The taxonomy of salmon, trout, char, grayling, and their relatives is far more complicated than one might expect on the basis of introductory biology courses. But learning this is fun and insightful. You should take an excursion into basic taxonomy because it is so interesting. A simple, basic introduction to scientific classification is found here.

Not only are the systematics and taxonomy of fish intricate and revealing about them, they are also exciting from a historical, social, and cultural perspective. That is, taxonomies reveal a lot about the people who make them.

The underlying modern idea of the fields in biology is that all life is related through biological descent. The names (or taxa) are arranged in a hierarchical order thought to represent evolutionary (phylogenetic) relationships. The closeness of these genetic relationships is made evident in the morphology, i.e., life forms and structures, of various kinds (species) of organisms. That is, the more alike two organisms appear, the nearer in space they originated, and the more recently they originated from a common ancestor. Systematics is the study of these relationships, and is closely intertwined with taxonomy, the naming of organisms in order to reflect those biological relationships.

The basic taxonomic hierarchy used by contemporary biologists was invented by Carolus Linneaus (Karl von LinnÈ) of late 18th century Sweden, just before the height of the modern era. He had a completely different purpose than modern taxonomists. He wanted to list all organisms in the Great Chain of Being. The Great Chain of Being refers to the theory that all living existence, from the most primitive to the most exalted, is related. Those relationships are hierarchical; some are better, purer, more powerful, and so on. At its apex is God. Human beings were the highest order of physical being ñ the first of the material world, and so humans and human relatives were classified as Primates. Here is a famous artistic representation of it.

Linneaus' approach to studying God's creation seems to have been, "These species are related to each other because God made the Great Chain of Being that way, and we can deduce these relationships (links in the Chain) by measuring them (leaving aside "sports" caused by the imperfections of the world)."

Linnaeus' approach to understanding nature identifies him also as a naturalist ñ a person who studies and describes organisms and natural objects. Other naturalists joined this project. They collected specimens from all corners of the world, and many traveled in difficult circumstances to intriguing and dangerous places. There they weighed, measured, illustrated, and preserved specimens of many organisms.

Charles Darwin, a minister's son, was active in this field. His extensive work, in particular observations on finches in the Galapagos Islands, is the foundation of his broad hypothesis of natural selection. Darwin transformed biology for the next 100 years by changing a naturalistic ñ purely descriptive ó approach to biology to a scientific one.

Darwin's approach is characterized by skepticism, empiricism, and inductivism, which contrasts decidedly from Linneaus' approach. The names are actually hypotheses suggesting or positing natural, physical relationships among organisms (skepticism). Scientists must test or confirm(inductivism) those suggestions by comparing measurements (empiricism) of the natural and physical attributes of living things.

From the perspective of earlier naturalists Darwin's approach is heretical. After all God had made all life in its various forms and in its various grades. And that ordering, according to this view, is sacred and evident in nature. Of life in the natural world, humans and their relatives were of the first and highest rank, Primates.

Darwin's view, on the other hand, was about change in kinds of organisms. This leads to immediate problems in a taxonomy designed for identifying immutable forms that have existed since the beginning of time. There has been a longstanding debate about the meaning of the terms Linneaus developed. His system remains in use, with some modification. But another perspective on taxonomy has been developed to deal with the evolutionary implications of Darwin's work.

The scientific approach is why systematics and taxonomy remain exciting fields. First of all, biologists are continually discovering new forms of life. Some of these unknown kinds of plants, animals, fungi, and other organisms are literally right under our noses. For example, early in my career I knew a graduate student in entomology who described three new species of caddis flies in 6 short weeks. He simply went to the nearest stream, captured caddis flies, and compared them with other types of caddis flies. These were different enough that they were recognized as new species.

This was classic work; for the past 200 years most taxonomy was based on morphological studies such as these. And exciting studies such as these continue. Indeed, every week seems to bring forward descriptions of new species of life. The wonder of it is how it reveals how little we know about our world.

Second of all, the names change as more is learned about the evolutionary and genetic relationships among organisms. There are two main areas of testing: paleontology and genetics.

Paleontologists still search through fossils stored in museums and dig up new ones. Paleontological studies reveal new forms every year, documenting the metamorphosis of the past into the present. At the same time, paleontology is a hit or miss approach ñ not everything is preserved, some things are only partly preserved, the kind of "preservation" varies, we don't know where to look for what was preserved, and so on. There are myriad reasons why we don't have all the information now and probably never will.

One important consequence of all this work is that the idea of "The Great Chain of Being" doesn't seem to be supported. Further, it means that there is no "missing link," an idea clearly derived from that theory. Rather, there are gaps in the record of the stream of genes, as manifested in visible, metamorphizing forms, from the distant past to the present.

Confusingly, there is disagreement in the scientific community about the principles of taxonomy. Conflicts within the system of names indicates at least two factors: 1) the changing nature of biologists' understanding of life and its evolution, and 2) differences among communities of biologists and their relative power to name something and make it stick. For example, some taxonomies identify the salmon order as "Salmoniformes," others use the term "Salmonoidea." Some taxonomies include the family Esocidae (pikes and mudminnows) in the salmon order. And there are a welter of generic and specific epithets.

And in recent years biologists have developed a revolutionary approach to taxonomy to categorize and relate these new and old specimens called cladistics. This approach seems necessary because even though today's genetic stuff is part of a stream going back a billion or so years, its organization has changed from over the generations. Keeping track of the protean stuff through time requires an approach such as cladistics. To learn more about cladistics, see Lynne M. Clos' article "What Is Cladistics?" and "Cladisitics."

A second, related, rapidly growing method of testing our knowledge of life and relationships among its forms is in genetics. Recent advances in studying the stuff of genes has shown in some cases that organisms that look alike are genetically quite dissimilar, and in other instances organisms that look very different are genetically similar. Thus, morphology seems to be somewhat unreliable for classifying/naming organisms in terms of biological origins.

Indeed, genetic studies are "rewriting" the biologists' taxonomy of life. Genetic studies are done through the comparison of the genetic stuff (DNA, mDna, and/or RNA) of various organisms.

Although this seems more "scientific," more "objective," more "hard science," more exact, more universal, and less affected by imagination than paleontology, it is not. Genetic studies are "hit-or-miss" in their way, too. After all, the work is expensive, requiring labs, lab equipment, technicians, and so on, so it is focused primarily on organisms that are commercially significant ñ like salmon and trout ñ or on an research group's interest.

One can ask a deeper question: why is classifying life forms by genetics better than some other principle of taxonomy? Here cultural values enter into the equation. As people create their culture from generation to generation, taxonomies and the systematic relationships change to reflect the changing concerns of society. In other words, taxonomies reflect the purposes of those making them.

And so systematics and taxonomy are exciting from a historical and social scientific point of view as well. They reflect the kind of knowledge a community has about the world ñ how "we" think about relationships among different elements of the living world, or biosphere, and "our" relationship with it. The conflict between the Linnean and Darwinian approaches clearly demonstrate this.

But the issue goes beyond the goals of science. All communities have "purposes" or "interests" which differ from those around them. So differences in taxonomies reflect differences in cultures. Which leads us to the question, "What are the purposes of contemporary taxonomies?" It also leads us to the question of power, "Whose taxonomies/purposes dominate society? In what contexts?"

Briefly, then, the shift from a naturalistic to a scientific approach in taxonomy occurred as Europe finally completed its change from a premodern to a modern stance. There was increasing centralization of power and authority, and an expansion of empire. It was the time of industrialism as well ñ which fostered Europe's rise and expansion. The language and culture of Europe's most powerful states ñ their taxonomies ñ were imposed everywhere.

Now, it seems, we are leaving the modern age and entering the postmodern eras, all of which seem to be simultaneous. The rise of genetic studies, and the loss of confidence in "macroscopic" classification ñ the loss of "seeing is believing" ñ seems to occur as we become postmodern. My bet is that we will encounter more different taxonomies being openly and successfully espoused by others.