Extinction and the fossil record

Article By:

McGuire, Jenny L. School of Environmental and Forest Sciences, University of Washington, Seattle, Washington.

Last reviewed:2013

DOI:https://doi.org/10.1036/1097-8542.YB133333

The Earth contains an incredible diversity of species that are important for maintaining a functional, healthy world. There are an estimated 8.7 million species living on Earth today (about 1.3 million of them have been documented by scientists), but these species represent only 1% of the species that have lived on the Earth since life originated approximately 3.5 billion years ago. Ninety-nine of every 100 species that have ever lived on Earth are extinct. Extinctions have occurred relatively constantly through time, punctuated by several periods of severe and relatively rapid extinction events. Paleontologists and conservation biologists have realized that these past extinctions can provide much information about the events that are occurring today and the extent of their impact on global biodiversity. By putting modern-day extinctions in the context of the rates and magnitudes of past extinctions, it is possible to understand the types of events that can lead to devastating biodiversity loss.

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