Characteristics of Animals
the type of animal that lacks a backbone
What are invertebrates?
The outer layer of cells in a sponge.
What is epidermis
What is a medusa?
A system of sensitive cells that respond to stimuli.
What is a nervous system?
An organism with a single shell.
What is a univalve?
An organism that can be cut into two identical halves by any cut that runs through the organism's center
What is spherical symmetry?
The inner layer of cells in a sponge.
What is endodermis?
Small capsules that contain a toxin that is injected into prey or predators.
What are nematocysts?
Masses of nerve cell bodies.
What are ganglia?
A sheath of tissue that encloses the vital organs of a mollusk.
What is the mantle?
The end of an animal that contains its head.
What is the anterior end?
Flagellated cells that push water through a sponge.
What are the collar cells?
The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other.
What is a polyp?
Segmented worms used for medicinal purposes.
What are leeches?
A muscular organ that is used for locomotion.
What is a foot?
An organism possesses this if it can be cut into two identical halves by a single longitudinal cut alongs its center that divides it into left and right halves.
What is bilateral symmetry?
The jellylike substance that separates the epidermis from the inner cells in a sponge.
What is the mesenchyme?
The jellylike substance that separates the epithelial cells in a cnidarian.
What is the mesoglea?
A system in which blood stays in vessels.
What is a closed circulatory system?
A hump that contains a mollusk's heart, digestive, and excretory organs.
What is the visceral hump?
An organism possesses this if it can be cut into two identical halves by any longitudinal cut through its center
What is radial symmetry?
Cells that move using pseudopods and perform different functions in different animals.
What are amoebocytes?
Animal tissue consisting of one or more layers of cells that have only one free surface.
What is the epithelium?
Animals that possess both the male and female reproductive organs.
What are hermaphrodites?
An organ covered with teeth that mollusks use to scrape food into their mouths.
What is a radula?