DOCSLIB.ORG

Marine Animals I

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Marine Animals I Marine Animals I. The Invertebrates OCN 201 Biology Lecture 6 Illustration : Ernst Haeckel Arthropods Segmented Worms The Animal Vertebrates Family Tree Mollusks Echinoderms Round Worms Cnidarians Bilateria Ctenophores Radiata Flatworms PlacozoaNo symmetry Sponges Ancestral Protist 1336 The Animal Animal The Family Tree Family (Science, Dec 2013) Dec (Science, ctenophores *Corresponding author. E-mail: [email protected] E-mail: author. *Corresponding The list of author affi liations is available in the full article online. article full the in available is liations affi author of list The all animal species, including our own. our including species, animal all shed light not only on the biology of these extant organisms but also on the evolutionary history of of history evolutionary the on also but organisms extant these of biology the on only not light shed this study, will yield myriad discoveries about our most distant animal relatives, many of which will will which of many relatives, animal distant most our about discoveries myriad yield will study, this evolutionary framework, along with the comprehensive genomic resources made available through through available made resources genomic comprehensive the with along framework, evolutionary for major losses and/or gains of sophisticated cell types, including nerve and muscle cells. This These results present a newly supported view of early animal evolution that accounts accounts that evolution animal early of view supported newly a present results These Discussion: therefore, may have independently evolved these cell types. cell these evolved independently have may therefore, mesodermal cells, they lack many of the genes involved in bilaterian mesodermal specifi cation and, and, cation specifi mesodermal bilaterian in involved genes the of many lack they cells, mesodermal We also fi nd that, although although that, nd fi also We necessary genetic machinery for a functioning nervous system but may have lost these cell types. types. cell these lost have may but system nervous for a functioning machinery genetic necessary and the sponge the sponge and extant animals. We fi nd that the sets of neural components present in the genomes of of genomes the in present components neural of sets the that nd fi We animals. extant Our phylogenetic analyses suggest that ctenophores are the sister group to the rest of the the of rest the to group sister the are ctenophores that suggest analyses phylogenetic Our Results: dermal cell types, among others. among types, cell dermal inventories on signaling pathway components and genes known to be critical to neural and meso- and neural to critical be to known genes and components pathway signaling on inventories using both sequence matrices and information on gene content. We conducted extensive genomic genomic extensive conducted We content. gene on information and matrices sequence both using phore phore We have sequenced, annotated, and analyzed the 150-megabase genome of the cteno- the of genome 150-megabase the analyzed and annotated, sequenced, have We Methods: of ctenophores affects how we think about the early evolution of these cell types. cell these of evolution early the about think we how affects ctenophores of complex cell types with bilaterians (such as neural and mesodermal cells), the phylogenetic position position phylogenetic the cells), mesodermal and neural as (such bilaterians with types cell complex Ctenophora as the earliest diverging animal lineage. Because ctenophores share some of the same same the of some share ctenophores Because lineage. animal diverging earliest the as Ctenophora era (sponges) was the earliest diverging animal lineage, but recent reports have instead suggested suggested instead have reports recent but lineage, animal diverging earliest the was (sponges) era other animals has been a source of long-standing debate. Until recently, it was thought that Porif- that thought was it recently, Until debate. long-standing of source a been has animals other occurred early in animal evolution. The phylogenetic relationship of ctenophores (comb jellies) to to jellies) (comb ctenophores of relationship phylogenetic The evolution. animal in early occurred Introduction: A Mark Q. Martindale, Andreas D. Baxevanis* D. Andreas Martindale, Q. Mark Steven H. D. Haddock, Casey W. Dunn, Tyra G. Wolfsberg, James C. Mullikin, Mullikin, C. James Wolfsberg, G. Tyra Dunn, W. Casey Haddock, D. H. Steven NISC Comparative Sequencing Program, Stephen A. Smith, Nicholas H. Putnam, Putnam, H. Nicholas Smith, A. Stephen Program, Sequencing Comparative NISC David K. Simmons, Bernard J. Koch, Warren R. Francis, Paul Havlak, Havlak, Paul Francis, R. Warren Koch, J. Bernard Simmons, K. David Joseph F. Ryan, Kevin Pang, Christine E. Schnitzler, Anh-Dao Nguyen, R. Travis Moreland, Moreland, Travis R. Nguyen, Anh-Dao Schnitzler, E. Christine Pang, Kevin Ryan, F. Joseph for Cell Type Evolution Type Cell for and Its Implications Implications Its and leidyi Mnemiopsis RESEARCH ARTICLE Ctenophore the of Genome The RESEARCH ARTICLE ARTICLE RESEARCH . We . We have leidyi performed Mnemiopsis detailed phylogenetic analyses on these new data An understanding of ctenophore biology is critical for reconstructing events that are quite similar, suggesting that are quite sponges have similar, the queenslandica Amphimedon has most of the genes coding for structural components of of components structural for coding genes the of most has Mnemiopsis 13 DECEMBER 2013 VOL 342 342 VOL 2013 DECEMBER 13 RESEARCH ARTICLE B Ctenophores Echinoderms SUMMARY Cnidarians P u b l i s h Sponges e d www.sciencemag.org www.sciencemag.org SCIENCE RESEARCH ARTICLE b 1242592-4 y replicates. acid characters. Circles on nodes indicate 100% bootstrap support. Support Fig. 3. analysis of Tree by produced the maximum-likelihood EST Set. A A Choanoflagellata Ctenophora A Porifera Placozoa Vertebrates Bilateria Cnidaria S Vertebrates = 100 bootstrap 100 = Mnemiopsis Text Fig. 1. M. leidyi life history and anatomy. (A)AdultM. leidyi (about 10 cm Later development of M. leidyi embryo shown oral side down. Embryos are about 72 long). ( B)Close-upviewofcombrows.(C)Aboralviewofcydippidstage.(D)One- 200 mm. See the supplementary materials fo ram o r ed e t a i l e dd e s c r i p t i o no ft h e celled fertilized embryo. ( E to H)E a r l yc l e a v a g es tI a)Gastrulastage.( g e s .( J to M) ctenophore body plan. [Photo credit for (A): courtesy of Bruno Vellutini] support 0.2 Radiata Phylogenetic Position of M. leidyi ABBi Bi CBi D E F Bi Bi Bi The availability of the complete genome of Cn Ct Cn Cn Cn Cn M. leidyi evolved independently in these two lineages. two these in independently evolved ently than in bilaterians, suggesting that they perhaps perhaps they that suggesting bilaterians, in than ently ctenophore mesodermal cell types are specifi ed differ- ed specifi are types cell mesodermal ctenophore many of many in these factors underlined. Absent components are in red. The lack of of lack The red. in are components Absent underlined. Mnemiopsis Mnemiopsis genes genes in fl fl a g e l l a t a . ( Arthropods has allowed us to improve on the ctenophore Choano- outgroup the and of animals branches main ) Summary of the relationships of the fi ve ve fi the of relationships the of Summary ) B ( . leidyi M. the the origin of cell types. mesodermal and its implications regarding regarding implications its and leidyi Mnemiopsis Ct Cn Tr Tr Ct Ct The phylogenetic position of the ctenophore References Tables S1 to S31 to S1 Tables Figs. S1 to S10 to S1 Figs. Materials and Methods and Materials SUPPLEMENTARY MATERIALS SUPPLEMENTARY in in Fig. 6. Inventory of myogenic components components myogenic of Inventory 6. Fig. Fig. 5. The origin of postsynaptic genes. postsynaptic of origin The 5. Fig. analysis of gene content. gene of analysis Fig. 4. Tree produced by maximum-likelihood maximum-likelihood by produced Tree 4. Fig. analysis of the EST set. EST the of analysis Fig. 3. Tree produced by maximum-likelihood maximum-likelihood by produced Tree 3. Fig. C of the fi ve deep clades of animals. of clades deep ve fi the of Fig. 2. Previously proposed relationships relationships proposed Previously 2. Fig. Tr sampling used in previous phylogenomic analyses Bilateria Tr 1. Fig. Ct Po Po Po ARTICLE FULL THE IN FIGURES Po Po Po Ct Tr Tr of gene sequence evolution. We assessed two data Wnt/Wg . leidyi M. Arthropods http://dx.doi.org/10.1126/science.1242592 READ THE FULL ARTICLE ONLINE ARTICLE FULL THE READ (Cn,Ct) (Ct,Bi) (Po,) (Ct,) matrices that differ in breadth of taxon sampling 96 (Tr,) (Bi,) 13 DECEMBER 2013 VOL 342 Shh/hh and fraction of missing data: a “Genome Set ” that 82 Fig. 2. Previously proposed relationships of the five deep clades of animals. The label at the includes only data from complete genomes (13 ani- Fig. 1. M. leidyi life history and anatomy. (A)Adult 77 bottom of each pane corresponds to the header of Table 1. ( A)C o e l e n t e r a t ah y p oB t)Ctenophoraas h e s i s .( mals, 19.6% missing data) and an “EST Set ” that M. leidyi (about 10 cm Later development of M. leidyi embryo shown oral side down. Embryos are about Ancestral Ancestral life history and anatomy. and history life leidyi M. Components present in the sister to Bilateria. ( C)P o r i f e r aa ss i s t e rg r o u pt ot h er e s toD)Ctenophoraassistergrouptothe fM e t a z o a .( includes partial genomic data from many taxa (58 Mnemiopsis DOI: 10.1126/science.1242592 DOI: Science Cite this article as J. F. Ryan Ryan F. J. as article this Cite Placozoa 98 rest of Metazoa. ( E)PlacozoaassistergrouptotherestofMetazoa.( long).
Load more

Recommended publications
  • Flatworms Phylum Platyhelminthes
    Flatworms Phylum Platyhelminthes The flatworms include more than 13,000 species of free-living and parasitic species.There are 3 classes of flat- worms, the planarians, flukes and tapeworms. General Physical Traits (Anatomy): Flatworms are bilaterally symmetrical. This means that they can only be cut them length-wise to produce two mirror-image halves. They have a distinct right and left half. This is differ- ent from radially symmetrical animals, like the anemones, which can be cut anywhere top to bottom to get two similar halves. Flatworms have 3 tissue layers, compared to the 2 layers in sponges and cnidarians (jellyfishes, anemones and corals). They also have only one opening for food to enter and waste to leave, like the sponges and cnidarians. This is called a “sac” body plan. Planarian (class Tubellaria) Habitat: They live mostly in saltwater (marine) habitats, but are also found in freshwater. Habits: They are free-living flatworms (not parasites). Physical Traits (Anatomy): Planarians are small - less than a centimeter long. They have a head, brain and sense organs. This is called “cephalization.” The sense organs – called eyespots – look like eyes and are sensitive to light changes, but are not like human eyes. They are made up of simple nerve cells that respond to stimuli, like light. When many nerve cells are gathered in one place, they are called a “ganglion,” so the two eyespots are actually ganglia. They also have points on either side of the head that look a bit like ears, called “sensory lobes” or auricles. They do not hear, but can sense food.
    [Show full text]
  • Growth and Growth Form of the Massive Coral, Porites
    ResearchOnline@JCU This file is part of the following reference: Darke, Wendy (1991) Growth and growth form of the massive coral, Porites. PhD thesis, James Cook University. Access to this file is available from: http://eprints.jcu.edu.au/24102/ The author has certified to JCU that they have made a reasonable effort to gain permission and acknowledge the owner of any third party copyright material included in this document. If you believe that this is not the case, please contact [email protected] and quote http://eprints.jcu.edu.au/24102/ Growth and Growth Form of the Massive Coral Porites .r ., .7.40kielfleiol.,4,,,, • ' • -. *. --`4" . AMIN. .0 ••:.. 4 _.4..,- .._ . _ ,..1. Alit, ... .... vs' ,''. *'v."7#...4**11111114".'=- ,... _, .,.,: s • ... ir ...,- . .. Thesis,9 March 1991 'Z.- ......- '11'4 k, .. - i,„.. , . y . _ .,.. .1.... • ••• .." -•••••• ■•••1_„,_, ...._,.. , 11,..._ .. • ...• ...•. 410,10.„,,, ._ -... ---7--"I‘‘,;:...b. 111m1....10.-..,47V ,..• W, w T. .&. ‘•Nillip7-1■ % - • • • • .,,' -.. '••• Na. % , • • •■ sr ..., •."' .- 1N•-• .: ^ 7,,ah alp% At, t '40011•14._ —^ • 44 .., 4,,* • Viol --4:, % ......"*:. .:::::: . "... 41A: "111 ii..:,....7•0•_„,... '.6111••• •kbao : IVA..., 1•••.' , ...441.... •:-,'-.• ... cr. il1/411‘.. `0, " ' N •-••-- -7k ,.. li k -...,,e41.:4z,-..7.....!.....•:.•- - ..., • Wendy Darke 4.• . -.14. e " ..• . • 444 . ,....... t-.._•-.... ' 1 4 . .".....7 w . IV ‘16 *••••-'' t .%•.). "t% t‘ . "' _, ,.... GROWTH AND GROWTH FORM OF THE MASSIVE CORAL PORITES Thesis submitted by Wendy Marilyn DARKE BSc(Hons) (Bristol, UK) in March 1991 for the degree of Doctor of Philosophy in the Marine Biology Department, School of Biological Sciences at James Cook University of North Queensland i I, the undersigned, the author of this thesis, understand that James Cook University of North Queensland will make it available for use within the University Library and, by microfilm or other photographic means, allow access to users in other approved libraries.
    [Show full text]
  • Associated Organisms Inhabiting the Calcareous Sponge Clathrina Lutea in La Parguera Natural
    bioRxiv preprint doi: https://doi.org/10.1101/596429; this version posted April 3, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Associated organisms inhabiting the calcareous sponge Clathrina lutea in La Parguera Natural 2 Reserve, Puerto Rico 3 4 Jaaziel E. García-Hernández1,2*, Nicholas M. Hammerman2,3*, Juan J. Cruz-Motta2 & Nikolaos V. 5 Schizas2 6 * These authors contributed equally 7 1University of Puerto Rico at Mayagüez, Department of Biology, PO Box 9000, Mayagüez, PR 8 00681 9 2University of Puerto Rico at Mayagüez, Department of Marine Sciences, Marine Genomic 10 Biodiversity Laboratory, PO Box 9000, Mayagüez, PR 00681 11 3School of Biological Sciences, University of Queensland, Gehrmann Laboratories, Level 8, 12 Research Road, St Lucia, QLD 4072, Australia 13 14 15 Nikolaos V. Schizas, [email protected], FAX: 787-899-5500 16 17 Running Head: Infauna of the calcareous sponge Clathrina lutea 18 19 20 1 bioRxiv preprint doi: https://doi.org/10.1101/596429; this version posted April 3, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 21 ABSTRACT 22 Sponges provide an array of ecological services and benefits for Caribbean coral reefs. They 23 function as habitats for a bewildering variety of species, however limited attention has been paid 24 in the systematics and distribution of sponge-associated fauna in the class Calcarea or for that 25 matter of sponges in the Caribbean.
    [Show full text]
  • Number of Living Species in Australia and the World
    Numbers of Living Species in Australia and the World 2nd edition Arthur D. Chapman Australian Biodiversity Information Services australia’s nature Toowoomba, Australia there is more still to be discovered… Report for the Australian Biological Resources Study Canberra, Australia September 2009 CONTENTS Foreword 1 Insecta (insects) 23 Plants 43 Viruses 59 Arachnida Magnoliophyta (flowering plants) 43 Protoctista (mainly Introduction 2 (spiders, scorpions, etc) 26 Gymnosperms (Coniferophyta, Protozoa—others included Executive Summary 6 Pycnogonida (sea spiders) 28 Cycadophyta, Gnetophyta under fungi, algae, Myriapoda and Ginkgophyta) 45 Chromista, etc) 60 Detailed discussion by Group 12 (millipedes, centipedes) 29 Ferns and Allies 46 Chordates 13 Acknowledgements 63 Crustacea (crabs, lobsters, etc) 31 Bryophyta Mammalia (mammals) 13 Onychophora (velvet worms) 32 (mosses, liverworts, hornworts) 47 References 66 Aves (birds) 14 Hexapoda (proturans, springtails) 33 Plant Algae (including green Reptilia (reptiles) 15 Mollusca (molluscs, shellfish) 34 algae, red algae, glaucophytes) 49 Amphibia (frogs, etc) 16 Annelida (segmented worms) 35 Fungi 51 Pisces (fishes including Nematoda Fungi (excluding taxa Chondrichthyes and (nematodes, roundworms) 36 treated under Chromista Osteichthyes) 17 and Protoctista) 51 Acanthocephala Agnatha (hagfish, (thorny-headed worms) 37 Lichen-forming fungi 53 lampreys, slime eels) 18 Platyhelminthes (flat worms) 38 Others 54 Cephalochordata (lancelets) 19 Cnidaria (jellyfish, Prokaryota (Bacteria Tunicata or Urochordata sea anenomes, corals) 39 [Monera] of previous report) 54 (sea squirts, doliolids, salps) 20 Porifera (sponges) 40 Cyanophyta (Cyanobacteria) 55 Invertebrates 21 Other Invertebrates 41 Chromista (including some Hemichordata (hemichordates) 21 species previously included Echinodermata (starfish, under either algae or fungi) 56 sea cucumbers, etc) 22 FOREWORD In Australia and around the world, biodiversity is under huge Harnessing core science and knowledge bases, like and growing pressure.
    [Show full text]
  • California Marine Life Protection Act (MLPA) Initiative
    California Marine Life Protection Act (MLPA) Initiative Evaluation of Existing Central Coast Marine Protected Areas DRAFT, v. 2.0 November 4, 2005 CONTENTS EXECUTIVE SUMMARY ..........................................................................................................................4 1.0 INTRODUCTION ................................................................................................................................8 2.0 EVALUATION OF EXISTING MPAs .................................................................................................11 2.1 Año Nuevo Special Closure...........................................................................................................11 2.2 Elkhorn Slough State Marine Reserve ...........................................................................................12 2.3 Hopkins State Marine Reserve......................................................................................................15 2.4 Pacific Grove State Marine Conservation Area.............................................................................16 2.5: Carmel Bay State Marine Conservation Area ..............................................................................17 2.6 Point Lobos State Marine Reserve................................................................................................19 2.7 Julia Pfeiffer Burns State Marine Conservation Area.....................................................................20 2.8 Big Creek State Marine Reserve....................................................................................................22
    [Show full text]
  • Review of the Mineralogy of Calcifying Sponges
    Dickinson College Dickinson Scholar Faculty and Staff Publications By Year Faculty and Staff Publications 12-2013 Not All Sponges Will Thrive in a High-CO2 Ocean: Review of the Mineralogy of Calcifying Sponges Abigail M. Smith Jade Berman Marcus M. Key, Jr. Dickinson College David J. Winter Follow this and additional works at: https://scholar.dickinson.edu/faculty_publications Part of the Paleontology Commons Recommended Citation Smith, Abigail M.; Berman, Jade; Key,, Marcus M. Jr.; and Winter, David J., "Not All Sponges Will Thrive in a High-CO2 Ocean: Review of the Mineralogy of Calcifying Sponges" (2013). Dickinson College Faculty Publications. Paper 338. https://scholar.dickinson.edu/faculty_publications/338 This article is brought to you for free and open access by Dickinson Scholar. It has been accepted for inclusion by an authorized administrator. For more information, please contact [email protected]. © 2013. Licensed under the Creative Commons http://creativecommons.org/licenses/by- nc-nd/4.0/ Elsevier Editorial System(tm) for Palaeogeography, Palaeoclimatology, Palaeoecology Manuscript Draft Manuscript Number: PALAEO7348R1 Title: Not all sponges will thrive in a high-CO2 ocean: Review of the mineralogy of calcifying sponges Article Type: Research Paper Keywords: sponges; Porifera; ocean acidification; calcite; aragonite; skeletal biomineralogy Corresponding Author: Dr. Abigail M Smith, PhD Corresponding Author's Institution: University of Otago First Author: Abigail M Smith, PhD Order of Authors: Abigail M Smith, PhD; Jade Berman, PhD; Marcus M Key Jr, PhD; David J Winter, PhD Abstract: Most marine sponges precipitate silicate skeletal elements, and it has been predicted that they would be among the few "winners" in an acidifying, high-CO2 ocean.
    [Show full text]
  • Simple Animals Sponges and Placozoa the Twig of the Tree That Is the Animals the Tour Begins
    Animal Kingdom Simple animals Sponges and placozoa Tom Hartman Asymmetry www.tuatara9.co.uk Animal form and function 1 Module 111121 2 The twig of the tree that is the animals Animals All other animals Animals Sponges Choanoflagellates Choanoflagellates Fungi Fungi 3 4 All other animals Animals (bilateralia) Radiata Sponges Choanoflagellates Fungi The tour begins 5 6 1 Animal Kingdom The Phylum Quirky phyla • In the standard Linnean system (and taxonomic systems • There are 39 animal phyla (+/- 10!) based on it), a Phylum is the taxonomic category between Kingdom and Class. • The Micrognathozoa were • A phylum is a major ranking of organisms, defined discovered in 2000 (1 species)in according to the most basic body-parts shared by that springs in Greenland. group. But we must include the creatures and their • Xenoturbellida removed from the common ancestor. molluscs and moved to the – Chordata (animals with a notochord - vertebrates and others), – Arthropoda (animals with a jointed exoskeleton) dueterostomes when DNA – Mollusca (animals with a shell-secreting mantle), evidence was discounted due to – Angiosperma (flowering plants), and so on. what it had eaten! – A number of traditional Phyla - e.g. Protozoa, possibly Arthropoda - • Cycliophora discovered on the are probably invalid (polyphyletic). lips of lobsters in 1995. 7 8 The Class Our journey • In the Linnean system (and taxonomic systems Kingdom Group Phylum based on it), a Class is the taxonomic category Porifera between Phylum and Order. Placozoa • A class is a major group of organisms, e.g. Cnidaria Mammalia, Gastropoda, Insecta, etc that Parazoa Ctenophora contains a large number of different Radiata Platyhelminthes sublineages, but have shared characteristics in Animalia Protostome Rotifera common e.g.
    [Show full text]
  • The Dietary Preferences, Depth Range and Size of the Crown of Thorns Starfish (Acanthaster Spp.) on the Coral Reefs of Koh Tao, Thailand by Leon B
    The dietary preferences, depth range and size of the Crown of Thorns Starfish (Acanthaster spp.) on the coral reefs of Koh Tao, Thailand By Leon B. Haines Author: Leon Haines 940205001 Supervisors: New Heaven Reef Conservation Program: Chad Scott Van Hall Larenstein University of Applied Sciences: Peter Hofman 29/09/2015 The dietary preferences, depth range and size of the Crown of Thorns Starfish (Acanthaster spp.) on the coral reefs of Koh Tao, Thailand Author: Leon Haines 940205001 Supervisors: New Heaven Reef Conservation Program: Chad Scott Van Hall Larenstein University of Applied Sciences: Peter Hofman 29/09/2015 Cover image:(NHRCP, 2015) 2 Preface This paper is written in light of my 3rd year project based internship of Integrated Coastal Zone management major marine biology at the Van Hall Larenstein University of applied science. My internship took place at the New Heaven Reef Conservation Program on the island of Koh Tao, Thailand. During my internship I performed a study on the corallivorous Crown of Thorns starfish, which is threatening the coral reefs of Koh Tao due to high density ‘outbreaks’. Understanding the biology of this threat is vital for developing effective conservation strategies to protect the vulnerable reefs on which the islands environment, community and economy rely. Very special thanks to Chad Scott, program director of the New Heaven Reef Conservation program, for supervising and helping me make this possible. Thanks to Devrim Zahir. Thanks to the New Heaven Reef Conservation team; Ploy, Pau, Rahul and Spencer. Thanks to my supervisor at Van Hall Larenstein; Peter Hofman. 3 Abstract Acanthaster is a specialized coral-feeder and feeds nearly solely, 90-95%, on sleractinia (reef building corals), preferably Acroporidae and Pocilloporidae families.
    [Show full text]
  • Phylum Chordata
    Phylum Chordata 48,000 species very diverse phylum but still more unity in major characteristics than in most other phyla most advanced phylum of animal kingdom one to which we belong along with fish, amphibians reptiles, birds and other mammals some of the largest or most massive animals true coelom 4 major identifying characteristics: 1. Notochord flexible rodlike structure enclosed by a fibrous sheath extends the length of the body in larva and/or adult provides basic support and serves as main axis for muscle attachments to permit “fishlike” undulatory movements first part of skeleton to form in embryo in primitive chordates the notochord persists through life Animals: Chordates & Introduction to Vertebrates; Ziser Lecture Notes, 2006 1 in most chordates the notochord is replaced by a vertebral column of bone remnants of the notochord remain as “intervertebral discs” 2. Dorsal tubular nerve cord in most invert groups; nerve cord is ventral & paired in chordates the nerve cord is a single dorsal hollow nerve cord front end usually enlarged to form brain 3. Pharyngeal (gill) slits slit-like opening sleading from throat to outside first evolved as a filter feeding apparatus still used by some to filter water for food in others as gills in some groups they are only found in embryo and lost as adults 4. endostyle or thyroid gland specific kind of tissue found only in chordates was originally part of the feeding apparatus endostyle secretes mucus and traps food inside the pharyngeal cavity eg. lamprey larva in most chordates the same tissue has become an endocrine Animals: Chordates & Introduction to Vertebrates; Ziser Lecture Notes, 2006 2 gland in the neck region that helps control metabolism 5.
    [Show full text]
  • Xenacoelomorpha's Significance for Understanding Bilaterian Evolution
    Available online at www.sciencedirect.com ScienceDirect Xenacoelomorpha’s significance for understanding bilaterian evolution Andreas Hejnol and Kevin Pang The Xenacoelomorpha, with its phylogenetic position as sister biology models are the fruitfly Drosophila melanogaster and group of the Nephrozoa (Protostomia + Deuterostomia), plays the nematode Caenorhabditis elegans, in which basic prin- a key-role in understanding the evolution of bilaterian cell types ciples of developmental processes have been studied in and organ systems. Current studies of the morphological and great detail. It might be because the field of evolutionary developmental diversity of this group allow us to trace the developmental biology — EvoDevo — has its origin in evolution of different organ systems within the group and to developmental biology and not evolutionary biology that reconstruct characters of the most recent common ancestor of species under investigation are often called ‘model spe- Xenacoelomorpha. The disparity of the clade shows that there cies’. Criteria for selected representative species are cannot be a single xenacoelomorph ‘model’ species and primarily the ease of access to collected material and strategic sampling is essential for understanding the evolution their ability to be cultivated in the lab [1]. In some cases, of major traits. With this strategy, fundamental insights into the a supposedly larger number of ancestral characters or a evolution of molecular mechanisms and their role in shaping dominant role in ecosystems have played an additional animal organ systems can be expected in the near future. role in selecting model species. These arguments were Address used to attract sufficient funding for genome sequencing Sars International Centre for Marine Molecular Biology, University of and developmental studies that are cost-intensive inves- Bergen, Thormøhlensgate 55, 5008 Bergen, Norway tigations.
    [Show full text]
  • A New Species of the Calcareous Sponge Genus Leuclathrina (Calcarea: Calcinea: Clathrinida) from the Maldives
    Zootaxa 4382 (1): 147–158 ISSN 1175-5326 (print edition) http://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2018 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4382.1.5 http://zoobank.org/urn:lsid:zoobank.org:pub:B222C2D8-82FB-414C-A88F-44A12A837A21 A new species of the calcareous sponge genus Leuclathrina (Calcarea: Calcinea: Clathrinida) from the Maldives OLIVER VOIGT1,5, BERNHARD RUTHENSTEINER2, LAURA LEIVA1, BENEDETTA FRADUSCO1 & GERT WÖRHEIDE1,3,4 1Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Ludwig-Maximilians-Universität München, Rich- ard-Wagner-Str. 10, 80333 München, Germany 2 SNSB - Zoologische Staatssammlung München, Sektion Evertebrata varia, Münchhausenstr. 21, 81247 München, Germany 3 GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333 München, Germany 4SNSB - Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, 80333 München, Germany 5Corresponding author. E-mail: [email protected], Tel.: +49 (0) 89 2180 6635; Fax: +49 (0) 89 2180 6601 Abstract The diversity and phylogenetic relationships of calcareous sponges are still not completely understood. Recent integrative approaches combined analyses of DNA and morphological observations. Such studies resulted in severe taxonomic revi- sions within the subclass Calcinea and provided the foundation for a phylogenetically meaningful classification. However, several genera are missing from DNA phylogenies and their relationship to other Calcinea remain uncertain. One of these genera is Leuclathrina (family Leucaltidae). We here describe a new species from the Maldives, Leuclathrina translucida sp. nov., which is only the second species of the genus. Like the type species Leuclathrina asconoides, the new species has a leuconoid aquiferous system and lacks a specialized choanoskeleton.
    [Show full text]
  • The NEURONS and NEURAL SYSTEM: a 21St CENTURY PARADIGM
    The NEURONS and NEURAL SYSTEM: a 21st CENTURY PARADIGM This material is excerpted from the full β-version of the text. The final printed version will be more concise due to further editing and economical constraints. A Table of Contents and an index are located at the end of this paper. A few citations have yet to be defined and are indicated by “xxx.” James T. Fulton Neural Concepts [email protected] July 19, 2015 Copyright 2011 James T. Fulton 2 Neurons & the Nervous System 4 The Architectures of Neural Systems1 [xxx review cogn computation paper and incorporate into this chapter ] [xxx expand section 4.4.4 as a key area of importance ] [xxx Text and semantics needs a lot of work ] Don’t believe everything you think. Anonymous bumper sticker You must not fool yourself, and you are the easiest person to fool Richard Feynman I am never content until I have constructed a model of what I am studying. If I succeed in making one, I understand; otherwise, I do not. William Thomson (Lord Kelvin) It is the models that tell us whether we understand a process and where the uncertainties remain. Bridgeman, 2000 4.1 Background [xxx chapter is a hodge-podge at this time 29 Aug 11 ] The animal kingdom shares a common neurological architecture that is ramified in a specific species in accordance with its station in the phylogenic tree and the ecological domain. This ramification includes not only replication of existing features but further augmentation of the system using new and/or modified features.
    [Show full text]