Permian

Examples of Permian in the following topics:

• Evolution of Gymnosperms

  • Following the wet Mississippian and Pennsylvanian periods, which were dominated by giant fern trees, the Permian period was dry.
  • This fossilized leaf is from Glossopteris, a seed fern that thrived during the Permian age (290–240 million years ago).
  • Explain how and why gymnosperms became the dominant plant group during the Permian period

• Evolution of Reptiles

  • Soon after the first amniotes appeared, they diverged into three groups (synapsids, anapsids, and diapsids) during the Permian period.
  • The Permian period also saw a second major divergence of diapsid reptiles into archosaurs (predecessors of crocodilians and dinosaurs) and lepidosaurs (predecessors of snakes and lizards).
  • These groups remained inconspicuous until the Triassic period when the archosaurs became the dominant terrestrial group due to the extinction of large-bodied anapsids and synapsids during the Permian-Triassic extinction.

• Biodiversity Change through Geological Time

  • The end-Permian extinction was the largest in the history of life.
  • Terrestrial tetrapod diversity took 30 million years to recover after the end-Permian extinction.
  • The Permian extinction dramatically altered earth's biodiversity composition and the course of evolution.
  • Recovery times for biodiversity after the end-Cretaceous extinction were shorter, in geological time, than for the end-Permian extinction: on the order of 10 million years.

• Past and Present Effects of Climate Change

  • The Permian extinction event occurred about 251 million years ago toward the end of the roughly 50-million-year-long geological time span known as the Permian period.
  • Scientists estimate that approximately 70 percent of the terrestrial plant and animal species and 84 percent of marine species became extinct, vanishing forever near the end of the Permian period.
  • Organisms that had adapted to wet and warm climatic conditions, such as annual rainfall of 300–400 cm (118–157 in) and 20 °C–30 °C (68 °F–86 °F) in the tropical wet forest, may not have been able to survive the Permian climate change.

• Evolution of Mammals

  • The modern mammals of today are synapsids: descendants of a group called cynodonts which appeared in the Late Permian period.
  • Throughout the Permian period, the synapsids included the dominant carnivores and several important herbivores.
  • Cynodonts, which first appeared in the Late Permian period 260 million years ago, are thought to be the ancestors of modern mammals.

• Post-Cambrian Evolution and Mass Extinctions

  • The end of the Permian period (and the Paleozoic Era) was marked by the largest mass extinction event in Earth's history, a loss of roughly 95 percent of the extant species at that time.
  • On land, the disappearance of some dominant species of Permian reptiles made it possible for a new line of reptiles to emerge: the dinosaurs.

• Evolution of Land Plants

  • It starts with the Cambrian period, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian.

• The Cambrian Explosion of Animal Life

  • These fossils (a–d) belong to trilobites, extinct arthropods that appeared in the early Cambrian period 525 million years ago and disappeared from the fossil record during a mass extinction at the end of the Permian period about 250 million years ago.

• Modern Reptiles

  • Squamata ("scaly") arose in the late Permian; extant species include lizards and snakes.

• Fossil Formation

  • These fossils from the Road Canyon Formation (Middle Permian of Texas) have been silicified (replaced with silica), which is a form of permineralization.