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
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 that is injected into prey or predators
Testes
Organs that produce sperm
Ovaries
Organs that produce eggs
Closed circulatory system
A system in which blood stays in vessels 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
Masses of nerve cell bodies
Hermaphroditic
Possessing both the male and the female reproductive organs
Regeneration
The ability to regrow a missing part of the body
Open circulatory system
A system in which blood is pumped through vessels into various chambers or body cavities where it comes in direct contact with cells, tissues, and organs
Mantle
A sheath of tissue that encloses the vital organs of a mollusk, makes the mollusk’s shell, and functions in respiration, waste disposal, and sensory perception
Visceral hump
A hump that contains a mollusk’s heart, digestive, and excretory organs
Foot
A muscular organ that is used for locomotion and takes a variety of forms depending on the animal
Radula
An organ covered with teeth that mollusks use to scrape food into their mouths
Univalve
An organism with a single shell
Bivalve
An organism with two shells
