LABORATORY 1: EXERCISE IN BASIC TAXONOMY: CLASSIFICATION -
NOMENCLATURE - IDENTIFICATION
Work in teams of two. Obtain a box of bolts to work with. BE
SURE THAT ALL BOLTS - NO MORE AND NO LESS - ARE RETURNED AT THE
END OF THE LAB PERIOD.
Our objectives for today are to: 1) develop a bolt
CLASSIFICATION system by placing bolts into groups having common
characters and arranging the groups into a system (TAXONOMY =
SYSTEMATICS), 2) apply names to the groups (NOMENCLATURE), and 3)
use characteristics of the bolts to construct a DICHOTOMOUS KEY
which can be used for IDENTIFICATION.
If you would like to review the basics of Classification, Nomenclature, or Key-makinig, click here
Identification cannot be accomplished until
all objects under consideration are included in a CLASSIFICATION
SYSTEM.
STEP 1:
Determine the nature of your basic unit. Analyze bolt
variation and find groups of bolts that have all characteristics in
common. You have _____ basic units with _____ bolts per unit.
Likewise, every individual flowering plant can be assigned to the
basic unit of plant systematics, the SPECIES, although the analogy
breaks down when we consider the nature of INTRA-SPECIFIC VARIATION
in plants vs. bolts. Why?______________________________________
STEP 2:
You have now defined 15 "species" of bolts. Develop your
bolt classification system by examining INTERSPECIFIC VARIATION--
look for KEY CHARACTERS, i.e., characteristics that are useful from
a taxonomic point of view. Communication about taxonomy requires
the association of verbal symbols (TERMS) with objects or
characters. Plant identification (and success in B201) depends
upon a good knowledge of flowering plant terminology. Working with
bolts, however, requires the use of only two specialized terms:
PILEUS and STIPE (see here). The pileus is similar to the
angiosperm flower in that it is rich in key characters.
Examine pileus variation among your bolt "species" and arrange
them into related groups. How many groups do you have? _______
Classification systems employ a series of categories, from the
most to the least inclusive. The taxonomic hierarchy of plant
systematics is as follows:
Kingdom (most inclusive: all plants)
Division
Class
Order
Family
Genus
Species (least inclusive)
Each category of the hierarchy has its RANK and
CIRCUMSCRIPTION. Rank defines the hierarchial position of the
category (Ex: Family is at a higher rank than Genus).
Circumscription, essentially an imaginary line around the taxon, is
based on key characters and separates a given category (TAXON) from
other categories (TAXA).
At what rank have you defined your related
groups?____________________________
Classification of your bolt "species" based on
characteristics of the pileus probably resulted in the creation of
three groups, each having five "species". Following the botanical
hierarchy, we can assign these three taxa the rank of "genus".
Now we can begin to name all of our categories, beginning at
the genus level:
| GENUS | KEY CHARACTERISTICS (BASIS OF CIRCUMSCRIPTION) |
|---|
| Carriage | Pileus circular in outline, no terminal groove |
| Machine | Pileus circular in outline, has a terminal groove |
| Hexhead | Pileus hexagonal |
|
You can now establish a nomenclatural system at the species level.
Following the rules of botanical nomenclature, each SPECIES NAME
must include the GENUS NAME (Carriage, Machine, or Hexhead) plus a
SPECIFIC EPITHET. This complete name is known as the BINOMIAL.
Establish binomials for your bolt "species" in the following
manner:
Examine the five "species" of each bolt "genus" and complete
the following data table. Provide each "species" with an epithet
once the description of that taxon is complete. Make up your own
epithets, or draw from the list of Latin epithets. The table will serve to fix your epithet to the taxon
for which it is intended. The TYPE SPECIMEN (an herbarium sheet of
the plant specimen chosen as the standard for a species) serves
this function for plant nomenclature.
DATA TABLE (measurements in mm.)
| GENUS | SP. EPITHET* | COLOR | PILEUS DIAM. | STIPE LGTH. | OTHER |
|---|
| Carriage | __________ | __________ | __________ | __________ | __________ |
| Carriage | __________ | __________ | __________ | __________ | __________ |
| Carriage | __________ | __________ | __________ | __________ | __________ |
| Carriage | __________ | __________ | __________ | __________ | __________ |
| Carriage | __________ | __________ | __________ | __________ | __________ |
| Machine | __________ | __________ | __________ | __________ | __________ |
| Machine | __________ | __________ | __________ | __________ | __________ |
| Machine | __________ | __________ | __________ | __________ | __________ |
| Machine | __________ | __________ | __________ | __________ | __________ |
| Machine | __________ | __________ | __________ | __________ | __________ |
| Hexhead | __________ | ___________ | __________ | __________ | __________ |
| Hexhead | __________ | ___________ | __________ | __________ | __________ |
| Hexhead | __________ | ___________ | __________ | __________ | __________ |
| Hexhead | __________ | ___________ | __________ | __________ | __________ |
| Hexhead | __________ | ___________ | __________ | __________ | __________ |
*NOTE: specific epithets cannot be repeated within a genus.
Your classification and nomenclatural systems
for the Stoveaceae are complete. Now you can put your work to
practical use through the development of a DICHOTOMOUS KEY . The key will allow anyone to identify any
individual member of the Stoveaceae to "genus" and "species" in
your classification system.
Organize your key in such a way that the user is confronted
with a series of COUPLETS, each offering two alternative choices.
The choices, based on key characteristics of the bolt to be
identified, should eventually lead to a species identification or
determination. It may be helpful to start by separating the genera
as shown below:
1. Pileus hexagonal, terminal surface mostly flat. . . . . . . Hexhead, go to _____
1. Pileus circular in outline, terminal surface mostly convex............................... 2
2(1) Upper surface of pileus smooth...............................Carriage, go to _____
2. Upper surface of pileus with central groove. . . . . . . . .Machine, go to _____
Now construct a key to all bolt "species". You
may use the above key as a starting point, filling in the couplet
numbers as you assign them. Contrasting characteristics can be
found in your data table, although you are free to use any aspect
of bolt morphology. Remember that the more concrete a
characteristic is, the better basis for a couplet it makes. When
your key is completed, run a few bolts through it to check for
accuracy. Finally, use keys that have been produced by other
teams. Compare methods of organization, key characters used, and
relative efficiency. Also note the confusion that results from
production of many names for the same object. This is a major
reason for the establishment of an International Code of Botanical
Nomenclature.
**Notice that the bolt family is called the Stoveaceae and not
the Boltaceae. Why? It is called the Stoveaceae because there used
to be a type of bolt called a Stove bolt that is considered to be
most typical of the family.
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