Do Now How do scientist know that different kinds of plants and animals lived in Earth’s past?...
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Transcript of Do Now How do scientist know that different kinds of plants and animals lived in Earth’s past?...
Do Now
• How do scientist know that different kinds of plants and animals lived in Earth’s past?
• What is a fossil?
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 StoryDirections: On a sheet of paper, write a story about fossilization from the point-of-view of the organism.
The following items should be included:1. Type of organism: give a detailed description2. How the organism died3. Where did they die: the surrounding environment4. How were they fossilized: include the process they went
through.5. What type of fossil did they turn into 6. Who found them and what did that person think of the
fossil
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?