Every biological organism has its unique characters. A taxonomic character is a set of characters that contribute to the description of a taxon.
The taxonomic trait is a property that distinguishes taxa — a feature that distinguishes one type of creature from another. Two beetle species can be distinguished by their punctate elytra.
A taxonomic character is defined by Mayr et al. (1953) as “any property of an organism or a collection of organisms by which it varies from (or resembles) an organism belonging to a different taxonomic category.”
Characters can be both qualitative and quantitative.
1. Quantitative characters are those that can be measured in terms of size, length, weight, and other factors.
2. Characters that are related to form and can be stated are referred to as qualitative characters.
Quantitative and qualitative characteristics are used together.
At the particular and infraspecific levels, quantitative features appear to be used more frequently in lower taxonomic groupings. As a result, leaf size, corolla length, and other characteristics can be used to distinguish species.
Higher layers of the hierarchy, such as family, frequently use qualitative characters.
Diagnostic characters
It describes that only includes the diagnostic features that separate a taxon from other taxa.
Characters in taxonomic classification are divided into two categories: continuous and discontinuous characters.
Continuous Characters
Continuous variation occurs when a taxon’s variants show a continuous gradation without a noticeable break.
1. Variations between species due to genetic and heritable alterations are linked to continuous traits.
2. Many genes and metabolic interactions play a role in these differences.
3. There is a whole range of measures in continuous variation, from one extreme to the other.
4. Individuals can have a wide variety of heights, such as 1.5, 1.51, 1.52, 1.525, and so on.
5. Other instances of constant variations are weight, body size, hand span, shoe size, and milk production.
Discontinuous characteristics
Discontinuous characteristics differ from continuous ones in that variation in the latter is always generated by genetic variation, whilst variation in the former can be environmental in origin as a result of the conditions experienced throughout development.
We use the term discontinues variation when a taxon’s variations show evident breaks or discontinuities.
1. The delimiting lines between taxa are drawn across these gaps.
2. The size of gaps in taxonomic practice usually affects taxonomic rankings; the larger the break or gap, the higher the taxonomic rank described.
3. Approximately 3 million species of organisms have been discovered so far based on such discontinuity, and this will continue to be the case unless and until further research reveals intermediates.
INFORMATION ON TAXONOMY (EVIDENCE)
Taxonomic traits can be derived from any portion and stage of the organism’s development.
Major sources of taxonomic information
The taxonomic characters can be roughly grouped into:
a) Morphological characters.
b)Physiological characters.
c) Behavioural characters.
d)Ecological and distributional characters.
e)Embryonic Character
Morphology’s Unique Features
Characteristics:
1. There isn’t a lot of diversity between specimens.
2. It is not easily altered by the surroundings.
3. Consistently stated
4. Available in the specimens you’re working with.
5. Well-documented.
Characters that do not differ between groups or vary at random are useless.
External Morphology:
The vast majority of characteristics are helpful. Shape, size, colour, colour pattern, and counts of various repeated or related structures are all possibilities.
Sexual Dimorphism
Characteristics of animals often differ sexually, making adult individuals appear different. This may only happen during the breeding season.
EVIDENCE FROM MORPHOLOGY AND ANATOMY
Taxonomists still rely heavily on morphological and anatomical characteristics.
Morphological traits have enormous benefits because we can see them easily and hence appreciate their variety with considerably less facility than other kinds of features.
Embryonic Character
Characters have an ontogeny, which can be continuous or discontinuous depending on whether there are discrete body forms undergoing metamorphosis. We must utilise equivalent forms as a result of these modifications.
1. Ontogenetic features aid in the formation of relationships.
2. Chromosomal alterations can lead to speciation, reduced fecundity, or sterility.
3. Chromosomes are often examined at three levels:
A.Alpha Karyology – Chromosome number and size
B.Beta Karyology – The number and location of centromeres, which allows chromosomal comparisons between species.
C.Gamma Karyology – Number, centromere, and staining for distinct chromosomal sections to identify homologous chromosome portions.
E.Haploid or diploid chromosome number.
F.Compare the numbers of metacentrics, acrocentrics, and telocentric in each group.
Physiological features
Morphology, quantity, size, and shape of secretory glands. Scale and mealy bug waxy secretions, for example.
Characters at the molecular level
1. Electrophoretic differences
2. Immunological information
3. DNA hybridization
4. DNA and RNA sequences
5. Protein amino acid sequences
Characters with distinct personalities
1. Courtship and other processes for ethological isolation:
2. Species mating and reproduction behaviour.
3. Assistance with taxonomic classification.
4. This leads to reproductive isolation and, as a result, speciation.
5. Habits of living, eating, and nesting.
Ecological characters and distributional characters
1. Habitats and environments
2. Variations in food and season
3. Hosts and parasites
4. Geographic characteristics, biogeographic patterns in general
5.Population sympatric-allopatric association
Geographical/ Ecological Evidence
Environmental Proof
In taxonomy, ecological data differs from other types of comparative data. Their study focuses on plant-environment interactions. All of the plant’s characteristics interact with all components of the environment, resulting in interactions.
Geographical Evidence
Allopatric – taxa that live in geographical zones that are mutually exclusive. Genotypic and phenotypic variation/divergence occurs in isolated populations.
Peripatric – In this new species, individuals form isolated, small peripheral communities that are unable to exchange genes with the main population. Isolated individuals quickly became incompatible with their former species, resulting in the formation of new species.
Parapatric – this is where two divergent populations’ zones are separated, but only partially, such as at the forest’s edge or the mountain’s snow line.
Sympatric –