Questions and Answers
Phylum Annelida falls under which of the following classifications?
What are Phylum Annelida commonly known as?
Segmented worms
List the three classes included in Phylum Annelida.
Polychaeta, Oligochaeta, Hirudinea
Phylum Annelida has no respiratory system; gas exchange occurs through the _____
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Which of the following is a characteristic of Phylum Annelida?
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What type of body symmetry do organisms in Phylum Annelida possess?
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Oligochaetes are a class within Phylum Annelida.
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What characteristic feature aids in movement for segmented worms in Phylum Annelida?
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What is the name of the structure at the anterior tip of an annelid?
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Define segmentation in the context of Phylum Annelida.
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What is the terminal portion bearing the anus of an annelid called?
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Study Notes
Phylum Annelida Overview
- Comprises segmented worms.
- Classified as eucoelomate, bilateral, and protostome organisms.
- Exhibits a true coelom and is triploblastic, having three tissue layers.
Classification of Annelids
- Three primary classes exist within Phylum Annelida:
- Polychaeta: Known as bristle worms, including marine species.
- Oligochaeta: Comprised of earthworms and related species.
- Hirudinea: Includes leeches, with a specialized reproductive structure called clitellum.
Characteristics of Annelida
- Respiratory System: Lacks dedicated system; gas exchange occurs through the skin.
- Digestive System: Functions through phagocytosis, featuring a complete digestive tract with a mouth and anus.
- Circulatory System: Exhibits a closed circulatory system.
- Nervous System: Contains a ventral solid nerve cord linking segmental ganglia and the brain.
- Movement: Utilizes hydrostatic skeleton and bristles (setae) for locomotion.
- Development: Features trochophore larva during early stages.
Importance of Segmentation
- Segmentation allows for the repetition of body parts, promoting specialization.
- Segments, called metameres or somites, can move independently.
- Annelids, arthropods, and chordates are noted for their segmented structures.
Anatomy of Annelids
- Anterior Segments: House specialized sensory organs, including the prostomium and peristomium.
- Terminal Portion: Known as pygidium, which bears the anus.
- Coelomate Structure: Supports complex organ development and larger body sizes due to fluid repositioning.
Natural Habitat
- Most annelids are marine; some are freshwater or terrestrial, showcasing ecological versatility.
Class-Specific Information
- Polychaeta Examples: Includes nautical species like Nereis (clam worm) and Aphrodite (sea mouse).
- Oligochaeta Features: Known for the presence of setae and unique reproductive structures.
- Hirudinea Traits: Characterized by a lack of setae and a more flattened body structure.
Evolutionary Notes
- Segmentation has evolved independently across different phyla, indicating a versatile adaptation strategy.
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Description
Test your knowledge on Phylum Annelida with these flashcards. Explore the characteristics, classes, and classification of segmented worms. Perfect for biology students and enthusiasts looking to reinforce their understanding of this fascinating group of organisms.
