Which one of the following is not a Platyhelminthes?

QUESTION: Which one of the following is not a Platyhelminthes?

A   Tapeworm

B    Liver fluke

C     Planaria

D     Hookworm

ANSWER:   Hookworm

                                                    Phylum Platyhelminthes
            Characteristics Examples Class Larva names
·        Members of phylum Platyhelminthes are known as Flatworms. Platy means flat, and “helminth” refers to worm. Their name reflects their flat, ribbon-like body shape

·        Members of the phylum Platyhelminthes exhibit bilateral symmetry, meaning their bodies can be divided into two identical halves along a central axis.

·        Platyhelminthes have three germ layers (ectoderm, mesoderm and endoderm) during their embryonic development, which gives rise to different tissue types in their body.

·        These organisms lack a true body cavity (coelom), and their tissues are directly in contact with each other.

·        Platyhelminthes have incomplete digestive system. They have a single opening that serves as both their mouth and anus. Thus food enters and waste exits through the same opening.

·        Protonephridia are excretory structures used for osmoregulation and waste elimination. They help to maintain the balance of water and solutes in the body.

·        Platyhelminthes do not have dedicated circulatory or respiratory systems for the transport of gases or nutrients throughout their bodies. Gas exchange occurs across body surfaces.

·        Nerve ladder arrangement with ganglia (nerve cell clusters) and longitudinal nerves.

·        Asexual (e.g., fission, regeneration) and sexual reproduction (hermaphroditic or cross-fertilization).

·        They exhibit muscular body movement. Some flatworms use cilia for locomotion.

·        They are found in aquatic environments such as freshwater and marine and terrestrial habitats.

·        Many species are parasitic in nature, adapting to life within other organisms.

 

Planarians

Tapeworms

Flukes

Turbellaria

 

Ciliated Larvae
 

Cestoda

 

Oncosphere

Trematoda

 

Miracidium
Trematoda Redia
Trematoda Cercaria
Trematoda Metacercaria
Turbellaria Muller’s Larva
Monogenea Furcocercous
Monogenea Oncomiracidium