Vocabulary Vocabulary ReviewReview

Ch 33 – Sponges, Ch 33 – Sponges, Cnidarians, and Cnidarians, and

CtenophoresCtenophores

An aquatic invertebrate of the

phylum Porifera that attaches to stones or plants and that has a

porous structure and a tough, elastic skeleton

Sponge

Describes an organism that

remains attached to a surface for its

entire life and does not move

Sessile

Any of the flagellate cells that line the cavities of a

sponge

Choanocyte

One of the small openings in a sponge’s body through which water enters

Ostium

An opening in a sponge’s body through which

water exits

Osculum

A fibrous protein that contains

sulfur and composes the fibers of the

skeleton of some spongesSpongin

A needle of silica or calcium

carbonate in the skeleton of some

sponges

Spicule

In an aquatic animal, a method

of feeding in which the animal traps organic material that is floating in the surrounding

waterFilter feeding

Within the body wall of a sponge, a specialized cell that crawls about and delivers nutrients from the choanocytes to the rest of the body

cells

Amoebocyte

An asexual reproductive

structure produced by some

freshwater sponges

Gemmule

The regrowth of missing tissues or

organs

Regeneration

An organism that has both male and

female reproductive

organs

Hermaphrodite

A free-swimming, jellyfish-like and often

umbrella-shaped sexual stage in the life

cycle of a cnidarian; also a jellyfish or a

hydra

Medusa

A form of a cnidarian that has

a cylindrical, hollow body and that is usually

attached to a rock or to another

objectPolyp

The outer surface layer of cells of a plant or animal

Epidermis

In cnidarians, the layer of cells

surrounding the digestive tract

Gastrodermis

In cnidarians, the jellylike material located between the ectoderm and

the endoderm

Mesoglea

A cavity that serves both

digestive and circulatory

purposes in some cnidarians

Gastrovascular cavity

A flexible appendage with which an animal

feeds itself, grasps objects, or feels its

environmentTentacle

A stinging cell of a cnidarian

Cnidocyte

In cnidarians, a stinging cell that is used to inject a

toxin into prey

Nematocyst

In cnidarians, a network of nerve cells

that lacks a central control; impulses pass in any or all directions

to produce a generalized response

Nerve net

The free-swimming, ciliated larva of a

cnidarian

Planula

A limestone ridge found in tropical

climates and composed of coral fragments that are deposited around

organic remains

Coral reef

A cell that is found on the tentacles of a ctenophore and

that secretes a sticky substance

Colloblast

In ctenophores, a sensory structure that enables the

animal to sense its orientation in water;

in annelids, a ciliated plate located

at the back of the larvaApical organ

The production of light by means of

a chemical reaction in an

organism

Bioluminescence