Gaia | Biosphere | Evolution | Ecology | Paleontology | Timescale

Mesozoic Era | Evolutionary Biotas | Terrestrial Paleozoic Ecosystems | Tetrapoda | Permo-Triassic tetrapods | Marine Reptiles

Author's note: these pages were written some years ago. I am not planning to update them. For a more current coverage, see the Palaeos website (to which many links on these pages point to anyway. More info here

The following quotation is from Terrestrial Ecosystems Thrugh Time (pp.289-290) and gives an excellent overview of terrestrial Paleozoic biota:

The Paleozoic was the time during which terrestrial ecosystems were organized and assembled. The plants, invertebrates, and tetrapods can be thought of as three separate subsystems of the larger terrestrial ecosystem. Dominance-diversity patterns, structure, and interactions within these subsystems modernized more or less independently and at different rates throughout most of the Paleozoic. Concomitantly, these three separate subsystems became integrated through trophic interactions and the creation or modification of habitat conditions. This partitioning of ecosystems into "phylogenetic" subunits differs radically from the organization of highly integrated modern systems.

The appearance of structurally and ecomorphically modern plant communities in some parts of the landscape primarily during the Late Devonian and Early Carboniferous included the evolution of life histories, particularly seed habit, that permitted the exploitation of a wide variety of terrestrial environments. The independent evolution of arborescence in nearly all major groups of plants was key to the development of multistratal forests in some habitats at this time. By the Late Carboniferous, complex forest structure and a wide variety of forest profiles and dynamics were clearly in existence across all major land masses.

Global provincialization of vegetation began during the Early Carboniferous and increased more or less continuously until the Permian, when it reached its Paleozoic maximum; this was perhaps the greatest provincialization known prior to the later Tertiary. Such provincialism was made possible by several factors. The physical opportunities increased in diversity and abundance during the Paleozoic as environments changed globally. Because the plants were at the base of the major terrestrial radiation, they evolved increasing tolerances to demanding physical conditions and expanded the extent of the vegetated land surface. This expansion into unoccupied parts of the terrestrial environment was accompanied by an increase in local and regional vegetational heterogeneity, a consequence of local variation in both physical conditions and evolutionary dynamics.

The first animal groups to exploit plant productivity were the arthropods, and then primarily as detritivores. Detritivory was the main entry point of plant primary productivity into animal food webs until the end of the Early Permian. Herbivory, largely by insects, is known from the Early Carboniferous and may have existed in the Devonian. Herbivory expanded rapidly during the Late Carboniferous and was an established part of ecosystem dynamics by the Stephanian or possibly late Westphalian and into the Early Permian. As suggested by the large size of medullosan pollen, insect pollination probably had evolved by the Westphalian. The selective effects of arthropods on plants may be seen in the evolution of sclerotic seed coats and other structural features that would have served to deter post- and pre- dispersal predation. Clear evidence of damage to living foliage does not appear until the later Westphalian.

Tetrapods were the final element to enter the web of interactions in terrestrial communities. They began, and continued, as carnivores and insectivores through the Carboniferous and Early Permian, situated at the ends of long food chains that were mediated primarily by arthropod detritivory. Although predation on insect herbivores would have shortened some of these pathways and added trophic links to the system, it was not until the expansion of tetrapod herbivory in the late Early Permian that a full integration of the three subsystems was established. The integration had progressed greatly by the Late Permian. However, even by the end of the Paleozoic, the tetrapod component of ecosystems was distinctly different in the sizes, modes of feeding, and range of resources exploited from Mesozoic and younger ecosystems

The following sequence of Terrestrial biota is suggested. These do not always follow or equate with the Marine succession:

Ordovician-Early Silurian (proto-landplants; simple invertebrates)

Siluro-Devonian (early vascular plants, progressing to small trees, many types of arthropods)

Late Devonian - middle Frasnian to late Famennian (proper trees (30 meters tall), two successive dynasties of proto-amphibians)

Early Carboniferous (ice age begins, smaller trees; early amphibians, rhizodont fish top freshwater preditors, giant semi-aquatic eurypterids)

Permocarboniferous - late Carboniferous to early Permian (ice age continues, mighty tropical coal swamp forests, many amphibians and early reptiles, winged insects appear, including many giant forms)

Late Permian - drying of climate, extinction of swamp trees and many amphibbians and reptiles; therapsidfs take over, Mesozoic trees and endopterygous insects appear.

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