FOSSILS AND PALEOBIOLOGY -- EVOLUTION AND EXTINCTION

THROUGH TIME

Fossils provide us with many valuable observations about the history of life.  They tell us about living forms that no longer survive ('extinct forms') and this enriches our view of the overall diversity of life far beyond what the study of forms that do survive ('extant forms') could do.  We treat fossils in much the same way as extant forms, giving them names, exploring their relations to other species, attempting to unravel their ecological preferences, and so on.  Ideas related to this aspect of fossils are presented first in the pages that follow.

Details of the morphology of both extant and extinct species are useful indicators of the 'relationships' among them, and provided the basis for early classifications.  They are still used, along with more modern comparative techniques, to discover these relationships and record them in our classification of organisms.  Both the adult morphologies and the developmental stages that produce those adult forms are important, and both will be covered in the second part of the pages that follow.

Fossils also give us a unique view of the order of appearance of living forms through geologic time.  We could not get this from studying extant forms alone.  They do this because each fossil species is preserved in rocks that were deposited during its life span.  Because these rocks are arranged according to the principle of superposition, so are the fossils in them.  This observation is called 'fossil succession' or some variation thereof.  It is treated third in the pages that follow.

The geographical distribution of organisms, both extant and extinct ones, tells us a lot about their relationships as well.  The distributions at many scales of observation reflect the supposed 'relationships' among the organisms.  This idea is treated in the fourth section of the pages that follow.

Finally, there exists a powerful and 'natural' explanation for how the 'relationships' among organisms that provide so much of the evidence discussed in the first four sets of pages.  Something very much like Darwin's 'Natural Selection' is a workable mechanism to drive organic evolution, to cause adaptation, and to create diversity.  The final pages of this site explore that mechanism.

 

FOSSILS AND BIOSTRATIGRAPHY

FOSSILS AND PALEOECOLOGY

FOSSILS AND EVOLUTION:

1 -- THE TAXONOMIC HIERARCHY

2 -- HOMOLOGIES

3 -- BIOGEOGRAPHY

4 -- BIOSTRATIGRAPHY

5 -- NATURAL SELECTION

6 -- THE ORIGIN OF DIVERSITY

RETURN TO PALEO PAGE