Module 13 Flashcards
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 possesses radial symmetry if it can be cut into two identical halves by any longitudinal cut through its 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 that divides it into right and left halves
Anterior end
The end of an animal that contains its head
Posterior end
The end of an animal that contains its tail
Epidermis
An outer layer of cells designed to provide protection
Endodermis
An inner layer of cells
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