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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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... During the end-Permian extinctions, some studies indicate that plant diversity declined by > 50% at the species level but plant families and orders showed a negligible global loss. In contrast, 62% of terrestrial faunal families became extinct (McElwain and Punyasena 2007). However, other studies suggest that land plants were not affected significantly at global scale and differential latitudinal responses have been invoked (Hochuli et al. 2016;Nowak et al. 2019;Gastaldo 2019;Feng et al. 2020). ...
... During the end-Permian and later extinctions, plant taxonomic losses above genus rank were rare, in contrast to taxonomic extinction patterns in animals (McElwain and Punyasena 2007). The reproductive, physiological, and behavioural traits of plants allowed small populations to withstand extreme environmental change. ...
Article
Synopsis The invasion of the land was a complex, protracted process, punctuated by mass extinctions, that involved multiple routes from marine environments. We integrate paleobiology, ichnology, sedimentology, and geomorphology to reconstruct Paleozoic terrestrialization. Cambrian landscapes were dominated by laterally mobile rivers with unstable banks in the absence of significant vegetation. Temporary incursions by arthropods and worm-like organisms into coastal environments apparently did not result in establishment of continental communities. Contemporaneous lacustrine faunas may have been inhibited by limited nutrient delivery and high sediment loads. The Ordovician appearance of early land plants triggered a shift in the primary locus of the global clay mineral factory, increasing the amount of mudrock on the continents. The Silurian-Devonian rise of vascular land plants, including the first forests and extensive root systems, was instrumental in further retaining fine sediment on alluvial plains. These innovations led to increased architectural complexity of braided and meandering rivers. Landscape changes were synchronous with establishment of freshwater and terrestrial arthropod faunas in overbank areas, abandoned fluvial channels, lake margins, ephemeral lakes, and inland deserts. Silurian-Devonian lakes experienced improved nutrient availability, due to increased phosphate weathering and terrestrial humic matter. All these changes favoured frequent invasions to permament establishment of jawless and jawed fishes in freshwater habitats and the subsequent tetrapod colonization of the land. The Carboniferous saw rapid diversification of tetrapods, mostly linked to aquatic reproduction, and land plants, including gymnosperms. Deeper root systems promoted further riverbank stabilization, contributing to the rise of anabranching rivers and braided systems with vegetated islands. New lineages of aquatic insects developed and expanded novel feeding modes, including herbivory. Late Paleozoic soils commonly contain pervasive root and millipede traces. Lacustrine animal communities diversified, accompanied by increased food-web complexity and improved food delivery which may have favored permanent colonization of offshore and deep-water lake environments. These trends continued in the Permian, but progressive aridification favored formation of hypersaline lakes, which were stressful for colonization. The Capitanian and end-Permian extinctions affected lacustrine and fluvial biotas, particularly the invertebrate infauna, although burrowing may have allowed some tetrapods to survive associated global warming and increased aridification.
... 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.
... 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). ...
... Botanical studies have been critical for understanding the evolution and structure of terrestrial ecosystems and the interactions of plants and the atmosphere as well as understanding how plants have responded to previous periods of mass extinction (McElwain & Punyasena, 2007). Studies of stomata helped understand how plants respond to changing atmospheric CO 2 and how much this has changed over geological time (Woodward, 1987). ...
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Civilization is dependent upon plants for survival. Plants permeate our every moment and our relationship with them will dictate how we will manage the threats of climate change and ecological collapse defining the Anthropocene. Yet, despite the significance of plants and the critical role they have played in shaping ecosystems, civilizations, and human cultures, many people are now disconnected from the botanical world. Students are presented with little plant content, particularly identification, compared with animal content. Consequently, we are producing few plant scientists and educating fewer scientists about plants. This drives a self‐accelerating cycle we term the extinction of botanical education. A process of knowledge erosion, that in this instance contributes to our separation from the natural world, makes us blind to the biodiversity crisis and inhibits our ability to restore it. We argue that neglecting the importance of plants within education threatens the foundations of industries and professions that rely on this knowledge. Furthermore, this extinction of botanical education creates an existential threat: Without the skills to fully comprehend the scale of and solutions to human‐induced global change, how do we as a society combat it? We present key research agendas that will enable us to reverse the extinction of botanical education and highlight the critical role plants play on the global stage. Civilization is dependent upon plants for survival and our relationship with them will dictate how we will manage the global impact of humanity which defines the Anthropocene. We document and define a self‐perpetuating educational cycle that we term the extinction of botanical education and its impact on the science of botany and potential ramifications for society to reverse and stabilise human included global change.
... The once widespread seed fern Dicrodium disappeared from the fossil record (van de Schootbrugge et al., 2009). There was a 90% species turnover in the terrestrial megaflora (McElwain and Punyasena, 2007). A "fern-spike" suggests widespread changes in vegetation across Europe and North Atlantic Bonis et al., 2010). ...
... This strategy is most likely related to its ability to regenerate under shady conditions and continue later growth under conditions of full irradiance (Finckh and Paulsch 1995, Lusk and Le-Quesne 2000, González et al. 2010. Based on the evolutionary history of gymnosperms, it has been reported that they dominated much of the Mesozoic, and their greatest abundance occurred after the Permian-Triassic extinction, possibly due to the opening of the canopy to direct light (McElwain and Punyasena 2007, Crisp and Cook 2011, Wang and Ran 2014. Many gymnosperms prefer sunny conditions (Kouřil et al. 2016), though there are some species of Podocarpaceae with a significant tolerance to shade, allowing them to successfully compete with angiosperms (Biffin et al. 2012. ...
Article
The study of ancient species provides valuable information concerning the evolution of specific adaptations to past and current environmental conditions. Araucaria araucana belongs to one of the oldest families of conifers in the world, despite this, there are few studies focused on its physiology and responses to changes in environmental conditions. We used an integrated approach aimed at comprehensively characterizing the ecophysiology of this poorly known species, focusing in its stomatal, mesophyll, and biochemical traits, hypothesizing that these traits govern the carbon assimilation of A. araucana under past and present levels of atmospheric CO2. Results indicated that A. araucana presents the typical traits of an ancient species, such as large stomata and low stomatal density, which trigger low stomatal conductance and slow stomatal responsiveness to changing environmental conditions. Interestingly, the quantitative analysis showed that photosynthetic rates were equally limited by both diffusive and biochemical components. The Rubisco catalytic properties proved to have a low Rubisco affinity for CO2 and O2, similar to other ancient species. This affinity for CO2, together with the slow carboxylation turnover rate, are responsible for the low Rubisco catalytic efficiency of carboxylation. These traits could be the result of the diverse environmental selective pressures that A. araucana was exposed during its diversification. The increase in measured temperatures induced an increase in stomatal and biochemical limitations, which together with a lower Rubisco affinity for CO2 could explain the low photosynthetic capacity of A. araucana in warmer conditions.
... Among the five well-known mass extinctions that took place during the Phanerozoic, the Permian-Triassic boundary event (PTB) was the most destructive, resulting in a substantial reduction in marine (Raup, 1979), terrestrial vertebrate (Maxwell, 1992) and insect fauna (Labandeira & Sepkoski, 1993) as well as in plants (McElwain & Punyasena, 2007). A gradual recovery of terrestrial fauna from the PTB mass extinction occurred during the Early and Middle Triassic (Grauvogel-Stamm & Ash, 2005;Irmis & Whiteside, 2012;Shcherbakov, 2008). ...
Article
More than 95% of phytophagous true bug (Hemiptera: Heteroptera) species belong to four superfamilies: Miroidea (Cimicomorpha), Pentatomoidea, Coreoidea, and Lygaeoidea (all Pentatomomorpha). These iconic groups of highly diverse, overwhelmingly phytophagous insects include several economically prominent agricultural and silvicultural pest species, though their evolutionary history has not yet been well resolved. In particular, superfamily- and family-level phylogenetic relationships of these four lineages have remained controversial, and the divergence times of some crucial nodes for phytophagous true bugs have hitherto been little known, which hampers a better understanding of the evolutionary processes and patterns of phytophagous insects. In the present study, we used 150 species and concatenated nuclear and mitochondrial protein-coding genes and rRNA genes to infer the phylogenetic relationships within the Terheteroptera (Cimicomorpha + Pentatomomorpha) and estimated their divergence times. Our results support the monophyly of Cimicomorpha, Pentatomomorpha, Miroidea, Pentatomoidea, Pyrrhocoroidea, Coreoidea, and Lygaeoidea. The phylogenetic relationships across phytophagous lineages are largely congruent at deep nodes across the analyses based on different datasets and tree-reconstructing methods with just a few exceptions. Estimated divergence times and ancestral state reconstructions for feeding habit indicate that phytophagous true bugs explosively radiated in the Early Cretaceous-shortly after the angiosperm radiation-with the subsequent diversification of the most speciose clades (Mirinae, Pentatomidae, Coreinae, and Rhyparochromidae) in the Late Cretaceous.
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.
Chapter
Horizons with plant fossils from the Keuper beds of Germany (germanotype Triassic, Upper Ladinian to Rhaetian) have been briefly reviewed in order to characterize their different levels of diversity and their palaeobotanical importance and phyto-taphonomical features. Lettenkeuperflora (Erfurt-Formation, Ladinian) and Schilfsandsteinflora (Stuttgart-Formation, Carnian) represent mixed assemblages of palaeozoic floral elements and of mesozoic components that emerged in the fossil record for the first time in the Anisian or Ladinian. The prominent evolutionary feature in Lettenkeuper- and Schilfsandsteinflora is the first appearance of leptosporangiate ferns and the Bennettitales, testified by fronds of Clathropteris meniscioides, Phlebopteris sp. and Pterophyllum filicoides. Axis of large herbaceous horsetails and sporophylls of Lepacyclotes zeilleri are ubiquitous in the Lettenkeuperflora. Conifers are prevailing in the Coburger-Sandsteinflora (Hassberge-Formation, Carnian) as well as in smaller macroplant assemblages from the Gipskeuper (Grabfeld-Formation, Carnian) and the Burgsandstein/Stubensandstein (Mainhardt- and Löwenstein-Formation, Carnian, Norian). Permineralized palaeosoils from the Knollenmergel (Trossingen-Formation, Norium) yield excellently preserved charcoal and macroplant remains. The highly diverse Rhätflora (Exter-Formation, Rhaetian) seemed to be quite similar with Lower Jurassic macroplant assemblages, but the palaeozoic floral component Lepidopteris ottonis occurs ultimately in the Rhätflora. Other selected topics addressed in this paper are petrographic features of the “Lettenkohle”, the presence of charcoal produced by wildfire in the Keuper and its palaeoecological importance, the biotic recovery of the Lettenkeuperflora from the Permian-Triassic mass extinction, long distance log transportation and wood decay by fungi and finally the fossil animal plant interaction in biomes of the Keuper.
Article
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).
Article
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.