Flatworms, Mollusks, and Annelids

Flashcards covering key vocabulary and concepts related to flatworms, mollusks, and annelids.

Complete digestive tract

A digestive tract with two openings, a mouth and an anus.

Radula

A file-like feeding organ found in mollusks.

Hemocoel

Spaces between cells within an animal's tissues where blood is pumped; part of the circulatory system in mollusks.

Segmentation

Repeated sections of an annelid's long body that contain a complex set of body structures.

Coelom

A fluid-filled space that is completely surrounded by muscle; found in annelids.

Planarians

Flatworms that are free-living and nonparasitic, possessing eyespots and a simple brain.

Pharynx

A muscular tube in planarians that extends from the mouth to collect food.

Flukes

Parasitic flatworms that feed on the body fluids of other animals.

Schistosomiasis

A disease caused by the fluke Schistosoma, affecting about 200 million people.

Tapeworms

Parasitic flatworms that live in vertebrate guts and absorb nutrients from digested food.

Mantle

The area of tissue covering the internal organs of a mollusk.

Ctenidia

Flat gills found in a pocket of the mantle tissue in mollusks.

Gastropoda

Class of mollusks including snails, nudibranchs, abalones, and limpets.

Pelecypoda (Bivalves)

Class of mollusks including clams, oysters, mussels, and scallops, characterized by having two hinged shells.

Cephalopoda

Class of mollusks including squid, octopuses, nautiluses, and cuttlefish, known for their well-developed nervous systems.

Hermaphrodite

An organism that has both male and female reproductive organs.

Castings

The digested material that earthworms excrete into the soil.