Annelids Flashcards

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Questions and Answers

What is the class of segmented worms containing earthworms?

Annelida

Hirudinea

Oligochaeta (correct)

Polychaeta

What are external bristles found on annelids that help to anchor the worm in the soil?

Setae

What are the fleshy appendages found in some marine worms called?

Parapodia

True or False: Annelids have an open circulatory system.

False Signup and view all the answers

What part of the earthworm's gut is thick and muscular, responsible for grinding the soil?

Gizzard Signup and view all the answers

What structure serves as a primitive brain in the earthworm?

Ganglia Signup and view all the answers

What structures eliminate wastes and excess water from the earthworm's body?

Nephridia Signup and view all the answers

What is the phylum of segmented worms?

Annelida Signup and view all the answers

What class of segmented worms contains marine worms?

Polychaeta Signup and view all the answers

What class of segmented worms contains leeches?

Hirudinea Signup and view all the answers

What segment of the earthworm body contains the reproductive organs?

Clitellum Signup and view all the answers

What structure covers the outside of the earthworm body and prevents excessive water loss?

Cuticle Signup and view all the answers

Name two structures found in the class Polychaeta that are not found in the class Oligochaeta.

Antennae and specialized mouth parts Signup and view all the answers

What structure found in earthworms is never found in leeches?

Setae Signup and view all the answers

Why must earthworms stay moist?

They exchange gases through the skin. Signup and view all the answers

How is sensory information transmitted from the ganglia in each segment to the brain in an annelid?

The nerve cord Signup and view all the answers

How is blood pumped through the earthworm body?

By a set of aortic arches Signup and view all the answers

What is the first segment of an earthworm that serves as a sort of upper lip?

Prostomium Signup and view all the answers

What does the term 'annelid' mean?

'little rings' Signup and view all the answers

What muscular structure found just behind the earthworm's mouth helps to suck in dirt and organic matter?

Pharynx Signup and view all the answers

What are the tubes through which sperm is transferred from one earthworm to another called?

Sperm ducts Signup and view all the answers

What type of muscles contract to make the earthworm long and skinny?

Circular muscles Signup and view all the answers

What type of muscles contract to make the earthworm shorter?

Longitudinal muscles Signup and view all the answers

List three benefits to earthworm activity.

<ol> <li>They fertilize the soil by taking in organic material for food and eliminating wastes. 2. Their burrows help to aerate the soil. 3. They loosen the soil, making it easier for roots to grow and for water to seep in.</li> </ol> Signup and view all the answers

What is the advantage of a segmented body?

It allows different parts of the body to move independently and some organ systems can be duplicated. Signup and view all the answers

What adaptations make leeches well suited for a parasitic life?

They have suckers that attach to the host and suck blood, secrete an anesthetic to prevent the host from feeling them, and a substance that keeps blood from clotting. Signup and view all the answers

How are segmented worms divided into their three classes?

Based on the number of setae and the presence or absence of parapodia. Signup and view all the answers

List the parts of the earthworm digestive system in order.

Mouth, pharynx, esophagus, crop, gizzard, intestine, anus. Signup and view all the answers

Study Notes

Annelids Overview

Annelids, also known as segmented worms, belong to the phylum Annelida.
They exhibit a segmented body structure, which allows for independent movement of body parts.

Classes of Annelids

Oligochaeta: Includes earthworms; characterized by minimal setae.
Polychaeta: Comprises marine worms; features setae and specialized structures like antennae and mouthparts.
Hirudinea: Contains leeches; lack setae and possess suckers for parasitism.

Key Structures and Functions

Setae: External bristles aiding in movement and anchoring in the soil.
Parapodia: Fleshy appendages for locomotion in polychaetes.
Ganglia: Serve as a primitive brain, located in each body segment.
Nephridia: Structures responsible for waste and excess water elimination.
Clitellum: Segment involved in reproduction.

Digestive System

Digestive path: Mouth → Pharynx → Esophagus → Crop (storage) → Gizzard (grinding) → Intestine → Anus.
Crop functions as a temporary storage area for soil and organic matter.

Circulatory Systems

Open circulatory system: Blood is not confined entirely within vessels.
Closed circulatory system: Blood is contained within a system of vessels.
Blood circulation is facilitated by a set of aortic arches.

Muscular Systems

Circular muscles: Contract to elongate the body.
Longitudinal muscles: Contract to shorten the body.

Sensory and Reproductive Systems

Sensory information is relayed from ganglia to the brain via a nerve cord.
Sperm ducts transport sperm between earthworms during reproduction.

Habitat and Adaptations

Earthworms require moist environments for gas exchange through their skin.
Leeches are adapted for parasitic life through suckers, anesthetics, and anticoagulants.

Ecology and Benefits

Earthworm activity enriches soil fertility, aerates soil, and enhances root growth conditions.
Segmented bodies allow for the redundancy of organ systems, increasing survival chances.

Terminology

Prostomium: The first body segment acting as an upper lip.
Cuticle: Protective outer layer preventing excessive water loss.

Distinguishing Characteristics

Number of setae and presence of parapodia are used to classify segmented worms into their respective classes.

Fun Fact

The term "annelid" translates to "little rings," referring to the segmented body structure.

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Description

Test your knowledge of segmented worms with these flashcards on Annelids. Learn about important terms like Oligochaeta, Setae, and Parapodia. This quiz is perfect for biology students studying invertebrates.