Carbon dating lava
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.
Studies of wood paedomorphosis may offer new clues on a possible Mesozoic origin of angiosperms (Carlquist 2009), but studies of potentially neotenous gymnosperm secondary xylem development in deep (Paleozoic) time are lacking. Additional discussion is available in several papers that reinvestigate conifer cone abnormalities (Flores-Rentería et al. A "No" response (the box is uncolored) indicates that the paper or book chapter in question favors a younger Jurassic or Cretaceous origin of flowering plants.
The picture of the rock slab on the left is of an indeterminate pentamerous fossil rosid flower (Celastrales, Rosanae) collected by Professor David L. Three of the largest islands (Viti Levu, Vanua Levu, and Taveuni) support harmonic "continental" floras (A. A common gnetophyte (Gnetum gnemon) and a narrowly distributed cycad (Cycas rumphii) occur in the archipelago. as intractable a mystery today as it was to Darwin 130 years ago" (page 318, Rothwell et al. Simply put, the origin of angiosperms is a conundrum. Another important reason for students of insect-seed plant coevolution to be conversant with arthropod tool kits is that evo-devo of the anterior (head) segment is linked to feeding, pollinating, and sensory perception. According to the discussion in Chapter 6 of Grimaldi and Engel (page 158-159, Insects Take to the Skies, 2005) a "plethora of ideas" on the evo-devo of insect flight "can be distilled into two current but contrasting theories." Studies of pterygote and polyneopteran nymphs suggest that wing pad development evolved independently several times over the past 400 million years (Haug et al. Respiratory enzymes, specifically hemocyanins and hemoglobins, and moulting storage proteins (hexamerins) are key elements of the early divergent arthropod developmental tool kit that tie-in with the evolution of insect legs and wings from bilaterian gills. Interestingly, hexamerins are also implicated as silencers of JH signaling in neotenous castes of hemimetabolous termites (X. Certain details of the Frasnian-famennian boundary extinction (De CARB) are discussed in a later section. New occurrences of the controversial late Triassic plant fossil Sanmiguelia Brown and associated ichnofossils in the Chinle Formation of Arizona and Utah, USA.
Dilcher from the Lower Cretaceous Dakota Formation of North America. Tropical forests of the larger islands yield ten genera of monocotyledonous palms including the monotypic Alsmithia longipes, and the enigmatic magnoliid flowering plant family, Degeneriaceae. Historical Context: Many bibliographies on angiosperm floral diversity and the origin and evolution of flowering plants are available. Labandeira (2010) states: The aforementioned passage is from page 471 of C. Labandeira (2010), The pollination of mid-Mesozoic seed plants and the early history of long-proboscid insects, Annals of the Missouri Botanical Garden 97(4): 469-513. Ancient insect wings probably functioned as respiratory organs. Molecular model systems used as tools in beetle genomic research and phylogenetic studies include proteins central to development (JH esterases), diapause proteins, heat shock proteins, ultraspiracle (an ecdysone nuclear receptor protein), cuticle proteins, hexamerins, genes encoding vitellogenin, and apolipophorins, among others (see review by Gómez-Zurita and Galián 2005). Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 268(1): 65-82.
The evo-devo of insect caste polyphenism is reviewed by Emlen and Nijhout (2000). Thummel and Chory (2002) point to a possible coevolutionary connection between the 20E-ecdysone/cytochrome P biosynthetic machinery of insect antagonists and seed plant hosts. Further, changes in the arthropod homeodomain and evolution of new protein motifs led to new Hox developmental tool kit functions in certain insect lineages (S. The paleobiology of insect flight in relation to the advent of arthropod-seed plant mutualisms remains unexplained.
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.
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.