AHABS... Issue Eleven
Ronald L. Shimek, Ph. D.How Can You Tell?
One of the fundamental problems confronting reef aquarists is their inability to precisely and unambiguously identify the animals that they keep in their tanks. Although it seems like it should be a simple process to identify these animals, the more one looks into the process, the less simple it becomes. Not surprisingly, aquarists tend to ignore the problems and opt for the simple solution; they put a name on them without any real regard to what the animals have been called before. Often they call their charges by the names applied to them by dealers or distributors, or they take a look at a picture either online or in a book and assume that image shows the animal in their tank. Unfortunately, this solution simply moves the level of imprecision one step backwards on the animal's chain of custody as, in general, these folks are no better at identifying the animals than the average hobbyist is; and it also ignores the fundamental problem of the identification of many reef animals; one simply cannot use an image alone to identify them. As a result, the names that are applied to the organisms are simply names of “convenience.”
It is worth cogitating a moment about this “problem.” At one level, it is not a problem at all. A name IS just a name; as has been so succinctly noted about flowers and odors, a “Rose is a rose is a rose,” “which by any other name would smell as sweet.” And as an aside, ya gotta love the ability to mangle quotations right along with mixing metaphors. It is a veritable author's stew… Still the point is, “What difference does a name make?” The particular coral specimen is still the same coral specimen regardless of the name applied to it. The name that is applied to it doesn't change its properties at all.
Or does it?
If different representatives of the same specimen of a coral, for example two fragments from the same parent colony, have been given two different names in two different aquaria, and those tanks have different conditions resulting in those specimens having dissimilar appearances, then it would be logical, but incorrect , to assume that the two specimens were actually different species. In this case, the misidentification would fog our knowledge of how the organism would respond to differing conditions. The logical assumption would have resulted in an incorrect deduction. In the long run, for our hobby, of such little wisps of misinformation are huge fogbanks of inaccuracy made.
Similar sorts of problems led some early biologists to develop the concept of a formal “scientific name.” As I hope to show, such a concept is logical and useful, to a point . Where it falls down with regards to hobbyists is in their inability to determine the appropriate scientific name for any given specimen. In trying to determine the valid scientific name for coral reef animals, problems...
Ronald L. Shimek
Although not the simplest animals, a few organisms in a couple of small obscure groups are probably better claimants to the title, sponges are widely regarded, and justifiably so, as one the simplest types of animals, and this simplicity notwithstanding, they are quite successful in aquatic or marine habitats (Barnes and Harrison, 1991). While from the human point of view, it is tempting to dismiss such simple organisms as some sort of failure, such a dismissal would be based more on arrogance than on fact. In one way or another, within their particular habitat, all organisms have to be able to do the same kinds of tasks or overcome the same sorts of general problems. Learning the different ways that various organisms accomplish these same tasks is, in a very real sense, the science of biology. While sponges are very unlike humans, in just about all their properties, humans and sponges or any other organisms must perform the same basic tasks of life. These basic tasks are:
- They must obtain nutrition or food.
- Without food, life stops. All other tasks are secondary to this one.
- They must get rid of wastes.
- All organisms create poisonous metabolic byproducts that are termed “wastes.” The materials that scientists consider wastes are specifically the byproducts of protein metabolism. For some reason, no animal has been able to extract, or utilize, the energy in the chemical bonds between nitrogen and hydrogen. The major waste product resulting from protein metabolism is ammonia, NH3, which, in water forms ammonium ion. In addition to containing three metabolically useless N-H bonds, ammonium is highly reactive and exceptionally toxic. As a point of order, what comes out of an animal's anus (or other such structure...) is indigestible or partially digested food, often partially processed by bacteria. While not particularly “tasty,” to many animals, this stuff is generally not particularly toxic, either.
- They must avoid becoming food for some other organisms.
- How organisms avoid predation often is a defining factor in their natural history.
- Everything must move during some part of its life cycle; including sessile animals and plants.
- If the perfect organism never moves, eventually something will happen to it because of its location, and it will die...