Biology Chapter 26
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39 terms
Terms | Definitions |
|---|---|
 invertibrate | animals with no backbone or vertebral column |
| vertibrate | animals with backbones |
| feedback inhibition | the product or result of a process stops or limits the process |
| blastula | a hollow ball of cells |
| protostome | an animal whose mouth is formed from a blastopore |
| deuterostome | an animal whose anus is formed from a blasopore |
| anus | the opening through which wastes leave the digestive tract |
| endoderm | the innermost germ layer. developes into the lining of the digestive tract and the respiratory system |
| mesoderm | middle germ layer. developes into muscles and much of the circulatory, reproductive and excretory organ systems |
| ectoderm | outermost germ layer. develops into sense organs, nerves, and the outer layer of skin |
| radial symmetry | animals with body parts that repeat around the center of the body |
| bilateral symmetry | only a single imaginary plane can divide the body into two equal halves |
| cephalization | the concentration of sense organs and nerve cells at the front end of the body |
| asymmetry | animals that do not show symmetry |
| characteristics | movement, feeding, respiration, response, excretion, reproduction, circulation |
| choanocyte | specialized cells that use flagella to move a steady current of water through sponges |
| osculum | a large hole at the top of a sponge that water leaves from |
| spicule | a spike shaped structure made of chalklike calcium carbonate or glasslike silica |
| archaeocyte | specialized cells that move around within the walls of a sponge |
| internal fertilization | eggs fertilized in the organism's body |
| gemmule | groups of archaeocytes surrounded by a layer of spicules |
| cnidocyte | stinging cells located along cnidarian's tentacles |
| nematocyst | a poison filled, stinging structure that contains a tightly coiled dart |
| polyp | a cylindrical body with armlike tentacles. the mouth points upward. usually sessile |
| medusa | a motile, bell shaped body with the mouth on the bottom |
| gastrovascular cavity | a digestive chamber with one opening |
| nerve net | a loosely organized network of nerve cells that together allow cnidarians to detect stimuli. usually distributed uniformly |
| hydrostatic skeleton | a layer of circular muscles and a layer of longitudinal musles that, with water in the gastrovascular cavity, enable the cnidarian to move |
| external fertilization | takes place outside the female's body |
| epithelial | covers surface. thin, flat. gas movement |
| connective | bones, blood. connects tissues |
| physiology | the study of function |
| blastopore | becomes digestive tract |
| porifera | simplest, most unusual phylum. most ancient (540 mil yrs), sessile. no mouth, gut, tissue, or organs |
| statocysts | groups of sensory cells that help determine direciton of gravity |
| ocelli | eyespots made of sun-detecting cells |
| seyphozoa | class of jellyfish. mainly medusas |
| hydrozoa | class of hydras. polyps grow in colonies. no medusas |
| anthozoa | flower plants. class of anemones and corals. only polyp, many colonial |
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