Lab 8 - Burgess Shale

     The Burgess Shale is a rock formation located in Western Canada in the Canadian Rocky Mountains, and was discovered in 1909. It is composed of black shale and has become famous for the various, large numbers of excellently preserved fossils that it contains. Below is a satellite image of the Burgess Shale.

      The fossils found in the Burgess Shale are from what is called the Cambrian Era and have been dated to about 505 million years old. These fossils are also part of what is called the "Cambrian explosion", which refers to the relatively sudden increase in the diversity and complexity of the fossils present without any apparent close predecessors. By the end of this event (which was first identified in the mid-19th century), fossil evidence shows that a large number of the phyla that exist today were represented then. Because of the rapid appearance of new, more complex types of organisms without any developmental history, this event was seen as one of the main bodies of evidence against the theory of evolution by its author Charles Darwin.
     To this day the Cambrian explosion continues to serve in that same capacity, having caused (and still causing) much debate within the scientific community, since the theory of evolution has been widely accepted as the explanation of life's origins on earth. However, there is much that remains uncertain about this even due to incomplete fossil records and other difficulties. Hopefully, continued work in the Burgess Shale and in similar formations around the world will continue to provide more details. Below, digital reconstructions of two organisms found fossilized in the Burgess Shale are shown: Opabinia (L) and Wiwaxia (R).