Friday, October 28, 2011

Fossil Records

We have moved on from plate tectonics, earthquakes and volcanoes and it is now time to move on to Life Over Time.  Over the next few weeks, we will explore how life developed on Earth, how it changed over time, and the theory of natural selection.  The very first section covers fossil evidence of earlier species.

There are three basic types of fossils that can be discovered:  parts of an organism, whole preserved organisms, or traces, molds and casts of organisms.  It is much more rare to uncover a whole organism or a part of an organism.  To demonstrate this point, we made a fossil record of our own lives and played a little guessing game to determine whose fossils we studied. 

It is worth noting that we took a few liberties here with our interpretation of "fossils."  The students selected five small objects that represented different stages in their lives - baby, toddler, early childhood, upper elementary grades, and middle school.  We made sure to discuss, however, that fossils are remains of living organisms, not objects.  Either way, students made fossils from air-dry clay of their objects then "buried" them in order of when they occurred.  The oldest fossils would be found below the newer ones.

Because I teach three sections of sixth grade science, it was easy to scramble up the samples the following day.  Each student in the class received the fossil record of another student in another homeroom.  They filled in a chart with their best hypotheses about what the imprints showed, what they represented and what they were able to learn about the person.  Finally, they made a guess about who they thought the created that record.  We revealed the guesses and made it into a fun game at the end of the second day of the lab.  


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