Fossils (chap. 11. 1 notes) (Vocabulary (fossil, catastrophism,…
Fossils (chap. 11. 1 notes)
Evidence of the distant past
Just like family albums provide clues to our past, rocks provide clues to earth's past. Some of the most obvious clues found in rocks are the remains or traces of ancient living things.
are the preserved remains or evidence of ancient living things.
The principle of
states that geologic processes that occur today are similar to those that have occurred in the past. According to this view, Earth's surface is constantly being reshaped in a steady uniform manner.
Catastrophism is the idea that conditions and organisms on Earth change in quick, violent events. These events include, volcanic eruptions and widespread flooding. Scientists then disagreed because Earth's history is full of violent events.
Formation of Fossils
Fossils are the remains or traces of an ancient living thing. Not all dead organisms become fossils. Fossils form only under certain conditions
Conditions fro Fossil Formation
Some conditions increase the chances of fossil formation.An organism is more likely to become a fossil if it has hard parts, such as shells, teeth, or bones. An organism is more likely to form a fossil if it is burried quickly after it dies. If layers of sand or mud bury an organism quickly, decay is slowed or stopped.
Scientists who study fossils are called
. Plaeontologists use the principal of uniformitarianism to learn about ancient organisms lived. For example, they can compare fossils of ancient organisms with organisms living today.
Today, Earth's continents are mostly above sea level. But sea level has risen, flooding Earth's continents, many times in the past. For example, a shallow ocean covered much of north america 450 million years ago. Fossils and organisms that lived in that shallow ocean help scientists reconstruct what the seafloor looked like at that time.