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PPT Fossils.ppt
- 1. Fossils How to telltime with rocks
- 3. Looking at Fossils ►Afossil is any naturally preserved evidence of life.
- 4. Mineralization / Petrification Fossil ►Organismscan also be preserved by mineralization (petrified), a process in which minerals fill in pore spaces of an organism’s tissues.
- 5. Fossils in Amber ►Whentree sap hardens, an insect may be preserved inside. Hardened tree sap is called amber. Some of our best insect fossils are found in amber.
- 6. Mummification ►When organisms diein dry places (such as deserts), they can sometimes dry out so fast that there isn’t enough time for their soft parts to decay.
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- 8. Trace Fossils ►Any naturallypreserved evidence of an animal’s activity is called a trace fossil.
- 9. Molds and Casts ►Amold is a cavity in the ground or rock where a plant or animal was buried. ►A cast is an object created when sediment fills a mold and becomes rock.
- 10. Fossils Show Changes inEnvironments ►Fossils can reveal changes that have occurred in parts of the Earth. ►How did sea creatures end up on dry land?
- 11. Fossils Show Changes inLife ►Older rock layers contain organisms different from those found in younger rock layers. ►Life forms have changed over millions of years. For example, giant sea reptiles came before giant land dinosaurs. Mammals arrived last!
- 12. ►47) A fossilis a remnant or trace of an organism from the past, such as a skeleton or leaf imprint.
- 13. ►48) Fossils areembedded and preserved in the earth's crust.
- 14. ►49) A TraceFossil is a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself
- 15. ► 50) Afootprint of an ancient animal in a rock is called a trace fossil.
- 16. ►51) Large animalsoccasionally became trapped in tar and become a fossil.
- 17. ►52) Fossils, the remainsof organisms preserved in sedimentary rocks, are part of the evidence scientists use to infer changing conditions at the Earth’s surface through time.
- 18. ►53) Oil andNatural Gas are formed from ocean plankton that died millions of years ago.
- 19. ►54) Coal, NaturalGas, and Oil are all examples of fossil fuels.
- 20. ►55) Petrified woodis a fossil. ► ►56) Petrified wood forms when water with natural minerals slowly fills the pores of wood. Over thousands of years the wood slowly decomposes leaving behind the minerals from the water. The minerals harden and form a rock that looks exactly like the original wood.
- 21. ► 57) Howmuch wood is actually located in petrified wood? 0%.
- 22. ►58) The geologic column ishow geologists have organized the entire history of the Earth in chronological order.
- 24. ROCKS TELL ASTORY ► Rocks can tell where they were made and when ► Sedimentary rocks can have fossils in them ► Rocks can tell when mass extinctions happened
- 25. LAW OF SUPERPOSITION Forundisturbed rocks, the oldest layer is on the bottom and the youngest is on top (Supai is oldest)
- 26. ►59) Superposition statesthat older layers of rock are below younger layers of rock.
- 27. LAW OF SUCCESSION ►Fossils are found in a predictable sequence ► Fossils in rock B are older then fossils in rock A
- 31. RELATIVE DATING &AGE ► Relative Dating: putting rocks and geological events in correct chronological order ► Relative Age: how old something is in comparison to something else ► HOW? Use of sedimentary rocks Use of fossils Study of strata
- 32. Absolute Dating ► Absolutedating is a process that establishes the precise age of an object, fossil, or rock layer by determining the number of years it has existed. ► Radiometric dating is how absolute dating is accomplished. Scientists determine the actual age of a fossil or rock by measuring the decay of certain atoms.
- 33. ►60) Radiometric datingis how geologists determine the age of rocks by measuring the decay of atoms.
- 34. ►61) Radiometric datingis the most accurate way to date rocks and fossils.
- 35. What kind ofrocks are these fossils in? Which layer is oldest? Which layer is youngest? How do you know?