4. Which animal possesses nerve cells forming a net without distinct organised nerves?
[AIPMT, 1993]
(A) Hydra
(B) Tapeworm
(C) Earthworm
(D) Frog tadpole
Answer: (A) Hydra
Explanation: Hydra has a diffuse nerve net rather than a centralised brain or nerves. Cnidarians represent a relatively simple level of nervous organisation compared with the specialised neural structures of annelids and vertebrates.
3. Planaria, the liver fluke and Taenia solium all belong to which common group?
[AIPMT, 1993]
(A) Segmented annelids
(B) Intestinal nematodes
(C) Coelomate animals
(D) Flatworms
Answer: (D) Flatworms
Explanation: Planaria, Fasciola and Taenia are members of Platyhelminthes. Although their lifestyles differ substantially, all share a fundamentally flattened, triploblastic and acoelomate organisation that distinguishes them from roundworms.
2. Which sequence of taxonomic ranks is correctly arranged from higher to lower?
[AIPMT, 1992]
(A) Class, phylum, tribe, order, family, genus, species
(B) Division, class, family, tribe, order, genus, species
(C) Division, class, order, family, tribe, genus, species
(D) Phylum, order, class, tribe, family, genus, species
Answer: (C) Division, class, order, family, tribe, genus, species
Explanation: In descending hierarchy, division or phylum precedes class, followed by order, family, optionally tribe, genus and species. A tribe is an intermediate rank generally positioned between family and genus.
1. Who introduced the taxonomic term phylum?
[AIPMT, 1992]
(A) Georges Cuvier
(B) Ernst Haeckel
(C) Theophrastus
(D) Carolus Linnaeus
Answer: (B) Ernst Haeckel
Explanation: Ernst Haeckel introduced the term phylum in the nineteenth century for major organismal lineages. Cuvier had earlier described major structural divisions of animals without using this exact term.180 exam-attributed taxonomy PYQs | The number decreases by one for each question. Examination years are sorted newest to oldest. Last item: 1992.
