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Animals and their larval stages.

1. Question: The table below represents a list of animals and larval stages.

    Animal                                                                                    Larval stage

A. Sponges                                                                                  i- cercariae

B. cnidarian                                                                                 ii-  amphiblastula 

C. Flatworms                                                                               iii- planula 

which one of the following options represents the combination of all correct matches.

1. A-ii, B-i, C -iii

2. A-i, B-iii, C-ii

3. A-ii, B-iii, C-i

4. A-iii, B-ii, C-i

Answer: A-ii, B-iii, C-i

2. Question: Column I lists the names of organisms and column II lists the life cycle stages. 

            Column I                                                                                Column  II

    P.  Taenia                                                                                   i. hexacanth 

    Q. Obelia                                                                                   ii. Glochidium

    R. Unio                                                                                       iii. Planula 

    S. Balanoglossus                                                                        iv. Tornaria 

                                                                                                         v. Miracidium

Which one of the following options represents all correct matches between the two columns?

a) P-i,    Q -ii,   R-iii,    S-v

b) P-iii,  Q- ii,   R- I,    S-v 

c) P-i,     Q- iii,   R-ii,   S-iv

d)P-ii,    Q- v,    R-iii,   S- iv

Answer:  c) P-i,  Q-iii,  R- ii,  S-iv

3. Question: Given below are larval stages and phylum to which they belong. selected the INCORRECT combination.

a) Parenchyma and Amphiblastula- Phylum Porifera

b) Bipinnaria and Auricularia -Phylum Echinodermata

c) Tornaria and Axolotl- Phylum hemichordata

d) Planula and Ephyra- Phylum Cnidaria

Answer: c) Tornaria and Axolotl

Note: Axolotl larva belongs to phylum Chordata. (Example - Salamander)


  • Facts about the animal larva

Explanation:

         Phylum                                                                       Their larval stages

  1. Porifera (sponges)              -                            Amphiblastula/Parenchymula larva  
  2. Coelenterata (Cnidaria) 

  1. Class-Hydrozoa
  •       Obelia                                   -                              Planula larva

    2. Class - Scyphozoa

  •   Aurelia                                    -                                    Ephyra
     3. Platyhelminthes (Flatwarm) 

  1. Class – Trematoda 

  •   Fasciola (liver flukes)  larval stages             
                                  Miracidium-sporocyst-redia-cercaria-metacercaria    

  • The primary host, sheep, is infected with metacercaria, while the secondary host, snail, is infected with miracidium.
   2. Class – Cestoda

  • Taenia (tapeworm) larval stages
                   Onchosphere – hexacanth - bladderworm

  • The primary host (human) becomes infected through the bladderworm (cysticercus), while the secondary host (pig) becomes infected through the oncosphere.h the oncosphere.

4. Annelida ( Class-Polychaeta)              -                             Trochophore larva

5. Arthropoda (Class- Crustacea)           -                             Nauplius larva                    

6. Mollusca (Class- Bivalvia)                   -                            Glochidium larva and                                                                                                               Veliger(some Gastropod)                                                                                                           Trochophore (Amphineura)

7. Echinodermata   

  • Crinoidea                                        -                             Doliolaria larva
  • Asteroidea                                       -                             Bipinnaria and Brachiolaria
  • Ophiuroidea                                    -                             Ophiopluteus
  • Echinoidea                                       -                             Echinopluteus        
  • Holothuroidea                                 -                             Doliolaria and Auricularia 
8. Hemichordata                                    -                               Tornaria larva            

9. Chordata                                                    -                       Axolotl (salamander)

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