THE UNITS OF CLASSIFICATION
The world of organic life has been divided into the plant and animal kingdoms. These kingdoms have been further divided into larger divisions called phyla (from the Greek word phylon, a race). Each [phylum] is composed of organisms with certain characteristics in common. For example, all animals with a spinal cord (or notochord) are assigned to the phylum Chordata.
The [phylum] is reduced to smaller divisions called classes, classes are divided into orders, orders into families, families into genera, and each genus is divided into still smaller units called [species]. A species may be further reduced to subspecies, varieties, or other subspecific categories, but these need not concern us in a publication of this nature.
The following table illustrates the use of [binomial nomenclature] in the classification of man, a clam, and a dog.
| Unit | Man | Dog | Clam |
| Kingdom | Animalia | Animalia | Animalia |
| [Phylum] | Chordata | Chordata | Mollusca |
| Class | Mammalia | Mammalia | Pelecypoda |
| Order | Primates | Carnivora | Eulamellibranchia |
| Family | Hominidae | Canidae | Veneridae |
| Genus | Homo | Canis | Venus |
| [Species] | sapiens | familiaris | mercenaria |
The generic name and the [trivial name] constitute the scientific name of a [species] and according to this [system] of classification the scientific name of all living men is Homo sapiens. It is obvious that there are many variations among individual men, but all men have certain general characteristics in common and are therefore placed in the same species.
In a scientific name, the generic name is always started with a capital letter and the [trivial name] with a small letter. Both names must be italicized or underlined.
The name of the author (the person who first described the [fossil]) usually appears following the scientific name. The date of the scientific publication containing the original description of the fossil is often placed after the author. For example:
Turrilites worthensis Adkins and Winton 1920
With the large numbers of plants and animals that are living today, plus those of the past, random naming would result in much confusion. For this reason scientists have established strict rules that must be followed when a specimen is named. The strict application of these rules enables scientists in all parts of the world to assign scientific names without fear of duplication.