PALEONTOLOGY

Paleontology (Gr. palaios, old on, existing logos, to study),
which is the study of the fossil record, provides some of the most
direct evidence for evolution. Fossils (L. fossilis, to dig) are evidence
of plants and animals that existed in the past and have become
incorporated into the earth’s crust (e.g., as rock or mineral).
For fossilization to occur, sediments must quickly
cover an organism to prevent scavenging and in a way that seals
out oxygen and slows decomposition. Fossilization is most likely to
occur in aquatic or semiaquatic environments. The fossil record is,
therefore, more complete for those groups of organisms living in or
around water and for organisms with hard parts. This documentation
provides some of the most convincing evidence for evolution.
In spite of gaps in the fossil record, paleontology has resulted in
nearly complete understanding of many evolutionary lineages.
Paleontologists estimate that the earth is about 4.6
billion years old. They have also used the fossil record to describe
the history of life on the earth.