Carbon 14 dating denotes the
The image above is the northwestern face of the Korombasabasaga Range, Viti Levu Island, Fiji as viewed from the road between Namosi and Wainimakutu villages. A review of neotenous development in termites is available (Korb and Hartfelder 2008). Structurally similar to bioactive plant brassinosteroids, 20E-ecdysone induces a cascade of TF biosynthesis important in the regulation of insect development (Truman and Riddiford 2002, De Loof 2008). One line of paleobiological thinking hypothesizes that insects took flight to exploit new habitat. Did ingestion of seed plant brassinosteroids by pterygote insects affect the evo-devo of wings from thoracic limb pads and JH signaling? 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. 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.
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. The artwork by Mark, which is furnished David Rohr, Ph. Presumed coevolution of insects and flowers is unsupported by macroecological data in a 35 million-year interval in geologic time from Barremian to Turonian (Labandeira 2014). Tetrapods might have had a surprising effect on the ecology of Mesozoic flowering plants but evidence of coevolution of dinosaurs and early angiosperms is weak (P. While composing the three essays on the origin and evolution of flowering plants, I integrated data from many scientific disciplines, which was key to possibly solving the riddle of the origin of angiosperms and certain coevolving Holometabola from disparate research perspectives. A cartoon was drawn by Sul Ross State University geology student Mark Munday in 1981. " The preceding statement is from Page 777 of Kevin J. 2013), which is strangely incongruent with the stratigraphic distribution of Afropollis throughout the Mesozoic. imply that the diversification that lead to living angiosperm species began sometime between the Upper Triassic and the early Permian." Further, ancient whole genome duplications (WGDs) are implicated in both the common ancestor of all flowering plants, and in the most recent common ancestor of all seed plants (MRCA) about 200 MYA, and 320 MYA, respectively (Jiao et al. Clusters of hermaphroditic pollen- and ovule bearing leaves known as bisexual strobili are the focus of most of the leading models of cone and floral organization (Melzer et al. Further, several studies of developmental abnormalities in cones of extant conifers offer a window for better understanding the origins of flowers and flower-like organs (Flores-Rentería et al. Many colleagues suggest a coevolutionary origin and later diversification of flowering plants based on co-radiations between specific groups of animals and seed plant hosts (Ehrlich and Raven 1964, Farrell 1998, Crepet and Niklas 2009). 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 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.