The Burgess Shale
The Burgess Shale helps us understand the following things about changes on the Earth:
- How life and geology has changed on Earth over time
- Climate change
- History and age of the rocks
The Burgess Shale contain the fossils of organisms that lived 500 million years ago during the Cambrian Period.
Fossils and Evolution
Many fossils share features of organisms found today and they give us a record how life on Earth has changed through time. Not all organisms get preserved, not all fossils are found, and so we do not have a complete history of life on Earth. The more fossils we find, the more complete our record of life becomes.
A transitional species is an past organism that has characteristics between an organism that exists in the more distant past and one that exists now. It is evidence for evolution. An example of a transitional species for humans is Australopithecus. The famous Lucy can be seen as a species that exists somewhere between modern humans and our more distant and extinct quadrupedal ape relatives.
The fossil record shows that evolution is gradual. It gives us physical proof of extinction and evidence of a single species branching into two(speciation). It also shows transitional species.