Biosystematics trends
1. Modern classification has as its primary goal not only the comprehension, identification, and right arrangement of creatures, but also the study of their development and evolution across time.
2. Initially, animals were examined solely based on their external structure, i.e. morphology, with distinct species, sub-species, and sub-groups being investigated separately.
3. Biological species have replaced morphologic species.
4. Along with morphological characteristics, the study of animals also incorporates genetics, hereditary, biochemical, and other traits.
5. This concept provides insight into the actual structure and evolution of species.
1. Chemotaxonomy:
Chemotaxonomy is a novel taxonomic technique that can be used on both plants and animals. Candolle (1813) was the first to use this strategy in his research and establish new methods for identifying closely related species.
It was previously understood that an organism’s metabolic processes are linked to complex chemical changes and that the body of an organism contains a variety of proteins, nucleic acids, enzymes, hormones, and other components.
Classification can also be influenced by the diversity or differences between these components.
This difference or change in these chemicals is thought to be the most fundamental and true difference in genetic and hereditary processes, which is more essential than physical alterations. Which were regarded as the classification’s starting point.
2. Cytotaxonomy :
Cytotaxonomy refers to the cytological approach to taxonomy, or how cytology facilitates taxonomists’ work. It is investigated in the following manner:
Complementary genetics: It compares the genome (the DNA in the nucleus) and the plasmid (the DNA outside the nucleus) (the DNA in cytoplasmic organelle). DNA is the most important component of heredity.
The amount of DNA per chromosome set is thought to be constant among animals. However, it is still unclear if variations in the size of heterochromatin segments are responsible for the ratio of DNA content of chromosomes.
Karyological studies: Each species’ karyotype, which is defined by the number of chromosomes, size, and morphology, is a distinct and constant feature.
Molecular taxonomy
1. Molecular taxonomy is the classification of organisms based on their chemical substance distribution and composition.
2. The amino acid sequence in an organism’s protein can be used to differentiate species, and different species have different amino acid sequences.
3. Lahni is the author of the term “molecular taxonomy” (1964).
4. Turner (1966) divided taxonomy into micromolecular and macromolecular groups.
Micromolecular taxonomy: The influence of small molecular weight chemicals on their distribution and biosynthetic interrelationships. Free amino acids, terpenes, and flavonoids are some examples of secondary chemicals.
Macromolecular taxonomy: This is a classification system for polymeric molecules such as DNA, RNA, polysaccharides, and proteins.
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