- alternating cleavage
see spiral cleavage.
Online Dictionary of Invertebrate Zoology. A.R. Maggenti and S.L. Gardne. 2005.
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Cleavage (embryo) — In embryology, cleavage is the division of cells in the early embryo. The zygotes of many species undergo rapid cell cycles with no significant growth, producing a cluster of cells the same size as the original zygote. The different cells derived … Wikipedia
nucleic acid — /nooh klee ik, klay , nyooh /, Biochem. any of a group of long, linear macromolecules, either DNA or various types of RNA, that carry genetic information directing all cellular functions: composed of linked nucleotides. [1890 95; NUCLE(US) + IC;… … Universalium
plant development — Introduction a multiphasic process in which two distinct forms succeed each other in alternating generations. One form, created by the union of sexual cells (gametes (gamete)), contains two sets of similar chromosomes (diploid). At sexual… … Universalium
Laser diode — Top: a packaged laser diode shown with a penny for scale. Bottom: the laser diode chip is removed from the above package and placed on the eye of a needle for scale … Wikipedia
syndrome — The aggregate of symptoms and signs associated with any morbid process, and constituting together the picture of the disease. SEE ALSO: disease. [G. s., a running together, tumultuous concourse; (in med.) a concurrence of symptoms, fr. syn,… … Medical dictionary
human embryology — ▪ biology Introduction the process encompassing the period from the formation of an embryo, through the development of a fetus, to birth. The human body, like that of most animals, develops from a single cell produced by the union of… … Universalium
animal — animalic /an euh mal ik/, animalian /an euh may lee euhn, mayl yeuhn/, adj. /an euh meuhl/, n. 1. any member of the kingdom Animalia, comprising multicellular organisms that have a well defined shape and usually limited growth, can move… … Universalium
annelid — /an l id/, n. 1. any segmented worm of the phylum Annelida, including the earthworms, leeches, and various marine forms. adj. 2. belonging or pertaining to the Annelida. Also, annelidan /euh nel i dn/. [1825 35; see ANNELIDA] * * * Any member of… … Universalium
France — /frans, frahns/; Fr. /frddahonns/, n. 1. Anatole /ann nann tawl /, (Jacques Anatole Thibault), 1844 1924, French novelist and essayist: Nobel prize 1921. 2. a republic in W Europe. 58,470,421; 212,736 sq. mi. (550,985 sq. km). Cap.: Paris. 3.… … Universalium
slate — slate1 /slayt/, n., v., slated, slating. n. 1. a fine grained rock formed by the metamorphosis of clay, shale, etc., that tends to split along parallel cleavage planes, usually at an angle to the planes of stratification. 2. a thin piece or plate … Universalium