scholarly journals The evolutionary dynamics of the early Palaeozoic marine biodiversity accumulation

2019 ◽  
Vol 286 (1909) ◽  
pp. 20191634 ◽  
Author(s):  
Björn Kröger ◽  
Franziska Franeck ◽  
Christian M. Ø. Rasmussen

The early Palaeozoic Era records the initial biodiversification of the Phanerozoic. The increase in biodiversity involved drastic changes in taxon longevity, and in rates of origination and extinction. Here, we calculate these variables in unprecedented temporal resolution. We find that highly volatile origination and extinction rates are associated with short genus longevities during the Cambrian Period. During the Ordovician and Silurian periods, evolutionary rates were less volatile and genera persisted for increasingly longer intervals. The 90%-genus life expectancy doubled from 5 Myr in the late Cambrian to more than 10 Myr in the Ordovician–Silurian periods. Intervals with widespread ecosystem disruption are associated with short genus longevities during the Cambrian and with exceptionally high longevities during the Ordovician and Silurian periods. The post-Cambrian increase in persistence of genera, therefore, indicates an elevated ability of the changing early Palaeozoic marine ecosystems to sustainably maintain existing genera. This is evidence of a new level of ecosystem resilience which evolved during the Ordovician Period.

2013 ◽  
Vol 151 (2) ◽  
pp. 349-364 ◽  
Author(s):  
ROGER A. COOPER ◽  
PETER M. SADLER ◽  
AXEL MUNNECKE ◽  
JAMES S. CRAMPTON

AbstractGraptoloid evolutionary dynamics show a marked contrast from the Ordovician to the Silurian. Subdued extinction and origination rates during the Ordovician give way, during the late Katian, to rates that were highly volatile and of higher mean value through the Silurian, reflecting the significantly shorter lifespan of Silurian species. These patterns are revealed in high-resolution rate curves derived from the CONOP (constrained optimization) scaled and calibrated global composite sequence of 2094 graptoloid species. The end-Ordovician mass depletion was driven primarily by an elevated extinction rate which lasted forc. 1.2 Ma with two main spikes during the Hirnantian. The early Silurian recovery, although initiated by a peak in origination rate, was maintained by a complex interplay of origination and extinction rates, with both rates rising and falling sharply. The global δ13C curve echoes the graptoloid evolutionary rates pattern; the prominent and well-known positive isotope excursions during the Late Ordovician and Silurian lie on or close to times of sharp decline in graptoloid species richness, commonly associated with extinction rate spikes. The graptoloid and isotope data point to a relatively steady marine environment in the Ordovician with mainly background extinction rates, changing during the Katian to a more volatile climatic regime that prevailed through the Silurian, with several sharp extinction episodes triggered by environmental crises. The correlation of graptoloid species diversity with isotopic ratios was positive in the Ordovician and negative in the Silurian, suggesting different causal linkages. Throughout the history of the graptoloid clade all major depletions in species richness except for one were caused by elevated extinction rate rather than decreased origination rate.


2019 ◽  
Vol 11 (1) ◽  
pp. 369-390 ◽  
Author(s):  
Piero Calosi ◽  
Hollie M. Putnam ◽  
Richard J. Twitchett ◽  
Fanny Vermandele

Evolution, extinction, and dispersion are fundamental processes affecting marine biodiversity. Until recently, studies of extant marine systems focused mainly on evolution and dispersion, with extinction receiving less attention. Past extinction events have, however, helped shape the evolutionary history of marine ecosystems, with ecological and evolutionary legacies still evident in modern seas. Current anthropogenic global changes increase extinction risk and pose a significant threat to marine ecosystems, which are critical for human use and sustenance. The evaluation of these threats and the likely responses of marine ecosystems requires a better understanding of evolutionary processes that affect marine ecosystems under global change. Here, we discuss how knowledge of ( a) changes in biodiversity of ancient marine ecosystems to past extinctions events, ( b) the patterns of sensitivity and biodiversity loss in modern marine taxa, and ( c) the physiological mechanisms underpinning species’ sensitivity to global change can be exploited and integrated to advance our critical thinking in this area.


2015 ◽  
Author(s):  
Tim Deprez ◽  
Magda Vincx ◽  
Adelino V.M. Canario ◽  
Karim Erzini ◽  
Katherine Brownlie

The first Mares Conference on Marine Ecosystems Health and Conservation was a successful event organized by the MARES doctoral programme bringing together over 150 researchers in Olhão, Portugal from November 17th to 21st 2014. The conference was opened by Prof. Dr. Hans-Otto Pörtner, whose keynote address focused on a sectoral analysis by the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) on the impacts of climate change on the world’s oceans. The first session on “Future oceans” was opened with a talk by Dr. Frank Melzner highlighting the problems calcifying invertebrates face in the warmer, more acidic and hypoxic waters. Other presenters dealt with changing global diversity patterns, ocean acidification, and the loss the genetic diversity. The second session on “Natural resources” was opened by Dr. Rainer Froese, who focused on whether or not the oceans can feed humanity. This talk introduced other contributions in the session, dealing with fisheries issues and Marine Protected Areas, as well as problems with proper identifications of species used for economic purposes. “Biodiversity effects” was the scope of the third session opened by a talk on oxygenation and marine biodiversity challenges in the 21st Century by Prof. Lisa Levin. Rapid ocean deoxygenation is a process which is currently less investigated but which has considerable effects on body size, taxonomic composition, habitat heterogeneity, and nutrient cycling. The following presentations focused on other factors having a strong effect on marine biodiversity, ranging from the harvesting of algae to the fragmentation of ecosystems. The fourth session addressed “Biological invasions”. Dr. Gregory Ruiz discussed biological invasions in North American marine ecosystems and the need for constant monitoring, and the use of a dynamic and multi-vector approach. Problems with invasive species in European waters were addressed with examples from the Baltic Sea, the North Sea, and the Mediterranean Sea. The fifth session on “Ocean Noise” was opened by Prof. Peter Tyack with a talk on the effects of anthropogenic sound on marine mammals. Although ocean noise issues are often linked to marine mammals, the effects of sound related to marine constructions on fish behaviour, nicely illustrated that ocean noise is a factor with a much broader impact than expected. The last session of the first Mares Conference dealt with “Habitat loss”. Dr. Michael Beck focused on this topic with his talk on ‘Building Coastal Resilience for Climate Adaptation and Risk Reduction’. Talks in the session ranged from the use of telemetry as a tool to monitor species in changed habitats, to cases dealing with sea level rise related problems in for example salt-marshes. The first Mares Conference offered a broad range of oral and poster presentations, as well as digital presentations. The poster and digital object presentations included over 100 contributions.


2020 ◽  
Vol 125 (7) ◽  
Author(s):  
Helen R. Powley ◽  
Jorn Bruggeman ◽  
Jo Hopkins ◽  
Tim Smyth ◽  
Jerry Blackford

2020 ◽  
Vol 12 (18) ◽  
pp. 7814
Author(s):  
Susana Perera-Valderrama ◽  
Sergio Cerdeira-Estrada ◽  
Raúl Martell-Dubois ◽  
Laura Rosique-de la Cruz ◽  
Hansel Caballero-Aragón ◽  
...  

In the Mexican Caribbean, 15 marine protected areas (MPAs) have been established for managing and protecting marine ecosystems. These MPAs receive high anthropogenic pressure from coastal development, tourism, and fishing, all in synergy with climate change. To contribute to the MPAs’ effectiveness, it is necessary to provide a long-term observation system of the condition of marine ecosystems and species. Our study proposes the establishment of a new marine biodiversity monitoring program (MBMP) focusing on three MPAs of the Mexican Caribbean. Five conservation objects (COs) were defined (coral reefs, seagrass beds, mangroves, marine turtles, and sharks-rays) for their ecological relevance and the pressures they are facing. Coral reef, seagrass and mangroves have multiple biological, biogeochemical and physical interactions. Marine turtles are listed as endangered species, and the status of their populations is unknown in the marine area of the MPAs. Elasmobranchs play a key role as top and medium predators, and their populations have been poorly studied. Indicators were proposed for monitoring each CO. As a technological innovation, all information obtained from the MBMP will be uploaded to the Coastal Marine Information and Analysis System (SIMAR), a public, user-friendly and interactive web platform that allows for automatic data management and processing.


2018 ◽  
Vol 4 (4) ◽  
pp. eaaq1508 ◽  
Author(s):  
Emanuela Di Martino ◽  
Jeremy B. C. Jackson ◽  
Paul D. Taylor ◽  
Kenneth G. Johnson

1987 ◽  
Vol 65 (5) ◽  
pp. 1053-1060 ◽  
Author(s):  
Philip D. Gingerich

Mammals have an unusually good Cenozoic fossil record providing evidence of their evolutionary diversification. We view this record in hindsight, which biases our perception in many ways. Overall worldwide diversity appears to increase exponentially through time, while intensive sampling in local areas indicates that modern levels of diversity were achieved early in the Cenozoic. The evident significance of Pleistocene extinctions depends critically on how extinction rates are quantified. Our taxonomic hierarchy probably reflects the number of major faunal turnovers a group has survived rather than declining intensity of successive turnovers. Morphological innovation and taxonomic diversification appear following intervals of climatic cooling, suggesting that major features of evolution are extrinsically controlled. Favorable stratigraphic settings yield detailed records of gradual anagenesis and cladogenesis in mammals, with intermediates present as evidence of transition. The apparent dichotomy between high evolutionary rates measured by neontologists over short intervals of time and low evolutionary rates measured by paleontologists over long intervals of time disappears when rates are measured on intermediate scales of time. Microevolution and macroevolution are manifestations of common underlying processes expressed on different time scales.


1997 ◽  
Vol 16 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Ludmila M. Melnikova ◽  
David J. Siveter ◽  
Mark Williams

Abstract. Some 40 bradoriid and phosphatocopid (Arthropoda) species are known from the Cambrian of the former Soviet Union. The faunas occur chiefly in Asia (mostly Siberia and Kazakhstan; also Kirghizia); west of the Urals bradoriid and phosphatocopid faunas are sparse, occurring in the Leningrad region, Belarus and Estonia. Most specimens are recovered as crack-out material from clastic and impure carbonate rocks; acid resistant valves from limestones are a minor component of the known faunas.Early Cambrian (Atdabanian-Botomian) faunas are widespread; middle and late Cambrian faunas are scarcer and are known largely from Siberia and Kazakhstan. Though many species are seemingly short-ranging, currently most have only local biostratigraphic significance, with only a few having practical international correlative value.Palaeogeographically, faunas west of the Urals show affinites with those of the Early Palaeozoic Baltica and Avalonia palaeocontinents (Olenellid trilobite realm). Siberian and central Asian (Kazakhstan, Kirghizia, Gorny–Altay–Mongolian belt) faunas show clear affinities with those of palaeocontinental South China and eastern Gondwana (Redlichiid trilobite realm).


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