Intro to animals, proiferia, and cnidarians

Cephalization

Concentration of sense organs and nerve cells at the anterior end of an animal

Dorsal

The upper side or back of an animal with bilateral symmetry

Ventral

The lower or abdominal side of an animal with bilateral symmetry

Anterior

The head end of an animal with bilateral symmetry

Posterior

The tail end of an animal with bilateral symmetry

Asymmetry

Lacking symmetry

Radial symmetry

Body parts are arranged around a central axis

Bilateral symmetry

Body can be divided into two equal halves

Sessile

Living permanently attached to a surface; not free-moving

Collar cells (choanocytes)

Flagellated cells lining the interior of sponges; create water currents

Amoebocyte

Mobile cells in sponges that transport food and wastes

Osculum

Large opening at the top of a sponge through which water exits

Spongin

Flexible protein that makes up the skeleton of some sponges

Spicules

Small, needle-shaped structures made of calcium carbonate or silica that form the skeleton of some sponges

Filter feeding

Method of feeding in sponges; water is filtered to obtain nutrients

Gemmules

Asexual reproductive structure produced by some freshwater sponges

Hermaphrodites

Organisms that possess both male and female reproductive organs

Budding

Asexual reproduction in which a new organism develops from an outgrowth or bud on another one

Regeneration

Regrowth of missing body parts

Polyp

Cylindrical body form of cnidarians

Medusa

Bell-shaped body form of cnidarians

Epidermis

Outer layer of tissue in cnidarians

Ectoderm

Outer germ layer in cnidarians; develops into skin and nervous tissues

Mesoglea

Jelly-like substance between the epidermis and gastrodermis in cnidarians

Endoderm

Inner germ layer in cnidarians; lines the gastrovascular cavity

Tentacles

Flexible extensions that surround the mouth of cnidarians

Cnidocyte

Stinging cell that contains a nematocyst

Gastrovascular cavity

Digestive chamber with a single opening, found in cnidarians