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Topic: Radial cleavage

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Oocyte

Deuterostomia

Radiata

Embryo

Blastula

Annelid

Animal

Nematoda

Arthropod

Protostomia

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	[No title] (Site not responding. Last check: 2007-10-14)
		Spiral cleavage is in which planes of cell division are diagonal to the
		Radial cleavage is in which planes of cell division are either
		Hydras and their relatives are the only group that have radial symmetry.
	www.nmc.edu /~ftank/temp/sg29.html (396 words)

	PlanetPapers - Differences In Animal Phyla
		Cleavage is the separating divisions that transform the zygote into a ball of cells.
		Spiral cleavage means that the planes of cell division are diagonal to the vertical axis of the embryo.
		In radial cleavage, the planes of cleavage are either perpendicular or parallel to the vertical axis of the egg.
	www.planetpapers.com /Assets/2995.php (918 words)

	[No title]
		] A branch of the brachial artery in the forearm; principal branches are the radial recurrent and the main artery of the thumb.
		One of the numerous canals that radiate from the spongocoel in certain Porifera.
		] The diversion of radiation (thermal, electromagnetic, or nuclear) from its orginal path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media between the source of radiation (for example, a nuclear explosion) and a point at some distance away.
	www.accessscience.com /Dictionary/R/R2/DictR2.html (2342 words)

	Cleavage patterns and the topology of the metazoan tree of life -- Valentine 94 (15): 8001 -- Proceedings of the ...
		Deuterostomy is presumably ancestral and is correlated with radial
		with radial cleavage at the deepest branch and idiosyncratic cleavages
		phoronids have radial cleavage, and mesoderm is derived from the
	www.pnas.org /cgi/content/full/94/15/8001 (3980 words)

	Development (Site not responding. Last check: 2007-10-14)
		The pattern of cleavage is influenced by two factors: the amount of yolk and the formation of mitotic spindles.
		Orientation of the mitotic spindles determine the cleavage planes and arrangements of daughter cells.
		Cleavage in mammals is slow, with divisions occurring 12 to 24 hours apart.
	scidiv.bcc.ctc.edu /SL/development.htm (2702 words)

	Feb 12 Lecture Outline
		The site of the first cleavage furrow is determined by the point of sperm entry and the subsequent cytoplasmic movements of the newly fertilized egg.
		Because of the concentration of yolk in the vegetal hemisphere the formation of the cleavage furrow in the yolk-containing ventral portion is slower and lags behind that in the animal hemisphere.
		Cleavage occurs at oblique angles with daughter cells either moving to the right or to the left.
	departments.oxy.edu /biology/linden/bio220/feb12.html (466 words)

	16anim5
		Cleavage begins with the first mitotic division of the zygote and ends when a hollow sphere of cells, the blastula, is produced.
		Although all developmental patterns are not identical, for the sake of simplicity, this discourse will use the holoblastic model and assume a more or less equal division of all cells in the embryo.
		Another developmental difference between the protostomes and the deuterostomes is the pattern of cell cytokinesis that occurs during cleavage.
	io.uwinnipeg.ca /~simmons/1116/16anim5.htm (2027 words)

	Comparative Development
		Radial Cleavage: Cleavage planes are alternately vertical and horizontal (cells are stacked upon one another symmetrically)
		As they form, the cleavage nuclei move to the peripheral of the egg and settle in the periplasm where they construct the membranes to form the individual cells.
		The first cleavage nuclei to reach the oosome stop dividing and are reserved to make germ line cells.
	www.msu.edu /~nguyen81/comp.htm (515 words)

	LBS 144-A Comparison of the Development of Sea Urchins and Medakas (Site not responding. Last check: 2007-10-14)
		During cleavage (transformation of a zygote into a similar-sized ball of tiny cells), neither of the embryos actually grows.
		An embryo has radial cleavage if it changes from a four-cell embryo to an eight-cell embryo, each cell in the top four cell plane are directly over the cells of the bottom plane and they line up.
		Holoblastic cleavage is cleavage, in which the blastomeres are completely separated and the entire egg participates in cell division rather than fragments.
	www.msu.edu /~hartwi15/compare.html (419 words)

	For Review
		Radial and spiral cleavage: Radial and spiral cleavage describe two different patterns of cell division that occur during cleavage in an embryo.
		The cleavage pattern is one of several fundamental embryological differences between the protostomes and deuterostomes.
		Amnion and chorion: The amnion and the chorion are two of the internal cell layers or membranes that form in the amniotic egg.
	www.mhhe.com /biosci/genbio/biolink/student/olc2/chap58review.html (533 words)

	[No title] (Site not responding. Last check: 2007-10-14)
		The cleavage pattern is called spiral cleavage because the new sequence of dividing cells spirals outwards from the polar axis.
		Radial cleavage is a dividing pattern where the cells divide parallel to and at the right angles of the polar axis.
		The Lophophorates were placed with the deuterostomes because they showed radial cleavage, enterocoely, and with the exception of phoronids, their mouths were not derived from the blastopore (Brusca and Brusca, 2003).
	www.susqu.edu /students/l/laitem/Growl3.doc (2484 words)

	PAE Virtual Glossary
		Canals along the ambulacra radiating from the ring canal of echinoderms; also choanocyte-lined canals in syconoid sponges.
		Embryonic development in which early cleavage planes are symmetrical to the polar axis, each blastomere of one tier lying directly above the corresponding blastomere of the next layer; indeterminate cleavage.
		radiation A form of energy that includes visible light, ultraviolet light, and X rays; means by which body heat is lost in the form of infrared rays.
	www.mhhe.com /biosci/pae/glossaryr.html (3738 words)

	EMBRYOGENY AND LARVAL DEVELOPMENT (Site not responding. Last check: 2007-10-14)
		The orientation of the blastomeres can also be described directionally by radial cleavage or spiral cleavage, refering to how the subsequent divisions took place.
		In indeterminate cleavage, the cells ìfateî is not fixed until after the 4-cell, or possible later, stage.
		In general, the ìolderî groups of invertebrates (protostomes) exhibit spiral, determinate cleavage, while the ìyoungerî groups (deuterostomes) exhibit radial, indeterminate cleavage, similiar to that of vertebrates.
	bioweb.wku.edu /courses/biol225/225urchins.html (584 words)

	Lecture 6 (Site not responding. Last check: 2007-10-14)
		Cleavage continues and eventually embryo is in morula stage (latin for mulberry)
		In some embryoes, a periblast forms which is a group of cells involved with breaking down yolk in meroblastically cleaving eggs.
		Although the cleavage nuclei may be considered to be 'toti potent" in terms of directory development, cytoplasm does appear to
	www.people.memphis.edu /~clessman/cleavage.htm (1442 words)

	Invertebrates (Site not responding. Last check: 2007-10-14)
		Examine the specimens on demonstration under a dissecting microscope and note the bell-like shape, the ring of tentacles around the edge of the bell, and the gonads along the radial canals of the intestine.
		The protostome branch evolved 1) spiral cleavage, 2) determinate cleavage, 3) schizocoely (coelom arises from splits in mesoderm), and 4) the blastopore becomes the mouth.
		In the deuterostomes, 1) radial cleavage is retained (a symplesiomorphy), 2) cleavage is indeterminate, 3) enterocoely (coelom arises from out pockets of mesoderm in archenteron), and 4) the blastopore becomes the anus.
	www.usd.edu /biol/labs/151/invert51.htm (2369 words)

	Biology 104 Spring 2004 (Site not responding. Last check: 2007-10-14)
		Sea urchins and amphibian eggs have radial cleavage; for example in the third cleavage (4 cells-> 8 cells), the 4 cells near the animal pole are each directly over one of the 4 vegetal cells.
		In spiral cleavage, the geometric arrangement is more like stacking cannon balls or oranges, in that the 4 top cells are centered over the boundaries between the 4 bottom cells.
		Polar lobes are large bumps that form on the surface of one of the cleaving cells, in some species during the first cleavage division, in other species during both of the first TWO cleave divisions and in a few species polar lobes form during all three of the first three cleavages.
	www.bio.unc.edu /courses/2003spring/biol104/lecture13.html (1706 words)

	test1
		During radial cleavage planes are symmetrical to the polar axis.
		During spiral cleavage, planes are oblique or slanted to the polar axis.
		In addition, animals undergoing radial cleavage have regulative development, whereas those that undergo spiral cleavage undergo mosaic development.
	www-class.unl.edu /bios112/Answers1.html (178 words)

	Bil160lec26 (Site not responding. Last check: 2007-10-14)
		• Radial cleavage = Cleavage during which the cleavage planes are either parallel or perpendicular to the vertical axis of the embryo.
		• Determinate cleavage = Cleavage in which the developmental fate of each embryonic cell is established very early; a cell isolated from the four-cell stage of an embryo will not develop fully.
		Deuterostomes undergo radial cleavage and indeterminate cleavage during their development.
	fig.cox.miami.edu /~blase/Bil160lec26.html (475 words)

	Intrinsic Bias and Lineage Restriction in the Phenotype Determination of Dopamine and Neuropeptide Y Amacrine Cells -- ...
		Radial progenitors are found slightly more frequently in intermediate (I, <40 µm) versus deep (D, >40 µm) cell layers, whereas layered progenitors are equally distributed throughout the depth of the neural plate.
		Radial clones were slightly larger yet (mean = 9.1).
		Huang S, Moody SA (1993) The retinal fate of Xenopus cleavage stage progenitors is dependent upon blastomere position and competence: studies of normal and regulated clones.
	www.jneurosci.org /cgi/content/full/20/9/3244 (6585 words)

	Re: What are the 'advantages' of developing a deuterostome pattern of embryonic
		The main feature of Deuterostomes that they have used to their advantages is radial cleavage, or more correctly, no spiral cleavage.
		By not requiring the rearrangement of the spindles, Deuterostome eggs can be filled with materials, like yolk proteins, that allow the embryo to develop further before hatching, so that the mother can supply the energy needed to develop into an adult, allowing the embryo to bypass a larval stage (direct development).
		Another advantage/disadvantage to randomizing cleavage is the inability to use the cleavage pattern as a foundation for the body plan.
	www.madsci.org /posts/archives/1999-02/918160589.Dv.r.html (799 words)

	NOAA's Coral Reef Data Discovery Glossary (Site not responding. Last check: 2007-10-14)
		In hydrozoan medusae, the radial canal is part of the gastrovascular cavity.
		The numerous chitinous teeth on this ribbon-like membrane are used to scrape, pierce, tear or cut off small pieces of food that are then directed in a continuous stream toward the digestive tract by conveyor belt like movements of the membrane.
		Specifically, a circumoral ring around the esophogus with connecting radial canals each leading to an ambulacrum.It connects to the madreporite via the stone canal; also, the part of the distributive portion of the digestive system of scyphozoan medusae that is located in the margin of the bell.
	www8.nos.noaa.gov /coris_glossary/index.aspx?letter=r (4095 words)

	[No title]
		Spiral cleavage- planes of cell division are diagonal to the vertical axis of the embryo.
		Radial cleavage- planes are either parallel or perpendicular to the vertical axis of the egg; as seen in the eight-cell stage, the tiers of cells are aligned, one directly above the other.
		Determinate cleavage- protostomes rigidly casts the developmental fate of each embryonic cell very early Indeterminate cleavage- each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.
	www.angelfire.com /ca/finkar/bio1202ch32.doc (1294 words)

	Radial vs. spiral cleavage (Site not responding. Last check: 2007-10-14)
		One of the hallmarks of deuterstome development is that early cleavage divisions are radial.
		Play the movie at the below right to get a sense for the difference between these two cleavage patterns in two generalized embryos.
		Differences in cleavage orientation in idealized spirally and radially cleaving embryos
	worms.zoology.wisc.edu /urchins/SUcleavage_radial.html (70 words)

	Kingdom
		symmetry radial about an oral-aboral axis; no head.
		radial symmetry as adults; bilateral symmetry as larvae.
		Radiated worldwide in marine as well as freshwater.
	bioweb.wku.edu /courses/Biol225/225phylacharacters.html (1937 words)

	Invertebrates II (Site not responding. Last check: 2007-10-14)
		Identify the spongocoel, incurrent canals, and radial canals (the incurrent and radial canals will appear identical in cross section - canals opening to the inside spongocoel are radial canals, and canals opening to the exterior are incurrent canals).
		The collar cells lining the radial canals will appear as blurry pink dots along the inner surface of the canals.
		Synapomorphies that unite cnidarians with all other animals are; 1) true tissues (diploblastic - two germ layers), 2) radial cleavage, 3) radial symmetry, 4) gastrovascular cavity with one opening, and 5) a nervous system.
	www.usd.edu /biol/labs/162/DiversityLabs/05InvertebratesI.html (2532 words)

	101 Deuterosomes - www.101science.com
		They develop from bilaterally symmetrical larvae that metamorphose into radially symmetrical, or in some cases into bilaterally symmetrical, adults (if the latter, they pass through a radially symmetrical stage first).
		Their radial symmetry is generally pentaradiality — based on five equal divisions of the body, like five slices of a pie.
		They possess a characteristic series of internal fluid-filled body spaces or cavities, surrounding the viscera, that are lined by epithelia derived from the embryonic tissue layer that gives rise to adult muscle and connective tissue.
	www.101science.com /Deuterostomes.htm (754 words)

	Lecture: Cleavage (Site not responding. Last check: 2007-10-14)
		For each, a) as an example of the technique, describe a classic experiment and its result; b) the advantages of the method; and c) the limitations or disadvantages of the method.
		7) Outline the major characteristics of the cleavage cell cycle and how they change during the midblastula transition to become similar to those of cell cycles in somatic cells.
		Rationalize how these differences help accomplish the apparent functions of cleavage during early development of the zygote.
	morgan.botany.uga.edu /devbio/syllabus/leccleavage.htm (440 words)

	[No title]
		Describe an experiment that illustrates the importance of induction in development.
		Explain how each of these pairs of features was important in constructing the phylogenetic tree shown below.
		= 2 points __ Radial: several planes passing through the long or central axis can divide the organism into similar parts.
	www.csun.edu /science/biology/AP_biology/development.doc (542 words)

	Chapter 32 Study Objectives for Biology 112 (Site not responding. Last check: 2007-10-14)
		What is meant by: ingestion, cleavage, blastula, gastrula, larva, metamorphosis.
		What is meant by: radial symmetry, bilateral symmetry, dorsal, ventral, anterior,
		archenteron, diploblastic, triploblastic, blastopore, spiral cleavage, determinate
	www.yhc.edu /external/bio/bioob32.html (131 words)

	[No title]
		Understand the meaning of asymmetry, radial symmetry and bilateral symmetry 3.
		In the space below, sketch examples of animals radial symmetry, including biradial, quadriradial, pentaradial and hexaradial symmetry.
		cleavage at the 4- to 8-cell stage (i.e., spiral or radial?) d.
	fig.cox.miami.edu /Faculty/Dana/animalbodyplans.doc (793 words)

	wordlist3 (Site not responding. Last check: 2007-10-14)
		spiral and indeterminate cleavage, coelom forms as split in solid mass of mesoderm
		radial and indeterminate cleavage, enterocoelous development, blastopore becomes anus
		radial and determinate cleavage, blastopore becomes mouth, schizocoelous development
	nersp.nerdc.ufl.edu /~herrera/wordlist3.html (219 words)

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