Fossils

A. Evidence of a Distant Past 1. Fossils- preserved remains or evidence of ancient living things. 2. Fossils represent plants and animals that no longer live on Earth. 3. Ideas about how these fossils formed have changed over time.

B. Catastrophism-Early belief 1. An early belief that conditions on Earth change in quick violent events like volcanic eruptions, widespread flooding, meterorite impact 2. Scientists believed that great catastrophic disasters killed the organisms that became fossils. 3. Scientists explained Earth’s history as a series of disasterous events occurring over short peoiods of time. 4. This idea eventually fell out of favor.

C. Uniformitarianism 1. theory that states that geologic processes ( weathering, erosion) that occur today are similar to those processes that have occurred in the past. 2. Earth’s surface is constantly being reshaped in a steady, UNIFORM manner. 3. Catastrophic events do occur, but the majority of changes on Earth happen slowly.

D. Paleontologists 1. scientists who study fossils 2. Fossils help scientists learn about past climates and the environments in which organisms lived. 3. Fossils show that Earth’s climate has warmed and cooled mnay times in the past.

Formation of Fossils

A. Fossil Formation 1. certain conditons have to be present for fossils to form. 2. an organism is more likely to form a fossil if it is buried quickly after it dies, decay is slowed or stopped 3. an organism is more likely to become a fossil if it has hard parts such as shells, teeth, or bones (fish, dinosaurs, shell) 4. Fossils come in all shapes and sizes

B. Types of Preservation 1. Preserved remains: Organisms trapped in amber, tar pits, or ice can be preserved for thousands of years. 2. Carbon film: a fossilized carbon outline of an organism, all gases and liquids foced out, only carbon remains 3. Mineral replacement: minerals in groundwater can replace the pore spaces and tissues of organisms 4. Molds: an impression in a rock is left by an organism, sediment forms around organism, it decays and an impression of its shape remains 5. Cast: A mold left by an organism is filled with sediments and mineral deposits. It creates a copy of an organism 6. Trace fossil: preserved evidence of an organism, footprints, droppings. Reveals information about the behavior of organisms, i.e., dinosaur size and speed

Carbon film- fish Mold- ammonite Preserved remains- baby mammoth Draw the picture and write the definition. Make sure you write the name of the fossil and the example given on this page. Cast- trilobite Trace Fossil- dinosaur tracks