On the other hand, certain hemimetabolous bugs (Hemiptera) possess abdominal stretch receptors that activate secretion of PTTH (Nijhout 2003). 2005, among others) of the Drosophila Hox complex are: Ancestral arthropods possess two additional homeotic selector genes of the Hox cluster that together comprise the HOM-C, ten gene complex (see discussion in Negre et al. These additional genes are: Genomic analyses suggest that derived winged insects lost functional copies of ftz and Hox3 through disintegration of the HOM-C complex (Negre et al. Duplication of the Hox3 gene of ancestral Cyclorrhaphan flies gave rise to two maternal effect genes, bcd and zen (Stauber et al. Based upon this study it is important to include Hox3 as part of the ancestral diverging insect developmental tool kit. Possible candidates for the early divergent insect developmental tool kit might include certain homeotic selector genes of the Hox complex such as homologs and paralogs of abd-A, Abd-B, Hox3, pb, Scr (Rogers et al. 2002) are probably behind many insect body plan novelties seen in the paleontologic record of the past 400 million years of arthropod and crustacean evolution (Pavlopoulos and Akam 2011, Pavlopoulos and Averof 2002).
Plant evolution occurs as variation in genetic and epigenetic developmental processes is winnowed by ecology..." The preceding quotation is from page 161 of P. Once JH circulating in the hemolymph is destroyed by juvenile hormone esterases, then PTTH secretion resumes under circadian (22-24 hour) photoperiodic control (Nijhout 2003). The importance of Ubx protein encoded by the Ubx gene in the early divergent insect developmental tool kit cannot be neglected in the present analysis since significant changes in the carboxy-terminal (C-terminal) region (Galant and Carroll 2002) and serine/threonine phosphorylation sites (Ronshaugen et al.
(1985), Labandeira and Sepkoski (1993), Farrell (1998), Labandeira (1998), Danforth and Ascher (1999), Grimaldi (1999), Wilf et al. 2009, Specht and Bartlett 2009, Licausi 2011, Glover 2014, among others). Evidence of arthropod-plant interactions in the Upper Triassic of the Southwestern United States.
All total in this rich flora of some 6,000 species, there are 812 endemic angiosperms and conifers, 12 endemic genera, and one endemic flowering plant family (A. Distant pinnacles and spires are weathered calc-alkaline Miocene andesites known as the Namosi Volcanics (Rodda and Kroenke 1984). (2008), Specht and Bartlett (2009), Dilcher (2010), D. Isoptera (termites) are hemimetabolous insects (Grimaldi and Engel 2005). The insect developmental tool kit is comprised of certain homeotic selector genes (including Hox genes), zygotic (gap- maternal-, and pair-rule-) genes, field-specific selector genes, compartment selector genes, cell-type-specific selector genes, and segment polarity genes; and the TFs they encode (Rosenberg et al. In addition, the insect developmental tool kit is comprised of controlling factors behind the cessation of insect growth including bioactive PTTH, JH, juvenile hormone esterases, and ecdysone steroids (Truman and Riddiford 2002, Nijhout 2003, S. Juvenile hormone biosynthesized in the corpora allata of the insect brain is a sesquiterpenoid epoxide methyl ester (Hartfelder 2000). Key elements of the Drosophila molecular tool kit include: Evolution of the Hox complex. Ice-free terrestrial environments in the Late Silurian were covered in vegetation. Understanding the origin and diversification of holometabolous insects in deep-time.
The image was captured in 1981 while the author was visiting Indiana University. both within and outside the paradigm of transcription-encoding factors ..." (page 129, Niklas 2006). The family Degeneriaceae was discovered in 1942 by I. Endress (1994, 2001 [a book chapter and two papers], 2004), Bateman et al. Several developmental gene families, TFs, and enzymes involved in hormone signaling cascades are known in invertebrates based in part, on experimental studies of the Drosophila model arthropod (S. Wings, halteres, arachnid spinnerets, and insect legs are all organs that develop from limb fields of cells where Ubx expression is prevalent (S. Several insect systematists studying beetle (Coleoptera) evolution are employing some genes and proteins of the insect development tool kit in their phylogenetic analyses (Gómez-Zurita and Galián 2005).
The three essays on the succeeding web pages are written from this research perspective. Gómez-Zurita and Galián (2005) discuss the utility of molecular phylogenetic characters appearing in the entomological literature in a review paper, which is organized along the lines of Floyd and Bowman (2007) for land plants (see section below). Understanding the land plant developmental tool kit and gene regulation from a deep time research perspective ties-in with models of cone and floral organization, cell geometry and regulation of growth from SAMs, paleobiology of homeodomain TF trafficking, phyllotaxis, leaf development, and morphogenesis of fertile organs.
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. 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. Erbar (2007) summarizes past ideas on a supposed Mesozoic origin of angiosperms from the research perspective of evolutionary-development (evo-devo). Retallack and Dilcher (1981) presented in-depth discussion of Melville's ideas on a glossopterid ancestry of the angiosperms including a reanalysis of glossopterid fructifications. Others suggest that flowering plants evolved from multiple, unrelated seed plant lineages (Edgar Anderson 1934). 2002) and Nair's Triphyletic Theory (Nair 1979) are best placed in this paragraph. Eichler (1976) proposed that unisexual gymnosperms may be the ancestors of angiosperms. Finally the column labeled "Paraphyly or Polyphyly" denotes whether the scientific paper in question attributes the origin of flowering plants to a natural, intergeneric hybridization event, allopolyploidy, or events that brought together two or more distinct lines of seed plant evolution. Doyle and Donoghue 1986, 1987) and classic research by Arber and Parkin (1907), Edgar Anderson (1934), Axelrod (1952), Ehrlich and Raven (1964), Raven and Kyhos (1965), Takhtajan (1969, 1976), and Raven (1977), dovetail with- and potentially support a coevolutionary hypothesis on the origin of flowering plants, which is developed on the following pages of the web site for purposes of classroom and seminar debate and discussion. Doyle 2008) of perianth parts, microsporophylls, and megasporophylls to form a flower was an improbable and unnecessarily complicated saltational event punctuating a long and gradual evolutionary history of angiosperms. Simply put, massive, shortened bisexual cone axes bearing megasporophylls, laminar microsporophylls, and spirally-arranged foliar tepals, probably existed in populations of poorly understood Paleozoic seed plants described as gigantopteroids and Vojnovskyales, groups omitted by J. Doyle and others in their many published phylogenetic analyses.