Abstract
The development of marine benthic communities in the Early Palaeozoic occurred mainly in the shallow water epicontinental seas. It included those stages of the Cambrian and Ordovician evolutionary radiations that were dominated by a high rate of morphogenesis, when new food and territory resources were not limited. This provided many opportunities for coadaptation of emerging organisms. At the time of the Cambrian radiation, the body plans of all animals were formed, while in the Ordovician, the maximum rank of emerging taxa did not exceed the level of class. The beginning of each radiation was explosive. Vendian benthic communities developed in cold seas and in the shallowest areas of warm seas, where organic matter from the surface layers was available at the bottom because of the absence of a thermocline. The Cambrian radiation began with the appearance of pelagic suspension feeders, because of which much of the primary production could penetrate the thermocline and settle at the bottom. This allowed the occupation of warmer seas and greater depths. At the same time, the productivity of the pelagic region sharply increased because of the emergence of positive feedback between the producers and consumers in the water, leading to increased water transparency and elongation of trophic chains. Arthropods, the first suspension feeders, were the launch group of the Cambrian radiation. Cambrian benthic suspension feeders could seize only the smallest particles, mostly bacteria, and dissolved organic matter. This food resource was contained in the thin bottom water layer. Therefore, the food grasping structures of all the Cambrian suspension feeders were near the bottom, without forming tiers. The Ordovician evolutionary radiation began with the launch of the Pelmatozoan echinoderms, which were the first benthic suspension feeders to begin feeding on plankton. The exploitation of this resource led to the creation of a 1-m tier above the bottom and an increase in their calcite productivity. Positive feedback emerged between the grounds and the community of its inhabitants and considerably changed the composition and diversity of grounds, which sharply increased the diversity of benthos. The appearance of positive feedback between different components of ecosystems resulted in explosive evolution in both the Cambrian and Ordovician.
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References
A. S. Alekseev, V. Yu. Dmitriev, and A. G. Ponomarenko, “Evolution of the Taxonomic Diversity,” in Ecosystem Rearrangement and Evolution of Biosphere (Geos, Moscow, 2001), Vol. 5, pp. 1–125 [in Russian]
S. Bengtson, “Origins and Early Evolution of Predation,” Paleontol. Soc. Pap. 8 (The Fossil Record of Prediation, Ed. by M. Kowalewski and P. H. Kelley), 289–317 (2002).
D. J. Bottjer and W. I. Ausich, “Phanerozoic Development of Tiering in Soft Substrate Suspension-feeding Communities,” Paleobiology 12, 400–420 (1986).
N. J. Butterfield, “Ecology and Evolution of Cambrian Plankton,” in The Ecology of the Cambrian Radiation, Ed. by A. Yu. Zhuravlev and R. Riding (Columbia Univ. Press, New York, 2001), pp. 200–216.
M. L. Droser and Li Xing, “The Cambrian Radiation and the Diversification of Sedimentary Fabrics,” in The Ecology of the Cambrian Radiation, Ed. by A. Yu. Zhuravlev and R. Riding (Columbia Univ. Press, New York, 2001), pp. 137–169.
M. A. Fedonkin, “Cold Water Cradle of Animal Life,” Paleontol. J. 30(6), 669–673 (1996).
M. A. Fedonkin, “Cold Outset of Animal Life,” Priroda, No. 9, 3–11 (2000).
M. L. McKinney and K. J. McNamara, Heterochrony: The Evolution of Ontogeny (Plenum, New York, 1991).
A. G. Ponomarenko, “Principal Events in the Evolution of the Ancient Biosphere,” in Problems of Pre-antropogenic Evolution of Biosphere (Nauka, Moscow, 1993), pp. 15–25 [in Russian]
A. G. Ponomarenko, “Ecological Consequence of Artropodization,” in Ecosystem Rearrangement and Evolution of Biosphere (Paleontol. Inst. Ross. Akad. Nauk, Moscow, 2004), Vol. 6, pp. 7–22 [in Russian].
S. V. Rozhnov, “New Data on Rhipidocystids (Eocrinoidea),” in Fossil and Recent Echinoderm Researches (Tallinn, 1989), pp. 38–57 [in Russian].
S. V. Rozhnov, “The Change in Hardground Communities at the Cambrian-Ordovician Boundary,” Paleontol. J. 3, 70–75 (1994).
S. V. Rozhnov, “Evolution of the Hardground Community,” in The Ecology of the Cambrian Radiation, Ed. by A. Yu. Zhuravlev and R. Riding (Columbia Univ. Press, New York, 2001), pp. 238–253.
S. V. Rozhnov, “Morphogenesis and Evolution of Crinoids and Other Pelmatozoan Echinoderms in the Early Paleozoic,” Paleontol. J. 36(Suppl. 6), 525–674 (2002).
S. V. Rozhnov and V. B. Kushlina, “Early Paleozoic Echinoderms: Alimentary Capabilities and Role in Benthic Assemblages,” in Ecosystem Rearrangement and Evolution of Biosphere (Paleontol. Inst. Ross. Akad. Nauk, Moscow, 2001), Vol. 4, pp. 184–192 [in Russian].
J. Sprinkle and T. E. Guensburg, “Origin of Echinoderms in the Paleozoic Evolutionary Fauna: The Role of Substrates,” Palaios 10, 437–453 (1995).
J. J. Sepkoski, Jr., “A Factor Analytic Description of the Phanerozoic Marine Fossil Record,” Paleobiology 7, 36–53 (1981).
J. J. Sepkoski, Jr., “The Ordovician Radiations: Diversification and Extinction Shown by Global Genus-level Taxonomic Data,” in Ordovician Odyssey: Short Papers, 7th International Symposium on the Ordovician System, Book 77, Pacific Section Society for Sedimentary Geology (SEPM) (Fullerton, California, 1995), pp. 393–396.
J. J. Sepkoski, Jr., “Patterns of Phanerozoic Extinction: A Perspective from Global Data Bases,” in Global Events and Event Stratigraphy in Phanerozoic, Ed. by O. H. Walliser (Springer, Berlin-Heidelberg, 1996), pp. 35–51.
S. V. Smirnov, “Pedomorphosis as a Mechanism of the Evolutionary Changes of Organisms,” in Modern Evolutionary Biology (Nauk. Dumka, Kiev, 1991), pp. 88–103 [in Russian].
L. P. Tatarinov, Morphological Evolution of Theriodonts and the General Problems of Phylogenetics (Nauka, Moscow, 1976) [in Russian].
J. W. Valentine, “Why No New Phyla after the Cambrian? Genome and Ecospace Hypotheses Revisited,” Palaios 10, 190–194 (1995).
J. W. Valentine, On the Origin of Plyla (Univ. Chicago Press, Chicago, 2004).
J. Vannier and Chen Junyuan, “Early Cambrian Food Chain: New Evidence from Fossil Aggregates in the Maotianshan Shale Biota, SW China,” Palaios 20(1), 3–26 (2005).
C. H. Waddington, The Strategy of the Genes (A Discussion of Some Aspects of Theoretical Biology) (Allen and Unwin, London, 1957).
B. D. Webby, “Introduction,” in The Great Ordovician Biodiversification Event, Ed. by B. D. Webby, F. Paris, M. L. Droser, and I. G. Percival (Columbia Univ. Press, New York, 2004), pp. 1–37.
M. A. Wilson and T. J. Palmer, “Hardgrounds and Hardground Faunas,” Univ. Wales, Aberystwyth, Inst. Earth Stud. Publ. 9, 1–131 (1992).
G. A. Zavarzin, Lectures on Natural History of Microbiology (Nauka, Moscow, 2003) [in Russian].
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Rozhnov, S.V. Appearance and evolution of marine benthic communities in the Early Palaeozoic. Paleontol. J. 40, S444–S452 (2006). https://doi.org/10.1134/S0031030106100042
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DOI: https://doi.org/10.1134/S0031030106100042