Why did Whittaker make five kingdoms? Fungi also have a cell wall like plants, so why a separate kingdom?
Yash Tiwari11th Sample
7 Sept 2026 · 1 min read
bhai bio sir ne aaj Biological Classification shuru kiya aur mera dimaag ghoom gaya. NCERT says Linnaeus gave two kingdoms, Plantae and Animalia, and then Whittaker came with five: Monera, Protista, Fungi, Plantae, Animalia. Fine. But I don't get why two kingdoms was even a problem. Sir said bacteria and fungi were stuffed inside "plants" earlier and that was wrong.
My doubts, in order of how much they are bothering me:
- Fungi have a cell wall, plants have a cell wall. So why is Fungi separate?
- NCERT lists criteria like cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships. Which of these actually separates Fungi from Plantae?
- Where are viruses in this system? I looked in the table and they are nowhere.
- In my notes Monera is "unicellular, no nuclear membrane" and Protista is "unicellular, has nuclear membrane". So is that the only difference or is there more?
I made a five-column table in my notebook but half the boxes are blank and I'm not sure about the ones I filled. Is there a clean way to remember how the five kingdoms differ? I was a backbencher till last year so I want this base solid from the start.
7 answers & replies
Sign in to join the conversation.
[+][–]Meera Patel11thSample· 1mo ago
Fungi versus Plantae is mainly about nutrition. Plants are photosynthetic autotrophs: they have chlorophyll and make their own food. Fungi are heterotrophs. They are saprophytes (feed on dead matter) or parasites, and they absorb food from outside rather than making it. Their body is also built differently, from thread-like hyphae forming a mycelium, not roots, stems and leaves.
The cell wall is also different in composition. Plant cell walls are cellulose. Fungal cell walls are made of chitin (and other complex polysaccharides). So yes, both have a wall, but "has a wall" is not the criterion, what the wall is made of and how the organism feeds is.
[+][–]Siddharth RaoDropperSample· 1mo ago
On viruses: NCERT itself says the five-kingdom system does not include acellular things like viruses and viroids, and also lichens (a symbiotic association, not a single organism). Whittaker's criteria start with cell structure, and a virus has no cell at all. It needs a host cell to multiply. So there is no box for it, and that is not an error in your notes.
Also one thing I wish I knew in my first attempt: the two-kingdom problem was that it did not separate prokaryotes from eukaryotes, unicellular from multicellular, or photosynthetic from non-photosynthetic organisms. Bacteria, cyanobacteria and fungi all got dumped in Plantae just because they have a wall. That is the line NCERT wants.
[+][–]Pooja Iyer12thSample· 1mo ago
omg yash I did this exact table drama in class 11 😭 here is my version, rows are the kingdoms:
- Monera: prokaryotic, unicellular, cell wall (non-cellulosic), no nuclear membrane, auto or heterotrophic
- Protista: eukaryotic, unicellular, cell wall present in some, auto or heterotrophic
- Fungi: eukaryotic, mostly multicellular (yeast is unicellular), cell wall of cellulose, heterotrophic
- Plantae: eukaryotic, multicellular, cellulose wall, photosynthetic
- Animalia: eukaryotic, multicellular, NO cell wall, heterotrophic (holozoic)
Stare at the "nutrition" and "cell wall" columns, that is where 90% of the questions come from. I put a star on Fungi because it is the odd one out.
[+][–]Yash Tiwari11thSample· 1mo agoAuthor
pooja didi thanks, copying this. but meera said fungi wall is chitin and you wrote cellulose, which one??
[+][–]Pooja Iyer12thSample· 1mo ago
ahh my bad, you are right to question it. Fungi = chitin, plants = cellulose. I was typing too fast and my brain pasted the plant row. Fix it in your notebook, and good catch honestly.
[+][–]Kavya NaikDropperSample· 1mo ago
Adding on Monera vs Protista, because it is more than the nucleus. Monera = bacteria (including archaebacteria), cyanobacteria and mycoplasma. They are prokaryotes: no nuclear membrane and no membrane-bound organelles like mitochondria or ER. Most have a peptidoglycan cell wall, but mycoplasma have no cell wall at all, which NCERT likes to ask.
Protista are eukaryotes (true nucleus plus membrane-bound organelles) and are mostly aquatic: chrysophytes, dinoflagellates, euglenoids, slime moulds, protozoans. So the clean split is prokaryote vs eukaryote, and the nucleus is just the visible sign of that.
[+][–]Nisha Verma12thSample· 1mo ago
Exam angle, since you are starting fresh: NEET likes the "which kingdom has X as a feature" type and the "which was not a criterion used by Whittaker" type. The five criteria are cell structure, body organisation, mode of nutrition, reproduction, phylogenetic relationships. Anything like "colour of the organism" or "habitat" is a trap. Also remember Whittaker's year is 1969, Linnaeus is the two-kingdom one. Make the table once, then redo it from memory every week for a month. By then it will be automatic.
