17 Questions
Which characteristic is true about the Class Turbellaria within Phylum Platyhelminthes?
They have a well-developed digestive system
What is a notable feature of the reproduction in Phylum Platyhelminthes?
Many species are simultaneous hermaphrodites
Which statement is correct regarding the regeneration ability of Phylum Platyhelminthes?
Regeneration is limited to external structures only
What is true about the digestive and excretory systems of Phylum Platyhelminthes?
They possess a simple digestive system
Which statement accurately describes the nervous system of Parasitic species in Phylum Platyhelminthes?
Their nervous system is decentralized
What type of organisms are flukes and tapeworms in terms of reproduction?
Simultaneous hermaphrodites
What is the characteristic feature of the head/scolex region of tapeworms?
Organs of attachment
Which part of the tapeworm body is responsible for segment proliferation?
Neck region
What is the main reproductive characteristic of tapeworms?
Unisexual with multiple ovaries and testes
Which larval form is found in cows and pigs as a stage in the life cycle of tapeworms?
Cysticercus larva
Which organ do flukes (Class Trematoda) possess that tapeworms lack?
Branched intestine for digestion
What is a unique feature of the nervous system in tapeworms?
Absence of a centralized brain
Where is the mouth usually located in Class Turbellaria flatworms?
Mid-body on ventral surface
What is the excretory system of Phylum Platyhelminthes characterized by?
Flame bulbs (flame cells)
Which feature is characteristic of the nervous system in most Turbellarian flatworms?
Centralized ganglia (brain)
How do flatworms in Phylum Platyhelminthes primarily reproduce?
Reciprocal exchange of sperm
What is a notable ability exhibited by many species in relation to regeneration?
Ability to regrow lost body parts and repair wounds
Study Notes
Phylum Platyhelminthes: Characteristics
- Acoelomates, lacking a body cavity, resulting in a flat body structure
- Exhibit bilateral symmetry and are triploblastic
- Possess parenchyma tissue
- Have a centralized nervous system and a complex reproductive system
- Lack a body cavity and circulatory system, but have a simple excretory system
Reproduction
- Most species are simultaneous hermaphrodites
- Parasitic species have complex lifecycles with various hosts and larval stages
- Possess incredible powers of regeneration
Nervous System
- Free-living species have a well-developed sensory system
- Parasites have less elaborate systems
Class Turbellaria
- Most are free-living, tiny, and inconspicuous
- Primarily found in marine, freshwater, or moist terrestrial environments
- Examples include Dugesia (Planaria)
Digestion and Excretion
- Mouth is usually located at the anterior end or mid-body on the ventral surface
- Excretory system contains flame bulbs known as flame cells
Regeneration
- Many species possess remarkable powers of regeneration and repair wounds
Turbellarian Lifestyles
- Most are benthic
- Possess several nerve cords with a centralized ganglia (brain)
Class Cestoda (Tapeworms)
- Flattened, elongated, and consist of segments called proglottids
- Body divided into three parts: head/scolex with organs of attachment, neck region, and a chain of proglottids called the strobila
- All parasitic, without a gut, and hermaphroditic
- Examples include Taenia saginatta (beef tapeworm) and Taenia solium (pork tapeworm)
Proglottids
- Each tapeworm can have 3,000-4,000 proglottids
- Proglottids contain several ovaries and 1,000 distinct testes
- Immature proglottids are close to the neck, and matured proglottids are towards the end of the body
Life Cycle of Tapeworms
- Generalized life cycle involves multiple hosts and larval stages
- Examples of tapeworms include Hymenolepsis nana, H. diminuta, Taenia saginata, T. solium, Diphyllobothrium latum, and Dipylidium caninum
Class Trematoda (Flukes)
- All are external and internal parasites of other animals
- Have oral and ventral suckers positioned at different parts of the body with other organs of attachment
- Have a gut with a branched intestine and a well-developed reproductive system, but are never segmented
This quiz covers the classification, characteristics, and body plans of Phylum Platyhelminthes, focusing on their flatworm body structure, bilateral symmetry, acoelomate nature, and triploblastic composition. Test your knowledge on this phylum!
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