Oligochaeta: Annelida Class Overview

Questions and Answers

What phylum and class do subclass oligochaete belong to?

Phylum Chordata and Class Mammalia

Phylum Annelida and Class Clitellata (correct)

Phylum Mollusca and Class Bivalvia

Phylum Arthropoda and Class Insecta

What type of feeders are oligochaetes?

Carnivores

Filter feeders

Direct deposit feeders and detritivores (correct)

Herbivores

What are calciferous glands?

They regulate pH and remove excess calcium from food.

How many pairs of setae do oligochaetes have?

A pair. Signup and view all the answers

What is different about longitudinal muscles in oligochaetes?

They are no longer arranged in blocks. Signup and view all the answers

Describe the locomotion of oligochaetes.

They use burrowing, giant axon coordination, and alternating contractions of longitudinal and circular muscles to create a peristaltic wave. Signup and view all the answers

What happens when the circular muscles contract?

The segment is squeezed, narrowing the diameter, and setae are pulled in. Signup and view all the answers

What happens when the longitudinal muscles contract?

The segment becomes wider and the setae are pushed outward. Signup and view all the answers

What is hemoglobin in oligochaetes composed of?

Protoporphyrin + iron + globin. Signup and view all the answers

What is the function of their pseudo heart?

To allow blood flow to the anterior part of the body. Signup and view all the answers

Why can't oligochaetes stay in the sun for too long?

They are burrowers needing to respire through their skin; UV interacts with hemoglobin, causing paralysis. Signup and view all the answers

What is a Clitellum?

It secretes mucus for copulation and also secretes the cocoon. Signup and view all the answers

What does Albumin do?

Surrounds eggs and allows for terrestrial adaptations. Signup and view all the answers

What are seminal receptors?

External openings for sperm storage of another worm. Signup and view all the answers

What do seminal grooves do?

Run clitellum surface to male pore. Signup and view all the answers

What do seminal vessels store?

Sperm. Signup and view all the answers

Describe the process of fertilization in oligochaetes.

<ol> <li>The clitellum secretes mucus sheath for moisture. 2. Male gametes transfer along seminal grooves to another worm's vesicles. 3. Worms move apart; mucus is removed.</li> </ol> Signup and view all the answers

What is external fertilization?

Eggs of cocoon + albumin + yolk provide nutrients to the developing embryo; no free larval stage. Signup and view all the answers

Study Notes

Phylum and Class

Oligochaeta belongs to Phylum Annelida and Class Clitellata.

Feeding Habits

Oligochaetes are direct deposit feeders and detritivores, contributing to soil fertility.

Calciferous Glands

These glands regulate pH levels and help remove excess calcium from ingested food.

Setae

Oligochaetes possess one pair of setae per segment, aiding in movement and traction.

Muscle Arrangement

Longitudinal muscles differ from other annelids as they are not arranged in block-like structures.

Locomotion

Movement involves burrowing and a giant axon, which coordinates muscle contractions, creating peristaltic waves for progress.

Circular Muscle Contraction

When circular muscles contract, segments narrow, and setae are retracted to aid in burrowing.

Longitudinal Muscle Contraction

Contraction of longitudinal muscles causes segments to widen, extending setae outward for stabilization.

Hemoglobin Composition

Hemoglobin consists of protoporphyrin, iron, and globin, essential for oxygen transport.

Pseudo Heart Function

A pseudo heart enables blood circulation to the anterior part of the body, facilitating nutrient and gas exchange.

Sun Exposure

Oligochaetes must limit sun exposure; prolonged UV exposure can interfere with hemoglobin, causing paralysis.

Clitellum

The clitellum secretes mucus for copulation and forms a protective cocoon for eggs.

Albumin

Surrounds eggs in the cocoon, providing nutrients and supporting terrestrial adaptations.

Seminal Receptors

These structures serve as openings for storing sperm from other worms during mating.

Seminal Grooves

Seminal grooves run along the clitellum surface to the male pore, guiding the movement of sperm.

Seminal Vessels

Seminal vessels store sperm, playing a critical role in reproduction.

Fertilization Process

Involves mucous sheath formation by the clitellum to protect gametes, transfer of male gametes between worms via seminal grooves, and subsequent separation of worms.

External Fertilization

The cocoon contains eggs, albumin, and yolk, providing nutrients to developing embryos; no free larval stage occurs, and the cocoon is sealed for overwintering, protecting embryos.

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Description

This quiz explores the characteristics of Oligochaeta, a class within the Phylum Annelida. Learn about their feeding habits, muscle arrangements, and unique locomotion techniques. Test your knowledge on how these organisms contribute to soil fertility and their biological adaptations.