Fossil Sucker 14-III
EVIDENCE OF EVOLUTION
Fossils
 
 
A fossil sucker fish found at Florissant, Colorado.
Click to enlarge.



Chapter Outline
  1. Introduction
  2. Radiometric and Astronomical Dating
  3. Fossils
  4. Biogeography
  5. Homologous Structures
  6. Vestigial Organs
  7. Developmental Similarities
  8. Molecular Evidence


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Picture by Conway Morris and Whittington, Courtesy of the Geological Survey of Canada		These fossils of Opabina and Marrella, found in the Burgess Shale of Canada, are part of just one type of evidence supporting the theory of evolution. No animals resembling these creatures have been found living anywhere on earth. Obviously life forms have changed from the past to the present. Click on the picture for a slightly enlarged view.
If you stumbled across a rock with a pattern in it that looked like one of those in the picture at right, what would you think? What about the pattern in the picture below? There are so many patterns that look like modern animals or plants in rocks that it seems obvious that organisms that were once living can end up preserved in rocks.
These leaves, the fish at top left and the insect on the first page of the chapter are fossils that look more like something most people recognize. Click on the picture for an enlarged view.
It is not a far step from there to say that organisms that do not look like modern animals, such as those in the pictures at top-right, could be preserved in rocks. But that could only mean that animals that we have not observed in modern times existed at some time in the past. The two questions then become "When did they live?" and "Why don't they exist today?"

A graphical view of geologic time. Click to enlarge.
Below and at right are tables representing the various divisions of geologic time. The division at the top, the Holocene Epoch, is the most recent. The Holocene began about 10,000 years ago (0.01 million years ago or MYA) and continues right up to the present. The divisions go back in time to the Hadean Eon which begins with the beginning of the earth approximately 4.6 billion years ago (4600 MYA). In most cases, each division is defined by the types of fossils found in rocks of those ages. Follow the links for more information from each division.

Palaeos

EonEraPeriodEpochSites
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Y		HOLOCENEThe epoch in which we are currently living started around 10,000 years ago. Tasmanian Wolves, Carolina Parakeets and Dodo Birds are but a few of the species which have gone extinct in this epoch.
PLEISTOCENE Fossils from the Pleistocene look quite similar to organisms currently living today. A good site to visit is the La Brea Tar Pits in Los Angeles.

Links:

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PALEOCENELinks:
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VANIAN		Links:
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DEVONIANLinks:
SILURIANLinks:
ORDOVICIANLinks:
CAMBRIANThe Burgess Shale in Canada's Yoho National Park is arguably the most famous fossil site on earth.

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PROTEROZOICLinks:
ARCHEANLinks:
HADEANLinks:

General Links:

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