[ Essays on the Origin of Angiosperms ]
Molecular coevolution of insect and seed plant developmental tool kits, cis-regulatory modules (CRMs), and gene-regulatory networks (GRNs), might explain diversification in Paleozoic seed plant lineages, origin of flowers, and the origin of angiosperms and coevolution with holometabolous insects.
Were insect and shrub coevolutionary compartments of the late Paleozoic hypoxic icehouse and later hot house, venues of the first angiosperms? ... ORIGIN OF ANGIOSPERMS
Pteridosperms might not constitute the "backbone of seed-plant phylogeny," but instead the "lineage" suffers from spinal bifida ... PALEOBOTANY OF ANGIOSPERM ORIGINS
A growing body of biochemical and morphological evidence suggests that cones and flowers are reproductive short shoots. Fertile spur shoots are demonstrably ancient organs known from Permo-carboniferous seed plant fossils. Further, molecular phylogenetic studies of homeodomain proteins and transcription factors (TFs) posit deep conservation of cone and floral CRMs, GRNs, auxin-based polarity networks, efflux carriers, and PINs.
"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 .."
The preceding statement is quoted from Page 86 of Pamela S. Soltis and Douglas E. Soltis (2014), Chapter 4. Flower diversity and angiosperm diversification. Pp. 85-102 In: J. L. Riechmann and F. Wellmer (eds.), Flower Development: Methods and Protocols. New York: Springer, 475 pp.
Do crown group basal angiosperms and magnoliids represent a loose amalgam of parallel evolutionary lines traceable to Middle Triassic, remarkably divergent, stem group flowering plants? ... EVOLUTION OF MESOZOIC ANGIOSPERMS
[ Library and Student Resources ]
This sample reading list of books and book chapters 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
Commentary on Gigantopteroid News and Outstanding Publication of the Year includes links to scientific research articles on the origin of flowering plants, Holometabola, and related subjects ... TOPICS FOR DEBATE AND DISCUSSION
[ Paleozoic Gigantopteroids and Vojnovskyales ]
Vojnovskyales and gigantopteroids are poorly understood Carboniferous and Permian gymnosperms with possible evolutionary ties to the angiosperms.
Potential importance of gigantopteroid 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.
Anatomical studies of permineralized material of fertile Delnortea abbottiae and Evolsonia texana foliar organs and their morphospace might help decipher the evolutionary relationships of these enigmatic gymnosperms with sympatric Paleozoic seed plant congeners ... GIGANTOPTEROIDS
Vojnovskyaleans were enigmatic Permo-carboniferous gymnosperms with possible affinities to angiosperms (Valentin A. Krassilov and V. I. Burago, 1981, New interpretation of Gaussia [Vojnovskyales], Review of Paleobotany and Palynology 32: 227-237). The growth habit, bisexual cones, and foliage of Vojnovskyales resembled the Triassic monocot-like plant Sanmiguelia according to others ... 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
Over millions of years of Paleozoic time as global atmospheric oxygen level fluctuated, certain chewing, crawling, ovipositioning, piercing, siphoning, sponging, stinging 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 pO2 the selective force driving the molecular evolution of gas-binding hemocyanin respiratory enzymes and moulting storage proteins of early arthropods? ... INSECT HEXAMERINS
Are the helix-turn-helix (HTH) DNA-binding motifs of seed plant Leafy enzyme and the insect homeodomain protein Engraled, products of molecular coevolution? ... LFY ENZYME STRUCTURE
One key ingredient left out of the steaming cauldron of past ideas on the origin of flowering plants is the potential modular evolution of a class of mobile chromosome parasites known as transposable elements (TEs) ... LTR RETROTRANSPOSONS
What did external biotic and physical factors have to do with the evo-devo of larval moult cycles and innovative mouthparts of phytophagous insects? ... ORIGIN OF THE HOLOMETABOLA
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
When supported by paleobotanical evidence, were anthocyanic, pinwheel shaped fertile short (spur) shoots of Permo-carboniferous seed plants visually discernable to pollinivores, paleodictyopterans, and predatory wasps? ... COEVOLUTION
There is growing consensus among molecular systematists and some paleobotanists on the existence of a 160 million year old ghost lineage beginning with divergence(s) of flowering plants from the most recent common ancestor (MRCA) prior to the end-Permian extinction ... ANGIOSPERM GHOST LINEAGE
Based on biochemical studies of an extremely conserved floral tool kit, some molecular-phylogenetic analyses, and the stratigraphic distribution of Afropollis and other diverse palynomorphs, is the statement [below] on Page 380 of Scott L. Wing and Lisa D. Boucher (1998), Ecological aspects of the Cretaceous flowering plant radiation. Annual Review of Earth and Planetary Sciences 26: 379-421, precise or accurate?
"Despite the singular ecological significance and species diversity of angiosperms, they are not in a genealogical sense one of the major branches of land plants and did not originate with other major land plant clades (e.g. lycopsids, ferns, conifers, cycads, ginkgos) during the middle or late Paleozoic."
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 PROTOFLOWERS
[ Biostratigraphy of the Permian Standard Section ]
Uplifted and tilted beds in the Del Norte and Glass Mountains of southwestern North America consist of massive Permian marine and transitional, deltaic, sedimentary rock exposures.
Rocks of these mountain ranges yield fossilized coral reefs with brachiopods, conodonts, graptolites, and sponges, and deltaic transitional layers with preserved freshwater snails, walchian conifers, and gigantopteroid seed plants ... ARTICLE