Biological classification is the process of classifying distinct organisms together based on their phylogenetic descent, similarity, and differences. R.H. Whittaker proposed a five-kingdom categorization system that categorized species based on their cellular structure, complexity, mechanism of nourishment, evolutionary link, and ecological role. Whittaker classified creatures into five groups: Monera, Protista, Fungi, Plantae, and Animalia.
Monera- All types of bacteria that have prokaryotic cells—cells without a clearly defined nucleus—fall into this category. Bacteria come in a variety of morphologies, including spherical cocci, rod-shaped bacillus, comma-vibro, and spirit spirilla. Fission, spore formation under unfavorable conditions, and DNA transfer from one bacterial cell to another are their primary methods of reproduction. Mycoplasma is the smallest cell that can exist without oxygen because it lacks a cell wall. Archaebacteria can be found in hot springs, salt marshes, and other extreme environmental conditions. Ruminant’s guts contain methanogens, which make biogas. In contrast to motile creatures, which have flagella, eubacteria are real bacteria and have stiff cell walls. Cyanobacteria (blue-green algae) are examples of photosynthetic autotrophs. They contain carotenoids and chlorophyll. Chemosynthetic molecules are crucial for recycling nutrients. The oxidation of numerous inorganic materials, including ammonia, nitrates, and nitrites, provides them with the energy they need to produce ATP. Heterotrophic bacteria come in a vast variety. As a decomposer, they work. They provide a variety of functions, including the production of curd, antibiotics, and fixing nitrogen.
Protista- This group contains eukaryotes with only one cell. A protist that uses photosynthetic organisms connects plants and mammals. It consists of protozoans, dinoflagellates, euglenoids, slime moulds, and chrysophytes. Diatoms and desmids are examples of chrysophytes; they are primarily photosynthetic organisms with silica-based cell walls that are impervious to damage. Dinoflagellates are photosynthetic sea organisms that vary in color depending on the pigment present, including yellow, green, red, and blue. Euglenoids, which produce photosynthesis but lack a cell wall, serve as a bridge between plants and animals. Slime moulds are saprophytic protists that eat decomposing twigs, leaves, and other organic matter. Unicellular, eukaryotic heterotrophs in the protozoan category can be either parasites or predators. These are separated into four main groups: sporozoans, flagellated, ciliated, and amoeboids.
Fungi- Fungi are universal and cosmopolitan organisms. Because they are heterotrophic, they absorb nutrients. Chitin, also known as fungal cellulose, makes up its cell wall. Several significant fungi include Yeast (used in the fermentation process to produce cheese, bread, and beer), Penicillium (a source of antibiotics), Puccinia (which causes wheat rust), Ustilago (which causes smut disease), Symbionts (lichens, mycorrhiza), Rhizopus (the bread mould), Albugo (the parasitic fungi on mustard), Neurospora (heavily utilized in genetic and biochemical research), etc.
Plantae- It is mostly inhabited by eukaryotic, autotrophic organisms that contain chlorophyll and have hard, cellulose-based cell walls. Some plants, like parasitic and insectivorous ones, are somewhat heterotrophic. Algae, bryophytes, pteridophytes, gymnosperms, and angiosperms are all members of the kingdom Plantae.
Animalia- The Kingdom Animalia encompasses all heterotrophic, eukaryotic, and multicellular organisms and they lack a cell wall.
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