Transcript Fossils
Fossils QuickTime™ and a Sorenson Video 3 decompressor are needed to see this picture. 1 What are fossils? Fossils are the remains of a prehistoric animal or plant preserved in sedimentary rock. Types of fossils: – Actual bones or remains – Imprint or mold – Cast (made when sediments fill in fossil) – Track or trail Mold a cephalopod Remains of a trilobite Footprint left by a dinosaur 2 What are the odds? Tree growing in a swamp Poor Horse drowned in a river flood plain Good Jellyfish in the ocean Poor Small animal caught in a tar pit Good 3 Studying Fossils Paleontology--The study of fossils before man. Geologic Time Scale--Rocks are placed in order from oldest to youngest. 4 Studying fossils cont’d Law of Superposition-Younger rocks lie on top of older rocks. Relative Age--Age of a rock when compared to other rocks. Geologic Column-Arrangement showing rock layers in the order they were formed. 5 Division of Time Era--The longest division of time. Period--Subdivision of an era. Epoch--Smallest division of time. The era divided in epochs is the Cenezoic Era. 6 Precambrian The Precambrian Era has the most primitive life forms. – Earliest era – Longest era – Fewest fossils, all invertebrate species – Only era with no periods or epochs Areas where Precambrian rock can be found Image sources: nasa.gov and nationalatlas.gov 7 Paleozoic The Paleozoic Era has the first vertebrates. – Plant life began to develop on land – First animals begin to appear on land Area where Paleozoic rock can be found Image sources: nasa.gov and nationalatlas.gov 8 Mesozoic The Mesozoic Era is considered era of middle life. – Three periods: Jurassic, Triassic, and Cretaceous – Era during which the dinosaurs lived Area where Mesozoic rock can be found Image sources: nasa.gov and nationalatlas.gov 9 Cenozoic The Cenozoic Era is the current era during which we live. – Shortest era – Era with the most fossils Area where cenozoic rock can be found Image sources: nasa.gov and nationalatlas.gov 10