This Blog discusses Biological Classification And how the organisms get classified into Five kingdom systems, Kingdom Monera, Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia by Whittaker.
At a Glance of Biological Classification
What will you picture if I told to imagine a eukaryotic organism whose cells have a nucleus enclosed within the nuclear envelope, possess a cell wall, have small vacuoles in it, heterotrophic in nature, motile living body with one control center? Confused…………?
Now, imagine HUMAN BODY, the complete description I have given above is about the human body. Still, as I haven’t mentioned its simplified word or common name, we cannot recognize even our own body. This the magic of “BIOLOGICAL CLASSIFICATION.” This biological classification gave us a complete description of every organism. In the previous blog, we are thoroughly gone through the terminologies used to describe the BIODIVERSITY in nature.
As we know, the classification of plants and animals was first proposed by Aristotle based on simple morphological character. All the living organisms later classify into TWO KINGDOM SYSTEM, KINGDOM PLANTAE, and KINGDOM ANIMALIA by Linnaeus.
This two-kingdom system shows many limitations. It is further classified and elaborate into FIVE KINGDOM SYSTEM: Monera, Protista, Fungi, Plantae, and Animalia by Whittaker. The classification of plants into trees, shrubs, and herbs on the basis of simple morphological characters is easy and done initially by Aristotle. He also divides animals on the basis of ‘with red blood’ and ‘without red blood’ animals.
That two-kingdom system was easy to understand, but many organisms did not fit under this category. This system was unable to explain eukaryotic and prokaryotic, unicellular and multicellular, photosynthetic and non-photosynthetic, and hence it is inadequate for use. Here is the basic knowledge hole created, which requires complete and elaborative classification that constitutes all types of organisms. Hence further five-kingdom system gets accepted as it fulfills all the classification criteria for all the living organisms.
Five kingdom system
In further years, morphology grows, which creates a need for the addition of some characters. R.H. Whittaker, in 1969 proposed a more elaborative and descriptive pattern for the classification, which is name as FIVE KINGDOM SYSTEM that depends on some special characteristics like,
- Cell Structure
- Nature of Cell Wall
- Mode of Nutrition
- Habitat
- Methods of Reproduction
- Evolutionary Relationship
However, The five-kingdom system comprises five different categories, including Monera, Protista, Fungi, Plantae, and Animalia. It gives a detailed description of various organisms, their cell structure, reproduction, etc.
We are well versed with the above table of the five-kingdom system. This table has a specialty to explain basic but unique and differentiating characteristics of the living organisms that do not specify in two-kingdom systems. According to this table, the cell types present in all four kingdoms are eukaryotic. And Monera is prokaryotic.
The cell wall is present in all kingdoms with special ingredients except kingdom Animalia; plants cell wall is a formation of cellulose. In Monera, it is of polysaccharides and amino acids. Nuclear membrane, which I have explained in an earlier blog, is absent only in Monera. Body organization of Monera and Protista is cellular, while in fungi, Thus it is multicellular or of loose tissues. The mode of nutrition is autotrophic in kingdom Monera, Protista, and Plantae. And heterotrophic in kingdom fungi and Animalia.
Kingdom Monera of Biological Classification
Monera kingdom includes single-celled organisms with prokaryotic cell types. Among the three domains of life, organisms under kingdom Monera are divided into two domains viz Archaea and Bacteria. Bacteria is the sole member of the Monera kingdom, which is present almost everywhere. It is the most abundant organism. It can survive in extreme cold and extreme hot climatic conditions too.
Habitat doesn’t affect its existence. These bacteria can live on the host body as a parasite.
Bacteria are divided into four categories viz.
- The spherical coccus (pl: cocci)
- The rod-shaped bacillus (pl: bacilli)
- The spiral spirillum (pl: spirilla)
- The comma shapes Librium (pl: vibrio)
Bacteria possess a simple structure but complex behavior. It has the most extensive metabolic diversity, which divides bacteria into autotrophic and heterotrophic. It includes archaebacteria and eubacteria.
Some bacteria are autotrophic or photosynthetic autotrophic or chemosynthetic autotrophic. Most of the bacteria are heterotrophic, which depends on other organisms or dead organic matter for food and nutrition. Cell wall composition of organisms under kingdom Monera is a polysaccharide and amino acid. The mode of reproduction in the bacteria is mostly through fission, spore formation, and sexual reproduction by transferring DNA from one bacteria to the other.
Kingdom Protista of Biological Classification
It consists of all eukaryotic organisms, including both single-celled and multi-celled organisms. It does not include animals, plants, or fungi. Primarily the members under this kingdom are aquatic. This kingdom forms a link between other kingdoms. Some organisms under this kingdom possess a cell wall, while the nuclear membrane is present in all organisms. These organisms have cellular body organization.
They show the autotrophic and heterotrophic modes of nutrition. Eukaryotes, the Protistan cell body, contain a well-defined nucleus and other membrane-bound organelles.
The organisms under this kingdom use flagella or cilia for locomotion. The reproduction process by organisms under kingdom protists is both asexual and sexual, including cell fission and zygote formation, respectively. Following are some examples of organisms under kingdom Protista viz, chrysophytes, dinoflagellates, slime molds, paramecium, euglena, etc.
Kingdom Fungi of Biological Classification
You must have seen some fine threads of grey color on moist bread or the chapati and some rotten things; that is called a fungus. All such category things are collect under kingdom fungi. It includes a unique kingdom of heterotrophic organisms, which shows great diversity in morphology and habitat. The organisms that come under this kingdom can be hazardous and useful. Many funguses are useful for industrial purposes in forming food items; for example, yeast is useful to prepare bread and beer. And some funguses are the source for antibodies, for example, penicillin, etc.
The fungus can occur in air, soil, water, and on animals and plants. This fungus can cause disease in plants and animals. The cell wall present in fungal cells is a composition of chitin and polysaccharide. The mode of nutrition shown by this kingdom is mostly heterotrophic. These are saprophytes that absorb soluble organic matter from dead substrates. These can be present as parasites and symbiont in association with lichens and with roots of higher plants as mycorrhiza.
The reproduction modes shown by fungi can be vegetative means by fragmentation, fission, and budding. It can be sexual by forming basidiospores, ascospores, and oospores. It can be asexual by conidia or sporangiospores, or zoospores.
The remaining two kingdoms we will study in upcoming blogs till the time stay connected with us.
CONNECT WITH US
Join our Newsletter for the Latest Updates
- An Extinct Species Found After 40 years – Hills Horseshoe Bat
- Everything you need to know about Blobfish
- Know the Ornithorhynchus Anatinus – A Platypus
- Fundamentals of the Mendelian genetics
- Concept of The Principle of Inheritance
- Process of the Translation to be Focused On
- Facts of the DNA Transcription
