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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. -
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. -
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. -
Biomineralization and Evolutionary History Andrew H
1 111 Biomineralization and Evolutionary History Andrew H. Knoll Department of Organismic and Evolutionary Biology Harvard University Cambridge, Massachusetts, 02138 U.S.A. INTRODUCTION The Dutch ethologist Niko Tinbergen famously distinguished between proximal and ultimate explanations in biology. Proximally, biologists seek a mechanistic understanding of how organisms function; most of this volume addresses the molecular and physiological bases of biomineralization. But while much of biology might be viewed as a particularly interesting form of chemistry, it is more than that. Biology is chemistry with a history, requiring that proximal explanations be grounded in ultimate, or evolutionary, understanding. The physiological pathways by which organisms precipitate skeletal minerals and the forms and functions of the skeletons they fashion have been shaped by natural selection through geologic time, and all have constrained continuing evolution in skeleton-forming clades. In this chapter, I outline some major patterns of skeletal evolution inferred from phylogeny and fossils (Figure 1), highlighting ways that our improving mechanistic knowledge of biomineralization can help us to understand this evolutionary record (see Leadbetter and Riding 1986; Lowenstam and Weiner 1989; Carter 1990; and Simkiss and Wilbur 1989 for earlier reviews). Figure 1. A geologic time scale for the past 1000 million years, showing the principal time divisions used in Earth science and the timing of major evolutionary events discussed in this chapter. Earlier intervals of time—the Mesoproterozoic (1600–1000 million years ago) and Paleoproterozoic (2500– 1600 million years ago) eras of the Proterozoic Eon and the Archean Eon (> 2500 million years ago)— are not shown. Time scale after Remane (2000). -
Abstract Book JMIH 2011
Abstract Book JMIH 2011 Abstracts for the 2011 Joint Meeting of Ichthyologists & Herpetologists AES – American Elasmobranch Society ASIH - American Society of Ichthyologists & Herpetologists HL – Herpetologists’ League NIA – Neotropical Ichthyological Association SSAR – Society for the Study of Amphibians & Reptiles Minneapolis, Minnesota 6-11 July 2011 Edited by Martha L. Crump & Maureen A. Donnelly 0165 Fish Biogeography & Phylogeography, Symphony III, Saturday 9 July 2011 Amanda Ackiss1, Shinta Pardede2, Eric Crandall3, Paul Barber4, Kent Carpenter1 1Old Dominion University, Norfolk, VA, USA, 2Wildlife Conservation Society, Jakarta, Java, Indonesia, 3Fisheries Ecology Division; Southwest Fisheries Science Center, Santa Cruz, CA, USA, 4University of California, Los Angeles, CA, USA Corroborated Phylogeographic Breaks Across the Coral Triangle: Population Structure in the Redbelly Fusilier, Caesio cuning The redbelly yellowtail fusilier, Caesio cuning, has a tropical Indo-West Pacific range that straddles the Coral Triangle, a region of dynamic geological history and the highest marine biodiversity on the planet. Caesio cuning is a reef-associated artisanal fishery, making it an ideal species for assessing regional patterns of gene flow for evidence of speciation mechanisms as well as for regional management purposes. We evaluated the genetic population structure of Caesio cuning using a 382bp segment of the mitochondrial control region amplified from over 620 fish sampled from 33 localities across the Philippines and Indonesia. Phylogeographic -
Diversity of Animals 355 15 | DIVERSITY of ANIMALS
Concepts of Biology Chapter 15 | Diversity of Animals 355 15 | DIVERSITY OF ANIMALS Figure 15.1 The leaf chameleon (Brookesia micra) was discovered in northern Madagascar in 2012. At just over one inch long, it is the smallest known chameleon. (credit: modification of work by Frank Glaw, et al., PLOS) Chapter Outline 15.1: Features of the Animal Kingdom 15.2: Sponges and Cnidarians 15.3: Flatworms, Nematodes, and Arthropods 15.4: Mollusks and Annelids 15.5: Echinoderms and Chordates 15.6: Vertebrates Introduction While we can easily identify dogs, lizards, fish, spiders, and worms as animals, other animals, such as corals and sponges, might be easily mistaken as plants or some other form of life. Yet scientists have recognized a set of common characteristics shared by all animals, including sponges, jellyfish, sea urchins, and humans. The kingdom Animalia is a group of multicellular Eukarya. Animal evolution began in the ocean over 600 million years ago, with tiny creatures that probably do not resemble any living organism today. Since then, animals have evolved into a highly diverse kingdom. Although over one million currently living species of animals have been identified, scientists are [1] continually discovering more species. The number of described living animal species is estimated to be about 1.4 million, and there may be as many as 6.8 million. Understanding and classifying the variety of living species helps us to better understand how to conserve and benefit from this diversity. The animal classification system characterizes animals based on their anatomy, features of embryological development, and genetic makeup. -
Evolutionary Crossroads in Developmental Biology: Cyclostomes (Lamprey and Hagfish) Sebastian M
PRIMER SERIES PRIMER 2091 Development 139, 2091-2099 (2012) doi:10.1242/dev.074716 © 2012. Published by The Company of Biologists Ltd Evolutionary crossroads in developmental biology: cyclostomes (lamprey and hagfish) Sebastian M. Shimeld1,* and Phillip C. J. Donoghue2 Summary and is appealing because it implies a gradual assembly of vertebrate Lampreys and hagfish, which together are known as the characters, and supports the hagfish and lampreys as experimental cyclostomes or ‘agnathans’, are the only surviving lineages of models for distinct craniate and vertebrate evolutionary grades (i.e. jawless fish. They diverged early in vertebrate evolution, perceived ‘stages’ in evolution). However, only comparative before the origin of the hinged jaws that are characteristic of morphology provides support for this phylogenetic hypothesis. The gnathostome (jawed) vertebrates and before the evolution of competing hypothesis, which unites lampreys and hagfish as sister paired appendages. However, they do share numerous taxa in the clade Cyclostomata, thus equally related to characteristics with jawed vertebrates. Studies of cyclostome gnathostomes, has enjoyed unequivocal support from phylogenetic development can thus help us to understand when, and how, analyses of protein-coding sequence data (e.g. Delarbre et al., 2002; key aspects of the vertebrate body evolved. Here, we Furlong and Holland, 2002; Kuraku et al., 1999). Support for summarise the development of cyclostomes, highlighting the cyclostome theory is now overwhelming, with the recognition of key species studied and experimental methods available. We novel families of non-coding microRNAs that are shared then discuss how studies of cyclostomes have provided exclusively by hagfish and lampreys (Heimberg et al., 2010). -
The Early History of the Metazoa—A Paleontologist's Viewpoint
ISSN 20790864, Biology Bulletin Reviews, 2015, Vol. 5, No. 5, pp. 415–461. © Pleiades Publishing, Ltd., 2015. Original Russian Text © A.Yu. Zhuravlev, 2014, published in Zhurnal Obshchei Biologii, 2014, Vol. 75, No. 6, pp. 411–465. The Early History of the Metazoa—a Paleontologist’s Viewpoint A. Yu. Zhuravlev Geological Institute, Russian Academy of Sciences, per. Pyzhevsky 7, Moscow, 7119017 Russia email: [email protected] Received January 21, 2014 Abstract—Successful molecular biology, which led to the revision of fundamental views on the relationships and evolutionary pathways of major groups (“phyla”) of multicellular animals, has been much more appre ciated by paleontologists than by zoologists. This is not surprising, because it is the fossil record that provides evidence for the hypotheses of molecular biology. The fossil record suggests that the different “phyla” now united in the Ecdysozoa, which comprises arthropods, onychophorans, tardigrades, priapulids, and nemato morphs, include a number of transitional forms that became extinct in the early Palaeozoic. The morphology of these organisms agrees entirely with that of the hypothetical ancestral forms reconstructed based on onto genetic studies. No intermediates, even tentative ones, between arthropods and annelids are found in the fos sil record. The study of the earliest Deuterostomia, the only branch of the Bilateria agreed on by all biological disciplines, gives insight into their early evolutionary history, suggesting the existence of motile bilaterally symmetrical forms at the dawn of chordates, hemichordates, and echinoderms. Interpretation of the early history of the Lophotrochozoa is even more difficult because, in contrast to other bilaterians, their oldest fos sils are preserved only as mineralized skeletons. -
Lesson 2 Craniate/Vertebrate Characteristics Lesson Outline
Lesson 2 Craniate/Vertebrate Characteristics ◊ Lesson Outline: ♦ Protostomes versus Deuterostomes ♦ The Chordate Body Plan ♦ Craniate Characteristics ♦ Vertebrate Characteristics ♦ Origin of the Chordates ◊ Objectives: At the end of this lesson you should be able to: ♦ Distinguish between prototomes and deuterostomes ♦ Describe the features of the basic chordate body plan ♦ Describe the characteristics common to all craniates ♦ Describe the characteristics that distinguish craniates and vertebrates ♦ Describe the origin of the Chordates ◊ References: ♦ Chapter 1 and 3 (read only) ◊ Reading for Next Lesson: ♦ Chapter 4 Chordate Body Plan Despite the tremendous diversity within the animal kingdom, there are only a few different types of body plan Large numbers of animals are descendent from common ancestors and the common ancestry determines much of the basic similarity in body organization Thus, all chordates have a common body plan that is unique to this group. Other plans include: Coelenterate Body Plan Flatworm Body Plan Round Worm Body Plan Annelid Body Plan Arthropod Body Plan Molluscan Body Plan Ecinoderm Body Plan Chordate/Vertebrate Body Plan There are departures from each plan (parasites for instance) raising questions about "Why" and "How" they have occurred. Protostomes vs Deuterostomes (not in textbook) The chordates are descended from ancestors that were distinguished by the fact that at some point in their development they were bilaterally symmetrical and had a coelom or body cavity. Within the coelomates two distinct and independent evolutionary lines are present. One line is the protostomes, which includes the molluscs, annelids, arthropods and many smaller groups. The other line is the deuterostomes which includes the echinoderms, protochordates and chordates The division into these two groups has been made based on embryonic characteristics. -
Life Science Journal, 2012;9(2)
Life Science Journal, 2012;9(2) http://www.lifesciencesite.com Anatomical Studied on the Cranial Nerves of Liza Ramada (Family: Mugilidae) Nervus Glossopharyngeus Dakrory, A.I1; Ali, R.S2. and Issa, A.Z1. 1Department of Zoology, Faculty of Science, Cairo University 2Department of Zoology, Faculty of Science, Helwan University [email protected] Abstract: This study deals with the nervus glossopharyngeus of Liza ramada. The microscopic observations showed that, the nervus glosspharyngeus arises by one root and leaves the cranial cavity through its own foramen. It gives visceromotor fibres for the first levator arcualis branchialis muscles. It has single extracranially located epibranchial (petrosal) ganglion. The ramus pretrematicus carries general viscerosensory fibres for the epithelial lining of the pharynx and special ones for the taste buds.The ramus posttrematicus carries both general viscerosensory fibres for the epithelial lining of the pharynx and special ones for the gill filaments, as well as visceromotor fibres for the first adductor arcualis branchialis and the first obliquus ventralis muscle. [Dakrory, A.I.; Ali, R.S. and Issa, A.Z. Anatomical Studied on the Cranial Nerves of Liza Ramada (Family: Mugilidae) Nervus Glossopharyngeus] Life Science Journal 2012;9(2):86-93]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 15 Key Words: Nervus glossopharyngeus- Liza ramada. 1. Introduction: studied the ciliary ganglion and its anatomical The study of the cranial nerves is important relations in some bony fishes. because their distribution is correlated with the habits It is quite evident from the above historical and habitats of animals and also because they show an review that there are numerous works on the cranial evolutionary trend among animals of the same group. -
KINGDOM ANIMALIA: the Deuterostomes Animal Diversity
KINGDOM ANIMALIA: The Deuterostomes Animal Diversity chordates Deuterostomes echinoderms arthropods tardigrades Ecdysozoa roundworms Protostomes rotifers mollusks Lophotrochozoa annelids flatworms Animals with a 3-layer embryo cnidarians Animals with tissues sponges placozoans Animals 2 Fig. 25-7b, p. 407 DEUTEROSTOME COELOMATES Phylum Echinodermata Phylum Chordata 3 DEUTEROSTOMES Phylum Echinodermata Echinoderm = “spiny skin” ~10,000 species (mostly marine) Examples Sea star, sea urchin, sea cucumber, sand dollar 4 Echinoderms Characteristics 5 part body plan Symmetry (most) Larvae bilateral Adult “radial” Water vascular system Movement 5 Water Vascular System 6 Animal Diversity chordates Deuterostomes echinoderms arthropods tardigrades Ecdysozoa roundworms Protostomes rotifers mollusks Lophotrochozoa annelids flatworms Animals with a 3-layer embryo cnidarians Animals with tissues sponges placozoans Animals 7 Fig. 25-7b, p. 407 PHYLUM CHORDATA ~50,000 species 4 common features Notochord Dorsal hollow nerve cord Pharyngeal slits Post anal tail Other common characteristics Bilateral Coelomate Cephalization Complete digestive system Closed circulatory system 8 Chordates Vertebrates & invertebrate species Invertebrate chordates No backbone ~2,100 species Vertebrate chordates Backbone of cartilage or bone Brain enclosed in skull 9 Chordate Phylogeny tunicates lampreys ray-finned fishes lungfishes “reptiles” lancelets hagfishes cartilaginous amphibians birds mammals fishes lobe-finned fishes amniotes tetrapods -
Sensory System Evolution at the Origin of Craniates
doi 10.1098/rstb.2000.0690 Sensorysystemevolution at theorigin of craniates AnnB. Butler Krasnow Institute for Advanced Studyand Department of Psychology,MSN 2A1,George Mason University, Fairfax,VA22030,USA ([email protected] ) Themultiple events atthe transitionfrom non-craniate invertebrate ancestors tocraniates included the gainand/ orelaborationof migratory neural crest andneurogenic placodes. These tissues giverise tothe peripherallylocated, bipolar neurons of allnon-visual sensory systems. Thebrain was also elaborated at orabout this same time. Were the peripheraland central events simultaneousor sequential ?Aserial transformationhypothesis postulates that pairedeyes andan enlarged brain evolved before the elabora- tionof migratory neural crest ^placodalsensory systems. Circumstantialevidence for this scenariois derivedfrom the independentoccurrence ofthe combinationof large,paired eyes plusa large,elaborated brainin atleast three taxa(cephalochordates, arthropods and craniates) andpartly from the exclusivity ofthe diencephalonfor visual system-related distalsensory components versus the restricted distribution ofmigratory neural crest ^placodalsensory systems tothe remainingparts ofthe neuraxis.This scenario accountsfor the similarity ofall central sensorysystem pathwaysdue to the primaryestablishment of descendingvisual pathways via the diencephalonand midbrain tectum tobrainstem motorregions and the subsequent exploitationof the same central beachheadby the migratoryneural crest ^placodal systems asatemplate fortheir organization.