DOCSLIB.ORG

Evolution of Nervous Systems Bio334

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evolution of Nervous Systems Bio334 Evolution of nervous systems Bio334 – Neurobiology 1 – Lecture 2 BIO 334 - Lecture 2 - Evolution of August 5th 2013 1 nervous systems Questions from the last lecture • Patients with Broca’s area lesions do have trouble writing • Golgi – Cajal debate – reticular theory of the brain vs. individual cells BIO 334 - Lecture 2 - Evolution of August 5th 2013 2 nervous systems Why study the evolution of nervous systems http://freethinkerperspective.blogspot.in/2013/05/mind-body-monismdualism.html • Curiousity • May provide fundamental insights into nervous system function and development BIO 334 - Lecture 2 - Evolution of August 5th 2013 3 nervous systems How to study evolution of nervous systems? • Soft tissue not preserved properly so fossil record is not useful • Instead study and compare the nervous systems of living animals from different phyla • Caveat – these animals have also gone through evolution BIO 334 - Lecture 2 - Evolution of August 5th 2013 4 nervous systems What is a nervous system? • A nervous system is an organized constellation of cells (neurons) specialized for the repeated conduction of an excited state from receptor sites or from neurons to effectors or to other neurons” • Bullock and Horridge (1965) • Additionally should be capable of endogenously generating activity • Passano (1963) BIO 334 - Lecture 2 - Evolution of August 5th 2013 5 nervous systems Metazoan (multicellular) phylogenetic tree http://genomebiology.com/2006/7/7/R64/figure/F1?highres=y BIO 334 - Lecture 2 - Evolution of August 5th 2013 6 nervous systems Metazoan (multicellular) phylogenetic tree http://genomebiology.com/2006/7/7/R64/figure/F1?highres=y BIO 334 - Lecture 2 - Evolution of August 5th 2013 7 nervous systems Sponges – no nervous system – just muscle- like organs • Non-motile • Just muscle-like effectors that can control the flow of water • These muscle-like cells also sense environmental cues http://www.thebioblog.com/ BIO 334 - Lecture 2 - Evolution of August 5th 2013 8 nervous systems Metazoan (multicellular) phylogenetic tree http://genomebiology.com/2006/7/7/R64/figure/F1?highres=y BIO 334 - Lecture 2 - Evolution of August 5th 2013 9 nervous systems Diversity of nervous systems among other members of metazoa http://www.pcsd.k12.ny.us/bwoods/Regents%20Biology/Chapter%2014%20Nervous %20Regulation/48-NervousSystems/48-15-NervSystemDiversit-L.gif BIO 334 - Lecture 2 - Evolution of August 5th 2013 10 nervous systems Nerve nets – diffuse nervous systems without a brain • Connect sensory neurons to muscles http://www2.estrellamountain.edu/faculty/farabee/biobk/biobooknerv.html BIO 334 - Lecture 2 - Evolution of August 5th 2013 11 nervous systems Bilateralia – animals with bilateral symmetry have a organised nervous system • Brain and nerve cord • Cephalization – brain and sense organs close to one end of the body http://www.prokop.co.uk/Research/Drosi-Info/nerve-cords.html BIO 334 - Lecture 2 - Evolution of August 5th 2013 12 nervous systems Did these all evolve from a common ancestor? • Examine the mechanisms and see if subsequent nervous systems could be viewed as modifications BIO 334 - Lecture 2 - Evolution of August 5th 2013 13 nervous systems Action potential present in unicellular organisms • Calcium based • Could have been adapted to use sodium and potassium based currents • Electrical signaling is fast and can travel quickly over long distances • High fidelity • Is also specific – can activate target neurons without activating neurons on the way BIO 334 - Lecture 2 - Evolution of August 5th 2013 14 nervous systems Post-synaptic density proteins expressed in sponges • Co-regulation maybe important for forming a functional synapse Sakarya et al. PLOS One (2007) Conaco et al. PNAS (2012) BIO 334 - Lecture 2 - Evolution of August 5th 2013 15 nervous systems Ventral nerve cord in invertebrates vs. dorsal nerve cord in vertebrates • Did they evolve independently? http://www.prokop.co.uk/Research/Drosi-Info/nerve-cords.html BIO 334 - Lecture 2 - Evolution of August 5th 2013 16 nervous systems Vertebrate dorsal nerve cord may be a result of inversion of ventral nerve cord • Geoffroy Saint-Hilaire, Anton Dohrn http://cambrianmammal.wordpress.com/tag/arthropods/l BIO 334 - Lecture 2 - Evolution of August 5th 2013 17 nervous systems Conserved expression of genes in the anterio-posterior direction in the CNS Origin and evolution of the first nervous system from the book Evolution of Nervous systems: Vol 1 edited by Jon Kaas BIO 334 - Lecture 2 - Evolution of August 5th 2013 18 nervous systems Vertebrate dorsal nerve cord may be a result of inversion of ventral nerve cord – more evidence Platynereis – Arendt lab http://www.embl.de/research/un its/dev_biology/arendt/ http://cambrianmammal.wordpress.com/tag/arthropods/l BIO 334 - Lecture 2 - Evolution of August 5th 2013 19 nervous systems Tripartite brain might have been present in an ancestor to Bilateria • Similar divisions in Drosophila and mouse and ascidians • Gene expression similar Basic Nervous System Types: One or Many? from the book Evolution of Nervous systems: Vol 1 edited by Jon Kaas BIO 334 - Lecture 2 - Evolution of August 5th 2013 20 nervous systems Ventral and dorsal nerve cords could also have arisen independently from nerve nets BIO 334 - Lecture 2 - Evolution of August 5th 2013 21 nervous systems Evolution of first nervous systems Origin and evolution of the first nervous system from the book Evolution of Nervous systems: Vol 1 edited by Jon Kaas BIO 334 - Lecture 2 - Evolution of August 5th 2013 22 nervous systems Evolution of first nervous systems Origin and evolution of the first nervous system from the book Evolution of Nervous systems: Vol 1 edited by Jon Kaas BIO 334 - Lecture 2 - Evolution of August 5th 2013 23 nervous systems Evolution of first nervous systems Origin and evolution of the first nervous system from the book Evolution of Nervous systems: Vol 1 edited by Jon Kaas BIO 334 - Lecture 2 - Evolution of August 5th 2013 24 nervous systems Brain complexity – expansion of cortex https://sphotos-b.xx.fbcdn.net/hphotos-prn1/p480x480/309155_515369375148492_2145532623_n.jpg BIO 334 - Lecture 2 - Evolution of August 5th 2013 25 nervous systems Brain size vs. brain weight correlation https://pantherfile.uwm.edu/rswain/www/class/SUM05/slect1.html BIO 334 - Lecture 2 - Evolution of August 5th 2013 26 nervous systems Encephalization quotent https://pantherfile.uwm.edu/rswain/www/class/SUM05/slect1.html BIO 334 - Lecture 2 - Evolution of August 5th 2013 27 nervous systems.
Load more

Recommended publications
  • Brains of Primitive Chordates 439
    Brains of Primitive Chordates 439 Brains of Primitive Chordates J C Glover, University of Oslo, Oslo, Norway although providing a more direct link to the evolu- B Fritzsch, Creighton University, Omaha, NE, USA tionary clock, is nevertheless hampered by differing ã 2009 Elsevier Ltd. All rights reserved. rates of evolution, both among species and among genes, and a still largely deficient fossil record. Until recently, it was widely accepted, both on morpholog- ical and molecular grounds, that cephalochordates Introduction and craniates were sister taxons, with urochordates Craniates (which include the sister taxa vertebrata being more distant craniate relatives and with hemi- and hyperotreti, or hagfishes) represent the most chordates being more closely related to echinoderms complex organisms in the chordate phylum, particu- (Figure 1(a)). The molecular data only weakly sup- larly with respect to the organization and function of ported a coherent chordate taxon, however, indicat- the central nervous system. How brain complexity ing that apparent morphological similarities among has arisen during evolution is one of the most chordates are imposed on deep divisions among the fascinating questions facing modern science, and it extant deuterostome taxa. Recent analysis of a sub- speaks directly to the more philosophical question stantially larger number of genes has reversed the of what makes us human. Considerable interest has positions of cephalochordates and urochordates, pro- therefore been directed toward understanding the moting the latter to the most closely related craniate genetic and developmental underpinnings of nervous relatives (Figure 1(b)). system organization in our more ‘primitive’ chordate relatives, in the search for the origins of the vertebrate Comparative Appearance of Brains, brain in a common chordate ancestor.
    [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]
  • Convergent Evolution of the Ladder-Like Ventral Nerve Cord in Annelida Conrad Helm1*, Patrick Beckers2, Thomas Bartolomaeus2, Stephan H
    Helm et al. Frontiers in Zoology (2018) 15:36 https://doi.org/10.1186/s12983-018-0280-y RESEARCH Open Access Convergent evolution of the ladder-like ventral nerve cord in Annelida Conrad Helm1*, Patrick Beckers2, Thomas Bartolomaeus2, Stephan H. Drukewitz3, Ioannis Kourtesis1, Anne Weigert4, Günter Purschke5, Katrine Worsaae6, Torsten H. Struck7 and Christoph Bleidorn1,8* Abstract Background: A median, segmented, annelid nerve cord has repeatedly been compared to the arthropod and vertebrate nerve cords and became the most used textbook representation of the annelid nervous system. Recent phylogenomic analyses, however, challenge the hypothesis that a subepidermal rope-ladder-like ventral nerve cord (VNC) composed of a paired serial chain of ganglia and somata-free connectives represents either a plesiomorphic or a typical condition in annelids. Results: Using a comparative approach by combining phylogenomic analyses with morphological methods (immunohistochemistry and CLSM, histology and TEM), we compiled a comprehensive dataset to reconstruct the evolution of the annelid VNC. Our phylogenomic analyses generally support previous topologies. However, the so far hard-to-place Apistobranchidae and Psammodrilidae are now incorporated among the basally branching annelids with high support. Based on this topology we reconstruct an intraepidermal VNC as the ancestral state in Annelida. Thus, a subepidermal ladder-like nerve cord clearly represents a derived condition. Conclusions: Based on the presented data, a ladder-like appearance of the ventral nerve cord evolved repeatedly, and independently of the transition from an intraepidermal to a subepidermal cord during annelid evolution. Our investigations thereby propose an alternative set of neuroanatomical characteristics for the last common ancestor of Annelida or perhaps even Spiralia.
    [Show full text]
  • Animal Phylum Poster Porifera
    Phylum PORIFERA CNIDARIA PLATYHELMINTHES ANNELIDA MOLLUSCA ECHINODERMATA ARTHROPODA CHORDATA Hexactinellida -- glass (siliceous) Anthozoa -- corals and sea Turbellaria -- free-living or symbiotic Polychaetes -- segmented Gastopods -- snails and slugs Asteroidea -- starfish Trilobitomorpha -- tribolites (extinct) Urochordata -- tunicates Groups sponges anemones flatworms (Dugusia) bristleworms Bivalves -- clams, scallops, mussels Echinoidea -- sea urchins, sand Chelicerata Cephalochordata -- lancelets (organisms studied in detail in Demospongia -- spongin or Hydrazoa -- hydras, some corals Trematoda -- flukes (parasitic) Oligochaetes -- earthworms (Lumbricus) Cephalopods -- squid, octopus, dollars Arachnida -- spiders, scorpions Mixini -- hagfish siliceous sponges Xiphosura -- horseshoe crabs Bio1AL are underlined) Cubozoa -- box jellyfish, sea wasps Cestoda -- tapeworms (parasitic) Hirudinea -- leeches nautilus Holothuroidea -- sea cucumbers Petromyzontida -- lamprey Mandibulata Calcarea -- calcareous sponges Scyphozoa -- jellyfish, sea nettles Monogenea -- parasitic flatworms Polyplacophora -- chitons Ophiuroidea -- brittle stars Chondrichtyes -- sharks, skates Crustacea -- crustaceans (shrimp, crayfish Scleropongiae -- coralline or Crinoidea -- sea lily, feather stars Actinipterygia -- ray-finned fish tropical reef sponges Hexapoda -- insects (cockroach, fruit fly) Sarcopterygia -- lobed-finned fish Myriapoda Amphibia (frog, newt) Chilopoda -- centipedes Diplopoda -- millipedes Reptilia (snake, turtle) Aves (chicken, hummingbird) Mammalia
    [Show full text]
  • Biology of Chordates Video Guide
    Branches on the Tree of Life DVD – CHORDATES Written and photographed by David Denning and Bruce Russell ©2005, BioMEDIA ASSOCIATES (THUMBNAIL IMAGES IN THIS GUIDE ARE FROM THE DVD PROGRAM) .. .. To many students, the phylum Chordata doesn’t seem to make much sense. It contains such apparently disparate animals as tunicates (sea squirts), lancelets, fish and humans. This program explores the evolution, structure and classification of chordates with the main goal to clarify the unity of Phylum Chordata. All chordates possess four characteristics that define the phylum, although in most species, these characteristics can only be seen during a relatively small portion of the life cycle (and this is often an embryonic or larval stage, when the animal is difficult to observe). These defining characteristics are: the notochord (dorsal stiffening rod), a hollow dorsal nerve cord; pharyngeal gills; and a post anal tail that includes the notochord and nerve cord. Subphylum Urochordata The most primitive chordates are the tunicates or sea squirts, and closely related groups such as the larvaceans (Appendicularians). In tunicates, the chordate characteristics can be observed only by examining the entire life cycle. The adult feeds using a ‘pharyngeal basket’, a type of pharyngeal gill formed into a mesh-like basket. Cilia on the gill draw water into the mouth, through the basket mesh and out the excurrent siphon. Tunicates have an unusual heart which pumps by ‘wringing out’. It also reverses direction periodically. Tunicates are usually hermaphroditic, often casting eggs and sperm directly into the sea. After fertilization, the zygote develops into a ‘tadpole larva’. This swimming larva shows the remaining three chordate characters - notochord, dorsal nerve cord and post-anal tail.
    [Show full text]
  • The Nervous System in Lumbriculus Variegatus C
    [ NOTE: The following is an unpublished summary about nervous system design and function in the blackworm, Lumbriculus variegatus (Class Oligochaeta). This worm is being used at high school and college levels for student laboratory exercises and research projects. It has proven quite useful and reliable for studies of segment regeneration, circulatory physiology, locomotion, eco-toxicology, and neurobiology (Drewes, 1996a; Lesiuk and Drewes, 1998; Drewes and Cain, 1998). The following article provides students and instructors with general information about this worm’s nervous system which is not currently available in any biology texts. Correspondence or questions about this information are welcome. Please address to: Charles Drewes, Zoology & Genetics, Room 339 Science II Building, Iowa State University, Ames, IA, 50011; or phone: (515) 294-8061; or email: [email protected] ]. ------------------------------------------------------------------------------------------------------------- Functional organization of the nervous system in Lumbriculus variegatus C. Drewes (April. 2002) The gross anatomy of the nervous system in Lumbriculus variegatus was originally described more than 70 years ago by Isossimow (1926), with an English summary of that work given in Stephenson’s book, The Oligochaeta (1930). Virtually no published studies of this worm’s neurophysiology or behavior were done until the late 1980’s. The central nervous system in Lumbriculus consists of a cerebral ganglion (or “brain”), located in segment #1, and a ventral nerve cord that extends through every body segment (Figure 1). In each segment, except the first two, the ventral nerve cord gives rise to four pairs of segmental nerves. [Comparative note: In the earthworm, Lumbricus terrestris, there are three pairs of segmental nerve in each segment.] The segmental nerves extend laterally into the body wall where they form a series of parallel rings that extend within and around the body wall (for review, see Stephenson, 1930.).
    [Show full text]
  • Study on the Efferent Innervation of the Body Wall Musculature of Lumbricus Terrestris (L)
    Loyola University Chicago Loyola eCommons Master's Theses Theses and Dissertations 1975 Study on the Efferent Innervation of the Body Wall Musculature of Lumbricus Terrestris (L) Carol A. Aslam Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_theses Part of the Anatomy Commons Recommended Citation Aslam, Carol A., "Study on the Efferent Innervation of the Body Wall Musculature of Lumbricus Terrestris (L)" (1975). Master's Theses. 2749. https://ecommons.luc.edu/luc_theses/2749 This Thesis is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Master's Theses by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 1975 Carol A. Aslam STUDY ON THE EFFERENT INNERVATION OF THE BODY WALL ~USCULATURE OF LUMBRICUS TERRESTRIS (L.) by Carol Aslam A Thesis Submitted to the Faculty of the Graduate School of Loyola University of Chicago in Partial Fulfillment of the Requirements for the Degree of Master of Science November 1975 .s. ' '.. ACKNOWLEDGMENTS The author will always be indebted to her advisor, Dr. Robert Hadek, for unfailing support and scientific criticism throughout the preparation of this manuscript. Special thanks are also due to members of the De­ partment of Anatomy who generously gave of their time, counsel and technical assistance. The encouragement of my husband and enduring patience of my children have made possible the completion of this program. ii BIOGkAPllY Carol A.
    [Show full text]
  • The Ventral Nerve Cord of Lithobius Forficatus (Lithobiomorpha): Morphology, Neuroanatomy, and Individually Identifiable Neurons
    76 (3): 377 – 394 11.12.2018 © Senckenberg Gesellschaft für Naturforschung, 2018. A comparative analysis of the ventral nerve cord of Lithobius forficatus (Lithobiomorpha): morphology, neuroanatomy, and individually identifiable neurons Vanessa Schendel, Matthes Kenning & Andy Sombke* University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Soldmannstrasse 23, 17487 Greifswald, Germany; Vanessa Schendel [[email protected]]; Matthes Kenning [[email protected]]; Andy Sombke * [andy. [email protected]] — * Corresponding author Accepted 19.iv.2018. Published online at www.senckenberg.de/arthropod-systematics on 27.xi.2018. Editors in charge: Markus Koch & Klaus-Dieter Klass Abstract. In light of competing hypotheses on arthropod phylogeny, independent data are needed in addition to traditional morphology and modern molecular approaches. One promising approach involves comparisons of structure and development of the nervous system. In addition to arthropod brain and ventral nerve cord morphology and anatomy, individually identifiable neurons (IINs) provide new charac- ter sets for comparative neurophylogenetic analyses. However, very few species and transmitter systems have been investigated, and still fewer species of centipedes have been included in such analyses. In a multi-methodological approach, we analyze the ventral nerve cord of the centipede Lithobius forficatus using classical histology, X-ray micro-computed tomography and immunohistochemical experiments, combined with confocal laser-scanning microscopy to characterize walking leg ganglia and identify IINs using various neurotransmitters. In addition to the subesophageal ganglion, the ventral nerve cord of L. forficatus is composed of the forcipular ganglion, 15 well-separated walking leg ganglia, each associated with eight pairs of nerves, and the fused terminal ganglion. Within the medially fused hemiganglia, distinct neuropilar condensations are located in the ventral-most domain.
    [Show full text]
  • Larval Nervous Systems
    © 2015. Published by The Company of Biologists Ltd | The Journal of Experimental Biology (2015) 218, 629-636 doi:10.1242/jeb.109603 REVIEW Larval nervous systems: true larval and precocious adult Claus Nielsen* ABSTRACT be specialized into rows of ganglia connected by connectives] and the The apical organ of ciliated larvae of cnidarians and bilaterians is a Chordonia by an unpaired dorsal neural tube. The division of the true larval organ that disappears before or at metamorphosis. It Bilateria into Protostomia and Deuterostomia (=Cordonia + appears to be sensory, probably involved in metamorphosis, but Ambulacraria) (Grobben, 1908) is still universally accepted and is knowledge is scant. The ciliated protostome larvae show now supported by numerous phylogenomic studies (Hejnol et al., ganglia/nerve cords that are retained as the adult central nervous 2009; Wheeler et al., 2009; Edgecombe et al., 2011). However, the system (CNS). Two structures can be recognized, viz. a pair of interpretation of the dorsal/ventral orientation of the two groups has cerebral ganglia, which form the major part of the adult brain, and a been challenged, and it now appears that the two longitudinal nerve blastoporal (circumblastoporal) nerve cord, which becomes cords are homologous (see below). differentiated into a perioral loop, paired or secondarily fused ventral The topology of the bilaterian part of the animal tree of life is nerve cords and a small perianal loop. The anterior loop becomes relatively well established, but there is not agreement about the part of the brain. This has been well documented through cell-lineage inter-relationships of the basal metazoan groups.
    [Show full text]
  • Imaging Neural Activity in the Ventral Nerve Cord of Behaving Adult
    bioRxiv preprint doi: https://doi.org/10.1101/250118; this version posted January 22, 2018. 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. Imaging neural activity in the ventral nerve cord of behaving adult Drosophila Chin-Lin Chen1,2,*, Laura Hermans1,2,*, Meera C. Viswanathan3,4, Denis Fortun5,6, Michael Unser5, Anthony Cammarato3,4, Michael H. Dickinson7, Pavan Ramdya1,2,‡ Affiliations: 1 Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland 2 Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland 3 Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA 4 Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA 5 Biomedical Imaging Group, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland 6 Signal Processing core of the Center for Biomedical Imaging (CIBM-SP), École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland 7 Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA * These authors contributed equally ‡ Correspondence should be addressed to: [email protected] bioRxiv preprint doi: https://doi.org/10.1101/250118; this version posted January 22, 2018. 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.
    [Show full text]
  • Fuxianhuiid Ventral Nerve Cord and Early Nervous System Evolution in Panarthropoda
    Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda Jie Yanga, Javier Ortega-Hernándezb,1, Nicholas J. Butterfieldb, Yu Liua,c,d, George S. Boyanc, Jin-bo Houa, Tian Lane, and Xi-guang Zhanga,2 aYunnan Key Laboratory for Paleobiology, Yunnan University, Kunming 650091, China; bDepartment of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom; cDevelopmental Neurobiology Group, Biocenter, Ludwig-Maximilians-Universität, 82152 Martinsried, Germany; dGeoBio-Center Ludwig-Maximilians-Universität, Munich 80333, Germany; and eCollege of Resources and Environmental Engineering, Guizhou University, Guiyang 550003, China Edited by Gregory D. Edgecombe, The Natural History Museum, London, United Kingdom, and accepted by the Editorial Board January 29, 2016 (received for review November 14, 2015) Panarthropods are typified by disparate grades of neurological feature as the VNC. This interpretation is supported by com- organization reflecting a complex evolutionary history. The fossil parisons with other preserved components of the internal anat- record offers a unique opportunity to reconstruct early character omy. For instance, the VNC can be readily distinguished from evolution of the nervous system via exceptional preservation in the digestive tract of C. kunmingensis, which is expressed as a extinct representatives. Here we describe the neurological archi- comparatively larger (maximum width, ∼860 μm) but fully tecture of the ventral nerve cord (VNC) in the upper-stem group compressed, linear structure running almost the entire length of euarthropod Chengjiangocaris kunmingensis from the early Cam- the animal (23, figure 1 d and e). The VNC extends from at least brian Xiaoshiba Lagerstätte (South China). The VNC of C. kunmin- the five anteriormost reduced trunk tergites (i.e., dorsal exo- gensis comprises a homonymous series of condensed ganglia that skeletal plates) to tergite T23 at the posterior end of the trunk extend throughout the body, each associated with a pair of bi- (Figs.
    [Show full text]
  • REVIEW the Neuroendocrine System of Invertebrates
    555 REVIEW The neuroendocrine system of invertebrates: a developmental and evolutionary perspective Volker Hartenstein Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, California 90095, USA (Requests for offprints should be addressed to V Hartenstein; Email: [email protected]) Abstract Neuroendocrine control mechanisms are observed in all the evolutionary origin and possible homologies between animals that possess a nervous system. Recent analyses of neuroendocrine systems. This review intends to provide a neuroendocrine functions in invertebrate model systems brief overview of invertebrate neuroendocrine systems and to reveal a great degree of similarity between phyla as far apart discuss aspects of their development that appear to be as nematodes, arthropods, and chordates. Developmental conserved between insects and vertebrates. studies that emphasize the comparison between different Journal of Endocrinology (2006) 190, 555–570 animal groups will help to shed light on questions regarding Endocrine and neuroendocrine cells through absorption and excretion, the formation and maturation of gametes, and growth and regeneration of the Cells in multicellular animals communicate through signaling body. In many instances, endocrine glands form an integrated mechanisms that take place at direct intercellular contacts, or system in which hormonal production and release is that involve signals released systemically into the extracellular controlled through feed back loops. space where they diffuse over large distances and are able to Most hormones found throughout the animal kingdom are affect targets far removed from the signaling source. The first short polypeptides, produced by proteolytic cleavage from mechanism, communication of cells that are in direct contact, larger precursor proteins, called prohormones.
    [Show full text]