Which of the following is the correct order of plant species from higher to lower order ?
- (a)Class – Phylum – Order – Plant Kingdom
- (b)Order – Class – Phylum – Plant Kingdom
- (c)Class – Plant Kingdom – Phylum – Order
- (d)Plant Kingdom – Phylum – Class – Order
Correct — D, Plant Kingdom – Phylum – Class – Order. Biological classification is a nested hierarchy of ranks running Kingdom → Phylum (called Division in botany) → Class → Order → Family → Genus → Species. Each rank sits wholly inside the one above it: a Kingdom contains several Phyla/Divisions, each Phylum contains several Classes, each Class contains several Orders, and so on. So reading from the highest (most inclusive) category downwards, the only sequence that respects the nesting is Plant Kingdom, then Phylum, then Class, then Order. For a plant such as wheat the chain runs Kingdom Plantae → Division/Phylum Angiospermae (flowering plants) → Class Monocotyledonae → Order Poales, and only then Family Poaceae, Genus Triticum, species Triticum aestivum.
- (a)Class – Phylum – Order – Plant Kingdom — It puts the most inclusive category, the Plant Kingdom, at the bottom and starts from Class — the exact inversion of what the question asks. It also breaks the internal nesting, since Phylum can never sit below Class.
- (b)Order – Class – Phylum – Plant Kingdom — This is a perfectly valid hierarchy but read in the wrong direction — it goes from the lower (narrower) rank to the higher one. The question explicitly asks for higher to lower, so this is the classic 'right ladder, wrong end' trap.
- (c)Class – Plant Kingdom – Phylum – Order — It inserts the Plant Kingdom between Class and Phylum, which is impossible: the Kingdom is the widest category of the four and must contain the Phylum, which in turn contains the Class.
Taxonomy arranges organisms into taxonomic categories (ranks) of decreasing inclusiveness — Kingdom, Phylum/Division, Class, Order, Family, Genus, Species. As you move down the ladder, the number of characters shared by the members of a group increases while the number of organisms in the group falls; moving up, groups get larger but share fewer common features. The scheme descends from Carl Linnaeus, who also gave botany its binomial system of naming (Genus + species).
Two of the four options (b and d) contain the correct nesting and differ only in direction, so the whole question turns on reading 'from higher to lower order'. Fix the widest category first — the Plant Kingdom has to be at one end — and then check which end the question wants. That single check kills (a), (b) and (c) at once. Note also that the paper uses 'Phylum' for plants: botanists conventionally say Division, but the botanical code itself recognises the rank as 'division (phylum)', so the usage is legitimate.
- Descending order of the main taxonomic categories: Kingdom → Phylum (Division in plants) → Class → Order → Family → Genus → Species.
- As one descends the hierarchy the number of shared characteristics increases and the number of organisms included in the taxon decreases.
- In botany the rank equivalent to the zoological Phylum is the Division; plant names are governed by the International Code of Nomenclature for algae, fungi and plants (ICN) and animal names by the ICZN.
- Binomial nomenclature — a two-part Latinised name of Genus plus species — was established for plants by Carl Linnaeus in Species Plantarum (1753); the genus is capitalised, the species epithet is not, and both are italicised.
- R.H. Whittaker's five-kingdom system (1969) — Monera, Protista, Fungi, Plantae, Animalia — is the classification most Indian textbooks use for the Kingdom rank.
The question asks only about the first four rungs — Plant Kingdom → Phylum → Class → Order — which is option (d). Going down the ladder, shared characters increase and group size shrinks.
- Reading the ladder in the wrong direction — the paper often supplies both the ascending and the descending sequence as options.
- Assuming 'Phylum' is wrong for plants because textbooks say Division; the two are the same rank and the botanical code allows both.
- Forgetting Family between Order and Genus when the question extends past four ranks.
UPPSC keeps this at the recall level — order the ranks, or match a plant to its group — while UPSC prefers the applied version, giving a species and asking about its family, or testing the five-kingdom criteria and nomenclature rules.
No directly related past PYQ was found.
- practice — not a real PYQ
Which one of the following is the correct sequence of taxonomic categories in ascending order (lowest to highest)?
- (a)Species – Genus – Family – Order – Class – Phylum – Kingdom
- (b)Species – Family – Genus – Class – Order – Phylum – Kingdom
- (c)Genus – Species – Family – Order – Phylum – Class – Kingdom
- (d)Species – Genus – Order – Family – Class – Phylum – Kingdom
Answer(a) Species – Genus – Family – Order – Class – Phylum – Kingdom — Family always lies between Order and Genus.
- practice — not a real PYQ
The five-kingdom system of classification, which places organisms in Monera, Protista, Fungi, Plantae and Animalia, was proposed by :
- (a)Carl Linnaeus
- (b)Charles Darwin
- (c)R. H. Whittaker
- (d)Ernst Haeckel
Answer(c) R. H. Whittaker, in 1969 — Linnaeus gave binomial nomenclature and a two-kingdom scheme; Haeckel had earlier added Protista as a third kingdom.