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Five mass extinction events have punctuated the geological record of marine invertebrate life. They are characterized by faunal extinction rates and magnitudes that far exceed those observed elsewhere in the geological record. Despite compelling evidence that these extinction events were probably driven by dramatic global environmental change, they were originally thought to have little macroecological or evolutionary consequence for terrestrial plants. New high-resolution regional palaeoecological studies are beginning to challenge this orthodoxy, providing evidence for extensive ecological upheaval, high species-level turnover and recovery intervals lasting millions of years. The challenge ahead is to establish the geographical extent of the ecological upheaval, because reconstructing the vegetation dynamics associated with these events will elucidate the role of floral change in faunal mass extinction and provide a better understanding of how plants have historically responded to global environmental change similar to that anticipated for our future.
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... The evolution of higher plants during the Ordovician (Lenton et al., 2012), and especially the Devonian (Algeo and Scheckler, 1998), has been implicated in the extinction of marine organisms during the end-Ordovician and end-Devonian extinction events. Plants may also be the cause of anoxic events following mass extinctions at the Permian-Triassic and Triassic-Jurassic boundaries (McElwain and Punyasena, 2007). Lenton et al. (2012) proposed a new scenario for the end-Ordovician extinction that elegantly links the evolution of land plants, the Hirnantian glaciation, and enhanced carbon burial episodes as reflected in the large HICE isotope excursion. ...
... The role of plants in driving extinction in early Triassic and early Jurassic oceans was likely slightly different but equally important (McElwain and Punyasena, 2007) then the role played during the end-Ordovician and end-Devonian. For the early Triassic and early Jurassic, it was not the arrival of new plants but rather the extinction of woody vegetation that led to the most important changes. ...
... B) Carbon isotope records modified fromLindström et al. (2012) andvan de Schootbrugge et al. (2008). C) Terrestrial primary producers based onvan de Schootbrugge et al. (2009) andMcElwain and Punyasena (2007). D) Marine primary producers based on. ...
Article
The Big Five mass-extinction events are characterized by dramatic changes in primary producers. Initial disturbance to primary producers is usually followed by a succession of pioneers that represent qualitative and quantitative changes in standing crops of land plants and/or phytoplankton. On land, a transient collapse of arborescent (tree-bearing) vegetation and the rapid spread of a pioneer vegetation dominated by ferns and fern allies characterizes the Permian/Triassic (P/T), Triassic/Jurassic (T/J), and Cretaceous/Paleogene (K/Pg) mass-extinction events. The availability of low-quality food, such as herbaceous low-growing plants, likely played a role in triggering secondary extinctions of herbivores (reptiles, insects). Furthermore, malformation of acritarchs, pollen, and spores during the end-Ordovician, end-Devonian, P/T and T/J extinctions also suggests primary producers were of lesser quality. More importantly, changes in vegetation drove important increases in weathering and erosion leading to elevated nutrient transfer from the continents to the oceans. In the marine realm, the end-Ordovician, end-Devonian, end-Permian, and end-Triassic extinction events are all followed by periods of high primary production, which is reflected in the widespread deposition of black shales. Due to their small size, low nutritional quality, and possible toxicity, the abundance of picoplankton, such as prasinophytes, acritarchs, as well as bacterioplankton (cyanobacteria and green sulfur bacteria) may have been additional factors in delaying ecosystem recovery.
... Understanding how plants respond to fluctuations in climate has long been of significant interest to biologists. Much of this early interest focused on changes in deep time and has revealed fairly dramatic periods of extinction, migration, ecological constriction, and proliferation (DiMichele and Phillips, 1996;Lezine and Cazet, 2005;McElwain and Punyasena, 2007;DiMichele et al., 2009;Brownsey, 2007, Shepherd et al., 2017). Studies like these have greatly informed our understanding about how plants respond to climate change. ...
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The coming decades are predicated to bring widespread shifts in local, regional, and global climatic patterns. Currently there is limited understanding of how ferns will respond to these changes and few studies have attempted to model shifts in fern distribution in response to climate change. In this paper, we present a series of these models using the country of New Zealand as our study system. Ferns are notably abundant in New Zealand and play important ecological roles in early succession, canopy biology, and understory dynamics. Here we describe how fern distributions have changed since the Last Glacial Maximum to the present and predict how they will change with anthropogenic climate change assuming no measures are taken to reduce carbon emissions. To do this, we used MaxEnt species distribution modelling with publicly available data from gbif.org and worldclim.org to predict the past, present, and future distributions of 107 New Zealand fern species. The present study demonstrates that ferns in New Zealand have and will continue to expand their ranges and migrate southward and upslope. Despite the predicted general increased range size as a result of climate change, our models predict that the majority (52%) of many species' current suitable habitats may be climatically unsuitable in 50 years, including the ecologically important group: tree ferns. Additionally, fern communities are predicted to undergo drastic shifts in composition, which may be detrimental to overall ecosystem functioning in New Zealand.
... Benton (1995) showed plots of land animal organisms with similar extinction intensities. Land plants also show extensive ecological upheaval for the mass extinctions at the end of the Permian, Triassic, and Cretaceous (McElwain and Punyasena, 2007). The synchronous mass extinctions for both the marine and terrestrial environments means that a widespread mechanism must be responsible (Metcalfe and Isozaki, 2009). ...
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A new property of Earth has been discovered. It is called "Earth's non-metal signature". This is a series of non-meal compounds and noble elements deposited throughout geologic time. All the mass extinctions are related to this. A theory of planetary evolution is formulated to explain this non-metal geologic overprint. The theory roughly explains all supercontinent formation and breakup cycles and why a supercontinent will never form again.
... A further reason includes the severe collapses occurring later in Earth's history resulted in mass extinctions. At least the extinction events 250 Ma and 359 Ma ago were associated with the destruction of the ozone layer and a consequently increased UV radiation [157][158][159]. The destruction of the ozone layer may also have contributed to the extinction of the dinosaurs 66 million years ago, albeit due to an asteroid impact and associated air pollution. ...
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The cryptochrome/photolyase (CRY/PL) family represents an ancient group of proteins fulfilling two fundamental functions. While photolyases repair UV-induced DNA damages, cryptochromes mainly influence the circadian clock. In this study, we took advantage of the large number of already sequenced and annotated genes available in databases and systematically searched for the protein sequences of CRY/PL family members in all taxonomic groups primarily focusing on metazoans and limiting the number of species per taxonomic order to five. Using BLASTP searches and subsequent phylogenetic tree and motif analyses, we identified five distinct photolyases (CPDI, CPDII, CPDIII, 6-4 photolyase, and the plant photolyase PPL) and six cryptochrome subfamilies (DASH-CRY, mammalian-type MCRY, Drosophila-type DCRY, cnidarian-specific ACRY, plant-specific PCRY, and the putative magnetoreceptor CRY4. Manually assigning the CRY/PL subfamilies to the species studied, we have noted that over evolutionary history, an initial increase of various CRY/PL subfamilies was followed by a decrease and specialization. Thus, in more primitive organisms (e.g., bacteria, archaea, simple eukaryotes, and in basal metazoans), we find relatively few CRY/PL members. As species become more evolved (e.g., cnidarians, mollusks, echinoderms, etc.), the CRY/PL repertoire also increases, whereas it appears to decrease again in more recent organisms (humans, fruit flies, etc.). Moreover, our study indicates that all cryptochromes, although largely active in the circadian clock, arose independently from different photolyases, explaining their different modes of action.
... Accordingly, the events for TD-duplicated IX genes was estimated to be during~181-319 Ma covering the origin of angiosperms after gymnosperm split (van der Kooi & Ollerton, 2020), much earlier than that of convergent expansion of CBFs/DREB1s in monocots and eudicots. During the period, the paleoenvironments were subject to dramatic changes with a rise of >8°C in temperature, an increase in CO 2 by 2 000 PPM (for comparison, the amount today is~413 PPM), and a significant decline in oxygen (McElwain & Punyasena, 2007;Kumar et al., 2017). In contrast to CBFs/DREB1s, the expressions of the TD-duplicated AP2/ERF IX genes are not changed under cold stress ( Figure S8C) and many of them (e.g., AT3G23220, AT3G23230, and AT3G23240) were in response to ethylene (Riechmann & Meyerowitz, 1998;Solano et al., 1998;Fujimoto et al., 2000). ...
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The C‐repeat binding factors/Dehydration‐responsive element binding protein 1s (CBFs/DREB1s) have been identified as major regulators of cold acclimation in many angiosperm plants. However, their origin and evolutionary process associated to cold responsiveness are still lacking. By integrating multi‐omics data of genomes, transcriptomes, and CBFs/DREB1s genome‐wide binding profiles, we unveil the origin and evolution of CBFs/DREB1s and their regulatory network. Gene collinearity and phylogeny analyses show that CBF/DREB1 is an innovation evolved from tandem duplication (TD)‐derived DREB III gene. A subsequent event of ε‐whole genome duplication (ε‐WGD) led to two CBF/DREB1 archetypes (Clade I and II) in ancient angiosperms. In contrast to cold‐insensitivity of Clade I and their parent DREB III genes, Clade II evolved a further innovation in cold‐sensitive response and was stepwise expanded in eudicots and monocots by independent duplications. In geological time, the duplication events were mainly enriched around the Cretaceous–Paleogene (K–Pg) boundary and/or in the Late Cenozoic Ice Age, when the Global Average Temperature (GAT) significantly decreased. Consequently, the duplicated CBF/DREB1 genes contributed to the rewiring of CBFs/DREB1s‐regulatory network for cold tolerance. Altogether, our results highlight an origin and convergent evolution of CBFs/DREB1s and their regulatory network probably for angiosperms adaptation to global cooling. This article is protected by copyright. All rights reserved.
... Ma; crown node ages; Ramírez-Barahona et al., 2020). The abrupt collapse of ecosystems caused by the Cretaceous-Paleogene (K-Pg) mass extinction at ca. 65 Ma catalyzed drastic floristic changes and extirpated up to 57% of plant species, mostly affecting lineages dispersed and pollinated by animals (McElwain and Punyasena, 2007). The recovery of plant diversity in the early Paleocene coincided with the establishment and diversification of modern tropical rainforests (e.g., Morley, 2000;Wang et al., 2012;Meseguer et al., 2018) and, in the early Eocene climatic optimum (52-50 Ma), rainforests reached higher latitudes and formed a relatively continuous boreotropical flora (Wolfe, 1978). ...
Article
Pleuromeia Corda is an iconic lycopod genus in the Early Triassic floras of the world. Pleuromeia fossils are very significant in stratigraphy and palaeoenvironmental interpretation and have been regarded as an important Lower Triassic index fossil. Although some recent studies show that the genus occurred in the lower part of the Middle Triassic, no definite Pleuromeia has been reported from the late Middle Triassic and the younger strata so far. In this paper, some reproductive organ fossils of Pleuromeia from the upper Middle Triassic Tongchuan Formation in Shaanxi Province (belonging to the Ordos Basin), North China, are described for the first time, belonging to the new species Pleuromeia obovata Deng nov. sp. Highly accurate dating results of tuff layers indicate that the age of the new species is between 241.06 ± 0.12 Ma and 241.558 ± 0.093 Ma, equivalent to the early Ladinian. This is the youngest species of genus Pleuromeia so far. Spatiotemporal distribution of Pleuromeia indicates that the genus first appeared in the Induan (Early Triassic) in North China, occurred widespread and flourished in both Laurasia and Gondwana during the Olenekian (late Early Triassic), declined from the Anisian (early Middle Triassic), survived in the Ladinian in North China, and may have gone extinct as early as the end of the Middle Triassic. North China may well have included the place of origination and the last habitats of this genus.
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In the last 500 million years, Earth's biota experienced periods of crises with extinctions on a large scale and significant turnover events, one of them being the Permian-Triassic extinction event. The following Early Triassic was a critical time marked by a series of biological and environmental changes with a complex recovery pattern of marine faunas and ecosystems. Generally, animals and plants respond to stress by using different strategies that help them tolerate or recover from unfavourable environmental conditions. In this contribution, we quantitatively and qualitatively describe a variety of malformations of spores and pollen grains from the extensively studied Nammal section (Salt Range, Pakistan) across the Smithian/Spathian boundary interval (Early Triassic). High dominance of malformed sporomorphs is recorded throughout the studied interval, indicating stressful conditions for plants on the Indian margin during the Early Triassic. One of the highest abundances of malformed sporomorphs coincides with the spore spike and the negative carbon isotope excursion during the middle Smithian, emphasising this intense biotic stress. Either a cocktail of volcanic gases, acid rains, soil acidification, and heavy metal pollution as a consequence of a late pulse of the Siberian Trap large igneous province or climatic extremes might have been responsible for these malformations. Here teratology is used as a tool/means to assess the severity of biotic crises in the plant kingdom, indicating its potential value as a signal of ecological disturbance.
Article
Whole-genome duplication (WGD or polyploidization) has been suggested as genetic contribution for angiosperm adaptation to environmental changes. However, many eudicot lineages did not undergo "recent WGD" (R-WGD) around and/or after the Cretaceous-Paleogene (K-Pg) boundary with severe environmental changes; how those plants survived has been largely ignored. Here, we collected 22 plants in the major branches of eudicot phylogeny and according to occurrence or nonoccurrence of R-WGD, those eudicots were classified into two groups: 12 R-WGD-contained plants (R-WGD-Y) and 10 R-WGD-lacked plants (R-WGD-N). Subsequently, we identified 496 gene-rich families in R-WGD-Y and unveiled that AP2/ERF transcription factor family were convergently over-retained following R-WGDs and showed an exceptional cold stimulation. The evolutionary trajectories of AP2/ERF family were then compared between R-WGD-Y versus R-WGD-N to reveal convergent expansions of AP2/ERF III and IX subfamilies through recurrently independent WGDs and tandem duplications (TDs) after the radiation of the plants. The expansions were coincidently enriched with the periods around and/or after the K-Pg boundary, when global cooling was a major environmental stressor. Consequently, those convergent expansions and co-retentions of AP2/ERF III C-repeat binding factor (CBF) duplicates and their regulons in different eudicot lineages contributed to the rewiring of cold-specific regulatory networks. Moreover, cold-responsive AP2/ERF genes deciphered a battery of the underlying cis-regulatory code (G-box: CACGTG). Altogether, we propose a seesaw model of WGDs and TDs in convergently expanding III and IX genes in contribution to eudicot adaptation during paleoenvironmental changes and suggest that TD might be a reciprocal/alternative mechanism for genetic innovation of WGD-lacked plants.
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This study reviews plant species richness and abundance change from the End Permian to Middle Triassic in South China and examines the co-evolutionary relationship between the flora and the environment through this critical interval in the history of terrestrial biotas. A normalized macro-fossil plant record, that considers only one taxon per whole plant, is produced. This identifies four broad phases of plant evolution. Phase 1 is marked by pre-extinction floras that demonstrate a long-term decline of species richness beginning in the Late Permian (lower Changhsingian) that culminates in the distinct End Permian Plant Crisis (EPPC) at the end of the Changhsingian. Other evidence for the health of the flora, including palynology, biomarkers, wildfire proxies, soil erosion and weathering proxies show a drastic loss of plant abundance (biomass) and increase of wildfire frequency (suggestive of increasing seasonal aridity) during the EPPC. A Phase 2 survival interval, during the Changhsingian–Griesbachian transition, has a severely impoverished plant assemblage consisting of opportunistic lycopods and a short-lived holdover flora. Phase 3 (Late Griesbachian–Smithian) saw the modest recovery of species richness as several groups began to radiate, notably conifers and ferns. Diversity increases substantially and persistently during the succeeding Phase 4 and sees the dominant lycopods/herbaceous bryophytes of Phase 3 replaced by conifer-dominated floras. Plant abundance recovery began earlier than the resumption of coal formation which only initiated in the Anisian following its disappearance during the EPPC. Only in the Late Triassic did the flora recover to a level comparable to that seen in the Permian. The flora of South China thus took ~15 million years to completely recover from the profound environmental and climatic effects of the Permo-Triassic mass extinction.
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The extinction of vertebrates around the time of the Permian-Triassic boundary has long been regarded as a gradual event occurring over millions of years. Our new field investigations of fluvial strata in the central and southern Karoo Basin of South Africa have revealed the presence of an event bed coinciding with a mass extinction of terrestrial fauna and flora. The bed is in a sedimentary sequence that is marked by a reddening of flood-plain mud rocks and a change from high- to low-sinuosity river channel systems. Here we show that the pattern of vertebrate taxa disappearing below this boundary and the subsequent appearance of new taxa above the boundary are consistent with a relatively sudden, possibly catastrophic event, perhaps of 50 000 yr duration or less.
Article
Mass extinctions generally are recognized as major features in the history of life. They sweep aside diverse, sometimes even dominant groups of organisms, freeing up resources that can then fuel the diversification and rise to dominance of lineages that survived the mass extinction. This view of the history of life has been developed in large part from the study of shelly marine animals, and to a lesser extent from studies of terrestrial vertebrates (e.g. Valentine, 1985). By compiling data on the stratigraphic ranges of genera and families of marine animals, palaeontologists have been able to recognize the ‘Big Five’ mass extinctions, occurring at the end of the Ordovician, in the Late Devonian and at the end of the Permian, Triassic and Cretaceous periods (e.g. Sepkoski, 1993; Chapters 1 and 5). Each of these episodes is a geologically sudden decrease in taxonomic diversity. Terrestrial vertebrates also show major declines in taxonomic diversity at the end of the Permian and at the end of the Cretaceous (Benton, 1993). In contrast, compilations of the stratigraphic ranges of species of land plants do not show major declines in diversity (Niklas et al., 1980, 1985; Niklas and Tiffney, 1994; Figure 3.1). The absence of major declines in the diversity of land plants as represented in these compilations of stratigraphic ranges has led to the suggestion that plants are more resistant to mass extinctions than animals (Niklas et al., 1980; Knoll, 1984; Traverse, 1988).
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Palynology is used to bracket or pinpoint the Cretaceous-Tertiary (K-T) boundary in 17 measured sections near the contact of the Hell Creek Formation and the Ludlow Member of the Fort Union Formation in southwestern North Dakota. Palynostratigraphy is the most reliable method for locating the K-T extinction horizon - which defines the K-T boundary - in nonmarine rocks. The palynological database includes 110 taxa for which relative abundance or presence or absence data were recorded in more than 350 samples based on surveys of more than 700 000 specimens. These data from laterally extensive outcrops in the badlands along the Little Missouri River provide a temporal framework for concurrent studies in the area on megafossil paleobotany, vertebrate paleontology, lithostratigraphy, magnetostratigraphy, and chemostratigraphy. Palynology demonstrates extinction of 30% or more of the Maastrichtian palynoflora, including characteristic Maastrichtian taxa ("K taxa"), at the K-T boundary. Most of the palynomorph taxa discussed probably represent higher-level plant taxa (botanical genera or families). The K-T boundary is shown to be coincident with the Hell Creek-Fort Union formational contact at only two localities; it is as much as 2.7mabove the base of the Fort Union Formation at others. Thus, a distinctive interval of Fort Union strata of Cretaceous age is recognized that is characterized by occurrences of numerous K taxa, usually in low percentage abundance, up to the K-T boundary. This interval documents a regional paleoenvironmental change that is independent of the extinction event and that is important to understanding the K-T transition throughout western North America.