One of the main sources that paleontologists use to discover hidden secrets about the past is through studying fossils. Geologists, paleontologists, biologists, and other scientists study fossils in order to uncover facts about the different species and organisms that roamed the Earth up to 3 billion years ago. Using this knowledge, scientists have learned more about the geological processes that continually happen today, as well as climate changes from the past and present, the origination and extinction of species, and the birth of certain deadly diseases. It has helped shape the hundreds of hypotheses and theories about the beginning of the earth. A fossil is defined in Clark Larsen’s book “Our Origins: Discovering Physical Anthropology” …show more content…
By studying the different “fossil assemblages that preserve soft- bodied organisms” it is useful in understanding “the composition and diversity of past life” (Jensen and Gehling, 1998). Fossils are most often found in sedimentary rock, which is the most common type of rock found on Earth. Three types that usually contain fossils are shale, sandstone, and limestone. Sedimentary rocks form over time from left over particles and are deposited by moving water. Heavy overlying pressure squeezes out water and cements it together with the different grains and particles found, thus leaving it as a rock. Plants and animals would sometimes be trapped and buried into the sediments; after a certain time of erosion these plants and dead animals’ fossils would be left over (Derricourt, 2009). Sometimes fossils can form in other materials besides sedimentary rocks. Some small animals and insects can get stuck in ancient tree resin (amber) and become entombed. The types of fossils that are found in amber “are often preserved with extreme detail” (Kuban, 1994). One of the most common fossils found are marine invertebrates. Marine invertebrates are animals that do not have a backbone and live in the sea. Examples of marine invertebrates are coral, ammonites, clams, and other extinct animals such as crinoids and trilobites. Scientists can tell where continents were located millions of years ago because of the fossils that have been found in certain locations. For example, one would expect to fine marine fossils in deep ocean basins, however, they are more commonly in sediments found on