Biological Classification

Hello, readers! 

Today let's understand Classification of Living things.

Biological classification of plants and animals was first proposed by Aristotle. 

Linnaeus classified all living organisms into two kingdoms - Plants and Animals.

Robert whittaker proposed an elaborate five kingdom classification: Monera, Protista, Fungi, Plantae and Animalia. 

Monera: unicellular, prokaryotic, autotrophic or heterotrophic organisms. Eg bacteria

1. Archaebacteria: Halophiles, thermoacidophils, methanogens etc. 

2. Eubacteria: Autotrophic bacteria, heterotrophic bacteria etc.

Protista: unicellular, eukaryotic, autotrophic or heterotrophic organisms. 

1. Chrysophytes: plant like, golden algae and diatoms. 

Diatoms have soap-box like silica shells. 

2. Dinoflagellates: plant like, red, yellow, green, brown or blue cells. May have strong cellulose plates with two flagella. 

3. Euglenoids: plant like, has protein pellicle layer on cell. May have two flagella, a long and a short.

4. Slime moulds: fungus like, saprophytes, collectively called plasmodium - spores are formed for reproduction in unfavorable conditions. 

5. Protozoa: animal like, predators or parasites, 

Amoeboid protozoa, flagellated protista, ciliated protozoa and sporozoans.

Fungi:

Multicellular, eukaryotic, heterotrophic organisms. 

1. Phycomycetes: aseptate and coenocytic mycelium

2. Ascomycetes: mycelium is branched and septate, 

3. Basidiomycetes: mycelium branched and septate, 

4. Deuteromycetes: mycelium branched and septate, only asexual reproduction is discovered in them. 

Plantae: multicellular, eukaryotic, autotrophic organisms with cell wall of cellulose. Shows alternation of generation

Animalia: multicellular, eukaryotic, heterotrophic organisms without cell wall. 

Viruses, viroids, prions and lichens are not included in any of the five kingdoms.