) interbred with and were essentially subsumed by H. sapiens, such that they are now generally regarded to be a subspecies**: H. sapiens neanderthalensis.

The problem, as this illustrates, is that recent speciation is a blurry place. Species that split apart eons ago usually now have sufficient differences that they can no longer interbreed. But speciation is occurring all around us, on a daily basis–zipping along at a breakneck pace rivaling that of continental drift.

Of course, there are a few organisms that are easily determined*** by their gross morphological characters. Unfortunately, these tend to be “living fossils” or threatened species representing a genetic deadend. The tree Ginkgo biloba L. 1771 is one such species. In fact, not only is G. biloba the only species in the genus Ginkgo, it’s the only member of the family Ginkgoaceae, the order Ginkgoales, the class Ginkgoopsida, and the phylum Ginkgophyta! Now that’s one lonely species!

For most species, though, determination is best left to experts. Merely looking at pictures in books or on websites may provide some idea of what the organism in question is called–but it may very well lead the neophyte astray! This is why even (especially?) experts often will not tell you what they think some species is, but instead say something along the lines of “Oh, that could be XYZ, but I’d really have to have the specimen in hand to be sure.”

So perhaps instead of asking “What is this?” a better question might be “Can you tell me something about this?”

*Insofar as we know, there is only one species among the almost 2 million extant on this planet that does this.
** Don’t get me started on the whole sub-, super-, infra-, etc. designations.
**When folks identify organisms to the species level, they are said to “determine” them.