page_title: History of paleontology
section_title: Cambrian explosion
hierarchical_section_title: History of paleontology / Overview of developments in the 20th century / Cambrian explosion
caption_attribution_description: Image of the first complete anomalocaris fossil found, residing in the Royal Ontario Museum, Toronto.
context_page_description: The history of paleontology traces the history of the effort to understand the history of life on Earth by studying the fossil record left behind by living organisms. Since it is concerned with understanding living organisms of the past, paleontology can be considered to be a field of biology, but its historical development has been closely tied to geology and the effort to understand the history of Earth itself.
  In ancient times, Xenophanes, Herodotus, Eratosthenes, and Strabo wrote about fossils of marine organisms, indicating that land was once under water. The ancient Chinese considered them to be dragon bones and documented them as such. During the Middle Ages, fossils were discussed by Persian naturalist Ibn Sina in The Book of Healing, which proposed a theory of petrifying fluids that Albert of Saxony would elaborate on in the 14th century. The Chinese naturalist Shen Kuo would propose a theory of climate change based on evidence from petrified bamboo.
  In early modern Europe, the systematic study of fossils emerged as an integral part of the changes in natural philosophy that occurred during the Age of Reason.
context_section_description: One area of paleontology that has seen a lot of activity during the 1980s, 1990s, and beyond is the study of the Cambrian explosion during which many of the various phyla of animals with their distinctive body plans first appear. The well-known Burgess Shale Cambrian fossil site was found in 1909 by Charles Doolittle Walcott, and another important site in Chengjiang China was found in 1912. However, new analysis in the 1980s by Harry B. Whittington, Derek Briggs, Simon Conway Morris and others sparked a renewed interest and a burst of activity including discovery of an important new fossil site, Sirius Passet, in Greenland, and the publication of a popular and controversial book, Wonderful Life by Stephen Jay Gould in 1989.
caption: A complete Anomalocaris fossil from the Burgess shale
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