Monday, April 11, 2011

Monday Quicky

As I have a total of 5 tests in the next week, I'm going to wuss out and do a quick post today.  In my Historical Geology course, we are currently pursuing our fossil unit.  Here are my favorite fossils we have covered so far (and almost covered I suppose).

Trilobites.   So Cool.   They were amazingly diverse prehistoric bugs that completely disappeared from the fossil record during the Permian Extinction.     I don't have pictures of any yet (lab tomorrow!), but you can find several online.

Brachiopods.  While I don't find them to be particularly interesting, this specimen in lab was fossilized in a manner called permineralization.  It resulted in the shell being filled with pyrite.

Top shell.  you can't see the pyrite very well with this picture as it was from my phone.

Bottom shell.  You can see the top shell overlaying at the top of the photo.
One neat way to tell Brachiopods from their similar looking friends the Pelecypods is the symmetry.  Brachiopods have a strong symmetry looking down at the top, while Pelecypods are symmetrical from the side.

Diatoms are really neat single celled organisms.  They still exist today, but have been found as far back as the Jurassic (200 million years ago).  What I love about them, is the unique shell shapes (well, cell wall shapes would be a better term) they secrete.  Pretty complex looking for a single cell. They also used to be used as an abrasive in toothpaste!

Anyway, off to take one more run at my Weather and Climate practice test.   Happy fossil hunting!

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