Terms : Hide Images
| 16619539 | invertebrate | animal that does not have a backbone | |
| 16619540 | radial symmetry | body plan in which body parts repeat around the center of the body | |
| 16619541 | bilateral symmetry | body plan in which only a single, imaginary line can divide the body into 2 equal halves | |
| 16619542 | cephalization | concentration of sense organs & nerve cells at the front of an animal's body | |
| 16619543 | spicule | spike-shaped structure that makes up the skeletons of harder sponges | |
| 16619544 | larva | immature stage of an organism that looks different from the adult form | |
| 16619545 | gemmule | group of archaeocytes surrounded by a tough layer of spicules; produced by some sponges | |
| 16619546 | polyp | sessile stage of the life cycle of a cnidarian; cylindrical body with armlike tentacles | |
| 16619547 | medusa | mobile stage of the life cycle of a cnidarian, has a bell-shaped body | |
| 16619548 | hydrostatic skeleton | layers of circular & longitudinal muscles, together with the water in the gastrovascular cavity, that enable movement | |
| 16619549 | coelom | fluid-filled body cavity lined with mesoderm | |
| 16619550 | hermaphrodite | individual that has both male & female reproductive organs | |
| 16619551 | septum | internal wall between the segments of an annelid's body | |
| 16619552 | seta | bristle attached to the segments of many annelids | |
| 16619553 | crop | part of the digestive system in which food can be stored | |
| 16619554 | gizzard | part of the digestive system in which food is ground into smaller pieces | |
| 16619555 | mantle | thin layer of tissue that covers most of a mollusk's body | |
| 16619556 | shell | structure in mollusks made by glands in the mantle that secrete calcium carbonate | |
| 16619557 | radula | tongue-shaped structure used for feeding by snails & slugs | |
| 16619558 | siphon | tubelike structure through which water enters & leaves a mollusk's body | |
| 16619559 | exoskeleton | external skeleton; tough external covering that protects & supports the body of many invertebrates | |
| 16619560 | chitin | complex carbohydrate found in the exoskeletons of arthropods | |
| 16619561 | appendage | structure, such as a leg or antenna, extending from the body wall | |
| 16619562 | spiracle | small opening located along the side of the body through which air enters & leaves | |
| 16619563 | book lung | organ with layers of respiratory tissue for exchange of gases | |
| 16619564 | molting | process of shedding an exoskeleton & manufacturing a larger one to take its place | |
| 16619565 | incomplete metamorphosis | type of insect development; all stages of life cycle look similar | |
| 16619566 | complete metamorphosis | type of insect deveropment; larvae look & act completely different from parents | |
| 16619567 | nymph | immature form that lacks functional sex organs & other adult structures | |
| 16619568 | pupa | stage of metamorphosis in which an insect changes from larva to adult | |
| 16619569 | society | group of closely related animals of the same species that work together for the benefit of the group | |
| 16619570 | caste | group of individual insects specialized to perform particular tasks, or roles | |
| 16619571 | pheromone | specific chemical messenger; affects behavior or development of other individuals of same species | |
| 16619572 | endoskeleton | structural support located inside the body of an organism | |
| 16619573 | tube foot | suction-cuplike structure attached attached to radial canals of echinoderms, used to walk & to open shells |
