Skip to Main Content
Have library access? Log in through your library
The Ecology of the Cambrian Radiation

The Ecology of the Cambrian Radiation

  • Cite this Item
  • Book Info
    The Ecology of the Cambrian Radiation
    Book Description:

    The Cambrian radiation was the explosive evolution of marine life that started 550,000,000 years ago. It ranks as one of the most important episodes in Earth history. This key event in the history of life on our planet changed the marine biosphere and its sedimentary environment forever, requiring a complex interplay of wide-ranging biologic and nonbiologic processes.

    The Ecology of the Cambrian Radiation offers a comprehensive and surprising picture of the Earth at that ancient time. The book contains contributions from thirty-three authors hailing from ten countries and will be of interest to paleontologists, geologists, biologists, and other researchers interested in the global Earth-life system.

    eISBN: 978-0-231-50516-1
    Subjects: Paleontology, Ecology & Evolutionary Biology, Zoology

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-vi)
  3. Acknowledgments
    (pp. vii-x)
  4. CHAPTER ONE Introduction
    (pp. 1-8)
    Andrey Yu. Zhuravlev and Robert Riding

    THE CAMBRIAN RADIATION, which commenced around 550 million years ago, arguably ranks as the single most important episode in the development of Earth’s marine biota. Diverse benthic communities with complex tiering, trophic webs, and niche partitioning, together with an elaborate pelagic realm, were established soon after the beginning of the Cambrian period. This key event in the history of life changed the marine biosphere and its associated sediments forever.

    At first glance, abiotic factors such us climate change, transgressive-regressive sea level cycles, plate movements, tectonic processes, and the type and intensity of volcanism appear very significant in the shaping of...


    • CHAPTER TWO Paleomagnetically and Tectonically Based Global Maps for Vendian to Mid-Ordovician Time
      (pp. 11-46)
      Alan G. Smith

      THOSE TECTONIC MODELS that suggest that during late Precambrian and early Paleozoic time Baltica and Siberia were close to one another and fringed by more or less laterally continuous island arcs imply that even if the two continents were geographically isolated, faunal interchange between them should have been possible. Other tectonic models may not have this requirement.

      The maps suggest that nearly all the tillites in the 620–580 Ma interval were deposited poleward of 40°, rather than reflecting high obliquity or a “snowball Earth.” Because of the way in which the maps have been made, some Vendian tillites from...

    • CHAPTER THREE Global Facies Distributions from Late Vendian to Mid-Ordovician
      (pp. 47-68)
      Kirill B. Seslavinsky and Irina D. Maidanskaya

      A VARIETY OF plate tectonic reconstructions has been proposed for the Neoproterozoic and early Paleozoic (e.g., Zonenshain et al. 1985; Courjault-Radé et al. 1992; Kirschvink 1992; Storey 1993; Dalziel et al. 1994; Kirschvink et al. 1997; Debrenne et al. 1999). Some of these are reproduced elsewhere in this volume (Brasier and Lindsay: figure 4.2; Eerola: figure 5.4). However, none of them wholly satisfies current data on paleobiogeography, facies distributions, and metamorphic, magmatic, and tectonic events. Pure paleomagnetic reconstructions often ignore paleontologic data and contain large errors in pole position restrictions. Paleobiogeographic subdivisions developed for single groups, mainly trilobites and archaeocyaths,...

    • CHAPTER FOUR Did Supercontinental Amalgamation Trigger the “Cambrian Explosion”?
      (pp. 69-89)
      Martin D. Brasier and John F. Lindsay

      THIS CHAPTER ATTEMPTS to put the “Cambrian explosion” into the wider context of events in the lithosphere. The formation and later rapid extensional subsidence of supercontinents in the Neoproterozoic have recently become apparent from a wide range of disciplines, including paleomagnetism, facies and fossil distributions, subsidence curves, and isotopic studies (e.g., Bond et al. 1984; Lindsay et al. 1987; Dalziel 1991; McKerrow et al. 1992; Derry et al. 1992, 1994). At some time before ca. 900 Ma B.P., Antarctica, Australia, Laurentia, Baltica, and Siberia appear to have been united in a Neoproterozoic supercontinent called Rodinia or Kanatia (Torsvik et al....

    • CHAPTER FIVE Climate Change at the Neoproterozoic-Cambrian Transition
      (pp. 90-106)
      Toni T. Eerola

      The Neoproterozoic-Cambrian transition was characterized by ophiolite formation (Yakubchuk et al. 1994), the formation and breakup of supercontinents (e.g., Bond et al. 1984), the Cambrian evolutionary explosion (Moores 1993; Knoll 1994), and intense climatic changes, among which the most important might be considered glaciations (e.g., Hambrey and Harland 1985) and the shift from Neoproterozoic icehouse to Cambrian greenhouse conditions (Veevers 1990; Tucker 1992).

      At least 10major glacial periods have been recorded prior to the Pleistocene (Young 1991; Eyles 1993) (figure 5.1). Probably the most extensive and enigmatic of these occurred during the Neoproterozoic and at the beginning of the Cambrian,...

    • CHAPTER SIX Australian Early and Middle Cambrian Sequence Biostratigraphy with Implications for Species Diversity and Correlation
      (pp. 107-136)
      David I. Gravestock and John H. Shergold

      AUSTRALIAN LOWER AND Middle Cambrian sedimentary rocks contain rich assemblages of fossil marine invertebrates, calcified and organic-walled microbial fossils, and traces of organic activity. Knowledge of the taxonomy and affinities of Australian Cambrian invertebrate fossils has increased significantly in the past decade, but at present only the archaeocyaths and trilobites have been studied in detailed stratigraphic successions. Progress is being made in the further study of mollusks and other small skeletal fossils, superbly described by Bengtson et al. (1990).

      In this chapter we document the species distribution of archaeocyaths in the Lower Cambrian and trilobites in the Middle Cambrian of...

    • CHAPTER SEVEN The Cambrian Radiation and the Diversification of Sedimentary Fabrics
      (pp. 137-170)
      Mary L. Droser and Xing Li

      WITH THE CAMBRIAN RADIATION of marine invertebrates, sedimentary rocks on this planet changed forever. The advent of skeletonized metazoans introduced shells and skeletons as sedimentary particles, and the tremendous increase in burrowing metazoans resulted in the partial or complete mixing of sediment and/or in the production of new sedimentary structures. Whereas constructional frameworks formed by stromatolites were common in the Precambrian (e.g., Awramik 1991; Grotzinger and Knoll 1995), metazoan reef builders first appeared near the Precambrian-Cambrian boundary, initiating complex reef fabrics in Early Cambrian time (Riding and Zhuravlev 1995). Diverse and well-defined calcified cyanobacteria and calcified algae appearing in the...


    • CHAPTER EIGHT Biotic Diversity and Structure During the Neoproterozoic-Ordovician Transition
      (pp. 173-199)
      Andrey Yu. Zhuravlev

      AT THE END of the Neoproterozoic and beginning of the Phanerozoic, there was a rapid succession of distinct faunas and a diversity increase that involved the brief flourishing of the enigmatic Ediacaran fauna, subsequent expansion of the Tommotian small shelly taxa, and finally replacement by the more standard Cambrian and Ordovician groups. Discussions of Vendian to Cambrian diversification by Sepkoski (1979, 1981) treated the fauna of this interval as homogeneous. Most of the important Cambrian classes, including archaeocyaths, trilobites, inarticulate brachiopods (mainly lingulates in the present sense), hyoliths, monoplacophorans (now, principally, helcionelloids), stenothecoids, cribricyaths, volborthellids, eocrinoids and some other echinoderm...

    • CHAPTER NINE Ecology and Evolution of Cambrian Plankton
      (pp. 200-216)
      Nicholas J. Butterfield

      THE PLANKTON COMPRISES the majority of all modern marine biomass and metabolism, is the ultimate source of most exported carbon, and plays an essential role at the base of most marine ecosystems (Nienhuis 1981; Berger et al. 1989). Thus, it is hardly surprising to find it figuring in broad-scale considerations of Early Cambrian ecology (e.g., Burzin 1994; Signor and Vermeij 1994; Butterfield 1997), biogeochemical cycling (e.g., Logan et al. 1995), and evolutionary tempo and mode (e.g., Knoll 1994; Rigby and Milsom 1996). The Cambrian is of course of particular interest in that it constitutes one side of the infamous Precambrian-Cambrian...

    • CHAPTER TEN Evolution of Shallow-Water Level-Bottom Communities
      (pp. 217-237)
      Mikhail B. Burzin, Françoise Debrenne and Andrey Yu. Zhuravlev

      CAMBRIAN DEPOSITIONAL SYSTEMS can be divided into clastic and carbonate regimes, because substrate type strongly influences community composition. These aspects of sedimentation were in general controlled by climate and the size of the area available for denudation. With few exceptions, environments of carbonate sedimentation were restricted to low latitudes and siliciclastic-dominated settings occurred mostly in temperate conditions. The Siberian Platform throughout the Cambrian exemplified carbonate-dominated habitats. Baltica, Bohemia, and Avalonia represented regions where siliciclastic sedimentation prevailed. Laurentia and Australia were characterized by a mosaic of facies.

      Although the entire set of trophic guilds existed from the beginning of the period,...

    • CHAPTER ELEVEN Evolution of the Hardground Community
      (pp. 238-253)
      Sergei V. Rozhnov

      HARDGROUNDS, areas of synsedimentarily lithified carbonate sea floor, occurred for the first time in the late Middle Cambrian and were widely distributed in the Ordovician. The time of their occurrence and wide distribution coincided with the Ordovician radiation of marine biota, which resulted in the replacement of the Cambrian Evolutionary Fauna by the Paleozoic Evolutionary Fauna (Sepkoski 1979, 1981, 1984) that was to dominate the remainder of the Paleozoic. A significant increase in biodiversity was connected with this radiation.

      The lack of appearance of new taxa of rank higher than class and subphylum, apart from the Bryozoa, was characteristic of...

    • CHAPTER TWELVE Ecology and Evolution of Cambrian Reefs
      (pp. 254-274)
      Brian R. Pratt, Ben R. Spincer, Rachel A. Wood and Andrey Yu. Zhuravlev

      FOR 3.5 BILLION YEARS tropical sea floors within the photic zone, which were relatively free from the influence of terrestrial runoff—sediment, freshwater, and nutrients—have hosted communities of aggregated sessile organisms. Such communities—sometimes mainly microbial, at other times mostly skeletal metazoan—acquired topographic relief and typically were the sites of synsedimentary cementation, thereby forming reefs.

      Here we summarize the composition of Cambrian reefs, outline its community reefs, outline its community structure, and trace its evolutionary history. It is clear that the Cambrian was a threshold for reef development no less than it was for many other sedimentary environments...

    • CHAPTER THIRTEEN Evolution of the Deep-Water Benthic Community
      (pp. 275-298)
      T. Peter Crimes

      The colonization of deep-sea environments appears to have been a slow process (Crimes 1974; Sepkoski and Miller 1985; Bottjer et al. 1988), and a high percentage of Precambrian and Cambrian megascopic body and trace fossils occur in sediments considered to have been deposited in shallow water, mostly above storm wave base.

      There are, however, several abiological factors that might emphasize this apparent distribution. First, deep-water sediments, by the nature of their tectonic setting, are more prone to deformation and metamorphism, and these processes will eliminate some forms and make recovery of others difficult. Second, shallow-water shelf seas were dominant late...


    • CHAPTER FOURTEEN Sponges, Cnidarians, and Ctenophores
      (pp. 301-325)
      Françoise Debrenne and Joachim Reitner

      RAPID DIVERSIFICATION near the Proterozoic-Phanerozoic boundary implies the mutual interactions of ecosystems and biotas. One of the most striking features in the distribution of Early Paleozoic sessile benthos is the poor Middle–Late Cambrian record (Webby 1984).

      The present contribution deals with the ecologic radiation of sponges and cnidarians.

      Sponges are a monophyletic metazoan group characterized by choanoflagellate cells (choanocytes). Based on studies made by Mehl and Reiswig (1991), Reitner (1992), Müller et al. (1994), and Reitner and Mehl (1995), the first sponges originated in the Proterozoic from a choanoflagellate ancestor. The ancestral sponge was probably an aggregate of choanoflagellates,...

    • CHAPTER FIFTEEN Mollusks, Hyoliths, Stenothecoids, and Coeloscleritophorans
      (pp. 326-349)
      Artem V. Kouchinsky

      THE CONTINUOUS Phanerozoic history of marine mollusks that bore mineralized skeletons began in the Early Cambrian. Molluskan remains constitute an important part of the earliest skeletal assemblages (Bengtson and Conway Morris 1992; Dzik 1994). In the present chapter, hyoliths, stenothecoids, and coeloscleritophorans are treated together because even now most of these are considered to be mollusks (Marek and Yochelson 1976; Bengtson 1992; Starobogatov and Ivanov 1996). Nonetheless, the systematic position among the class Mollusca of many of these Cambrian groups is still disputed (Runnegar and Pojeta 1974, 1985; Yochelson 1978; Linsley and Kier 1984; Missarzhevsky 1989; Peel 1991; Geyer 1994;...

    • CHAPTER SIXTEEN Brachiopods
      (pp. 350-369)
      Galina T. Ushatinskaya

      BRACHIOPODS BELONG to the subkingdom Eumetazoa and are characterized by two unique features. First, they have an intermediate protostomian-deuterostomian embryology. It is likely that brachiopods separated from other Bilateralia prior to protostomian-deuterostomian differentiation (Malakhov 1976, 1983). Second, the Brachiopoda is the only phylum that produces both calcium carbonate and phosphatic shells.

      By the second half of the twentieth century, the brachiopod systematics developed by Huxley (1869) became widely accepted (Sarycheva 1960; Williams and Rowell 1965). This subdivided brachiopods into two classes, Articulata and Inarticulata, based on presence or absence of valve articulation, respectively. Therefore, the Inarticulata included brachiopods with calcium...

    • CHAPTER SEVENTEEN Ecologic Evolution of Cambrian Trilobites
      (pp. 370-403)
      Nigel C. Hughes

      THE BIOMASS OF TRILOBITES in scientific collections far exceeds that of all other Cambrian metazoans put together. This fact reflects the volumetric and taxonomic abundance of trilobites in a wide range of Cambrian sediments, their intricate and labile morphology, and their occurrence throughout the majority of Cambrian time. These attributes have given the group unrivaled utility as zonal fossils in Cambrian strata, and as the principal faunal element used to assess Cambrian paleobiogeogra- phy. Paradoxically, while trilobites serve as the timekeepers by which we gauge the ecologic evolution of other Cambrian metazoans, the ecology of Cambrian trilobites remains poorly resolved....

    • CHAPTER EIGHTEEN Ecology of Nontrilobite Arthropods and Lobopods in the Cambrian
      (pp. 404-427)
      Graham E. Budd

      THE ARTHROPODS TODAY make up perhaps 80 percent of animals, and their dominance was scarcely less in the historic record: indeed, their importance in the marine realm is likely to have been even greater in the past than it is today. On the basis of trace fossils (Rusophycus), arthropods are known from at least the Tommotian onward. They have certainly been important contributors to ecologic webs and hierarchies throughout the Cambrian. Discerning ecologic paths and strategies of the past is, however, fraught with difficulties. It is essential, if a better understanding of arthropod ecologies in the past is to be...

    • CHAPTER NINETEEN Ecologic Radiation of Cambro-Ordovician Echinoderms
      (pp. 428-444)
      Thomas E. Guensburg and James Sprinkle

      DOCUMENTATION OF ECOLOGIC diversification in the fossil record provides the road map of life’s temporal patterns and the context of evolutionary history. Most studies of diversification have emphasized intrinsic biotic driving factors for changes in diversification patterns and evolutionary pathways (see Sepkoski 1991 for a review), but recent field-based studies have emphasized the role of extrinsic causes. This latter approach requires extensive field observation and integration of sedimentologic, facies, and sequence stratigraphic information with paleobiologic observations (Guensburg and Sprinkle 1992; Rozhnov 1994; Droser et al. 1995). Broad-scale linkages are emerging as a result. For instance, we have previously correlated global...

    • CHAPTER TWENTY Calcified Algae and Bacteria
      (pp. 445-473)
      Robert Riding

      THE LONG-TERM HISTORY of microbes and metazoans has been seen as a displacement of prokaryotes by eukaryotes (Garrett 1970). In the Cambrian, it is tempting to emphasize invertebrate newcomers and to expect that microbial fossils should be scarce and in decline. Yet calcified microbial fossils are common in the Cambrian, and they appeared rapidly, early in the period, as if switched on by some event (Riding 1984). In part, this biota represents continuation of the old Proterozoic order, but in many respects it was a new development, with few earlier counterparts. Marine calcified microbes had never been so abundant and...

    • CHAPTER TWENTY-ONE Molecular Fossils Demonstrate Precambrian Origin of Dinoflagellates
      (pp. 474-494)
      J. Michael Moldowan, Stephen R. Jacobson, Jeremy Dahl, Adnan Al-Hajji, Bradley J. Huizinga and Frederick J. Fago

      IN A SURVEY OF marine rocks of various geological ages, Moldowan et al. (1996) reported triaromatic dinosteroids (1—numbers in this style refer to figure 21.1) in Precambrian to Devonian organic-rich sedimentary rocks. Also, in an earlier report Summons et al. (1992) noted dinosterane (2) occurrences in extracted organic matter from Precambrian rocks. These data appear to provide the long sought-for evidence that dinoflagellates (or closely related protists) have an ancient origin, a hypothesis previously suggested by evolutionary biologists. Dinoflagellates are to a large extent primary producers, and rRNA and ultrastructure studies suggest their primitive nature (Margulis 1970; Wainright et...

  8. List of Contributors
    (pp. 495-498)
  9. Index
    (pp. 499-526)