In class we will be going over Section 4.1 in the book, looking at examples of fossils, using a video on the La Brea tar pits, and going over Science Contracts for Week 7.
What do you know about fossils?
Where have you seen fossils?
Most importantly, what can we learn from fossils?
As we go through the week, some of your ideas about dinosaur "bones" might change.
Here are some images of students teaching students for their A Contracts.
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| Contract Week 7 |
8 comments:
Fossils are are prserved in amber, ice, and tar. They are organisms that were trapped.
Are these the only ways fossils form?
pshtt tyler toattly took my answer!
gosh tyler!
your still my best friend.
^(:
and fossils are anyhing that has died, and minerals have flowed over it, and formed the fossile.
^thanks for the answer paul (:
thats all (:
byee**
well you see i have seen quite a few fossiles before becaue in like 4th and 5th grade we had these people come in and talk about fossils and it was pretty cool i have seen different kinds of fossils and now when i was in your class i have seen alot more now some i never knew even existed. Well you see, fossils are formed when things die and and then they get preserved in amber or ice or tar. They are dead organisms that are preserved in one of those things.
ok this is how fossils are formed.
1. some animals are buried by mud after they died.
2.after a long period of time sediment covered the remains.
3.In the right circumstances (no scavengers, quick burial, not much weathering), parts of the animal turned into fossils over time.
4.After a long time, the chemicals in the buried animals' bodies underwent a series of changes. As the bone slowly decayed, water infused with minerals seeped into the bone and replaced the chemicals in the bone with rock-like minerals. The process of fossilization involves the dissolving and replacement of the original minerals in the object with other minerals (and/or permineralization, the filling up of spaces in fossils with minerals, and/or recrystallization in which a mineral crystal changes its form).
5.This process results in a heavy, rock-like copy of the original object - a fossil. The fossil has the same shape as the original object, but is chemically more like a rock! Some of the original hydroxy-apatite (a major bone consitiuent) remains, although it is saturated with silica (rock).
^^thats how fossils are formed.
sorce:
www.enchantedlearning.com
^i typed it all though (:
Again, are those the only three ways organisms are preserved? What about the fossils of trilobites that we looked at in class?
And what types of fossils have you seen?
Fossils reveal that things lived long before humans. They also show what time period the animal was from, and how it behaved.
Recrystallization is one of the best ways to preserve a fossil. Shells are made up of a mineral called aragonite, this mineral breaks down over a long period of time and changes into calcite. This type of recrystallization breaks down the microscopic details of the shell but doesn't change the overall shape. Shells have been found from millions of years ago, preserved by this way. Some even found in the Jurassic Period. Most of those found have recrystallized to calcite.
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