Invertebrate and Chordate Anatomy and Classification

Vocabulary flashcards covering the anatomical structures, life stages, and physiological functions of Porifera, Cnidaria, Lophotrochozoa, Ecdysozoa, Echinodermata, and Chordata.

Spicule (Phylum Porifera)

Intermeshing structures used for body support; unique to each species and used to identify species.

Pore

Opening that allows water flow through the body in sponges.

Cnidocyst

Specialized cells found in Phylum Cnideria.

Nematocyst

Organelles within cnidocysts that sting other organisms for food or defense.

Polyp

Sessile body form in Phylum Cnideria.

Medusa

Free-floating body form in Phylum Cnideria.

Gastrovascular Cavity

Internal chamber used for food indigestion and waste disposal.

Eyespots

Light-sensitive cells found in flatworms.

Acoelomate

An organism that lacks a body cavity (coelom).

Scolex

Structure used by parasitic flatworms to attach to a host for nutrition.

Proglottid

Reproductive structures containing both male and female organs in flatworms.

Parapodia

Foot-like appendages used for movement in Phylum Annelida.

Seta

Hair-like structures used for movement in Phylum Annelida.

Clitellum

Structure in Phylum Annelida that holds sperm and eggs in a cocoon made from skin.

Crop

Organ in Phylum Annelida that briefly holds food.

Gizzard

Organ in Phylum Annelida that grinds food.

Seminal receptacle

Organ in Phylum Annelida that receives sperm.

Seminal vesicle

Organ in Phylum Annelida that produces sperm.

Pharynx (Phylum Annelida)

Structure that extends out of the mouth for food consumption.

Ganglia

Simple brain in Phylum Annelida.

Dorsal blood vessel

Circulatory structure in Phylum Annelida that pumps blood toward the head.

Muscular Foot

Structure in Class Gastropoda that creates contraction waves for movement.

Radula

Feeding structure found in Class Gastropoda.

Glochidium

Larval stage in Class Bivalvia.

Siphon (Class Cephalopoda)

Organ located in the mantle used for jet propulsion.

Chromatophore

Structure located in the skin of cephalopods used for iridescence.

Ink sac

Organ in Class Cephalopoda used to evade predators.

Pen

Internal shell found in squid.

Cecum

Organ in Class Cephalopoda responsible for digestion and absorption of nutrients.

Nidamental glands

Glands in Class Cephalopoda that package eggs.

Pseudocoelom

Body cavity surrounded by one layer of mesoderm, characteristic of Phylum Nematoda.

Pharynx (Phylum Nematoda)

Structure that connects the mouth to the intestine.

Oviducts (Phylum Nematoda)

Structures that connect the ovary to the uterus.

Spicule (Phylum Nematoda)

Structure that clasps the female and injects sperm into her reproductive tract.

Chelicerae

Jointed appendages used for piercing and capturing prey in Subphylum Chelicerata.

Spinnerets

Silk-producing organ found in Subphylum Chelicerata.

Book gills

External breathing structure found in Subphylum Chelicerata.

Book lungs

Internal breathing structure found in Subphylum Chelicerata.

Pedipalps

Jointed appendages used for sensing the environment in Subphylum Chelicerata.

Carapace

Structure that protects the body in Subphylum Crustacea.

Mandibles

Mouthparts used to bite and chew food in Subphylum Crustacea.

Chela

Appendage used to capture and immobilize prey in Subphylum Crustacea.

Cirri (Subphylum Crustacea)

Structures that filter food particles from water to the mouth.

Cheliped

Thoracic leg used for defense and feeding in crustaceans.

Female swimmerets

Abdominal appendages that hold eggs in crustaceans.

Male swimmerets

Abdominal appendages used for sperm transportation in crustaceans.

Gastric mill

Section of the stomach used for grinding food in crustaceans.

Digestive gland

Organ in crustaceans that absorbs nutrients and stores food.

Pupae

Immature developmental stage present only in complete metamorphosis.

Test

Hard, calcaneus plates found in Phylum Echinodermata.

Tube feet

Fluid-filled appendages used for locomotion in Phylum Echinodermata.

Madreporite

Intake valve located on the dorsal side of echinoderms.

Pedicellaria

Small, claw-like appendages used for cleaning and defense in Phylum Echinodermata.

Water vascular system

System that controls the extension and contraction of tube feet in echinoderms.

Pharyngeal slits

Structures in Subphylum Cephalochordata that aid gas exchange.

Dorsal hollow nerve cord

Structure that forms part of the central nervous system in Subphylum Cephalochordata.

Notochord

Flexible rod that supports the body in chordates.

Cirri (Subphylum Cephalochordata)

Structures that trap materials for feeding in lancelets.

Pharyngeal basket

A form of pharyngeal slit found in Subphylum Urochordata.

Gut loop

Site where food particles are digested in Subphylum Urochordata.

Operculum

Hard bony flap protecting gills in Subphylum Vertebrata.

Swim bladder

Gas-filled internal organ used for buoyancy, respiration, sound production and hearing, and stability in bony fish.

Spleen

Blood-filtering organ in Subphylum Vertebrata.

Pyloric caecum

Structure located in the digestive tract that maximizes internal surface area of the gut.