See Also: Permian Period(encyclopedia)
Permian(dictionary)
permian(medicine)
Time period principle or accounting period assumption(finance)
T-period holding-period return(money)
T-period holding-period return(finance)
Period certain(finance)
period(encyclopedia)
period(1)(dictionary)
Net period(money)

Permian Period (sh)




Interval of geologic time, 290-248 million years ago.

The last of the six periods of the Paleozoic Era, it follows the Carboniferous Period. During the Permian, the continents joined to form a single supercontinent, Pangea. Hot, dry conditions prevailed almost everywhere, and deserts were widespread. Life evolved as a continuation of established lines. Marine invertebrates evolved into several lineages. Marine and freshwater fish and amphibians thrived. Reptiles evolved into three distinct groups: the cotylosaurs, the pelycosaurs, and the therapsids. Land plants evolved from ferns and seed ferns to conifers and adapted to drier and well-drained land conditions. Toward the close of the Permian, many forms of life suffered mass extinction, whose causes are unknown.