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Cambrian Explosion Remains an Enigma for Organic Evolution: the Ediacaran Fauna: Much Ado About Ancient Lichens?
HOME GODTUBE BOOKSTORE YOUTUBE ESSAYS PANORAMIO VIDEOS FAQ PHOTOS LINKS BLOG GENESIS WEEK The Cambrian Explosion Remains an Enigma for Organic Evolution: The Ediacaran Fauna: Much Ado About Ancient Lichens? Author: John Woodmorappe Subject: Geology Date: John Woodmorappe's Articles About John Woodmorappe According to the conventional evolutionary-uniformitarian time scale of Earth history, multicellular organisms first appeared in abundance about 550 million years ago, in the "Big Bang of Evolution," the Cambrian explosion. But (again, according to the conventional time scale) a handful of odd multicellular organisms existed before the astonishing explosion of new forms in the Cambrian. These organisms, from the so- called Ediacaran fauna, named after the town of Ediacara in southern Australia where their fossil remains were discovered in 1947, are said to be 600 million years old. Figure 1 shows one well-known Ediacaran form, Dickinsonia.1 Now a novel interpretation of these puzzling fossils is generating considerable controversy within the paleontological community. Some scientists (notably the German paleontologist Adolf Seilacher and Harvard's Stephen Jay Gould) have suggested that the Ediacaran fauna--known also as the Vendozoa or Vendobionta (from the Vendian geological period in which they occur)--were "failed experiments" in the evolution of multicellular animals. Unlike the Cambrian organisms, these odd designs left no ancestors.2 But the novel interpretation, from University of Oregon paleontologist Gregory Retallack, suggests -
Of Time and Taphonomy: Preservation in the Ediacaran
See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/273127997 Of time and taphonomy: preservation in the Ediacaran CHAPTER · JANUARY 2014 READS 36 2 AUTHORS, INCLUDING: Charlotte Kenchington University of Cambridge 5 PUBLICATIONS 2 CITATIONS SEE PROFILE Available from: Charlotte Kenchington Retrieved on: 02 October 2015 ! OF TIME AND TAPHONOMY: PRESERVATION IN THE EDIACARAN CHARLOTTE G. KENCHINGTON! 1,2 AND PHILIP R. WILBY2 1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK <[email protected]! > 2British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK ABSTRACT.—The late Neoproterozoic witnessed a revolution in the history of life: the transition from a microbial world to the one known today. The enigmatic organisms of the Ediacaran hold the key to understanding the early evolution of metazoans and their ecology, and thus the basis of Phanerozoic life. Crucial to interpreting the information they divulge is a thorough understanding of their taphonomy: what is preserved, how it is preserved, and also what is not preserved. Fortunately, this Period is also recognized for its abundance of soft-tissue preservation, which is viewed through a wide variety of taphonomic windows. Some of these, such as pyritization and carbonaceous compression, are also present throughout the Phanerozoic, but the abundance and variety of moldic preservation of body fossils in siliciclastic settings is unique to the Ediacaran. In rare cases, one organism is preserved in several preservational styles which, in conjunction with an increased understanding of the taphonomic processes involved in each style, allow confident interpretations of aspects of the biology and ecology of the organisms preserved. -
Morphological and Behavioural Evolution Through
MORPHOLOGICAL AND BEHAVIOURAL EVOLUTION THROUGH THE EDIACARAN AND BASAL CAMBRIAN OF THE MACKENZIE MOUNTAINS, NW CANADA by Calla Agnes Carbone A thesis submitted to the Department of Geological Sciences and Geological Engineering In conformity with the requirements for the Degree of Master of Science Queen’s University Kingston, Ontario, Canada (January, 2014) Copyright © Calla Agnes Carbone, 2014 i Abstract The Mackenzie Mountains of NW Canada contains a superb record of biotic evolution through the late Ediacaran-early Cambrian that is ideal for studying the biological, ecological, behavioural, and environmental innovations that occurred during the Ediacaran and basal Cambrian. Newly discovered Ediacara-type megafossils in the uppermost Blueflower Formation at Sekwi Brook include tubes possibly attributable to suspension-feeding annelids, the preserved top of a large frond holdfast, and several problematica. These fossils represent the youngest and shallowest Ediacaran fossils known from NW Canada, and differ significantly from the communities of deep-water rangeomorphs preserved lower in the succession. Behavioural evolution of the infauna through the Ediacaran and earliest Cambrian can be observed in the rich trace fossil records of the Blueflower and Ingta formations. Trace fossils in the lower part of the Blueflower Formation are characterized by millimeter-diameter, simple, horizontal burrows of microbial grazers and deposit feeders that demonstrated very primitive and inconsistent two-dimensional avoidance strategies. Upper Blueflower trace fossils additionally include three-dimensional avoidance burrows and oblique burrows of filter-feeders or predators, reflecting new behavioural innovations and increased three-dimensional use of the substrate. The Cambrian strata of the Ingta Formation further include probing, U-shaped, and radiating burrows, irregular networks, and arthropod trails. -
'Savannah' Hypothesis for Early Bilaterian Evolution
Biol. Rev. (2017), 92, pp. 446–473. 446 doi: 10.1111/brv.12239 The origin of the animals and a ‘Savannah’ hypothesis for early bilaterian evolution Graham E. Budd1,∗ and Soren¨ Jensen2 1Palaeobiology Programme, Department of Earth Sciences, Uppsala University, Villav¨agen 16, SE 752 40 Uppsala, Sweden 2Area´ de Paleontología, Facultad de Ciencias, Universidad de Extremadura, 06006 Badajoz, Spain ABSTRACT The earliest evolution of the animals remains a taxing biological problem, as all extant clades are highly derived and the fossil record is not usually considered to be helpful. The rise of the bilaterian animals recorded in the fossil record, commonly known as the ‘Cambrian explosion’, is one of the most significant moments in evolutionary history, and was an event that transformed first marine and then terrestrial environments. We review the phylogeny of early animals and other opisthokonts, and the affinities of the earliest large complex fossils, the so-called ‘Ediacaran’ taxa. We conclude, based on a variety of lines of evidence, that their affinities most likely lie in various stem groups to large metazoan groupings; a new grouping, the Apoikozoa, is erected to encompass Metazoa and Choanoflagellata. The earliest reasonable fossil evidence for total-group bilaterians comes from undisputed complex trace fossils that are younger than about 560 Ma, and these diversify greatly as the Ediacaran–Cambrian boundary is crossed a few million years later. It is generally considered that as the bilaterians diversified after this time, their burrowing behaviour destroyed the cyanobacterial mat-dominated substrates that the enigmatic Ediacaran taxa were associated with, the so-called ‘Cambrian substrate revolution’, leading to the loss of almost all Ediacara-aspect diversity in the Cambrian. -
Geobiology and the History of Life Lab 8: Paleozoic Animals in the Oceans
Name:____________ Date:____________ EPS/OEB 56 – Geobiology and the History of Life Lab 8: Paleozoic Animals in the Oceans Part I: Ediacaran Fossils Goal: The goal of this section of the lab is to grapple with the problems of interpreting Ediacaran macrofossils. What features, if any, support their interpretation as animals? If animals, where do they fall on the metazoan tree? Introduction: The so-called Ediacaran biota records some of the first large organisms in the stratigraphic record. Early reports of Ediacaran organisms interpreted them as early representatives of the animal groups that went on to populate Phanerozoic oceans. In 1984, however, Adolf Seilacher proposed that these fossils record a macroscopic biota not closely related to animals at all. Seilacher suggested that the way forward is to ask basic questions of growth and function, and only after these have been answered, try to evaluate their phylogenetic placement. Some fundamental questions regarding these organisms are as follows: 1. Are these fossils of individuals of colonies? 2. How did they grow – can you describe a plausible trajectory from the fossils? 3. How did they function? Can you tell whether or not they were motile? How did they get food? Could they have harbored symbionts? To do: 1. Examine the casts of Dickinsonia from the Pound Quartzite, Australia. Try to answer the three questions posed in the previous paragraph for these fossils. 2. Now examine the cast of Charniodiscus and answer the questions again. 3. Ediacaran microbialite reefs contain the earliest known calcified macrofossils. Examine slabs containing Namacalathus and Cloudina. Can you draw inferences about ontogeny and function in these organisms? Do these skeletal fossils provide better insights into phylogeny than the canonical Ediacaran fossils? Part II: Cambrian Animals Goal: The goal of this section is to appreciate the lines of evidence that document Cambrian animal diversification. -
Phyllozoon and Aulozoon: Key Components of a Novel Ediacaran
Geological Magazine Phyllozoon and Aulozoon: key components of www.cambridge.org/geo a novel Ediacaran death assemblage in Bathtub Gorge, Heysen Range, South Australia 1 2 Original Article James G. Gehling and Bruce Runnegar 1 2 Cite this article: Gehling JG and Runnegar B. Palaeontology, South Australian Museum, North Terrace, Adelaide, SA 5000, Australia and Department of Phyllozoon and Aulozoon: key components of a Earth, Planetary and Space Sciences and Molecular Biology Institute, University of California, Los Angeles, CA novel Ediacaran death assemblage in Bathtub 90095-1567, USA Gorge, Heysen Range, South Australia. Geological Magazine https://doi.org/10.1017/ Abstract S0016756821000509 The recognition of fossiliferous horizons both below and above the classical Ediacara levels of Received: 12 December 2020 the Flinders Ranges, South Australia, significantly expands the potential of this candidate Revised: 5 May 2021 Accepted: 10 May 2021 World Heritage succession. Here we document a small window into the biology and taphonomy of the late Ediacaran seafloor within the new Nilpena Sandstone Member of the Rawnsley Keywords: Quartzite in Bathtub Gorge, northern Heysen Range. A 1 m2 slab extracted from the gorge, Phyllozoon; Ediacaran; Australia; now on permanent display at the South Australian Museum, has a death assemblage dominated palaeoecology; taphonomy by the erniettomorph Phyllozoon hanseni Jenkins and Gehling 1978 and a newly named Author for correspondence: macroscopic tubular body fossil – Aulozoon soliorum gen. et sp. nov. – on its fine sandstone Bruce Runnegar, Email: [email protected] bed sole. The orientations and juxtaposition of these taxa suggest overprinting of an in situ benthic Phyllozoon community by sand-filled tubes of Aulozoon carried in by a storm wave-base surge. -
The Fate of the Method of 'Paradigms' in Paleobiology
Journal of the History of Biology (2018) 51:479–533 Ó The Author(s). This article is an open access publication 2017 https://doi.org/10.1007/s10739-017-9501-z The Fate of the Method of ‘Paradigms’ in Paleobiology MARTIN J. S. RUDWICK Department of History and Philosophy of Science University of Cambridge Cambridge UK E-mail: [email protected] Abstract. An earlier article described the mid-twentieth century origins of the method of ‘‘paradigms’’ in paleobiology, as a way of making testable hypotheses about the functional morphology of extinct organisms. The present article describes the use of ‘‘paradigms’’ through the 1970s and, briefly, to the end of the century. After I had proposed the paradigm method to help interpret the ecological history of brachiopods, my students developed it in relation to that and other invertebrate phyla, notably in Euan Clarkson’s analysis of vision in trilobites. David Raup’s computer-aided ‘‘theoretical morphology’’ was then combined with my functional or adaptive emphasis, in Adolf Seilacher’s tripartite ‘‘constructional morphology.’’ Stephen Jay Gould, who had strongly endorsed the method, later switched to criticizing the ‘‘adaptationist program’’ he claimed it embodied. Although the explicit use of paradigms in paleobiology had declined by the end of the century, the method was tacitly subsumed into functional morphology as ‘‘biomechanics.’’ Keywords: Paleobiology, Functional morphology, Paradigm, Stephen Jay Gould, David Raup, Adolf Seilacher, Martin Rudwick Introduction A previous article (Rudwick, 2017) summarized the history of research in the early to mid-twentieth century on the functional morphology of extinct organisms, in relation to the concept of Pala¨obiologie. -
When Life Got Smart: the Evolution of Behavioral Complexity Through the Ediacaran and Early Cambrian of Nw Canada
Journal of Paleontology, 88(2), 2014, p. 309–330 Copyright Ó 2014, The Paleontological Society 0022-3360/14/0088-309$03.00 DOI: 10.1666/13-066 WHEN LIFE GOT SMART: THE EVOLUTION OF BEHAVIORAL COMPLEXITY THROUGH THE EDIACARAN AND EARLY CAMBRIAN OF NW CANADA CALLA CARBONE AND GUY M. NARBONNE Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, ON, K7L 3N6, Canada, ,[email protected].; and ,[email protected]. ABSTRACT—Ediacaran and early Cambrian strata in NW Canada contain abundant trace fossils that record the progressive development of complex behavior in early animal evolution. Five feeding groups can be recognized: microbial grazing, deposit-feeding, deposit-feeding/predatory, filter-feeding/predatory, and arthropod tracks and trails. The lower Blueflower Formation (ca. 560–550 Ma) contains abundant burrows that completely cover bedding surfaces with small (~1mm diameter) cylindrical burrows that were strictly restricted to microbial bedding surfaces and exhibited only primitive and inconsistent avoidance strategies. The upper Blueflower contains three-dimensional avoidance burrows and rare filter- feeding or possibly predatory burrows, suggesting increased behavioral responses in food gathering that marked the beginning of the agronomic revolution in substrate utilization. Cambrian strata of the Ingta Formation contain systematically meandering burrows and more diverse feeding strategies, including the onset of treptichnid probing burrows that may reflect predation. These observations imply that Ediacaran burrowers were largely characterized by crude, two- dimensional avoidance meanders that represented simple behavioral responses of individual burrowers to sensory information, and that the subsequent development of more diverse and complex feeding patterns with genetically programmed search pathways occurred during the earliest stages of the Cambrian explosion. -
UC Riverside UC Riverside Electronic Theses and Dissertations
UC Riverside UC Riverside Electronic Theses and Dissertations Title Ecology and Biology of Dickinsonia, an Iconic Member of the Ediacara Biota From Nilpena, South Australia Permalink https://escholarship.org/uc/item/43t1h9sf Author Evans, Scott Publication Date 2015 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE Ecology and Biology of Dickinsonia, an Iconic Member of the Ediacara Biota From Nilpena, South Australia A Thesis submitted in partial satisfaction of the requirements for the degree of Master of Science in Geological Sciences by Scott Daniel Evans June 2015 Thesis Committee: Dr. Mary L. Droser, Chairperson Dr. Nigel C. Hughes Dr. Richard A. Minnich Copyright by Scott Daniel Evans 2015 The Thesis of Scott Daniel Evans is approved: Committee Chairperson University of California, Riverside Acknowledgements Chapter 1 of this thesis was published online, February 2015, in the journal Palaeogeography, Palaeoclimatology, Palaeoecology. This research was supported by a GSA student research grant, an SEPM student research grant, a Paleontological Society student research grant, a Lewis and Clark fund for Exploration and Field Research in Astrobiology and an NSF EAPSI fellowship. I would like to thank Dr. Jim Gehling for significant contributions to this work as well as access to material at the South Australia Museum. I thank J. Fargher and R. Fargher for access to their property and permission to excavate fossiliferous beds. Fieldwork was facilitated by D. Rice, J. Perry, M. A. Binnie, J. Doggett, N. Anderson, M. Dzaugis, M. E. Dzaugis, P. Dzaugis, R. Droser, C. Casey, E. Hughes, I. -
Dickinsonia Liftoff: Evidence of Current Derived Morphologies
PALAEO-07159; No of Pages 6 Palaeogeography, Palaeoclimatology, Palaeoecology xxx (2015) xxx–xxx Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Dickinsonia liftoff: Evidence of current derived morphologies Scott D. Evans a,⁎,MaryL.Drosera, James G. Gehling b a Department of Earth Sciences, University of California at Riverside, 900 University Ave, Riverside, CA 92521, United States b South Australian Museum, University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia article info abstract Article history: Dickinsonia, an iconic member of the Ediacara biota, is abundant in the Ediacaran deposits found at the Nilpena Received 15 June 2014 field site, South Australia. Despite exquisite fossil preservation at this site, many specimens of Dickinsonia appear Received in revised form 14 January 2015 to be incomplete, with an apparently “missing piece” on the periphery. Orientation measurements from Accepted 4 February 2015 specimens on three fossil beds suggest that these so-called “missing pieces” are aligned irrespective of the Available online xxxx axial orientation of Dickinsonia. The nonrandom orientation of incomplete specimens matches that of other Keywords: aligned structures found on two of these beds. The preferred directionality of this feature suggests the molding fl Ediacara biota of incomplete specimens under the in uence of current activity prior to or during burial. We propose that this Ediacaran period feature originates where part of a Dickinsonia was lifted off of the substrate during a storm event and that sand Dickinsonia was deposited beneath this lifted portion. This model suggests that Dickinsonia was easily separated from the South Australia sea floor and was not attached to the substrate on which it lived.