Results 171 to 180 of about 7,947 (216)
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Regulatory Blueprint for a Chordate Embryo
Science, 2006Ciona is an emerging model system for elucidating gene networks in development. Comprehensive in situ hybridization assays have identified 76 regulatory genes with localized expression patterns in the early embryo, at the time when naïve blastomeres are determined to follow specific cell fates.
Imai, Kaoru S. +3 more
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Origin of the chordate central nervous system – and the origin of chordates
Development Genes and Evolution, 1999Contrary to traditional views, molecular evidence indicates that the protostomian ventral nerve cord plus apical brain is homologous with the vertebrates' dorsal spinal cord plus brain. The origin of the protostomian central nervous system from a larval apical organ plus longitudinal areas along the fused blastopore lips has been documented in many ...
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2002
Abstract We next focus on one of the branches of the protostomia/deuterostomia divide. The figure shown below (p. 113) is the dendrogram or branch of the animal tree of the deuterostomia. This is the branch that includes us. As with all such dendrograms, there is some uncertainty in where they are rooted.
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Abstract We next focus on one of the branches of the protostomia/deuterostomia divide. The figure shown below (p. 113) is the dendrogram or branch of the animal tree of the deuterostomia. This is the branch that includes us. As with all such dendrograms, there is some uncertainty in where they are rooted.
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Vetulicolians—are they deuterostomes? chordates?
BioEssays, 2002AbstractA recent paper by Shu et al.(1) reinterprets the fossil Vetulicola and related forms, all from the Lower Cambrian, as basal deuterostomes, assigning them their own phylum, Vetulicolia. Their conclusion is based on the presence of structures resembling gill slits and a trunk‐like region that shows evidence of segmentation. This report summarizes
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Acta Zoologica, 1973
AbstractThe study of development and comparisons of the adult structures of the several groups of protochordate animals reveals something of their interrelationships and origin. The hemichordates are perhaps closer to the echinoderms than to the chordates, but these groups appear to have been derived from a bilaterally symmetrical dipleurula ancestor ...
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AbstractThe study of development and comparisons of the adult structures of the several groups of protochordate animals reveals something of their interrelationships and origin. The hemichordates are perhaps closer to the echinoderms than to the chordates, but these groups appear to have been derived from a bilaterally symmetrical dipleurula ancestor ...
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1975
Eucoelomata in which:- 1. The body may be metamerically segmented or regionally differentiated. 2. A head is usually present, although the anterior region of the body in the Hemichordata is represented by a proboscis. 3. The gut is usually straight, U-shaped or coiled, with pharyngeal clefts. 4.
J. E. Webb, J. A. Wallwork, J. H. Elgood
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Eucoelomata in which:- 1. The body may be metamerically segmented or regionally differentiated. 2. A head is usually present, although the anterior region of the body in the Hemichordata is represented by a proboscis. 3. The gut is usually straight, U-shaped or coiled, with pharyngeal clefts. 4.
J. E. Webb, J. A. Wallwork, J. H. Elgood
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Geobios, 1992
Abstract It is classically known that the oldest representatives of vertebrates are Ordovician, heterostracan-like, dermal bone-bearing animals from Australia and North America. Another taxon, phylogenetically related to one of the Australian species, has recently been discovered in the Ordovician of Bolivia.
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Abstract It is classically known that the oldest representatives of vertebrates are Ordovician, heterostracan-like, dermal bone-bearing animals from Australia and North America. Another taxon, phylogenetically related to one of the Australian species, has recently been discovered in the Ordovician of Bolivia.
openaire +1 more source