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The Ordovician–Silurian extinction events may have been caused by an ice age that occurred at the end of the Ordovician Period, due to the expansion of the first terrestrial plants, [54] as the end of the Late Ordovician was one of the coldest times in the last 600 million years of Earth's history.
The Sandbian is the first stage of the Upper Ordovician.It follows the Darriwilian and is succeeded by the Katian.Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.2 million years ago.
The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician .
The evidence of plant evolution changes dramatically in the Ordovician with the first extensive appearance of embryophyte spores in the fossil record. The earliest terrestrial plants lived during the Middle Ordovician around 470 million years ago , based on their fossils found in the form of monads and spores, with resistant polymers in their ...
The Darriwilian is the upper stage of the Middle Ordovician.It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 469.4 million years ago.
Ordovician plants (6 P) T. Ordovician life by Linnaean taxonomic rank (3 C) This page was last edited on 1 November 2023, at 10:18 (UTC). Text is available under ...
A Palmer oak in Jurupa Valley is estimated to be 13,000 to 18,000 years old. The plant, which looks like a sprawling, dark green shrub, is now at the center of a development battle.
The Ordovician Period of the Paleozoic Era, in the Phanerozoic Eon. This category contains events which happened in the Ordovician , a division of the geologic time scale . See geologic time scale for information about its divisions and how they relate to each other.