Question

Identify the proper sequence in the life history of liver fluke
(1) Cercaria
(2) Metacercaria
(3) Sporocyst
(4) Redia
(5) miracidium
(a) 2-1-3-5-4
(b) 5-3-4-1-2
(c) 5-4-2-1-3
(d) 5-4-3-1-2

Answer 1

Hint: Organisms in Platyhelminthes phylum show complex lifecycle history and they include different stages in the lifecycle like miracidium, sporocyst, redia, etc.

Complete answer:
Liver flukes belong to the class Trematoda of Platyhelminthes phylum. Organisms in Trematoda are commonly called flukes. Most of them are parasites i.e., depend on other animals. Trematodes have a complex life history with many hosts. They have different types of stages in life history starting from miracidium, sporocyst, redia, cercaria, metacercaria, etc.

Additional Information: - Organisms that belong to the phylum Platyhelminthes have a dorsoventrally flattened body. So, they are also called flatworms.
- They are the first bilaterally symmetrical, acoelomate, triploblastic organisms with an organ-system level of organization.
- These organisms show complex life history with many stages like miracidium, sporocyst, redia, cercaria, etc.
- Turbellaria, Trematoda, and Cestoda are the three classes of Platyhelminthes
- Dugesia and Convoluta are examples of class turbellaria that are mostly free-living unsegmented flatworms. Development is indirect and includes Muller’s larva.
- Fasciola, Schistosoma are examples of class Trematoda which are commonly called flukes. Development is indirect and shows cysticercus larva
-Taenia solium, echinococcus granulosus are examples of class Cestoda which are commonly called tapeworms. They exhibit pseudometamerism. They exhibit different stages in life history starting from miracidium, sporocyst, redia, cercaria, metacercaria, etc.
So, the correct answer is ‘5-3-4-1-2’.

Note: Fasciola hepatica is also called sheep liver fluke and it is a parasite that causes a disease called fasciolosis. Fascioliasis is a type of helminthiasis. Symptoms include abdominal pain, nausea, and cause complications like anemia and pancreatitis.