Animals 1
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Created by:
kennethhartley on November 17, 2009
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25 terms
Terms | Definitions |
|---|---|
 Acoelmate | A solid-bodied animal lacking a cavity between the gut and outer body wall. |
| anus | a muscular opening at the end of the rectum |
| asymmetry | no symmetry |
| bilateral symmetry | arrangement of body parts so there are distinct left and right halves that mirror each other |
| blastula | hollow ball of cells |
| cephalization | concentration of sense organs and nerve cells at the front of an animal's body |
| closed circulatory system | a circulatory system in which the oxygen-carrying blood cells never leave the blood vessels |
| coelom | fluid-filled body cavity lined with mesoderm |
| deuterostome | animal whose anus is formed from the blastopore of a blastula |
| ectoderm | the outer germ layer that develops into skin and nervous tissue |
| endoderm | the inner germ layer that develops into the lining of the digestive and respiratory system |
| external fertilization | the process by which the female lays eggs and the male fertilizes them once they are outside of the female |
| gastrovascular cavity | An extensive pouch that serves as the site of extracellular digestion and a passageway to disperse materials throughout most of an animal's body |
| hermaphrodite | one having both male and female sexual characteristics and organs |
| hydrostatic skeleton | layers of circular and longitudinal muscles, together with the water in the gastrovascular cavity, that enable movement |
| internal fertilization | Process in which eggs are fertilized inside the female's body |
| invertebrates | Animals without backbones |
| medusa | a free-swimming cnidarian with a bell-shaped body and tentacles |
| mesoderm | the middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue |
| open circulatory system | A circulatory system that allows the blood to flow out of the blood vessels and into various body cavities so that the cells are in direct contact with the blood |
| polyp | the sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other |
| protostome | Animal whose mouth is formed from its blastopore |
| pseudocoelom | A body cavity that is not completely lined by tissue derived from mesoderm |
| radial symmetry | body plan in which body parts repeat around the center of the body |
| testes | The male gonads, which produce sperm and secrete male sex hormones. |
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