Thalloid carbonaceous incrustations and the asynchronous evolution of embryophyte characters during the Early Paleozoic

Strother, Paul K.

doi:10.1016/j.coal.2009.10.013

Cited by 31 publications

(27 citation statements)

References 39 publications

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“…Their composition, reflecting ecological responses to substrate, temperature and water availability, is impossible to quantify. An interesting approach was adopted by Strother (), who estimated the proportions of axial and thalloid fossils on bedding planes. Using seven slabs collected by Lang (), he estimated 50% of the surface was occupied by incrustation and 1% by axial fossils.…”

Section: Discussionmentioning

confidence: 99%

“…It would clearly be impossible to undertake anatomical investigations on all coalified encrustations in mid‐Palaeozoic rocks and also unwise to conclude that all belonged to the nematophytes or Bacteria. Indeed, Strother introduced the possibility that some were the remains of thalloid gametophytes such as are present in major clades of liverworts and hornworts today (Strother ). A liverwort‐like dorsiventral thallus has been proposed for the last common ancestor of present‐day land plants (Mishler and Churchill ) although, based on the nature of the gametophyte apical cell in extant basal liverworts and mosses, Ligrone et al .…”

Section: Fossil Evidence For Pre‐devonian Phytoterrestrialization (Exmentioning

confidence: 99%

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Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

2015

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The Ordovician and Silurian periods were times of major geological activity as regards palaeogeography, volcanism and climate change, the last of these evidenced by a series of cooling episodes and glaciations that climaxed in the Hirnantian (Late Ordovician). The presence of cryptospores in the Darriwilian (Middle Ordovician) marked the advent of higher plants on land. A critical survey of direct (mega-and microfossils) and some indirect evidence in succeeding rocks indicates the presence of algae, Bacteria, Cyanobacteria, Fungi, probable lichens, cryptophytes and basal tracheophytes. Similar associations of photosynthesizers and decomposers occur today in cryptogamic covers (CCs), for example biological crusts, except that bryophytes replace cryptophytes (basal embryophytes) and tracheophytes are absent. Thus, extant CCs, which make significant contributions today to global carbon and nitrogen fixation and prevention of erosion, provide an excellent analogue for the impacts of early land vegetation on both lithosphere and atmosphere. As a prerequisite to assessing impacts in Ordovician-Silurian times, with particular consideration of parameters used by climate modellers, the effects of a number of abiotic factors on the growth and survival of extant cryptogamic ground covers and their environmental impacts are reviewed. Factors include photosynthetically active radiation, ultraviolet radiation, temperature, water, oxygen, carbon dioxide, nitrogen, phosphorus, iron, surface roughness and albedo. A survey of the nature and extent of weathering facilitated by such vegetation concludes that it was limited based on depth of weathering when compared with that from rooted tracheophytes today, with minor effects on carbon dioxide drawdown. As global net productivity from Ordovician-Silurian CCs was very probably lower than today, and while the small fraction of intractable material in their organic carbon would have resulted in a more rapid turnover of terrestrial biomass, we conclude that there was decreased possibility of long-term organic carbon burial. Hence, there would have been very limited increase in atmospheric oxygen and decrease in carbon dioxide resulting from carbon burial.

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Section: Discussionmentioning

confidence: 99%

Section: Fossil Evidence For Pre‐devonian Phytoterrestrialization (Exmentioning

confidence: 99%

Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

2015

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“…One of the problems in acquiring additional data for this crucial event in the history of the Earth is that the fossil record is generally poor: only single-celled spores remain from that period [4]. There is an abundance of fossils in the records starting from around 400 [ 9 _ T D $ D I F F ] mya[ 4 _ T D $ D I F F ] [4], but, at that time, the embryophytes had already conquered Earth.…”

Section: History Behind the Current Hypothesis Of Land Plant Terrestrmentioning

confidence: 99%

Why Plants Were Terrestrial from the Beginning

Harholt

Moestrup

Ulvskov

2016

Trends in Plant Science

128

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“…All of this remains controversial, and the isomorphy of the life history of the Rhynie chert plants is arguable, as is the inference of the existence of such isomorphic life cycles in all early polysporangiophytes. Rather, various authors have suggested that some early polysporangiophytes might already have had a heteromorphic, diploid dominant alternation of generations (Gerrienne et al, 2006; Niklas & Kutschera, 2009b; Strother, 2010). In order to address this, the life history of two emblematic early land plants from Rhynie, Aglaophyton and Rhynia , is described and discussed below.…”

Section: Rhynie Chert Gametophytes: Size Mattersmentioning

confidence: 99%

Early evolution of life cycles in embryophytes: A focus on the fossil evidence of gametophyte/sporophyte size and morphological complexity

Gerrienne

Gonez

2010

Journal of Systematics and Evolution

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Embryophytes (land plants) are distinguished from their green algal ancestors by diplobiontic life cycles, that is, alternation of multicellular gametophytic and sporophytic generations. The bryophyte sporophyte is small and matrotrophic on the dominant gametophyte; extant vascular plants have an independent, dominant sporophyte and a reduced gametophyte. The elaboration of the diplobiontic life cycle in embryophytes has been thoroughly discussed within the context of the Antithetic and the Homologous Theories. The Antithetic Theory proposes a green algal ancestor with a gametophyte-dominant haplobiontic life cycle. The Homologous Theory suggests a green algal ancestor with alternation of isomorphic generations. The shifts that led from haplobiontic to diplobiontic life cycles and from gametophytic to sporophytic dominance are most probably related with terrestrial habitats. Cladistic studies strongly support the Antithetic Theory in repeatedly identifying charophycean green algae as the closest relatives of land plants. In recent years, exceptionally well-preserved axial gametophytes have been described from the Rhynie chert (Lower Devonian, 410 Ma), and the complete life cycle of several Rhynie chert plants has been reconstructed. All show an alternation of more or less isomorphic generations, which is currently accepted as the plesiomorphic condition among all early polysporangiophytes, including basal tracheophytes. Here we review the existing evidence for early embryophyte gametophytes. We also discuss some recently discovered plants preserved as compression fossils and interpreted as gametophytes. All the fossil evidence supports the Antithetic Theory and indicates that the gametophytic generation/sporophytic generation size and complexity ratios show a gradual decrease along the land plant phylogenetic tree.

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Thalloid carbonaceous incrustations and the asynchronous evolution of embryophyte characters during the Early Paleozoic

Cited by 31 publications

References 39 publications

Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

Could land‐based early photosynthesizing ecosystems have bioengineered the planet in mid‐Palaeozoic times?

Why Plants Were Terrestrial from the Beginning

Early evolution of life cycles in embryophytes: A focus on the fossil evidence of gametophyte/sporophyte size and morphological complexity

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