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Caytoniales and angiosperms diverged from a common ancestor with Bennettitales in the Lower Triassic according to Cascales-Miñana et al. Why assume that flowering plants constitute a single clade first appearing 256 MYA without discussing Mathews (2009), Mathews et al. Discerning Fingerprints of Developmental Regulation: This chapter of the essay considers experimental approaches and paleobiological evidence drawn from the research perspective of evo-devo, which is necessary to identify lineages of seed plants involved in the origin and evolution of flowering plants. D., and Mark's help at the delnortea beds is gratefully acknowledged. the [angiosperm] clade probably first appeared during Triassic times," which is a stratigraphically-perplexing Gordian Knot. The preceding statement is quoted from page 399 of David Grimaldi and Michael S. This challenging and daunting approach was facilitated by ready access to several world class research libraries at the University of California, Berkeley. The enigmatic Paleozoic plants Spermopteris and Phasmatocycas reconsidered. Were insect and shrub coevolutionary compartments of the late Paleozoic hypoxic icehouse and later hot house, venues of the first angiosperms? This question among others is explored in this first of three essays on the origin of angiosperms. Long-branch attraction (LBA) continues to cloud molecular-phylogenetic studies of seed plants, including angiosperms (Lipeng Zeng et al. Evolutionary-development of early land plants was probably intertwined with regulatory changes in polycomb repressive 2 gene complexes and other stem cell factors as evidenced from studies of the extant model bryophyte Physcomitrella (Okano et al. Floyd and Bowman (2007) are the first workers to estimate the developmental tool kit of early land plants including Paleozoic seed plant homeotic genes potentially important in the later evolution and diversification of angiosperms and origin of the first flowers from bisexual cone axes sensu Melzer et al. The work by Floyd and Bowman (2007) focuses on a molecular-phylogenetic analysis of Chara (a green alga), Physcomitrella (a moss), Selaginella (a lycophyte), Arabidopsis (angiosperm malvid), Antirrhinum (angiosperm asterid), Oryza (angiosperm monocot), Populus (angiosperm fabid), Picea (gymnosperm conifer), and Pinus (among others). Certain aspects of coevolution of Mesozoic arthropods and seed plants that have a bearing on the origin and diversity of angiosperms are reviewed by Takhtajan (1969), Raven (1977), Thien et al. A review of plant homeobox genes and homeodomain proteins offers additional insight into critical elements of the land plant developmental tool kit (Mukherjee et al. Many developmental gene families and cis-acting TFs have been identified in land plants (Langdale 2008, Mukherjee et al. Coevolution between phytophagous insect antagonists and Carboniferous, Permian, and Triassic seed plant hosts at the level of their respective developmental tool kits with focus on selective forces that drive the logic of transcriptional regulation is proposed in the following essay to explain the origin and evolution of flowering plants and certain Holometabola. A second species of Degeneria has been reported (A. Despite several decades of effort by morphologists, paleobotanists, and plant biologists, the origin of angiosperms remains enigmatic and mysterious. Taylor and Hickey (1996 [a book and one paper]), D. Interestingly, many naturally-occurring plant sesquiterpene esters and lactones are bioactive and exhibit insecticidal properties. Molecular diversification of the Hox gene complex over the course of 600 million years of metazoan evolution is analogous to the 400 million year old molecular evolution of MIKC-type MADS-box genes and related cis-acting TFs of land plants (Theißen et al. Evolution of the Hox complex probably involved small gene duplications, WGDs, divergence of homeodomains, disintegration of the Hox cluster at breakpoints, and rapid changes in the nucleotide sequence of homeodomains (S. Shrub-like lignophytes or small trees produced reproductive modules, which were exploited by flying insects. 2007) and caste polyphenism in holometabolous wasps (J. Understanding the nature and timing of early molecular diversification of homeotic selector genes, developmental proteins, nuclear receptor proteins, and cis-acting TFs of both invertebrate antagonists and vascular plant hosts might be a critical first step in understanding the Paleozoic origin of holometabolous insects and their putative coevolution with the earliest angiosperms. I discuss potential coevolution of insect and seed plant helix-turn-helix proteins, specifically Engraled and Leafy enzymes that bind to cis-regulatory promoters controlling downstream expression of genes determining paedomorphic insect body patterns and plant cone and floral organ development. (2017) report low support ( The Fiji Islands have long been of interest to biogeographers (Raven and Axelrod 1974, Thorne 1986, Morley 2001), to geologists as a tectonic puzzle (Rodda and Kroenke 1984), and to botanists as a "cradle of flowering plants" (title, Chapter 12, Takhtajan 1969), where some "missing links in the chain of angiosperm phylogeny" are known (page 141, Between Assam and Fiji, Takhtajan 1969). There are several conifers endemic to the Fiji Archipelago including Agathis vitiensis, Acmopyle sahniana, Dacrycarpus imbricatus, Dacrydium nausoriense, Dacrydium nidulum, and Decussocarpus vitiensis. The only known species at the time, Degeneria vitiensis (pictured below), combines a number of primitive features that have ignited many debates (I. Some paleontologists regard the problem of flowering plant origins, "... Juvenile hormone and its homologs are integral in vitellogenesis (Hartfelder 2000), regulation of moult cycles (Truman and Riddiford 2002), and caste development and behavior in social Hymenoptera (Guidugli et al. Were bioactive brassinolides and sesquiterpenes manufactured by Paleozoic seed plants used as chemical warfare agents to affect growth, development, and behaviour of herbivorous insects? Another avenue of deduction somehow ties-in insect evo-devo of wings from gill halteres with increases in atmospheric oxygen during the De CARB. The place and time to begin a molecular phylogenetic analysis is the late Frasnian-Famennian Age hypoxic icehouse that extended into the Tornaisian Age of the Carboniferous Period.

Taylor and Hickey (1992, 1996), Loconte (1996), and Krassilov (1997, 2002), among others. "The idea is that plants have a plastic and modular developmental system such that simple changes in regulatory genes need not lead to inviability but can generate novel, potentially favored phenotypes." The preceding quotation is from page 83 of D. "Ontogeny in land plants can be viewed as a complex, partly hierarchical, series of developmental processes, which together with their underlying genetic controls, provide the raw material for morphological innovation. The interface between development and ecology may be studied from such perspectives, among others (Enquist et al. "In theoretical morphospaces, the axes of the reduced space are determined by a small set of parameters of morphogenetic or other biological models, derived from theoretical considerations rather than from the organisms themselves" (page 841, Chartier et al. Scaling studies of reproductive short- (spur-) shoots of living Ginkgo are particularly revealing to plant morphologists (Christianson and 2009). Cessation of growth in holometabolous insects leading to a new moulting cycle is triggered by PTTH that initiates the ecdysone growth regulatory cascade. The International Journal of Plant Sciences devotes most of Number 7 of Volume 169 (2008) toward the ongoing search for the earliest flowers, based on an international symposium held during the summer of 2007 at the Swedish Museum of Natural History (von Balthazar et al. More than twenty articles in Volume 96, Number 1 of the American Journal of Botany explore the origin, evolution, and radiation of flowering plants to celebrate the Charles Darwin Bicentennial (Stockey et al. Conrad Labandeira's several reviews on fossil insect-plant phytophagous associations (Labandeira 2000, 2006, 2007 [two papers], 2010, 2014) contain extensive bibliographies. 2008) and assembly of chitin and cuticle proteins into the exoskeleton (Charles 2010, Moussian 2010). Another Hox protein Abd-B, when combined with the Dsx enzyme, represses expression of the wg gene in fruit flies (W. I also add hexamerin moulting storage proteins which are related to hemocyanin respiratory enzymes (Burmester et al. 2006, Burmester and Hankein 2007), JH esterases, vitellogenin genes and yolk proteins (Isoe and Hagedorn 2007), pheromone chemoreceptors (Robertson and Wanner 2006), and certain nuclear receptor proteins (Bonneton et al. 2008) including ultraspiracle, and ecdysone inducible TFs to the list of molecular developmental tools among early diverging arthropod lineages. The first appearance of insect wings in the rock record of the Paleozoic Era has yet to be established. Arthropod body allometry is intertwined with development of larval and imaginal disc tissues (Stern and Emlen 1999, Shingleton et al. 1997), Ubx (Pavlopoulos and Akam 2011), and the field-specific selector gene necessary for limb development in Drosophila (Diptera) known as dll (S. Fushi-tarazu protein encoded by the ftz gene, intracellular tertiary enzyme structure folding environments, and the apparent flexibility of Ftz and other Hox proteins in the evolution of arthropods, are discussed in a recent review by Merebet and Hudry (2011). These studies, among others underway or already published by Sean Carroll and colleagues, underscore the importance of Hox proteins in evolution of the arthropod tool kit. Mesozoic paleogeography and early angiosperm history. The clade probably first appeared during Triassic times, possibly as a result of the re-setting of plant evolutionary history following the devastating global extinction event of the Permian Triassic boundary ..." (4. The fossil dataset used by the Cascales-Miñana team is grossly incomplete. Simply put, paleontologic data are required to calibrate and validate molecular phylogenies (Peterson et al. "The interface of these three subject areas (Figure 1 on Page 778), molecular evolution, evolutionary developmental ('evo-devo') biology, and palaeoecology, is the theme of Molecular Palaeobiology, as it [the approach] uniquely integrates the patterns written in the two historical records, genomic and geological ... Labandeira's findings (2014) might also help disprove the notion of a Hauterivian (Lower Cretaceous) origin of flowering plants (Hughes 1994, Friis et al. Errors in molecular-phylogenetic inference may result from effects of LBA (Barrett and Willis 2001, Magallón 2010, Zhenxiang Xi et al. Paraphyly may be underappreciated (Krassilov 2002, Stuessy 2010) and effects on seed plant evolution attributable to possible HT might cloud our understanding of relationships among basal clades of the angiosperm crown group (Bergthorsson et al. "Darwin himself referred to the 'early origin and diversification of angiosperms' as 'an abominable mystery,' and the origin of the flower- and therefore flowering plants- is still a question ..." (page 86, Pamela S. Soltis 2014) Molecular-phylogenetic analyses by Magallón (page 395, 2010) when calibrated with fossil data and compared with different relaxed-clock methods "... Coevolution between phytophagous insect antagonists and Carboniferous, Permian, and Triassic seed plant hosts at the level of their respective developmental tool kits with focus on selective forces that drive the logic of transcriptional regulation is proposed to explain the origin of angiosperms and certain clades of holometabolous insects. Modern syntheses on the abominable mystery of the origin of angiosperms from unknown Paleozoic seed plant ancestors and modern radiations are published by Frohlich and Chase (2007), Maheshwari (2007), Sokolov and Timonin (2007), Zavada (2007), J. After integrating evidence as a whole with our results, the resulting scenario suggests that there is nothing particularly mysterious about the diversification of angiosperms during Cretaceous times or how it is reflected in the fossil record. The preceding statement is an optimistic appraisal of methodology used by Cascales-Miñana et al. Some "current viewpoints" are left out of the analysis. The preceding statement is from page 35 of Armen Takhtajan (1969), Flowering Plants: Origin and Dispersal (translated by C. Conrad Labandeira is apparently less than enthusiastic on the idea of a coevolutionary origin of the group (2014). "Tight coevolution" between animal disperser and plant was probably rare (page 3, Tiffney 2004). 2007) expressed as often disarticulated and shed, wood-, pollen-, seed-, foliar-, and cone- and floral- organs preserved in the fragmentary rock record of the Carboniferous, Permian, and Triassic periods.

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