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Science test#5
Question | Answer |
---|---|
Relative Age | Age of a rock compaired to other rock layers. |
Fossile | Zny trace, or imprint or remains of a liveing thing preserved in Earth's crust. |
Half- life | The time it takes for half of the mass of a radioactive element to decay into another element |
Absolute Age | Age of a rock by compairing the original element amount of decay products present |
Era | Long streaches of time to mesure Earht's geogolical history |
Peroid | One of the primary divisions of a geogolical era. |
Original Horizontiality | Sedimentary rock forms in horizontial layers. |
Superposition | In a serious of rock layers, the bottom layer is the oldest and the top is the youngest. |
Geologic comomn | Listings of earth's rock layers from oldest to youngest |
Cast | Organisms covered by sediment soonn after death, soft parts decay and hard parts (bones, teeth) last long enough to be preserved. |
Imprint | Buried or squeezed between layers and fluids removed. |
Petrifited | Buried organisms trapped in sediment. |
Index fossile | Live for a short peroid of time widespread over earth and evove rapidly. |
Trilobites | Sea animals. |
Precambrian | Began 4.6 billion years ago earths formation earliest life formed in sea multi- cellur, marine organisms few fossils |
Paleozic | 600 Million years ago life abundunt sea and land insects amphibans trilobites fish reptiles farests. |
Mesozic | 245 Million years ago dinosaurs mammles birds flowering plants pangea began to break apart climats milder |
Cenozoic | 65 Million years ago mammles dominate humans appear about 2 million years ago. |
Peroid | Part of era associated with major changes in earth's crust. |
Geogoligical timescale | major events and life forms on earth during each era. |