DOCSLIB.ORG

Multiple Opsin Genes in the Ancestral Vertebrates

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Multiple Opsin Genes in the Ancestral Vertebrates View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Magazine R864 Correspondence were isolated by 5′- and 3′-RACE- species Petromyzon marinus and PCR and the complete coding Lampetra japonica are most sequence of each gene was closely related to the G. australis reconstructed. The sequence of RhA opsin gene, rather than to the Ancient colour the G. australis opsin genes was gnathostome Rh1 gene, with vision: multiple confirmed by amplification of which they have previously been each cDNA as a single fragment grouped [5]. We therefore suggest opsin genes in the using a proof reading DNA that the northern hemisphere polymerase. The sequences of lamprey genes be renamed P. ancestral the PCR primers and sequence marinus RhA opsin and L. japonica alignments of the five G. australis RhA opsin. vertebrates opsin genes are provided as Other investigators have supplementary material (Genbank speculated that the ancestors of Shaun P. Collin1*, Maree A. accession numbers: all vertebrates must have Knight1, Wayne L. Davies1, Ian C. AY366491–AY366495). possessed the five major types of Potter2, David M. Hunt3 and Ann The five G. australis opsin cDNA opsin genes: LWS, SWS1, SWS2, E.O. Trezise1 sequences were compared with Rh1 and Rh2 [5]. However, this the major groups of opsin genes study is the first to demonstrate Molecular investigation of the from a broad range of unequivocally that the molecular origin of colour vision has representative vertebrate species. events giving rise to four of the discovered five visual pigment A codon-matched nucleotide five classes of vertebrate opsin (opsin) genes, all of which are sequence alignment provided the genes must have already taken expressed in an agnathan (jawless) basis for estimating the place by the early Cambrian fish, the lamprey Geotria australis. evolutionary distances between (approximately 540 mya [1]), prior Lampreys are extant the gnathostome (jawed to the evolution of the jawed representatives of an ancient group vertebrate) and G. australis opsins vertebrates. Uniquely, our results of vertebrates whose origins are and the neighbour-joining method suggest that the duplication of the thought to date back to at least the [4] was used to infer phylogenetic ancestral Rh gene, to give rise to early Cambrian, approximately 540 relationships. The resulting the true rod (Rh1) and the green million years ago [1]. Phylogenetic phylogenetic tree (Figure 1C) cone (Rh2) opsins of the jawed analysis has identified the visual shows that the G. australis LWS, vertebrates, occurred specifically pigment opsin genes of G. australis SWS1 and SWS2 opsin genes are within the gnathostomes and as orthologues of the major orthologous to the LWS, SWS1 independently of the agnathan classes of vertebrate opsin genes. and SWS2 opsin genes of the lineage. This finding provides Therefore, multiple opsin genes jawed vertebrates, with the insight into previous work, which must have originated very early in branching order within each gene identified rod-like photoreceptors vertebrate evolution, prior to the group largely following the in some jawless fishes. However, separation of the jawed and accepted order of appearance of these rod-like cells also show jawless vertebrate lineages, and the vertebrate species. The two some morphological [6,7] and thereby provided the genetic basis remaining G. australis opsin genes, physiological [8] characteristics of for colour vision in all vertebrate RhA and RhB, are most closely cone photoreceptors. As this species. related to the gnathostome Rh1 study suggests that the true rod The southern hemisphere and Rh2 genes. However, both Rh1 gene did not appear before lamprey Geotria australis (Figure RhA and RhB are equally distantly the evolution of the jawed 1A,B) possesses a predominantly related to the gnathostome Rh1 vertebrates, the agnathan lineage cone-based visual system gene as they are to the Rh2 gene. probably does not possess a true designed for photopic (bright This suggests that the most recent rod photoreceptor and retains light) vision [2,3]. Previous work common ancestor of the jawed cone-like features in all identified multiple cone types and jawless vertebrates most likely photoreceptors. suggesting that the potential for possessed a single ancestral Rh Therefore, the ancestral colour vision may have been opsin gene, as well as LWS, SWS1 vertebrates possessed four major present in the earliest members of and SWS2 opsin genes. After the types of vertebrate cone opsins, this group. In order to trace the separation of the agnathan and each presumably sensitive to molecular evolution and origins of gnathostome groups, two different parts of the spectrum. vertebrate colour vision, we have independent gene duplication Although the selection pressure examined the genetic events occurred, one in the underlying the origins of colour complement of visual pigment Agnatha to yield the RhA and RhB vision is still unknown, the early opsins in G. australis. opsins, and the other in the jawed vertebrates lived in a shallow We used RT-PCR with a set of vertebrates to produce the Rh1 water environment [9,10], where a degenerate primers to amplify (rod) and Rh2 (green cone) opsin wide light spectrum could be and clone partial cDNA genes. Our analysis also shows exploited by the evolution of sequences from each of the G. that the previously isolated multiple visual pigments. The australis opsin genes. rhodopsin sequences from the presence of multiple cone opsins Overlapping cDNA sequences northern hemisphere lamprey provides the potential for colour Magazine R865 References 1. Shu, D.G., Morris, S.C., Han, J., Zhang, Z.F., Yasui, K., Janvier, P., Chen, L., Zhang, X.L., Liu, J.N., Li, Y., et al. (2003). Head and backbone of the early Cambrian vertebrate Haikouichthys. Nature 421, 526–529. 2. Collin, S.P., Potter, I.C., and Braekevelt, C.R. (1999). The ocular morphology of the southern hemisphere lamprey Geotria australis Gray, with special reference to optical specializations and the characterisation and phylogeny of photoreceptor types. Brain Behav. Evol. 54, 96–111. 3. Collin, S.P., Hart, N.S., Shand, J., and Potter, I.C. (2003). Morphology and spectral absorption characteristics of retinal photoreceptors in the southern hemisphere lamprey (Geotria australis). Vis. Neurosci. 20, 119–130. 4. Saitou, N., and Nei, M. (1987). The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol. Biol. Evol. 4, 406–425. 5. Yokoyama, S. (2000). Molecular evolution of vertebrate visual pigments. Prog. Retin. Eye Res. 19, 385–419. 6. Dickson, D.H., and Graves, D.A. (1979). Fine structure of the lamprey photoreceptors and retinal pigment epithelium (Petromyzon marinus L.). Exp. Eye Res. 29, 45–60. 7. Collin, S.P., and Potter, I.C. (2000). The ocular morphology of the southern hemisphere lamprey Mordacia mordax Richardson with special reference to a single class of photoreceptor and a retinal tapetum. Brain Behav. Evol. 55, 120–138. 8. Govardovskii, V.I., and Lychakov, D.V. (1984). Visual cells and visual Figure 1. pigments of the lamprey, Lampetra The head (A) and suctorial mouth (B) of the southern hemisphere lamprey Geotria aus- fluviatilis L. J. Comp. Physiol. [A] tralis (reproduced from [3] with permission from Cambridge University Press). Scale bars, 154, 279–286. 1mm (A), 10 mm (B). (C) Phylogenetic tree showing the relationships between the opsin 9. Parker, A.R. (1998). Colour in genes of G. australis, the northern hemisphere lampreys Lampetra japonica and Petromy- Burgess Shale animals and the zon marinus, representative jawed vertebrates and an invertebrate outgroup. The black effect of light on evolution in the vertical line indicates the predicted genetic complement of opsins present in the most Cambrian. Proc. R. Soc. Lond. B recent common ancestor of the jawed and jawless vertebrates, approximately 540 million Biol. Sci. 265, 967–972. years ago [1]. A codon-matched nucleotide sequence alignment was used to estimate 10. Maximov, V.V. (2000). evolutionary distances between sequences and the tree was generated using the neigh- Environmental factors which may bour joining method [4]. The number at each branch point reflects the robustness of that have led to the appearance of branch point (maximum 100). The scale bar is calibrated in nucleotide substitutions per colour vision. Philos. Trans. R. site. Details of the sequences and methods are provided as Supplemental Data. Soc. Lond. B Biol. Sci. 355, 1239–1242. discrimination and thus a dependent on the evolution of the significant selective advantage for Rh1 opsin gene probably only 1School of Biomedical Sciences, The these early vertebrates. Based on within the jawed vertebrate University of Queensland, Brisbane 2 our findings, we suggest that lineage. 4072, Queensland, Australia. School of Biological Sciences and Biotechnology, photopic (bright light, cone-based) Murdoch University, Murdoch, Western colour vision originated first in the Supplemental Data Australia 6150, Australia. 3Institute of ancestral vertebrates, while full Supplemental data are available at Ophthalmology, University College scotopic (dim light, rod-based) http://www.current- London, Bath Street, London EC1V 9EL, vision developed later, being biology.com/supplemental UK.*E-mail: [email protected].
Load more

Recommended publications
  • Timeline of the Evolutionary History of Life
    Timeline of the evolutionary history of life This timeline of the evolutionary history of life represents the current scientific theory Life timeline Ice Ages outlining the major events during the 0 — Primates Quater nary Flowers ←Earliest apes development of life on planet Earth. In P Birds h Mammals – Plants Dinosaurs biology, evolution is any change across Karo o a n ← Andean Tetrapoda successive generations in the heritable -50 0 — e Arthropods Molluscs r ←Cambrian explosion characteristics of biological populations. o ← Cryoge nian Ediacara biota – z ← Evolutionary processes give rise to diversity o Earliest animals ←Earliest plants at every level of biological organization, i Multicellular -1000 — c from kingdoms to species, and individual life ←Sexual reproduction organisms and molecules, such as DNA and – P proteins. The similarities between all present r -1500 — o day organisms indicate the presence of a t – e common ancestor from which all known r Eukaryotes o species, living and extinct, have diverged -2000 — z o through the process of evolution. More than i Huron ian – c 99 percent of all species, amounting to over ←Oxygen crisis [1] five billion species, that ever lived on -2500 — ←Atmospheric oxygen Earth are estimated to be extinct.[2][3] Estimates on the number of Earth's current – Photosynthesis Pong ola species range from 10 million to 14 -3000 — A million,[4] of which about 1.2 million have r c been documented and over 86 percent have – h [5] e not yet been described. However, a May a -3500 — n ←Earliest oxygen 2016
    [Show full text]
  • Chordates (Phylum Chordata)
    A short story Leathem Mehaffey, III, Fall 201993 The First Chordates (Phylum Chordata) • Chordates (our phylum) first appeared in the Cambrian, 525MYA. 94 Invertebrates, Chordates and Vertebrates • Invertebrates are all animals not chordates • Generally invertebrates, if they have hearts, have dorsal hearts; if they have a nervous system it is usually ventral. • All vertebrates are chordates, but not all chordates are vertebrates. • Chordates: • Dorsal notochord • Dorsal nerve chord • Ventral heart • Post-anal tail • Vertebrates: Amphioxus: archetypal chordate • Dorsal spinal column (articulated) and skeleton 95 Origin of the Chordates 96 Haikouichthys Myllokunmingia Note the rounded extension to Possibly the oldest the head bearing sensory vertebrate: showed gill organs bars and primitive vertebral elements Early and primitive agnathan vertebrates of the Early Cambrian (530MYA) Pikaia Note: these organisms were less Primitive chordate, than an inch long. similar to Amphioxus 97 The Cambrian/Ordovician Extinction • Somewhere around 488 million years ago something happened to cause a change in the fauna of the earth, heralding the beginning of the Ordovician Period. • Rather than one catastrophe, the late-Cambrian extinction seems to be a series of smaller extinction events. • Historically the change in fauna (mostly trilobites as the index species) was thought to be due to excessive warmth and low oxygen. • But some current findings point to an oxygen spike due perhaps to continental drift into the tropics, driving rapid speciation and consequent replacement of old with new organisms. 98 Welcome to the Ordovician YOU ARE HERE 99 The Ordovician Sea, 488 million years 100 ago The Ordovician Period lasted almost 45 million years, from 489 to 444 MYA.
    [Show full text]
  • Fish and Amphibians
    Fish and Amphibians Geology 331 Paleontology Phylum Chordata: Subphyla Urochordata, Cephalochordata, and: Subphylum Vertebrata Class Agnatha: jawless fish, includes the hagfish, conodonts, lampreys, and ostracoderms (armored jawless fish) Gnathostomates: jawed fish Class Chondrichthyes: cartilaginous fish Class Placoderms: armored fish Class Osteichthyes: bony fish Subclass Actinopterygians: ray-finned fish Subclass Sarcopterygians: lobe-finned fish Order Dipnoans: lung fish Order Crossopterygians: coelocanths and rhipidistians Class Amphibia Urochordates: Sea Squirts. Adults have a pharynx with gill slits. Larval forms are free-swimming and have a notochord. Chordates are thought to have evolved from the larval form by precocious sexual maturation. Chordate evolution Cephalochordate: Branchiostoma, the lancelet Pikaia, a cephalochordate from the Burgess Shale Yunnanozoon, a cephalochordate from the Lower Cambrian of China Haikouichthys, agnathan, Lower Cambrian of China - Chengjiang fauna, scale is 5 mm A living jawless fish, the lamprey, Class Agnatha Jawless fish do have teeth! A fossil jawless fish, Class Agnatha, Ostracoderm, Hemicyclaspis, Silurian Agnathan, Ostracoderm, Athenaegis, Silurian of Canada Agnathan, Ostracoderm, Pteraspis, Devonian of the U.K. Agnathan, Ostracoderm, Liliaspis, Devonian of Russia Jaws evolved by modification of the gill arch bones. The placoderms were the armored fish of the Paleozoic Placoderm, Dunkleosteus, Devonian of Ohio Asterolepis, Placoderms, Devonian of Latvia Placoderm, Devonian of Australia Chondrichthyes: A freshwater shark of the Carboniferous Fossil tooth of a Great White shark Chondrichthyes, Great White Shark Chondrichthyes, Carcharhinus Sphyrna - hammerhead shark Himantura - a ray Manta Ray Fish Anatomy: Ray-finned fish Osteichthyes: ray-finned fish: clownfish Osteichthyes: ray-finned fish, deep water species Lophius, an Eocene fish showing the ray fins. This is an anglerfish.
    [Show full text]
  • New Evolutionary and Ecological Advances in Deciphering the Cambrian Explosion of Animal Life
    Journal of Paleontology, 92(1), 2018, p. 1–2 Copyright © 2018, The Paleontological Society 0022-3360/18/0088-0906 doi: 10.1017/jpa.2017.140 New evolutionary and ecological advances in deciphering the Cambrian explosion of animal life Zhifei Zhang1 and Glenn A. Brock2 1Shaanxi Key Laboratory of Early Life and Environments, State Key Laboratory of Continental Dynamics and Department of Geology, Northwest University, Xi’an, 710069, China 〈[email protected]〉 2Department of Biological Sciences and Marine Research Centre, Macquarie University, Sydney, NSW, 2109, Australia 〈[email protected]〉 The Cambrian explosion represents the most profound animal the body fossil record of ecdysozoans and deuterostomes is very diversification event in Earth history. This astonishing evolu- poorly known during this time, potentially the result of a distinct tionary milieu produced arthropods with complex compound lack of exceptionally preserved faunas in the Terreneuvian eyes (Paterson et al., 2011), burrowing worms (Mángano and (Fortunian and the unnamed Stage 2). However, this taxonomic Buatois, 2017), and a variety of swift predators that could cap- ‘gap’ has been partially filled with the discovery of exceptionally ture and crush prey with tooth-rimmed jaws (Bicknell and well-preserved stem group organisms in the Kuanchuanpu Paterson, 2017). The origin and evolutionary diversification of Formation (Fortunian Stage, ca. 535 Ma) from Ningqiang County, novel animal body plans led directly to increased ecological southern Shaanxi Province of central China. High diversity and complexity, and the roots of present-day biodiversity can be disparity of soft-bodied cnidarians (see Han et al., 2017b) and traced back to this half-billion-year-old evolutionary crucible.
    [Show full text]
  • LETTER Doi:10.1038/Nature13414
    LETTER doi:10.1038/nature13414 A primitive fish from the Cambrian of North America Simon Conway Morris1 & Jean-Bernard Caron2,3 Knowledge of the early evolution of fish largely depends on soft- (Extended Data Fig. 4f). Incompleteness precludes a precise estimate of bodied material from the Lower (Series 2) Cambrian period of South size range, but themostcomplete specimens (Fig.1a,b) areabout 60 mm China1,2. Owing to the rarity of some of these forms and a general in length and 8–13 mm in height. Laterally the body is fusiform, widest lack of comparative material from other deposits, interpretations of near the middle, tapering to a fine point posteriorly (Fig. 1a, b and Ex- various features remain controversial3,4, as do their wider relation- tended Data Fig. 4a), whereas in dorsal view the anterior termination is ships amongst post-Cambrian early un-skeletonized jawless verte- rounded (Fig. 1d and Extended Data Fig. 4c–e). The animal was com- brates. Here we redescribe Metaspriggina5 on the basis of new material pressed laterally, as is evident from occasional folding of the body as well from the Burgess Shale and exceptionally preserved material collected as specimensindorso-ventral orientation being conspicuously narrower near Marble Canyon, British Columbia6, and three other Cambrian (Fig. 1a and Extended Data Fig. 5a). Along the anterior ventral margin Burgess Shale-type deposits from Laurentia. This primitive fish dis- there was a keel-like structure (Fig. 1b, g, i, k, l), but no fins have been plays unambiguous vertebrate features: a notochord, a pair of prom- recognized. In the much more abundant specimens of Haikouichthys1,3,4 inent camera-type eyes, paired nasal sacs, possible cranium and arcualia, fins are seldom obvious, suggesting that their absence in Metaspriggina W-shaped myomeres, and a post-anal tail.
    [Show full text]
  • The Fossil Record of the Cambrian “Explosion”: Resolving the Tree of Life Critics As Posing Challenges to Evolution
    Article The Fossil Record of the Cambrian “Explosion”: 1 Resolving the Tree of Life Keith B. Miller Keith B. Miller The Cambrian “explosion” has been the focus of extensive scientifi c study, discussion, and debate for decades. It has also received considerable attention by evolution critics as posing challenges to evolution. In the last number of years, fossil discoveries from around the world, and particularly in China, have enabled the reconstruction of many of the deep branches within the invertebrate animal tree of life. Fossils representing “sister groups” and “stem groups” for living phyla have been recognized within the latest Precambrian (Neoproterozoic) and Cambrian. Important transitional steps between living phyla and their common ancestors are preserved. These include the rise of mollusks from their common ancestor with the annelids, the evolution of arthropods from lobopods and priapulid worms, the likely evolution of brachiopods from tommotiids, and the rise of chordates and echinoderms from early deuterostomes. With continued new discoveries, the early evolutionary record of the animal phyla is becoming ever better resolved. The tree of life as a model for the diversifi cation of life over time remains robust, and strongly supported by the Neoproterozoic and Cambrian fossil record. he most fundamental claim of bio- (such as snails, crabs, or sea urchins) as it logical evolution is that all living does to the fi rst appearance and diversi- T organisms represent the outer tips fi cation of dinosaurs, birds, or mammals. of a diversifying, upward- branching tree This early diversifi cation of invertebrates of life. The “Tree of Life” is an extreme- apparently occurred around the time of ly powerful metaphor that captures the the Precambrian/Cambrian boundary over essence of evolution.
    [Show full text]
  • A Paleontological Perspective of Vertebrate Origin
    http://www.paper.edu.cn Chinese Science Bulletin 2003 Vol. 48 No. 8 725-735 Cover: The earliest-known and most primitive vertebrates on the A paleontological perspective Earth---Myllokunmingia fengjiaoa ， (upper) Zhongjianichthys rostratus of vertebrate origin （ middle ）， Haikouichthys ercaicunensis (lower left and lower right). They were SHU Degan Early Life Institute & Department of Geology, Northwest products of the early Cambrian Explosion, University, Xi’an, 710069, China; School of Earth excavated from the famous Chengjiang Sciences and Resources, China University of Geosciences, Beijing, 100083, China Lagersttat, which was formed in the (e-mail:[email protected]) eastern Yunnan about 530 millions of years ago. These ancestral vertebrates not only Abstract The Early Cambrian Haikouichthys and Haikouella have been claimed to be related to contribute in an important developed primitive separate vertebral way to our understanding of vertebrate origin, but there have elements, but also possessed principal been heated debates about how exactly they are to be interpreted. New discoveries of numerous specimens of sensory organs, including a pair of large Haikouichthys not only confirm the identity of previously lateral eyes, nostril with nasal sacs, then described structures such as the dorsal and the ventral fins, and chevron-shaped myomeres, but also reveal many new had led to the transition from acraniates to important characteristics, including sensory organs of the head craniates (true vertebrates). The (e.g. large eyes), and a prominent notochord with differentiated vertebral elements. This “first fish” appears, discoveries of these “naked” agnathans however, to retain primitive reproductive features of have pushed the earliest record of acraniates, suggesting that it is a stem-group craniates.
    [Show full text]
  • Questions About the Cambrian Explosion, Evolution, and Intelligent Design
    Questions about the Cambrian Explosion, Evolution, and Intelligent Design 1. What was “Darwin’s dilemma”? “Darwin’s dilemma” refers to Charles Darwin’s bafflement that the fossil record contradicted what his theory of evolution predicted. In his classic book On the Origin of Species, Darwin declared that if his theory of evolution were true “it is indisputable that before the lowest Cambrian stratum was deposited… the world swarmed with living creatures.”1 Yet Darwin admitted that the fossil record below the Cambrian strata seemed to be bereft of such creatures. Instead “species belonging to several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks”—without any evidence of prior ancestral forms. Darwin frankly acknowledged that this lack of ancestral forms was “a valid argument” against his theory. But he hoped that time—and more research—would provide the evidence that was lacking. Some 150 years later, the documentary Darwin’s Dilemma probes how Darwin’s dilemma has been aggravated—not resolved—by the last century of fossil discoveries, starting with the strange and wonderful creatures uncovered a century ago in the Burgess shale in British Columbia, Canada. 2. Has the Precambrian fossil record solved “Darwin’s dilemma”? Those who think that papers like J. William Schopf’s 2000 PNAS paper, “Solution to Darwin’s dilemma: Discovery of the missing Precambrian record of life,”2 actually solve the mystery of the Cambrian explosion, probably did not read past the paper’s title, or haven’t been paying close attention to this debate in recent years.
    [Show full text]
  • Recent Advances in the (Molecular) Phylogeny of Vertebrates
    30 Sep 2003 15:59 AR AR200-ES34-12.tex AR200-ES34-12.sgm LaTeX2e(2002/01/18) P1: GCE 10.1146/annurev.ecolsys.34.011802.132351 Annu. Rev. Ecol. Evol. Syst. 2003. 34:311–38 doi: 10.1146/annurev.ecolsys.34.011802.132351 Copyright c 2003 by Annual Reviews. All rights reserved First published online as a Review in Advance on September 2, 2003 RECENT ADVANCES IN THE (MOLECULAR) PHYLOGENY OF VERTEBRATES Axel Meyer Department of Biology, University of Konstanz, 78457 Konstanz, Germany; email: [email protected] Rafael Zardoya Museo Nacional de Ciencias Naturales, CSIC, Jose´ Gutierrez´ Abascal, 2, 28006 Madrid, Spain; email: [email protected] Key Words molecular systematics, Agnatha, Actinopterygii, Sarcopterygii, Tetrapoda ■ Abstract The analysis of molecular phylogenetic data has advanced the knowl- edge of the relationships among the major groups of living vertebrates. Whereas the molecular hypotheses generally agree with traditional morphology-based systematics, they sometimes contradict them. We review the major controversies in vertebrate phylo- genetics and the contribution of molecular phylogenetic data to their resolution: (a) the mono-paraphyly of cyclostomes, (b) the relationships among the major groups of ray- finned fish, (c) the identity of the living sistergroup of tetrapods, (d ) the relationships among the living orders of amphibians, (e) the phylogeny of amniotes with partic- ular emphasis on the position of turtles as diapsids, (f ) ordinal relationships among birds, and (g) the radiation of mammals with specific attention to the phylogenetic relationships among the monotremes, marsupial, and placental mammals. We present a discussion of limitations of currently used molecular markers and phylogenetic meth- ods as well as make recommendations for future approaches and sets of marker genes.
    [Show full text]
  • History of Earth
    History of Earth The history of Earth concerns the development of planet Earth from its formation to the present day.[1][2] Nearly all branches of natural science have contributed to understanding of the main events of Earth's past, characterized by constant geological change and biological evolution. The geological time scale (GTS), as defined by international convention,[3] depicts the large spans of time from the beginning of the Earth to the present, and its divisions chronicle some definitive events of Earth history. (In the graphic: Ga means "billion years ago"; Ma, "million years ago".) Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula.[4][5][6] Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen. Much of the Earth was molten because of frequent collisions with other bodies which led to extreme volcanism. While the Earth was in its earliest stage (Early Earth), a giant impact collision with a planet-sized body named Theia is thought to have formed the Moon. Over time, the Earth cooled, causing the formation of a solidcrust , and allowing liquid water on the surface. The Hadean eon represents the time before a reliable (fossil) record of life; it began with the formation of the planet and ended 4.0 billion years ago. The following Archean and Proterozoic eons produced the beginnings of life on Earth and its earliest evolution. The succeeding eon is the Phanerozoic, divided into three eras: the Palaeozoic, an era of arthropods, fishes, and the first life on land; the Mesozoic, which spanned the rise, reign, and climactic extinction of the non-avian dinosaurs; and the Cenozoic, which saw the rise of mammals.
    [Show full text]
  • Supplemental Information Phylogenetic Analysis We Used the Matrix from Conway-Morris and Caron (5), Which Was Modified from That
    Electronic Supplementary Material (ESI) for Journal of Analytical Atomic Spectrometry. This journal is © The Royal Society of Chemistry 2018 Supplemental Information Phylogenetic analysis We used the matrix from Conway-Morris and Caron (5), which was modified from that of Samson et al. (45). We were unable to completely replicate their study in the numbers of MPTs obtained, never getting fewer than 7 (they reported 5); however, the topology we derived was mostly consistent with their findings with the exception of the placement of Euphanerops. We then modified the coding of Conway-Morris and Caron (5) for euconodonts for characters: 57 (from 0 to 1; this study), 62 (? to 1 (46)), 77 (1 to 0 (10)), 80 (1 to 0 (10)), 81 (? to inapplicable (10)), 82 (1 to inapplicable (10)), 85 (1 to ? (10)), 108 (1 to inapplicable (10)), 115 (corrected from 1 to 2), and 116 (corrected from ? to 1). Parsimony analysis was conducted in PAUP* 4.0b10 following the methods detailed in Conway-Morris and Caron (5) (heuristic analysis, 1000 random replicates, TBR branch swapping, unordered characters). The topological constraint of Conway-Morris and Caron (5) was employed to enforce cyclostome monophyly. All parsimony statistics were calculated in PAUP. Bremer support was calculated using Treerot v. 3. Characters All characters used in this analysis are taken from Conway-Morris and Caron (5) and are listed below. 1. Neural crest: absent = 0, present = 1 2. Olfactory peduncles: absent = 0, present = 1 3. Pineal organ (extra-ocular photoreceptor region expressing pineal opsins): absent = 0, present = 1 4. Adenohypophysis: absent = 0, present = 1 5.
    [Show full text]
  • Fishes of the World
    Fishes of the World Fishes of the World Fifth Edition Joseph S. Nelson Terry C. Grande Mark V. H. Wilson Cover image: Mark V. H. Wilson Cover design: Wiley This book is printed on acid-free paper. Copyright © 2016 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at www.wiley.com/go/permissions. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with the respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be createdor extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation.
    [Show full text]