Word Roots

a- = without; -koilos = a hollow (acoelomate: the condition of lacking a coelom)

arch- = ancient, beginning (archenteron: the endodermlined cavity, formed during the gastrulation process, that develops into the digestive tract of an animal)

bi- = two (Bilateria: the branch of eumetazoans possessing bilateral symmetry)

blast- = bud, sprout; -pore = a passage (blastopore: the opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes)

cephal- = head (cephalization: an evolutionary trend toward the concentration of sensory equipment on the anterior end of the body)

deutero- = second (deuterostome: one of two lines of coelomates characterized by radial, indeterminate cleavage, enterocoelous formation of the coelom, and development of the anus from the blastopore)

di- = two (diploblastic: having two germ layers)

ecdys- = an escape (Ecdysozoa: one of two proposed clades within the protostomes; it includes the arthropods)

ecto- = outside; -derm = skin (ectoderm: the outermost of the three primary germ layers in animal embryos)

endo- = within (endoderm: the innermost of the three primary germ layers in animal embryos)

entero- = the intestine, gut (enterocoelous: the type of development found in deuterostomes; the coelomic cavities form when mesoderm buds from the wall of the archenteron and hollows out)

gastro- = stomach, belly (gastrulation: the formation of a gastrula from a blastula)

in- = into; -gest = carried (ingestion: a heterotrophic mode of nutrition in which other organisms or detritus are eaten whole or in pieces)

lopho- = a crest, tuft; -trocho = a wheel; (Lophotrochozoa: one of two proposed clades within the protostomes that includes annelids and mollusks)

meso- = middle (mesoderm: the middle primary germ layer of an early embryo)

meta- = boundary, turning point; -morph = form (metamorphosis: the resurgence of development in an animal larva that transforms it into a sexually mature adult)

para- = beside; -zoan = animal (parazoan: grade of body form lacking symmetry and tissues, describes the sponges)

proto- = first; -stoma = mouth (protostomes: a member of one of two distinct evolutionary lines of coelomates characterized by spiral, determinate cleavage, schizocoelous formation of the coelom, and development of the mouth from the blastopore)

pseudo- = false (pseudocoelom: a body cavity that is not completely lined by mesoderm)

radia- = a spoke, ray (Radiata: the radially symmetrical animal phyla, including cnidarians)

schizo- = split (schizocoelous: the type of development found in protostomes; initially, solid masses of mesoderm split to form coelomic cavities)

tri- = three (triploblastic: having three germ layers)

©2005 Pearson Education, Inc., publishing as Benjamin Cummings