[ Origin of Angiosperms ]
Molecular coevolution of insect and seed plant developmental tool kits and cis-regulatory modules is proposed in this first of three essays to explain diversification in Paleozoic seed plant lineages, origin of the flower, and the origin of angiosperms including clades of phytophagous holometabolous insects.
Were insect-shrub compartments of the late Devonian-early Carboniferous hypoxic icehouse and Permo-Triassic hot house venues of a coevolutionary origin of angiosperms? ... ESSAY
Angiosperms are probably a loose amalgam of parallel evolutionary lines traceable to surviving geographically disparate early Triassic remnants of already divergent Permian seed plant lineages.
[ Reading List ]
This annual reading list of scientific papers, review articles, and books is intended for persons with advanced college level biology training who have an interest in current research on the origin of flowering plants ... KEY TO THE LITERATURE
Each year a scientific paper, book chapter, or book will be selected from the Reading List as being of paramount importance toward finding a solution to the enigmatic origin of flowering plants (angiosperms).
Based on a survey of scientific literature published in 2009 the publication of the year is:
Taylor, T. N., E. L. Taylor, and M. Krings. 2009. Paleobotany: The Biology and Evolution of Fossil Plants, Second Edition. Burlington: Elsevier Academic Press, 1230 pages ... LINK
The 2008 publication of the year was: Hamès et al. (2008), Structural basis for LEAFY floral switch function and similarity with helix-turn-helix proteins. The EMBO Journal 27: 2628-2637.
[ Paleozoic Gigantopterids and Vojnovskyales ]
Gigantopterids and Vojnovskyales are poorly understood Carboniferous and Permian gymnosperms with possible evolutionary ties to the angiosperms.
Gigantopterids were almost certainly not angiosperms. Fossils in Permian rocks of Cathaysia are regarded by some workers as morphological analogs of flowering plants and not direct antecedents ... GIGANTOPTERIDS
Vojnovskyaleans were late Paleozoic seed plants with both long- and short- (spur) shoots. The bisexual cone axes and monocot-like foliage resembled the enigmatic Triassic fossil seed plant Sanmiguelia lewisii ... VOJNOVSKYALES
[ Statement on Evolution ]
The gigantopteroid web site owner and writer, peer reviewers, and contributors adopt the Botanical Society of America's policy on evolution ... BOTANICAL SOCIETY OF AMERICA
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Over millions of years of Paleozoic time as global atmospheric oxygen level fluctuated, certain chewing, crawling, ovipositing, piercing, and sucking insects probably became obligate residents of host seed plant shrubs and trees.
Air pockets at the base of sheathing leathery leaves and around developing stems and organs, and reproductive modules of monopodial Carboniferous seed plants might have provided phytophagous insects with oxygen gas, food, and shelter from predators, cold, and ultraviolet radiation.
Phytophagous insect associates of developmentally plastic Permian seed plant shrubs survived the end-Permian extinction. Acidification of substrates, hypoxia, increases in ambient temperature, and "trigger and kill" events adversely affected both insects and tetrapods in a hot-house world ... PALEOECOLOGY OF GLOBAL CATASTROPHE
Were Paleozoic changes in atmospheric oxygen level the selective force driving the molecular evolution of gas-binding hemocyanin respiratory enzymes and moulting storage proteins of early arthropods? ... INSECT HEXAMERINS
Are the HTH DNA-binding motifs of seed plant LEAFY enzyme and the insect homeodomain protein engraled, products of molecular coevolution? ... HELIX-TURN-HELIX PROTEINS
Consideration of both small gene duplications and whole genome duplications (WGDs) is important in understanding the timing of the origin of angiosperms and radiation of basal flowering plants and eudicots ... GENE DUPLICATIONS
Were secretions of insect eggs, instars, larvae, pupae, and adults, when applied to shoot apical meristems (SAMs) with mechanical force, a source of signals that affected plant growth and development at the genetic level in nuclei of host cells of certain monopodial Permo-Triassic seed plants? ... SIGNALS
Understanding the selective forces behind molecular coevolution of insect and seed plant developmental cis-acting regulatory modules in deep-time (>160 million of years) might be important in solving the enigmatic origin of angiosperms and certain insect antagonists ... COEVOLUTION
Further, our knowledge of carpel, floral, and ovular transcriptional regulators in extant angiosperm model organisms does not preclude derivation of evo-devo models that explain curling, inrolling, and fusion of ovule-bearing Phasmatocycas bridwellii leaves to form carpels, ovaries, and pistils ... HYPOTHETICAL PALEOFLOWERS
[ Biostratigraphy of the Permian Standard Section ]
A nearly complete sedimentary sequence of Paleozoic rock layers is exposed in the Marathon Fold Belt and adjacent mountain ranges of southwestern North America.
Sedimentary beds in the Del Norte and Glass Mountains comprise the standard North American type section through rocks of Permian age.
These uplifted and eroded mountains consist of massive Permian deltaic transitional and marine exposures of conglomerate, limestones, and mudstones that contain fossilized coral reefs with brachiopods, freshwater snails, walchian conifers, and gigantopterid seed plants ... ARTICLE
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