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| | Chordata |
 | | Among the living chordates there is little doubt that lancelets are most closely related to the Craniates based on synapomorphies such as segmented axial muscles and metameric organization of the visceral (pharyngeal) arches. | | | As noted below, the relationships of some of the presumed fossil chordates is based on scant evidence and there is debate about the position of especially the calcichordates and conodonts (see references cited below and Chen et al. | | | The nerve cord of chordates develops dorsally in the body as a hollow tube above the notochord. |
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http://tolweb.org/tree?group=Chordata
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| | Duffy: Chordate Origins |
| | However, Jefferies' interpretations of the characters in this group are subject to criticism from the majority of the scientific community, who believe the calcichordates should be allied with the echinoderms. | | | For any origin theory to be deemed viable, it seems as though an amalgamation of fossil and living studies would be most prudent. | | | However, the vague and enigmatic nature of these fossils has allowed for widely varying interpretations of their relationships to living groups. |
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http://www.biology.ualberta.ca/courses.hp/biol606/OldLecs/Lecture2K.08.Duffy.html
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| | American Zoologist: Chordate evolution and autonomous specification of cell fate: The ascidian embryo model |
| | Many of these details prove to be features of chordate affinity which suggest in turn that the present day ascidian larva preserves the primitive chordate body plan from which vertebrates arose in the course of evolution (Garstang, 1928; Berrill, 1955). | | | The present contribution attempts to unite the two themes by postulating that autonomous specification further enhanced the modular nature of the developing tunicate embryo and permitted natural selection to act differentially on the largely independent organ systems of larvae and paedomorphs, in what amounts to a mosaic selection pattern. | | | Larvae of the ascidian tunicates were known for some time before their internal anatomy was studied histologically by Alexander Kowalevsky (1866). |
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http://www.findarticles.com/p/articles/mi_qa3746/is_199706/ai_n8778775
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| | CarlZimmer.com |
| | The conclusion that bone was born after the rise of vertebrates is not yet certain, as more primitive chordates may turn out to have possessed the precursors of conodont mouth parts. | | | Donoghue and his co-workers tried to resolve the debate with a massive study of both fossil and living creatures, analyzing 103 different traits in 17 different groups of chordates, ranging from lancelets to jawed vertebrates. | | | But it does possess vertebrate traits such as gill slits, rows of muscle blocks along its flanks, and a notochord, a stiff rod of tissue that supports the nerve cord along its back. |
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http://www.carlzimmer.com/articles/2000/articles_2000_6.html
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| | Cambrian Primitive Chordate Fossil |
| | Chordate origins are not fully understood though there are several theories. | | | Paleontologists who examined this specific fossil believe there is about a 50/50 chance this it is a chordate. | | | All chordates have a notochord at some stage in their lives, but in some the notochord is lost in the adult, whereas in others such as the vertebrates, the notochord present in the embryo but is later largely replaced and surrounded by the vertebrae, or backbones. |
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http://www.fossilmuseum.net/Cambrian-Explosion/Chordate/Chordate.htm
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| | chordate |
| | The cladists are claiming the present evolutionary scheme is wrong and that their method is a superior indicator of phylogenetic relationships among the chordates. | | | The circulatory system has only a two chambered heart and the blood flow to the body is under very low pressure. | | | The brain is poorly developed relative to higher chordates. |
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http://io.uwinnipeg.ca/~simmons/1116/chordate.htm
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| | The Shape of Life . Chordates PBS |
| | Another chordate feature is a hollow nerve structure called a dorsal nerve cord that in most members becomes the spinal cord and brain. | | | Also included in the chordate body plan are structures called pharyngeal gill slits, or clefts. | | | Learn more about Chordates in "Bones, Brawn and Brains" |
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http://www.pbs.org/kcet/shapeoflife/animals/chordates.html
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| | Chordate - Wikipedia, the free encyclopedia |
| | They do not match up very well with the traditional groups, and as a result vertebrate classification is in a state of flux, although their relationships are not very well understood. | | | They are united by having, at some stage in their life, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a muscular tail extending past the anus. | | | Chordates (phylum Chordata) include the vertebrates, together with several closely related invertebrates. |
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http://en.wikipedia.org/wiki/Chordata
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| | CHORDATE ZOOLOGY – LAB 1: |
| | This is our first vertebrate, so think about the chordate characters you have just learned. | | | 1) How have the chordate characters been changed in the vertebrates? | | | Also be aware of the characters that unite the vertebrates. |
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http://life.bio.sunysb.edu/ugbio/bio344/bio344labexercise.html
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| | Chordate Subphyla |
| | In the Appendicularia, individuals become reproductively active while in the planktonic stage. | | | In the sea squirts, "tadpole larvae" are planktonic; when they metamorphose to adults, they become sessile and lose most of the chordate characteristics. |
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http://tidepool.st.usm.edu/Crswr/chordatesubphyla.html
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| | Cryptozoology.com |
| | > define a chordate, a hollow nerve cord, a dorsal notochord, pharyngeal slits, | | | Yunnanozoon is a weirdo that could either represent an extinct group of early chordates, an early hemichordate or something teetering on the chordate/hemichordate borderline. | | | A form known as Cheungkongella was also thought to be a seasquirt but has since turned out to be a syonym of Phlogites, a weird lophophorate (ie. |
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http://www.cryptozoology.com/forum/topic_view_thread.php?tid=12&pid=240927
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| | USATODAY.com - Tiniest chordate genome found |
| | Animals with highly developed backbones, such as humans, and those with even more primitive backbones, such as squid or sea squirts, are grouped in a category of organisms called "chordates." | | | As a result, by understanding what a single gene does for Oikopleura, scientists can apply that research to human gene functions. | | | These findings may also make it possible to distinguish whether high gene density is an ancestral trait of chordates, or if the genome was just reduced for this group of marine animals. |
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http://www.usatoday.com/news/science/aaas/2001-12-21-small-gene.htm
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| | Evolution: Change: Deep Time |
| | Made of cartilage-like material, not bone, the notochord provides support for the nerve cord. | | | In many chordates like the vertebrates, some of these features are apparent only in the early stages of embryonic development. | | | Other features characteristic of the chordate body plan are a tail and gill-like openings between the throat and the neck. |
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http://www.pbs.org/wgbh/evolution/change/deeptime/paleoz.html
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| | Comparative Vertebrate Anatomy - Lecture Notes 1 |
| | Comparative vertebrate anatomy - the study of structure, of the function of structure, and of the range of variation in structure and function among vertebrates: | | | Lecture Notes 1 - Chordate Origins and Phylogeny | | | Researchers think that Cathaymyrus is a fossil relative of modern lancelets (amphioxus). |
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http://people.eku.edu/ritchisong/342notes1.htm
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| | ADW: Chordata: Information |
| | Help improve this site — take our survey! | | | Chordates are defined as organisms that possess a structure called a notochord, at least during some part of their development. | | | The notochord is a rod that extends most of the length of the body when it is fully developed. |
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http://animaldiversity.ummz.umich.edu/chordata.html
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| | Search Results for chordate - Encyclopædia Britannica |
| | The chordate notochord is a stiff rod with a turgid core and fibrous sheath. | | | Chordates are capable of locomotion by means of muscular movements at some stage in life. | | | Chordates have many distinctive features, suggesting that there has been extensive modification from simple beginnings. |
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http://www.britannica.com/search?miid=1129920&query=chordate
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| | Introduction to the Chordata |
| | All chordates have the following features at some point in their life (in the case of humans and many other vertebrates, these features may only be present in the embryo): |
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http://www.ucmp.berkeley.edu/chordata/chordata.html
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| | Craniata |
| | As chordates, all craniates develop a notochord, which is primitively large (hagfishes, lampreys), but becomes transitory in most vertebrates and is replaced by elements of the vertebral column, the centra and arcualia. | | | There is a theory that the jaws of the gnathostomes are derived from the velum. | | | Blieck, A. At the origin of chordates; Géobios, 25, 101-113. |
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http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/craniata.html
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| | Untitled Document |
| | The chordates have the most developed brains of all the phyla and complex nervous systems. | | | A chordate can be almost any color in nature. | | | An chordate has a brain and nervous system. |
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http://www.mcwdn.org/Animals/Chordate.html
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| | Respiration (from chordate) -- Encyclopædia Britannica |
| | The vertebrate gill may retain some role in feeding, although the current is now produced by the action of muscles, not cilia. | | | A primitive chordate gill is present in tunicates and cephalochordates, where it serves in both respiration and feeding. | | | The amphioxus is characteristic of the most primitive chordates. |
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http://www.britannica.com/eb/article-49555
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| | Dictionary of Animals - chordate |
| | A new chordate Yunnanozoon lividum, a cephalochordate, was found 1995 in Chengjiang, China. | | | Chordates are divided into three major groups: tunicates, cephalochordates (see lancelet), and craniates (including all vertebrates). | | | All these animals, at some stage of their lives, have a supporting rod of tissue (notochord or backbone) running down their bodies. |
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http://www.tiscali.co.uk/reference/dictionaries/animals/data/m0007516.html
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| | Chordate Lecture |
| | Features which distinguish the vertebrates from other chordates are: | | | a longitudinal flexible rod formed from dorsal mesoderm and located between the gut and the nerve cord in all chordate embryos. | | | Chordates are divided into 3 subphyla which include: |
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http://home.earthlink.net/~dayvdanls/AE_lecture3.htm
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| | Palaeos Vertebrates 10.100 Chordata: Chordata |
| | Note: many of these characters may not be present during some phase of the life cycle. | | | Image: Pikaia a possible chordate from the Early Cambrian Burgess Shale. |
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http://www.palaeos.com/Vertebrates/Units/010Chordata/010.100.html
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| | Chordate Introduction 1 |
| | In the invertebrate phyla, the nerve cord (often paired) is ventral to the alimentary canal and is solid. | | | All chordates possess (at least at some time in their development) the following unique characteristics... | | | Furthermore, many of the chordate species are those that are most conspicuous and familiar to us. |
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http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-9a/Introduction-9a_1_/introduction-9a_1_.htm
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| | CC211: Invertebrate-vertebrate transition |
| | Haikouella, a chordate similar to Yunnanozoon, but with additional traits, such as a heart and a relatively larger brain (Chen et al. | | | Conodont animals had bony teeth, but the rest of their body was soft. | | | They differ from earlier invertebrate chordates in having a zigzag arrangement of segmented muscles, and their gill arrangement is more complex than a simple slit (Monastersky 1999). |
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http://www.talkorigins.org/indexcc/CC/CC211.html
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| | Introduction to the Cephalochordata |
| | However, because of their remarkable morphology, they have proved crucial in understanding the morphology and evolution of chordates in general -- including vertebrates. | | | Known as lancelets or as amphioxus (from the Greek for "both [ends] pointed," in reference to their shape), cephalochordates are small, eel-like, unprepossessing animals that spend much of their time buried in sand. | | | In some parts of the world, amphioxus are eaten by humans or by domestic animals; they are important food items in some parts of Asia, where they are commercially harvested. |
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http://www.ucmp.berkeley.edu/chordata/cephalo.html
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| | An early Cambrian craniate-like chordate |
| | Haikouella had a relatively large brain and possibly a pair of lateral eyes, which indicate that this animal might be considered as an early craniate. | | | The body is broadly triangular in its anterior half but narrowly triangular in the rest. | | | Anatomic findings such as the brain and possible lateral eyes in its close relative Haikouella pose a question as to whether Yunnanozoon may also be an early craniate. |
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http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v402/n6761/full/402518a0_r.html
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| | Chordate innovations in evolution via EST analysis of Saccoglossus kowalevskii |
| | Saccoglossus kowalevskii, the Acorn worm, found on the east coast of the United States, is a tractable, model organism to study such developmental innovations introduced after the divergence of the deuterostomes and proteostomes. | | | Conversely, we have found that only 0.3% of genes found only in the fly and worm had been lost in list of model chordate organisms. | | | Evolutionary biologists continue to puzzle over the correct relationship of our own phylum Chordata and its closest ancestors. |
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http://www.iscb.org/ismb2004/posters/bob_freemanAThms.harvard.edu_629.html
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| | CD Baby: DR CHORDATE: Songs of Biology , Plus . . . |
| | Dr Chordate has been in the education business for many years and has presented seminars and programs on the use of music and humor in science education everywhere from local libraries and schools to conferences of the National Science Teachers Association and other educational groups. | | | As you probably know, Dr. Chordate's name is derived from "friendly" Chordates (members of the Phylum Chordata family). | | | Doubtless, Chordate's previous album (Parts Is Parts) contains irreproducible classics that will remain infinitesimally indelible upon our cultural psyche. |
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http://www.cdbaby.com/cd/drchordate
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| | Chordate Introduction 2 |
| | Pharyngeal gill slits are also found in some hemichordates (acorn worms), a closely related sister group previously considered to be a subphylum within the Phylum Chordata. | | | The slits have a supporting framework of gill bars, which in aquatic vertebrates become the gills. | | | As a structure added to the body behind the end of the digestive tract, the tail has evolved specifically for propulsion in water. |
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http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-9a/Chordate_Introduction_2/chordate_introduction_2.htm
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| | CHORDATE ZOOLOGY (BIO 344), SPRING 2000 |
| | Chordate Zoology is a general introduction to the biology of the vertebrates and other chordates. | | | There will be a short natural history paper on a single chordate species of your choice (70 pt; due Th, 3/2). | | | The weekly assignments for use with the laboratory manual are posted on the Chordate Zoology webpage. |
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http://life.bio.sunysb.edu/ugbio/bio344/bio344syllabus.html
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| | Dr. Chordate: Products and Programs |
| | Chordate and/or The Notochords are also available for to make presentations to conventions, organizations, and schools at all grade levels, from local to international. | | | Chordate's original tunes, as well as the lyrics to the parodies of popular songs (such as Fifty Ways to Love Your Liver). | | | Chordate: Parts Is Parts - More Songs of Science. |
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http://www.tranquility.net/~scimusic/notochordsproducts.html
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| | The Notochords Sing! Funny, educational science by Dr. Chordate |
| | CHORDATE'S Ain't Nothin' but a Groundhog and Parts Is Parts are available on CD. | | | A lot of folks have asked what Dr Chordate looks like (well, at least 2, anyway), so I have added a page of Dr. Chordate in Action which will have one or more recent photos for your viewing pleasure. | | | Check the Notochords: Products for the most up-to-date listing of science music products, from Dr. Chordate. |
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http://www.tranquility.net/~scimusic
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| | Chordate from LiveJournal |
| | chordate Strickland.powerfully egg tastefulness party poker Bush, who called the program vital and necessary," dodged a question about whether he was aware of any resistance to the program at high levels of his administration and how that might have influenced his decision to approve it. | | | I can't hope for any improvement on my science gpa from those classes. | | | ...in other animals, such as the sea squirt (a tunicate), which has a tadpole larva that looks completely different from the adult tunicate which lacks a backbone and other features that make it a chordate. |
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http://www.ljseek.com/search/Chordate
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| | Pikaia: A chordate |
| | This zigzag shape is not seen in arthropod segments, but is the typical shape of chordate muscle bundles. | | | Furthermore, the markings on the sides of its body were unusually shaped: they formed V-shapes (pointing towards the head). | | | Pikaia was probably a chordate — the same group that includes fish, dinosaurs, and humans! |
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http://evolution.berkeley.edu/evolibrary/article/0_0_4/cambrian_11
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| | JGI - Why Sequence Sea Squirt cDNA? |
| | They are, however, composed of a very small number of cells (2600 for Ciona intestinalis), have a stereotyped development due to invariant cleavage patterns, and are therefore simpler to study than vertebrate embryos. | | | The fulfillment of the sea squirt's potential as a model organism is, however, dependent on an improved collection of gene models. | | | Their larvae have a tadpole structure that closely resembles lower vertebrate larvae. |
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http://www.jgi.doe.gov/sequencing/why/CSP2006/seasquirtcDNA.html
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| | Resources |
| | The Notochords and Dr. Chordate (that's where you are now!). | | | Her stuff is available here from Dr. Chordate. | | | List of Resources for Music (other than the products available from Dr. Chordate) and Humor in the Science Classroom. |
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http://www.tranquility.net/~scimusic/resources.html
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| | chordate |
| | All animals in the Chordate Phylum have backbones. | | | They are also called "vertebrates." The Chordate Phylum is split into Classes. | | | To learn more about each Class, click the links below: |
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http://www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/chordate.htm
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| | Chordate Quiz |
| | Chordates are among the most advanced and complex animals. | | | Click on the radio button in front of the correct answer to the question: |
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http://www.mcwdn.org/Animals/ChordateQuiz.html
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| | Music for Environmental Education |
| | Resources for Science music and humor from Dr. Chordate | | | Chordate Sings - science meets music for an education in fun! |
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http://www.aeoe.org/resources/songs/index.html
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