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| | Gould article |
 | | Thus, we do have evidence for the existence, and even the activities, of precursors of modern animals before the Cambrian explosion, but no data about their anatomy and appearance-a situation akin to the frustration we might feel if we could hear birdsong but had never seen birds. | | | As a final point, this developing scenario for the early history of animals might foster humility and generate respect for the complexity of evolutionary pathways. | | | Theories about the affinities of Ediacaran organisms span the full gamut-from viewing them (most conventionally) as simple ancestors for several modern phyla to interpreting them (most radically) as an entirely separate, and ultimately failed, experiment in multicellular animal life. |
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http://www.neuroblast.net/EI/PDFs/gouldart.htm
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| | American Zoologist: Major transitions in animal evolution: A developmental genetic perspective |
| | The Cambrian explosion-the rapid appearance of a diversity of new body plans in the Cambrian-is well known, but subject to a variety of interpretations. | | | Perhaps the genetic changes close to vertebrate origins not only enabled major developmental change, but also in turn enabled successful adaptive radiation of the taxon. | | | As with the vertebrate example, it is possible that genetic changes occurring on the triploblast stem lineage (transition 3) not only enabled major developmental change, but also successful adaptive radiation of the taxon. |
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http://www.findarticles.com/p/articles/mi_qa3746/is_199812/ai_n8819584/pg_6
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| | SYSTEMATIC BIOLOGY |
| | Triploblastic Relationships with Emphasis on the Acoelomates and the Position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognatha: a Combined Approach of 18S rDNA Sequences and Morphology. | | | The Position of Arthropods in the Animal Kingdom: A Search for a Reliable Outgroup for Internal Arthropod Phylogeny. |
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http://comenius.susqu.edu/bi/202/Animals/Sources-Animal-Kingdom.htm
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| | Balavoine.abs |
| | This cluster was already functioning in the patterning of the anterior-posterior axis of the animal. | | | A complex of Hox genes was present in the last ancestor of all triploblast animals (Urbilateria). |
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http://www.mbl.edu/CASSLS/Balavoine.abs.html
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| | Planaria_Home |
| | Triploblast tissue organization (in development, body develops from 3 germ layers) | | | Bilaterally symmetrical body plan (body is divisible only along one central axis, into mirror image left and right halves) |
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http://www.drmichaellevin.org/Planaria/biology/Biology.htm
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| | Pharyngula |
| | It's also a triploblast, which means it primitively possesses three body layers, an ectoderm (skin and nervous system) and endoderm (gut), with mesoderm (muscle and connective tissue) sandwiched in between. | | | The structural complexity is that of an adult rather than larval form. | | | nov.) had paired coeloms extending the length of the gut; paired external pits that could be sense organs; bilateral, anterior-posterior organization; a ventrally directed anterior mouth with thick walled pharynx; and a triploblastic structure. |
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http://development.pharyngula.org/index/pre_cambrian_coelomate
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| | Palaeos Vertebrates: Glossary E |
| | Ectoderm may be the "original" tissue of all animals. | | | It is associated with attachment of the extensor muscles of the lower forelimb. | | | Ectoderm: One of the three primordial germ layers of all triploblast animals. |
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http://www.palaeos.com/Vertebrates/Lists/Glossary/GlossaryE.html
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| | .::Dictionary Entries T::. |
| | Triploblast: An organism that forms three distinct embryonic tissue layers, namely the mesoderm, the ectoderm, and the endoderm. | | | Tuber: In plants, a structure found at the end of a rhizome which becomes swollen, and acts as food storage. | | | Transpiration: The loss of water vapor from a plant's surface. |
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http://www.freewebs.com/whatwoulddarwindo/dict_t.html
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| | [No title] |
| | Chapter 30: The Protostomes For protostomes and deuterostomes, describe: cleavage type; structure associated with blastopore; type of coelom. | | | Which of the organisms in this chapter are: multicellular; diploblasts; triploblasts; pseudocoelomate? | | | Briefly describe the life cycle of (and disease caused by, if applicable): Ascaris; Trichinella; filarial worms. |
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http://www.mid.tec.sc.us/science/kelleherk/102/StudyGuides/102SQ3.doc
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| | Mesozoa |
| | The mesozoans may be paraphyletic and at least one group related more closely to the nematodes (Pawlowski, et al. | | | This would be consistant with considering mesozoans as degenerate turbellarian flatworms | | | o 18S ribosomal DNA most similar to triploblastic metazoans than to protozoans. |
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http://science.kennesaw.edu/~jdirnber/InvertZoo/LecMesozoa/Mesozoa.html
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| | SICB - 2004 meeting - Abstract Details |
| | The limited number of only four somatic cell types, the smallest metazoan genome, and the lack of any foot or head structures, of any anterior-posterior organization, any kind of organs, and of both a basal lamina and an extracellular matrix (ECM) placed Trichoplax in a basal and isolated position relative to all other metazoan phyla. | | | Bütschlis’ placula hypothesis of the “urmetazoon” was based on this view and provided a hypothetical scenario for both, the evolution of diploblast and triploblast bauplans.. | | | We have been analysing (i) the sum of morphological data, (ii) the molecular sequence data from two mitochondrial genes, COII and COIII, (iii) the molecular sequence data from two regulatory nuclear genes, Cnox-2 and the PaxB gene, (iv) the secondary structure of the 16S rRNA molecule, and (v) the putative cluster organization of Hox genes. |
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http://www.sicb.org/meetings/2004/schedule/abstractdetails.php3?id=553
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| | Identification of Planarian Homeobox Sequences Indicates the Antiquity of Most Hox/Homeotic Gene Subclasses -- ... |
| | A phylogenetic analysis shows that two genes are clear orthologues of Drosophila labial, four others are members of a Dfd/Antp superclass, and a seventh gene, although more difficult to classify with certainty, may be related to the pb/Hox3 class. | | | This article has been cited by other articles in HighWire Press-hosted journals: | | | Together with previously identified Hox/HOM genes in other flatworms, our analyses demonstrate the existence of an elaborate family of Hox/HOM genes in the ancestor of all triploblast animals. |
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http://www.pnas.org/cgi/content/abstract/92/16/7227
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| | Lab9review |
| | # of embryonic tissue layers - diploblast or triploblast | | | bilateral symmetry, triploblastic, acoelomate, developmental pattern not applicable |
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http://www.library.csi.cuny.edu/dept/biology/Lab9review.html
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