The Study of Change Over Time:
Researching evolutionary relationships between
organisms that lived tens to hundreds of millions of years ago can be
difficult. The most pressing problem associated with the study of
evolution in an ancient organism is the
lack of fossilized creatures to study, because in many environments
fossil preservation is a rather uncommon occurrence. Fossilized
remains of organisms are best preserved under water, when an animal's
"hard parts" (mostly shell or bone) can fill with sediment or
be replaced by mineral precipitation. This makes the study of
terrestrial organisms especially difficult. Because only
organisms that
dwell under water and contain "hard
parts," are preferentially preserved, the fossil record is especially
rich in marine organisms with shells or skeletons. If
geologists are lucky enough to find a fossil
species preserved in abundance in sediments, then
examination of evolutionary change within the species can
begin.
Within this module we present detailed information on two such
locations, one along the western shores of
Chesapeake Bay, MD, the other in north of Utica, N.Y., at Trenton Falls, NY.