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Questions and Answers
What are the two classes within Phylum Annelida?
What are the two classes within Phylum Annelida?
What is the main characteristic of Class Errantia?
What is the main characteristic of Class Errantia?
Marine with parapodia and setae.
Which class includes Oligochaeta?
Which class includes Oligochaeta?
Class Sedentaria.
Group Hirudinea has retained the septa, parapodia, and setae.
Group Hirudinea has retained the septa, parapodia, and setae.
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What type of reproduction does Earth Worm Reproduction primarily exhibit?
What type of reproduction does Earth Worm Reproduction primarily exhibit?
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What is the function of Chlorogogon cells?
What is the function of Chlorogogon cells?
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What disease is associated with Tubifex worms?
What disease is associated with Tubifex worms?
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What is a characteristic of the nervous system in Annelida?
What is a characteristic of the nervous system in Annelida?
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Annelida has a ____ larval stage called Trochophore.
Annelida has a ____ larval stage called Trochophore.
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The Phylum Sipuncula is entirely freshwater.
The Phylum Sipuncula is entirely freshwater.
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Study Notes
Phylum Annelida
- Composed of two main classes: Errantia and Sedentaria.
- Characterized by segmented body plan with septae compartmentalizing the coelom.
- Features a hydrostatic skeleton and a complete digestive tract.
- Possesses an integrated nervous system.
Class Errantia
- Marine creatures known for parapodia and setae adaptations.
- Predatory lifestyle; utilizes epitoke for reproduction.
- Contains clade Siboglinidae, which have modified oblique muscles.
Class Sedentaria
- Primarily inhabit tubes or burrow into substrates.
- Includes Oligochaeta, divided into epigeic, endogenic, and anecic groups.
- Houses the Hirudinea group, known for their specific adaptations.
Group Hirudinea
- Exhibit reduced body features: lost septa, parapodia, and setae.
- Possess diagonal muscle structures for movement.
- Complete mouth-to-anus digestive system with diverticula for blood storage.
- Reproduce sexually via temporary clitellum; can be used medicinally.
Clade Siboglinidae
- Commonly referred to as "beard worms."
- Lack a digestive system and segmentation; live in deep sea environments.
Earth Worm Reproduction
- Found in Class Sedentaria, hermaphroditic and cross-fertilizing.
- Mating occurs above ground; no larval stage present.
- Clitellum connects the reproductive ducts of mating partners.
- Capable of asexual reproduction through fragmentation.
Class Sedentaria: Feeding and Digestion
- Features a complete digestive tract with distinct regions: muscular pharynx, crop (food sorting), gizzard (mechanical grinding), and intestine.
- Chlorogogon cells in the intestine are involved in nitrogenous waste removal.
Chlorogogon Cells
- Specialized cells lining the intestine, detach to expel nitrogenous wastes efficiently.
Tubifex
- A type of oligochaete found in sedimentary environments.
- Exhibits positive thigmotaxis, seeking contact with surfaces.
- Acts as an intermediate host for the whirling disease.
Whirling Disease
- Parasitic condition caused by protozoan-like parasites affecting trout.
- Tubifex worms ingest spores that mature and invade trout brains, impairing swimming ability and causing circular swimming patterns.
Annelida: Nervous System
- Centralized ventral nerve cord with a main central ganglia and additional segmental ganglia.
- Errantia exhibits greater variability in nerve structure compared to Sedentaria.
Annelida: Basic Body Plan
- Body covered by a protective cuticle secreted by specialized cells.
- Underlying simple columnar epithelium with distinct setae controlled by muscles.
- Each segment contains two pairs of excretory systems, tyclosomes enhance intestinal surface area.
Annelida: Reproductive System
- Features trochophore larvae, a feeding larval stage.
- Most polychaetes from Errantia are dioecious.
Annelida: Excretory System
- Utilizes an open funnel system for nephridia, drawing coelomic fluid by ciliary action.
- Gonad development is hormonally regulated.
Phylum Sipuncula
- Often considered along with Annelida; includes peanut worms.
- Characterized by a bilateral, unsegmented body with an introverted tentacle.
- Generally marine, lacks significant circulatory or respiratory systems.
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Description
Test your knowledge of Phylum Annelida with these flashcards. Explore the characteristics of the two main classes: Errantia and Sedentaria. Understand their anatomy, reproduction, and ecological roles in marine and terrestrial environments.
