Palaeontology Observations

It is important to appreciate that on an Expansion Tectonic Earth you do not have to invent or invoke mechanisms for the various species to disperse across vast alien distances in order to colonise remote lands. Instead, the small Earth models show that these remote lands assemble in close proximity and dispersal is via normal opportunistic propagation via an established network of continental seas or lands. For example: the distribution of Trilobites during the Cambrian Period.

Species evolution, dispersion, and extinction on Expansion Tectonic small Earth models is instead shown to be intimately related to changing continental seas and sea levels. These models show that during the Precambrian and early Palaeozoic times there was a common interconnected network of continental seas extending across much of the ancient Earth. Species evolving in one area were then able to rapidly disperse and colonise the entire network of seas forming cosmopolitan species distributions. For example, the distribution of Anthozoa corals during the Palaeozoic Era: , , , ,

During these early times important provincial colonies consistently show up in the plotted data distribution, in particular for the various marine species. These provincial colonies include western North America, Western Europe, and China, with important connections to Eastern Australia, North Africa, South America, New Zealand, and Russia. For example, the distribution of Brachiopods during the Ordovician Period for Europe and North America: , and the distribution of Molluscs during the Cambrian Period for China with links to Russia, and North America with links to Australia:

During the mid- to late-Palaeozoic times tectonism and mountain building became increasingly prominent, resulting in disruption to the established network of continental seas, isolation of seas, plus decimation or extinction of various species. This was followed by mergence and ultimately to draining of the continental seas during the late-Permian breakup of the Pangaean supercontinent. For example, decimation of the Bryozoans during the Permian to Early Triassic extinction event: ,

This disruption to the continental seas is considered to be the prime mechanism driving species evolution during the Palaeozoic Era. Species either evolved to take advantage of the changing environmental conditions or were driven to extinction by disruptions to their environment, failing to keep pace with change, or competition from more adaptive species. A number of prominent and well documented extinction events occurred during the Palaeozoic and Mesozoic Eras resulting in severe loss of species and creating favourable opportunities for many surviving species.

On the Expansion Tectonic small Earth models the evolution of species can be readily traced through the ages. Simply choose from the list of species and pass your cursor across the time periods at left. This evolution of species extends from the various plant and invertebrate marine species through to the more advanced vertebrates. Our own lineage stems from the vertebrates, originating during the Cambrian and Ordovician Periods. Mammalian ancestors diverged in the early Mesozoic Era and modern mammalian orders arose in the early to middle Cenozoic Era after extinction of the non-avian dinosaurs some 65 million years ago. Our own specific lineage, the primates, first appeared during the Eocene to Paleocene Epochs with modern humans becoming prominent during the recent Holocene Epoch (included in the Pliocene to present-day model here).