[ 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 neotenous 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.
How might fossilized pieces or whole plants of Paleozoic ancestors of flowering plants appear to a paleobotanist, based upon knowledge gained from shoot apical meristem (SAM) models of homeodomain proteins and FLO/LFY transcription factors? ... HYPOTHETICAL ANGIOSPERM ANCESTOR
[ Library Resources ]
This sample 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 I will select a scientific paper, book chapter, or book as being of paramount importance toward finding a solution to the enigmatic origin of angiosperms ... PAPER OF THE YEAR
[ Paleozoic Gigantopterids and Vojnovskyales ]
Gigantopterids, spermopterids, Vojnovskyales, and gigantopteroids are poorly understood Carboniferous and Permian gymnosperms with possible evolutionary ties to the angiosperms.
Potential importance of gigantopteroid, spermopterid, and vojnovskyalean seed plant fossils in deciphering the ancestry of flowering plants and paraphyletic clades of gymnosperms reflects my choice of the unusual title for this web site.
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 PALEOZOIC PROTOFLOWER
[ 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.
Fossiliferous 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 gigantopteroid seed plants ... ARTICLE
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