Phylum Annelida

Flashcards covering key vocabulary and concepts related to Phylum Annelida.

Phylum Annelida

The biological classification that includes segmented worms.

Segmented body

A characteristic feature of annelids, where the body is divided into repeated units.

Metamerism

The division of an organism's body into segments that may contain repeated internal structures.

Serial homology

The concept referring to the evolutionary relationship between segmented body parts within the same organism.

Polychaeta

A class of annelids known as bristle worms, which typically have many setae (bristles) and are mainly marine.

Oligochaeta

A class of annelids including earthworms and freshwater worms, characterized by fewer setae.

Hirudinoidea

A subclass of annelids commonly known as leeches, usually characterized by a fixed number of segments and suckers.

Clitellum

A thickened, glandular section of the body in some annelids, involved in reproduction.

Proboscis

An evertable feeding structure found in some polychaetes used for capturing prey.

Hydrostatic skeleton

A skeletal system found in annelids that uses fluid pressure to maintain body shape and assist in movement.

Ectoparasitic

A term describing organisms, like some leeches, that live on the outside of a host and feed on its blood or bodily fluids.

Chaetae

Bristle-like structures found in segmented worms, used for locomotion and anchoring.

Dorsal vessel

A part of the circulatory system found in annelids that runs along the top side of the body and transports blood.

Nephridium

A tubular structure in annelids that functions in excretion and osmoregulation.

Cocoon

A protective case formed by the clitellum to encase fertilized eggs in some annelids.

Hermaphroditic

An organism that has both male and female reproductive organs, common in oligochaetes.

Trochophore larva

A free-swimming larval stage in the life cycle of some annelids, including polychaetes.