1. Govt. College Bundi
Aims and fundamental
components of taxonomy
M.Sc. botany sem-III
Submitted by
Simran
Submitted to
Dr. Rajendra Prasad
2. Aims of taxonomy
The modern taxonomy includes three major aims which are widely
accepted-
1. To provide a convenient method for identification and communication.
2. To provide a classification which expresses natural relationship of
organisms as far as possible.
3. To detect evolution at work, discovering its process and interpreting the
results.
➤The approach required to counter first two aims is empirical- based on the
observed characters and results in a basic classification.
➤ The Interpretative approach is required for the third aim that improves
classification and interpreted in evolutionary and phylogenetic terms.
3. The knowledge of universe-flora is quite uneven and its classification can be
considered in four overlapping phases,
1. Pioneer or exploratory phase
➤ Concerned with the identification.
➤Flora is known mainly from the herbarium material.
2. Consolidation phase
➤ Species have been studied both in herbarium and field.
➤Initiated the publication of floras and monographs.
3. Biosystematics phase
➤ The phase includes geographical and ecological variations on cytological ground
including morphology, chromosome number, breeding behavior and barriers.
4. Encyclopedic phase
➤ Taken evidences from first three phases and tried to express systematic and
evolutionary relationships of plants at every taxonomic unit.
➤ Emphasized on infraspecific categories like ecotypes, ecophene and biotypes.
4. Fundamental components of taxonomy
• Component of Taxonomy
1. Identification
2. Description
3. Nomenclature
4. Classification
• Component of Systematics
1. Identification
2. Description
3. Nomenclature
4. Phylogeny
5. • It is the foremost step of taxonomic
studies which involves recognizing an
unknown specimen with an already known
taxon by assigning a correct rank and
position in an existing classification.
• The identification of the specimen is
done by visiting a herbarium and
comparing unknown specimen with duly
identified specimens of the herbarium.
• Identification can also be carried out by
using various sources of literature such
as floras, monograph or manuals and
making use of identification keys.
1.Identification
6. 2. Discription
• The description of a specimen involves
listing its features by recording the
appropriate character states.
• A shortened description consisting of only
those taxonomic characters which help in
separating a taxon from other closely
related taxa
• The description is recorded in a set
pattern (habit, stem, leaves, flower, sepals,
petals, stamens, carpels, fruit, etc.).
• Description = assign features
Character = a feature (e.g., "petal
color")
Character states = (e.g., "red,"
"white").
• The description is recorded for a
proper documentation of data.
7. 3.Nomenclature
➤ Nomenclature deals with the determination of a correct name
for a taxon.
➤ There are different sets of rules for different groups of living
organisms.
➤ Nomenclature is governed by different codes through its rules
and recommendations
• Plant, fungi and algae- International Code for Botanical
Nomenclature (ICBN)
•Bacteria- International Code for the Nomenclature of
Bacteria (ICNB), now called Bacteriological Code (BC)
• Viruses- International Code of Virus Classification and
Nomenclature (ICVCN).
8. 4.Classification
• Classification is an arrangement of
organisms into groups on the basis
of similarities.
• The groups are, in turn, assembled
into more inclusive groups, until all
the organisms have been assembled
into a single most inclusive group.
• In sequence of increasing
inclusiveness, the groups are
assigned to a fixed hierarchy of
categories such as species, genus,
family, order, class and division, the
final arrangement constituting a
system of classification.
9. • The process of classification includes assigning
appropriate position and rank to a new taxon
• Taxon = a taxonomic group (plural = taxa)
1.Artificial classification- This classifies plants with the
help of one or few characters and assist in easy
identification of the organism e.g., Banhin, Tournefort,
John Ray, Carl Linnaeus etc.
2.Natural classification- It is mainly based on from
relationship realizing all informations available at that
time. e.g., de Candolle, Robert Brown, de Lamarck,
Bentham and Hooker's classification.
• There are many types of classification
10. 3.Phylogenetic classification- Plants are classified based on their
genetic relationships and according to their evolutionary history
e.g., Eichler, Hutchinsm, Bessey.
4.Phenetic classification- Maximal generalizations of the totality
of the features of all phenotypes e.g., Hutchinson.
