In 1969, biologist Robert H. Whittaker proposed the ‘Five World Taxonomy’, dividing the entire biosphere into 5 worlds or kingdoms, including bacteria and other microorganisms. In 1974, biologist Dr. Lynn Margulies introduced the modern taxonomy by modifying and refining the five world taxonomy in Symbiotic Planet. He considered plants and animals together as biota. He divided the living world into two super kingdoms and five worlds. Hence, it is called the five world classification. These are-
Super kingdom- Prokaryota and Super kingdom- Eukaryota
Super Kingdom- 1 Prokaryotes: They do not have a well-structured nucleus. They are unicellular and microscopic. Prokaryotes consist of only one world.
1. World-1: Monera
(i) They are unicellular, filamentous, colonial or mycelial.
(ii) The cell does not have a well-formed nucleus.
(iii) Chromatin bodies contain DNA, but no proteins.
(iv) Cells do not contain plastids, mitochondria, endoplasmic reticulum, lysosomes etc. Dr. Siddique Publications
(v) Cell wall is composed of polysaccharides and proteins.
(vi) Cell division occurs in the process of amitosis.
(vii) Takes food mainly by absorptive system. But in some cases they are photosynthetic or chemosynthetic.
(viii) Manara consists of 15 episodes.
Examples: Nostoc linka, Anabaena, Spirulina, Esherichia coli, Bacillus albus.
Super Kingdom- 2 Eukaryota: Their cells have a well-structured nucleus. They are unicellular or multicellular. Eukaryota consists of 4 kingdoms.
2. World-2: Protoctista
(i) They are unicellular or multicellular and unicellular or colonial.
(ii) Their cells have a well-formed nucleus.
(iii) Chromatin bodies contain DNA, RNA and proteins.
(iv) Cells contain plastids, mitochondria, endoplasmic reticulum, lysosomes etc. Dr. Siddique Publications
(v) Cell division takes place in the process of mitosis and meiosis.
(vi) They are mostly aquatic.
(vii) Their nutrition occurs by eating or absorbing or photosynthetically.
(viii) Multicellular embryos are not formed in their life cycle.
(ix) They are green, autophagous and self-sustaining. ie contain photosynthetic pigments.
(x) Algae are mainly gametophytic plants.
(xi) Their cell wall is composed of cellulose and pectin.
(xii) Their stored dietary sugars.
(xiii) Their genitalia are unicellular and not covered by a sterile sheath (exception- Chara).
(xiv) They do not have transport organs or vasculature. That is, they are avascular.
(xv) Sexual reproduction isogamous, anisogamous and eugamous.
(xvi) Sunlight is essential for their survival.
(xvii) Protoctista consists of 7 episodes.
Examples: Spirogyra hyalina, Amoeba proteus, Ulothrix, Chlamydomonas.
3. World-3: Fungi
(i) They are colourless, parasitic or dead.
(ii) They are unicellular or multicellular and mycelial.
(iii) Their cell walls are made of chitin.
(iv) There are no transport channels and embryos are not formed.
(v) Their stored food is glycogen.
(vi) Cells have well-organized nucleus.
(vii) Their chromatin bodies contain DNA, RNA and proteins.
(viii) Their genitalia are single-celled and not covered by a sterile sheath.
(ix) They do not have transport vessels or vascular bundles. That is, they are avascular.
(x) Their cell division is in the nature of amitosis, mitosis and meiosis.
(xi) Sexual reproduction is isogamous, anisogamous and eugamous.
(xii) Sunlight is not essential for their survival.
(xiii) Their stored food is glycogen and oil droplets.
(xiv) Their cell wall is mainly composed of chitin.
(xv) They reproduce by haploid spores.
(xvi) Their adaptability is severe (5-50°C).
4. World- 4: Plantae
(i) The main plant body is the sporophyte.
(ii) They are unicellular or multicellular and centripetal plants.
(iii) Tissue structure developed and cell wall composed of cellulose.
(iv) Stored food bleaches.
(v) Sexual reproduction is anisogamous and eugamous in nature.
(vi) They are vascular. That is, there are vascular bundles.
(vii) They produce seeds.
(viii) Their spermatozoa are flagellated or non-flagellated.
(ix) The life cycle has a clear sequence.
Example: Paddy, Wheat, Sugarcane, Bhutra etc.
Plant kingdom is divided into two grades. Bryophyta and Tracheophyta
Grade-1: Bryophyta
(i) Plants are gametophytic.
(ii) They are avascular plants. That is, there is no transport tissue.
Example: Semibarbula orientalis
Grade-II: Tracheophyta
(i) Plants are sporophytic.
(ii) They are vascular plants. That is, there is transport tissue.
Example: Oryza sativa
5. World-5: Animalia
(i) They are multicellular and centripetal organisms.
(ii) Their nutrition is Holozoic.
(iii) They are interdependent as they lack chlorophyll.
(iv) Absence of cell wall, plastid and cell cavity.
(v) Cell division occurs through mitosis and meiosis.
Examples: Homo sapiens, Panthera tigris, Labeo rohita, Bombyx mori