Name: _____________________________________ Class: __________ Date: _______

Isotope Worksheet

Instructions:

Study the graph above and then answer the following questions based upon the information in the graph.

1.      The bottom axis of the graph indicates the number of years before present.  What is the time frame represented on this graph?  

2.      What does the red dotted line represent? 

3.      How did sea level 400,000 years ago compare to sea level today? 

4.      How did sea level 150,000 years ago compare to sea level today

5.      At roughly what time was sea level at its highest during this time frame? 

6.      At roughly what time was sea level the lowest during this time frame?

7.      What happened to sea level between 400,000 and 350,000 years ago? 

8.      How do you think that might have affected marine life at that time?