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Invertebrates
Exploring Creation with Biology - Module 11 (Invertebrates) Definitions
Question | Answer |
---|---|
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 which divides it into right and left halves. |
Epidermis | An outer layer of cells designed to provide protection |
Mesenchyme | The jelly-like substance that separates the epidermis from the inner cells in a sponge |
Collar cells | Flagellated cells that pump water into a sponge |
Amebocytes | Cells in a sponge that perform digestion and transport functions |
Gemmule | A cluster of cells encased in a hard, spicule-reinforced shell |
Polyp | A sessile, tubular 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 jelly-like substance that separates the epithelial cells in a cnidarian |
Nematocysts | Small capsules that contain a toxin which is injected into prey or predators |
Testes | The organ that produces sperm |
Ovaries | The organ that produces 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 | Masses of nerve cell bodies |
Hermaphroditic | Possessing both the male and the female reproductive organs |
Regeneration | The ability to re-grow a missing part of the body |
Mantle | A sheath of tissue that encloses the vital organs of a mollusk, makes the mollusk's shell, and performs respiration |
Shell | A tough, multilayered structure secreted by the mantle. It is usually used for protection, but sometimes for body support |
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 |