Term | Definition |
Invertebrates | Animals that lack a backbone |
Vertebrates | Animals that possess a backbone |
Spherical symmetry | An organism possesses spherical symmetry if it can be cut into two identical halves by any cut that runs through the organism's center |
Radial symmetry | An organism posses radial symmetry if it can by cut into two identical halves by any longitudinal cut through the center |
Bilateral symmetry | An organism possesses bilateral symmetry if it can only be cut into two identical halves by a single longitudinal cut along its center which divides it into right and left halves |
Epidermis | An outer layer of cells designed to provide protection |
Mesenchyme | The jellylike substance that separates the epidermis from the inner cells in a sponge |
Collar cells | Flagellated cells that push water through a sponge |
Amoebocytes | Cells that move using pseudopods and perform different functions in different animals |
Gemmule | A cluster of cells encased in a hard, spicule-reinforced shell |
Polyp | The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other |
Medusa | A free-swimming cnidarian with a bell-shaped body and tentacles |
Epithelium | Animal tissue consisting of one or more layers of cells that have only one free surface, because the other surface adheres to a membrane or other substance |
Mesoglea | The jellylike substance that separates the epithelial cells in a cnidarian |
Nematocysts | Small capsules that contain a toxin which is injected into prey or predators |
Testes | Organs that produce sperm |
Ovaries | Organs that produce eggs |
Anterior end | The end of an animal that contains its head |
Posterior end | The end of an animal that contains its tail |
Circulatory system | A system designed to transport food and other necessary substances throughout a creature's body |
Nervous system | A system of sensitive cells that respond to stimuli such as sound, touch , and taste |
Ganglia | |
Hermaphroditic | |
Regeneration | |
Mantle | |
Shell | |
Visceral hump | |
Foot | |
Radula | |
Univalve | |
Bivalve | |