Chordate Evolution and the Origin of Craniates: an Old Brain in a New Head
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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. -
PALEONTOLOGICAL TECHNICAL REPORT: 6Th AVENUE and WADSWORTH BOULEVARD INTERCHANGE PHASE II ENVIRONMENTAL ASSESSMENT, CITY of LAKEWOOD, JEFFERSON COUNTY, COLORADO
PALEONTOLOGICAL TECHNICAL REPORT: 6th AVENUE AND WADSWORTH BOULEVARD INTERCHANGE PHASE II ENVIRONMENTAL ASSESSMENT, CITY OF LAKEWOOD, JEFFERSON COUNTY, COLORADO Prepared for: TEC Inc. 1746 Cole Boulevard, Suite 265 Golden, CO 80401 Prepared by: Paul C. Murphey, Ph.D. and David Daitch M.S. Rocky Mountain Paleontology 4614 Lonespur Court Oceanside, CA 92056 303-514-1095; 760-758-4019 www.rockymountainpaleontology.com Prepared under State of Colorado Paleontological Permit 2007-33 January, 2007 TABLE OF CONTENTS 1.0 SUMMARY............................................................................................................................. 3 2.0 INTRODUCTION ................................................................................................................... 4 2.1 DEFINITION AND SIGNIFICANCE OF PALEONTOLOGICAL RESOURCES........... 4 3.0 METHODS .............................................................................................................................. 6 4.0. LAWS, ORDINANCES, REGULATIONS AND STANDARDS......................................... 7 4.1. Federal................................................................................................................................. 7 4.2. State..................................................................................................................................... 8 4.3. County................................................................................................................................. 8 4.4. City..................................................................................................................................... -
The Origins of Chordate Larvae Donald I Williamson* Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
lopmen ve ta e l B Williamson, Cell Dev Biol 2012, 1:1 D io & l l o l g DOI: 10.4172/2168-9296.1000101 e y C Cell & Developmental Biology ISSN: 2168-9296 Research Article Open Access The Origins of Chordate Larvae Donald I Williamson* Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom Abstract The larval transfer hypothesis states that larvae originated as adults in other taxa and their genomes were transferred by hybridization. It contests the view that larvae and corresponding adults evolved from common ancestors. The present paper reviews the life histories of chordates, and it interprets them in terms of the larval transfer hypothesis. It is the first paper to apply the hypothesis to craniates. I claim that the larvae of tunicates were acquired from adult larvaceans, the larvae of lampreys from adult cephalochordates, the larvae of lungfishes from adult craniate tadpoles, and the larvae of ray-finned fishes from other ray-finned fishes in different families. The occurrence of larvae in some fishes and their absence in others is correlated with reproductive behavior. Adult amphibians evolved from adult fishes, but larval amphibians did not evolve from either adult or larval fishes. I submit that [1] early amphibians had no larvae and that several families of urodeles and one subfamily of anurans have retained direct development, [2] the tadpole larvae of anurans and urodeles were acquired separately from different Mesozoic adult tadpoles, and [3] the post-tadpole larvae of salamanders were acquired from adults of other urodeles. Reptiles, birds and mammals probably evolved from amphibians that never acquired larvae. -
Phylum Arthropod Silvia Rondon, and Mary Corp, OSU Extension Entomologist and Agronomist, Respectively Hermiston Research and Extension Center, Hermiston, Oregon
Phylum Arthropod Silvia Rondon, and Mary Corp, OSU Extension Entomologist and Agronomist, respectively Hermiston Research and Extension Center, Hermiston, Oregon Member of the Phyllum Arthropoda can be found in the seas, in fresh water, on land, or even flying freely; a group with amazing differences of structure, and so abundant that all the other animals taken together are less than 1/6 as many as the arthropods. Well-known members of this group are the Kingdom lobsters, crayfish and crabs; scorpions, spiders, mites, ticks, Phylum Phylum Phylum Class the centipedes and millipedes; and last, but not least, the Order most abundant of all, the insects. Family Genus The Phylum Arthropods consist of the following Species classes: arachnids, chilopods, diplopods, crustaceans and hexapods (insects). All arthropods possess: • Exoskeleton. A hard protective covering around the outside of the body (divided by sutures into plates called sclerites). An insect's exoskeleton (integument) serves as a protective covering over the body, but also as a surface for muscle attachment, a water-tight barrier against desiccation, and a sensory interface with the environment. It is a multi-layered structure with four functional regions: epicuticle (top layer), procuticle, epidermis, and basement membrane. • Segmented body • Jointed limbs and jointed mouthparts that allow extensive specialization • Bilateral symmetry, whereby a central line can divide the body Insect molting or removing its into two identical halves, left and right exoesqueleton • Ventral nerve -
Abstract Introduction
Marine and Freshwater Miscellanea III KEY TRAITS OF AMPHIOXUS SPECIES (CEPHALOCHORDATA) AND THE GOLT1 Daniel Pauly and Elaine Chu Sea Around Us, Institute for the Oceans and Fisheries University of British Columbia, Vancouver, B.C, Canada Email: [email protected] Abstract Major biological traits of amphioxus species (Cephalochordata) are presented with emphasis on the size reached by their 32 valid species in the genera Asymmetron (2 spp.), Branchiostoma (25 spp.), and Epigonichthys (5 spp.) and on related features, i.e., growth parameters and size at first maturity. Overall, these traits combined with features of their respiration, suggest that the cephalochordates conform to the Gill Oxygen Limitation Theory (GOLT), which relates the growth performance of water-breathing ectotherms to the surface area of their respiratory organ(s). Introduction The small fish-like animals know as ‘lancelet‘ or ‘amphioxius’ belong the subphylum Cephalochordata, which is either a sister group, or related to the ancestor of the vertebrate animals (see Garcia-Fernàndez and Benito-Gutierrez 2008). The cephalochordates consist of 3 families (the Asymmetronidae, Epigonichthyidae and Branchiostomidae), with one genus each, Asymmetron (2 spp.), Branchiostoma (24 spp.) and Epigonichthys (6 spp.), as detailed in Table 1 and SeaLifeBase (www.sealifebase.org). This contribution is to assemble some of the basic biological traits of lancelets (Figure 1), notably the maximum size each of their 34 species can reach, which is easily their most important attribute, though it is often ignored (Haldane 1926). Finally, reported lengths at first maturity of cephalochordates were related to the corresponding, population-specific maximum length, to test whether these animals mature as predicted by the Gill- Oxygen Limitation Theory (GOLT; see Pauly 2021a, 2021b). -
Alyssa Weinrauch
The digestive physiology of the Pacific hagfish, Eptatretus stoutii by Alyssa Weinrauch A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physiology, Cell and Developmental Biology Department of Biological Sciences University of Alberta © Alyssa Weinrauch, 2019 Abstract Hagfish are considered the oldest living representatives of the vertebrates and as such are of interest for studies in evolutionary biology. Moreover, hagfish occupy a unique trophic niche wherein they are active predators and benthic scavengers of a wide range of invertebrate and vertebrate prey, yet can tolerate nearly a year of fasting. Hagfish are also capable of acquiring nutrients across the integument in a manner similar to that of marine invertebrates, a hallmark of their position between the invertebrate and vertebrate lineages. Despite many interesting modes of feeding, relatively few studies have examined the digestive physiology of the hagfishes. Feeding and digestion cause many physiological perturbations, which result in elevated metabolic rate. I have characterised the increased metabolic demand (specific dynamic action) and determined that its peak in hagfish corresponds with the peak of acid-base alterations. Specifically, the rate of base efflux reaches a maximum 8 h post- feeding when the intestinal blood supply is significantly more alkaline. The offloading of base to the circulation (alkaline tide) is common of vertebrates that employ an acidic digestion in order to maintain cellular acid-base homeostasis. Likewise, the hagfishes employ a luminal acidification, despite lacking a stomach. I further investigated the cellular mechanisms responsible for hindgut luminal acidification and found that soluble adenylyl cyclase and cAMP are utilised to enhance proton secretion via proton-potassium exchangers (HKA), as is found in later-diverging vertebrates. -
Vertebrates and Invertebrates
Vertebrates and invertebrates The animal kingdom is divided into two groups: vertebrates and invertebrates. Vertebrates have been around for millions of years but have evolved and changed over time. The word vertebrate means “having a backbone." Many animals have backbones. You have a backbone. So does a cow, a whale, a fish, a frog, and a bird. Vertebrates are animals that have a backbone. Most animals have a backbone that is made of bones joined together to form a skeleton. Our skeleton gives us our shape and allows us to move. Mammals, fish, birds, reptiles, and amphibians have Vertebrae backbones so they are all vertebrates. Each bone that makes up the backbone Scientists classify vertebrates into five classes: is called a vertebra. These are the • Mammals building blacks that form the backbone, • Fish also known as the spinal cord. The • Birds vertebrae protect and support your • Reptiles spine. Without a backbone, you would not • Amphibians be able to move any part of your body. Animals without a backbone are called invertebrates. Most The human animals are invertebrates. In fact, 95% of all living creatures backbone has 26 on Earth are invertebrates. vertebrae. Arthropods are the largest group of invertebrates. Insects make up a large part of this group. All insects, such as ladybugs, ants, grasshoppers, and bumblebees have three body sections and six legs. Most arthropods live on land, but some of these fascinating creatures live in water. Lobsters, crabs, and shrimp are arthropods that live in the oceans. Many invertebrates have skeletons on the outside of their A frog only has bodies called exoskeletons. -
Using Information in Taxonomists' Heads to Resolve Hagfish And
This article was downloaded by: [Max Planck Inst fuer Evolutionsbiologie] On: 03 September 2013, At: 07:01 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Historical Biology: An International Journal of Paleobiology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ghbi20 Using information in taxonomists’ heads to resolve hagfish and lamprey relationships and recapitulate craniate–vertebrate phylogenetic history Maria Abou Chakra a , Brian Keith Hall b & Johnny Ricky Stone a b c d a Department of Biology , McMaster University , Hamilton , Canada b Department of Biology , Dalhousie University , Halifax , Canada c Origins Institute, McMaster University , Hamilton , Canada d SHARCNet, McMaster University , Hamilton , Canada Published online: 02 Sep 2013. To cite this article: Historical Biology (2013): Using information in taxonomists’ heads to resolve hagfish and lamprey relationships and recapitulate craniate–vertebrate phylogenetic history, Historical Biology: An International Journal of Paleobiology To link to this article: http://dx.doi.org/10.1080/08912963.2013.825792 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. -
Introduction to Phylum Chordata
Unifying Themes 1. Chordate evolution is a history of innovations that is built upon major invertebrate traits •bilateral symmetry •cephalization •segmentation •coelom or "gut" tube 2. Chordate evolution is marked by physical and behavioral specializations • For example the forelimb of mammals has a wide range of structural variation, specialized by natural selection 3. Evolutionary innovations and specializations led to adaptive radiations - the development of a variety of forms from a single ancestral group Characteristics of the Chordates 1. Notochord 2. dorsal hollow nerve cord 3. pharyngeal gill slits 4. postanal tail 5. endostyle Characteristics of the Chordates Notochord •stiff, flexible rod, provides internal support • Remains throughout the life of most invertebrate chordates • only in the embryos of vertebrate chordates Characteristics of the Chordates cont. Dorsal Hollow Nerve Cord (Spinal Cord) •fluid-filled tube of nerve tissue, runs the length of the animal, just dorsal to the notochord • Present in chordates throughout embryonic and adult life Characteristics of the Chordates cont. Pharyngeal gill slits • Pairs of opening through the pharynx • Invertebrate chordates use them to filter food •In fishes the gill sits develop into true gills • In reptiles, birds, and mammals the gill slits are vestiges (occurring only in the embryo) Characteristics of the Chordates cont. Endostyle • mucous secreting structure found in the pharynx floor (traps small food particles) Characteristics of the Chordates cont. Postanal Tail • works with muscles (myomeres) & notochord to provide motility & stability • Aids in propulsion in nonvertebrates & fish but vestigial in later lineages SubPhylum Urochordata Ex: tunicates or sea squirts • Sessile as adults, but motile during the larval stages • Possess all 5 chordate characteristics as larvae • Settle head first on hard substrates and undergo a dramatic metamorphosis • tail, notochord, muscle segments, and nerve cord disappear SubPhylum Urochordata cont. -
Single Cell Chromatin Accessibility of the Developmental
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.17.994954; this version posted March 19, 2020. 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. Single cell chromatin accessibility of the developmental cephalochordate Dongsheng Chen1, Zhen Huang2,3, Xiangning Ding1,4, Zaoxu Xu1,4, Jixing Zhong1,4, Langchao Liang1,4, Luohao Xu5, Chaochao Cai1,4, Haoyu Wang1,4, Jiaying Qiu1,4, Jiacheng Zhu1,4, Xiaoling Wang1,4, Rong Xiang1,4, Weiying Wu1,4, Peiwen Ding1,4, Feiyue Wang1,4, Qikai Feng1,4, Si Zhou1, Yuting Yuan1, Wendi Wu1, Yanan Yan2,3, Yitao Zhou2,3, Duo Chen2,3, Guang Li6, Shida Zhu1, Fang Chen1,7, Qiujin Zhang2,3, Jihong Wu8,9,10,11 &Xun Xu1 1. BGI-shenzhen, Shenzhen 518083, China 2. Life Science College, Fujian Normal University 3. Key Laboratory of Special Marine Bio-resources Sustainable Utilization of Fujian Province, Fuzhou 350108, P. R. China 4. BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China 5. Department of Neuroscience and Developmental Biology, University of Vienna 6. State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, Fujian 361102, China 7. MGI, BGI-Shenzhen, Shenzhen 518083, China 8. Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China 9. Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China 10. -
Hemichordate Phylogeny: a Molecular, and Genomic Approach By
Hemichordate Phylogeny: A molecular, and genomic approach by Johanna Taylor Cannon A dissertation submitted to the Graduate Faculty of Auburn University in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Auburn, Alabama May 4, 2014 Keywords: phylogeny, evolution, Hemichordata, bioinformatics, invertebrates Copyright 2014 by Johanna Taylor Cannon Approved by Kenneth M. Halanych, Chair, Professor of Biological Sciences Jason Bond, Associate Professor of Biological Sciences Leslie Goertzen, Associate Professor of Biological Sciences Scott Santos, Associate Professor of Biological Sciences Abstract The phylogenetic relationships within Hemichordata are significant for understanding the evolution of the deuterostomes. Hemichordates possess several important morphological structures in common with chordates, and they have been fixtures in hypotheses on chordate origins for over 100 years. However, current evidence points to a sister relationship between echinoderms and hemichordates, indicating that these chordate-like features were likely present in the last common ancestor of these groups. Therefore, Hemichordata should be highly informative for studying deuterostome character evolution. Despite their importance for understanding the evolution of chordate-like morphological and developmental features, relationships within hemichordates have been poorly studied. At present, Hemichordata is divided into two classes, the solitary, free-living enteropneust worms, and the colonial, tube- dwelling Pterobranchia. The objective of this dissertation is to elucidate the evolutionary relationships of Hemichordata using multiple datasets. Chapter 1 provides an introduction to Hemichordata and outlines the objectives for the dissertation research. Chapter 2 presents a molecular phylogeny of hemichordates based on nuclear ribosomal 18S rDNA and two mitochondrial genes. In this chapter, we suggest that deep-sea family Saxipendiidae is nested within Harrimaniidae, and Torquaratoridae is affiliated with Ptychoderidae. -
Fins, Limbs, and Tails: Outgrowths and Axial Patterning in Vertebrate Evolution Michael I
Review articles Fins, limbs, and tails: outgrowths and axial patterning in vertebrate evolution Michael I. Coates1* and Martin J. Cohn2 Summary Current phylogenies show that paired fins and limbs are unique to jawed verte- brates and their immediate ancestry. Such fins evolved first as a single pair extending from an anterior location, and later stabilized as two pairs at pectoral and pelvic levels. Fin number, identity, and position are therefore key issues in vertebrate developmental evolution. Localization of the AP levels at which develop- mental signals initiate outgrowth from the body wall may be determined by Hox gene expression patterns along the lateral plate mesoderm. This regionalization appears to be regulated independently of that in the paraxial mesoderm and axial skeleton. When combined with current hypotheses of Hox gene phylogenetic and functional diversity, these data suggest a new model of fin/limb developmental evolution. This coordinates body wall regions of outgrowth with primitive bound- aries established in the gut, as well as the fundamental nonequivalence of pectoral and pelvic structures. BioEssays 20:371–381, 1998. 1998 John Wiley & Sons, Inc. Introduction over and again to exemplify fundamental concepts in biological Vertebrate appendages include an amazing diversity of form, theory. The striking uniformity of teleost pectoral fin skeletons from the huge wing-like fins of manta rays or the stumpy limbs of illustrated Geoffroy Saint-Hilair’s discussion of ‘‘special analo- frogfishes, to ichthyosaur paddles, the extraordinary fingers of gies,’’1 while tetrapod limbs exemplified Owen’s2 related concept aye-ayes, and the fin-like wings of penguins. The functional of ‘‘homology’’; Darwin3 then employed precisely the same ex- diversity of these appendages is similarly vast and, in addition to ample as evidence of evolutionary descent from common ances- various modes of locomotion, fins and limbs are also used for try.