The Precambrian and Vendian Mass Extinctions
Fast Facts
- Precambrian period (4.6 billion to 523 million years ago)
- Vendian period (523-543 million years ago)
- Both Precambrian and Vendian periods host to at least one mass extinction each
Geological Setting
The Precambrian era was a period in earth history before the evolution of hard-bodied and complex organisms. Throughout the extent of both periods, dominant Precambrian and Vendian organisms were soft-bodied, simple, and entirely marine. Diversification of the hard-bodied organisms did not occur until the beginning of the Cambrian, when the first shelly fauna appeared.
Species Affected
Extinctions are proposed to have affected even life's earliest organisms. About 650 million years ago, seventy percent of the dominant Precambrian flora and fauna perished in the first great extinction. This extinction strongly affected stromatolites and acritarchs, and was also the predetermining factor that encouraged the diversification of the following Vendian fauna. However, this distinct fauna, resembling modern-day soft-bodied organisms such as sea pens, jellyfish, and segmented worms also perished in a second extinction event at the close of the Vendian. This event, responsible for the demise of the Vendian organisms, may have been reponsible for the ensuing diversification of the Cambrian shelly fauna.
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Causes of the Precambrian and Vendian Extinctions
Mass Extinctions of the Phanerozoic Menu