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Cards In This Set
| Front | Back |
 Fertilization ( of a starfish) |
 The sperm and the egg unite to form a zygote |
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Biphashic
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After fertilization, a series of cell divisions (clevage) occurs in the zygote, resulting in the formation of new cells. For several generations, the daughter cells are roughly half the size of the mother cells. These early cells are called...
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Holoblastic cleavage
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(in some flatworms, most annelids, many molluscs, echinoderms, amphibians, and mammals), in which the whole zygote divides.
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Meroblastic cleavage
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(in most arthropods, cephalopods, fishes, reptiles, and birds) in which only part of the zygote divides.
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Blastomere
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 In many developing embryos, cleavage divisions are synchronized, resulting in an embryo containing 2,4,6...Each new cell resulting from division is called a .... |
 Morula (of a starfish) |
 At 16-32 cells, growing embryo reminded scientists of a mulberry hence called |
 Blastula ( of a starfish) |
 At approximately 64 cells, developing organism resembles a hollow sphere called a blastula. In some organisms, the blastula is not hollow. |
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Blastocoel
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 The cells that make up the blastula are called blastomeres, and the central cavity is called a Blastocoel. |
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Gastrula
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 Migration and specialization of cells result in formation of the gastrula |
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Neurula
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In chordates, the neurula follows the gastrula and is characterized by development of the notochord,neural tube, and coelom.
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Archenteron
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 The gastrulae are noted by the presence of the primitive gut called... |
 Ectoderm |
 The gastrulae are noted also by these germ layers. This layer covers the surface of the embryo, gives rise to the outer covering of the animal and in some phyla, to the central nervous system. |
 Mesoderm |
 All bilaterally symmetrical animals have a third layer which fills up most of the space between the Ectoderm and Endoderm. |
 Endoderm |
 The innermost germ layer, lines the pouch that forms during gastrulation ( the archenteron) and gives rise to the lining of the digestive tract ( or cavity) and organs such as the liver and lungs of vertebrates. |
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Organogenesis
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As embryological development continues, organs begin to form in a process called...
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