Data

Copy and paste the text below. It is read-only. Select All

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.