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Do Now. How do scientist know that different kinds of plants and animals lived in Earth’s past? What is a fossil?. Objective. I will be able to describe how different fossils are formed. What is a fossil?.
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Do Now • How do scientist know that different kinds of plants and animals lived in Earth’s past? • What is a fossil?
Objective I will be able to describe how different fossils are formed.
What is a fossil? • Are the preserved remains or traces of living things that provide evidence of how life and Earth’s surface has changed over time
How are fossils formed? • Most fossils form when living things die and are buried by sediments. • The sediments slowly harden into rock and preserve the shapes of the organisms. • The remains or traces of an organism must be protected from decay http://www.youtube.com/watch?v=KxDQwBZj9o8&feature=related
Petrified fossils • Water rich in dissolved minerals seeped into spaces in the plant cells and then evaporated leaving hardened minerals behind.
Molds and Casts • Mold • A hollow area in sediment in the shape of the organism • Forms when the hard part of the organism is buried in sediment • Casts • Later water carrying minerals and sediment may seep into the empty space of a mold--resulting in a cast • Is a copy of the shape of an organism
Carbon fossil • All living things contain carbon • When sediment buries an organism some of the material turns to gas. • The gas escapes from the sediment leaving a thin film of carbon • Can preserve the delicate parts of plant leaves and insects.
Trace fossils • Provide evidence of the activities of organisms • Provide clues about an animals size and behaviors • Ex. Fossilized footprints
Preserved remains • Preserve remains with little or no change to the organism • Ex. Trapped in tar, preserved in amber, freezing
A Fossil’s Story Directions: On a sheet of paper, write a story about fossilization from the point-of-view of the organism. The following items should be included: • Type of organism: give a detailed description • How the organism died • Where did they die: the surrounding environment • How were they fossilized: include the process they went through. • What type of fossil did they turn into • Who found them and what did that person think of the fossil
Objective I will be able to describe how different fossils are formed.
Exit Ticket • Make a list of the different types of fossils. • What is the difference between a mold fossil and a cast fossil? • What is the difference between a petrified fossil and a preserved remains?
ACT Prep • John is faster than Pete. Dave is faster than Harvey. Dave is slower than Pete. Which man is fastest and which is slowest? • If Bob and Fred are both taller than Tom, while Hal is taller than Bob but shorter than Fred, which man is tallest and which is second tallest?