Taxonomy: Scientific Classification
by Robert Fenner
Reprinted with permission from Bob's website in San Diego, www.wetwebmedia.com
Aquarticles
Wait! Don't touch that dial! I know what you're thinking. Another wanna be pet-fish
ichthyologist taking up precious paper space to try his hand at the world's most boring
subject? Nay, nay nay! I promise, this section, will not be only practical and
informative, but chock-full (yes, that's how it's spelled) with entertainment value.
Let's take this subject, taxonomy. What!? Another tax? No; you remember,
classification. Kingdoms, Orders, Families, Species, blah, blah, blah. What's it to you?
Well, if you stick with me, I'll show you how taxonomy will help you thrill, amaze and
impress your friends, and (gasp!) make money.
The principal purpose of classification is to take a whole bunch of data: facts, ideas,
methods and attitudes, that might seem almost totally unrelated and put them together in a
system to make them more useful/useable. How's this work with your livestock? Example: You
might know that the percula clownfish (Amphiprion ocellaris et al.) are sensitive
to metal medications and contamination. Knowing that maroons (Premnas biaculeatus)
are also members of the same sub-family, Amphiprionae might/would/should lead you
have a notion that these species might share similar tolerances, foods, diseases... &
so they do! As a matter of fact, should you be so inclined to delve into the literature
you'd definitely be impressed with this sub grouping of the damsels. There are about two
genera with about twenty nine described species so far. They're all obligate sybionts with
certain species of anemones; synchronous hermaphrodites with males becoming larger females
with age and need... susceptible to Glugea infections...
Now, isn't easier to just remember that percs and sebaes, maroons, tomato clowns, and
other related species share family habits and conditions than committing so much ROM
(read-only-memory) in your brain for each species separately? Of course! In fact, the
related families of fishes in the same Order, the Perciformes (=
perch-like fishes), with such notable aquarium species as marine angels and
butterflyfishes (Chaetodontidae), the basses (Serranidae), hawkfishes (Cirrhitidae),
and many more all have structural and useful life-history characteristics in common. And
you wondered how anyone could possibly remember so much of this stuff!
And the brain-space savings don't stop here. The "higher taxonomy of fishes
involves groups greater than the family level. You will be amazed. For now, let's get on
with a discussion of taxonomy itself. I'll give you a brief historical approach, putting
in concepts not generally covered in pet-fish periodicals. Keep in mind the utility of
this tool, and enjoy!
Taxonomy or systematics is the science of classifications. There are two divisions:
Numerical, which reorders groups along arbitrary lines; such as the Dewey Decimal System;
and Biological, which deals with the classification of whole organisms.
It seems that all forms of life on this planet evolved from one, or at most, several
common progenitors about three billion years ago. It is, therefore, easy to see why every
living thing bears so much in common. According to how much life forms have in common
taxonomists place them into more and more definitive groups, e.g. family, genus,
species... The study and representation of these relationships is termed phylogeny (Latin
for "branch origin") a/the story of life's evolutionary "coming
down"...with time organisms radiate in form and function to fill and empty certain
ecological niches.
Who's on First?:
Archelaus of Miletus in the sixth century B.C. gets credit by some for coming up with
fundamental concepts like species and the sense of need for using one "good"
name for each type. But it's Aristotle (384-322 B.C.) with his cadre of graduate students,
who generally grabs the credit for the rudiments of scientific classification. Aristotle
was aware of the differences between fishes and aquatic mammals (e.g. Cetaceans like
dolphins & whales). Many people who followed did not know this. He accurately
described some 118 species of fishes from the Aegean Sea, but had little idea of the
mutability of local names, or evolution.
A few others, who came later in the "ancient" world made further recordings
of what they recounted as types of organisms. Pliny, Aelianus, Authinecus... In the
sixteenth and seventeenth centuries Belom (1518-64, Rondelet (1507-57, Salviani (1513-72)
and Ray and Willoughby (publ. 1686) were noted chroniclers of fish-naming.
The real "birth" of modern taxonomy has it's point of origin the tenth
edition of Systema Naturae, (1758) by Carolus Linnaeus (Karl von Linne), the
"father" of modern taxonomy. Linnaeus gets the big credit for innovations like
the "two-word naming" (binomial nomenclature) of species and arrangement of
categories like classes, orders, and families (taxa, singular taxon).
What this all means is that, when you're out and about, collecting fishes and trying to
determine whether you've got a new species or not, you've got to go back all the way to
the year 1758 and search the pertinent literature to determine whether or not you've found
something new. Similarly, around the world, folks who study structure, biochemistry,
genetics, behavior et al. are trying to make sense of higher/greater similarities of these
organisms and grouping these assemblages into larger and smaller genera, families,
orders... You start to see that this is a very human, read that artificial enterprise. One
subject to change with new and better data.
The fishes themselves don't arrange themselves in the "families" we put them
into; and the folks in Natural History Museums, Zoos, Aquaria, learning institutions and
private investigators who do the studies and the lumping/splitting are mere mortals like
us. These classifications are mere useful fabrications for ranking and ordering related
information. With perhaps as many as forty thousand valid species to be counted,
scientific classification goes a long way to, on the one hand, work-out the phylogenetic
relationships of organisms and their implications, and on the other hand, keep track of
all the disparate information about our fishes. For real spiffy specifics on the minutiae
of naming check out Leibel and Ford's pieces cited below.
Further Reading & Where I Lifted This Stuff:
Ford, David. 1981. Understanding Basic Aquarium Science & Calculations. Freshwater
& Marine Aquarium (FAMA) 4(5)
Leibel, Wayne S. 1985. Of Pickled Fish & Ichthyological Sleuthing: A Primer for the
Advanced Aquarist Part 1: The Whys and Wherefores of Scientific Nomenclature. FAMA January
Issue
Nelson, Joseph S. 1976.Fishes of the World. John Wiley & Sons.
Sterba, Gunther. 1966. Freshwater Fishes of the World. The Pet Library Ltd. English
Translation
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