Introduction
Taxonomy, according to the scientific definition, is the classification of living and extinct creatures. It also encompasses the naming and grouping of organisms into larger groups. Taxonomy is the study of living organisms such as animals, plants, microbes, and humans in order to classify and distinguish them into different categories. Taxonomy is either a sub-branch of systematics or a synonym for the latter term, depending on definitions. Biological nomenclature is also regarded to be either a part of taxonomy or a unit of systematics. Consider the following definition of systematics to clear things up:
Systematics is the study of the taxonomy and nomenclature of organisms, their classification based on natural relatedness, and the study of variation and evolution among taxa.
Biologists who study the relationships between creatures and classify them into categories are known as taxonomists. Insect taxonomists, for example, comprehend the relationship between distinct fly kinds and vice versa in order to put them into a single category.
Classification Systems
The scientist required a system that could supply all of this data in order to obtain complete knowledge on the similarities and differences between various creatures. Earlier classification methods split and grouped the creature into two kingdoms: plants and animals. After creating the two-kingdom classification system and three-kingdom classification systems in previous years, taxonomists agreed on a five-kingdom classification system. The sole distinction between the five-kingdom and six-kingdom categorization systems is that Protista was further separated into two kingdoms in the six-kingdom classification system.
1. Two kingdom classification system
Initially, creatures were simply divided into two kingdoms: Animalia and Plantae. Kingdom Plantae comprises species that can prepare their sustenance from simple inorganic components, according to this approach. Autotrophs are another term for them. Those species, on the other hand, that are unable to make their food from simple inorganic material and must rely on other autotrophs for nourishment were classified as heterotrophs and put in the Kingdom Animalia. Taxonomists classified bacteria, fungus and algae as Kingdom Plantae under this categorization system.
2. Three-kingdom classification system
In 1866, Ernst Hackel, a taxonomist, solved the previous difficulty. He created the Protista kingdom to house species like Euglena. In the third kingdom, he also included bacteria. The fungi, on the other hand, have remained in the Plantae kingdom. As a result, the three-kingdom classification scheme was still insufficient to classify creatures clearly. Furthermore, the distinctions between prokaryotes and eukaryotes are not taken into account in this classification system.
Fungi are similar to plants in many respects, yet they are unable to prepare food (not considered autotrophs). Instead, they consume food by absorption. They are heterotrophs because they lack cellulose in their cell walls and have chitin in their cell walls.
3. Five-kingdom classification system
In 1967, Robert Whittaker proposed the five-kingdom classification scheme. The following were the foundations of the system:
•The system assigned prokaryotic, unicellular eukaryotic and multicellular eukaryotic stages to cellular organisation.
•Based upon Photosynthesis, absorption, and ingestion the three modes of nourishment.
The organisms were divided into five kingdoms based on these criteria: Monera, Protista, Fungi, Plantae and Animalia. Margulis and Schwartz also made improvements to the five-kingdom classification system in 1988. Nonetheless, the division of the Protista kingdom is one of the most recent alterations made to this categorization scheme.
Kingdoms
(1) Kingdom Animalia
Animalia is the kingdom that encompasses almost all animals. Food is ingested and digested by these animals via specific organs. They are multicellular eukaryotic creatures with no cell wall. These creatures travel from one location to another. Humans (in casual language) are included in the kingdom Animalia; nonetheless, the term “animal” is reserved for animals other than humans.
(2) Kingdom Plantae
All plants are classified as eukaryotic, multicellular autotrophs in this kingdom. The Plantae kingdom is sometimes known as the Metaphyta kingdom. Multicellular and eukaryotic photosynthetic plants belong to this kingdom. Photosynthesis is the method through which these plants produce their food. They reproduce and have multicellular developing embryos as sex organs. Plants have existed in the world for a long time and there are over 250,000 species.
(3) Kingdom Monera
The kingdom Monera includes the organisms that are made up of prokaryotic cells. Although some types generate clusters, colonies, and cell changes, they are unicellular. Some Monera species make their food through photosynthesis, but the majority are heterotrophs, meaning they cannot produce their own food and must rely on other plants and animals, such as algae. Chlorophyll is found in the cytoplasm of organisms that undertake photosynthesis. Cyanobacteria and bacteria are two types of creatures that belong to the Monera kingdom.
(4) Kingdom Fungi
The absorptive nutritional method is used by organisms in the kingdom fungus. Mushrooms, for example, are eukaryotic, multicellular heterotrophs. The majority of fungi are decomposers. They secrete digestive enzymes from the organic matter they eat. They also take in tiny organic molecules that arise as a result of enzyme digestion. Molds and yeasts are examples of other microorganisms found in fungus. The presence of chitin in fungi’s cell walls is the rationale for its classification as a distinct kingdom. The biodiversity of the kingdom fungus is estimated to be between 2. 2 million and 3. 8 million species.
(5) Kingdom Chromista
The kingdom chromista is derived from the kingdom Protista, which was established in 1981 by Thomas Cavalier to distinguish all protists from plant protozoans. Eukaryotic creatures, both single-celled and multicellular, are included in the kingdom chromista. The algae were first included in the chromista kingdom, however this was later removed due to protozoans belonging to a different category.
(6) Kingdom Protozoa
Protozoa are single-celled eukaryotic organisms that are parasite-free, which means they eat bacteria, detritus, and organic tissues (organic matter). Furthermore, because protozoans are single-celled eukaryotic organisms with heterotrophic eating properties, they are granted their own kingdom.
(7) Kingdom Archaea
Kingdom Archaea contains the unicellular prokaryotes microbes, which are thought to be the world’s oldest organisms.
Conclusion
There are eight different taxonomic groups. Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species are the different classifications. As a result, taxonomy is the methodology and principles of systematic botany and zoology, and it organises plant and animal species into hierarchies of superior and subordinate groups.