Name: ______________________________________ Date: ______________Period: ____

Mr. Lazaroff's Biology Classes

EVOLUTION PUZZLE ACTIVITY

Introduction:

    The following activity simulates what paleontologists do when studying a fossil assemblage. The drawing below represents a mixed assemblage of vertebrate fossils (Can you name the animal phylum?). In this exercise your goal is to organize these fossils in a manner which depicts the gradual evolution of characteristics. Begin with a generalized ancestral form and show the evolution of this organism via a logical sequence of orderly changes. Remember, evolution may be linear and/or branching.

    There is more than one correct interpretation for the "fossils" seen below.  With more detailed data, however, only one interpretation would ultimately be accepted as the truth.  Don't ever forget that scientific explanations often change, in most cases getting more refined, as scientists gather more data.  On some occasions, new data will contradict an earlier explanation (as the heliocentric explanation of the universe was challenged by Copernicus and Gallileo); this requires a new theory.  Such drastic revisions are more rare nowadays.  A more likely change will be like the changes in Darwin's theory of evolution, which has gotten more detailed and sophisticated, but the core of the theory remains the same.

I. Problem: In what order did these fossils form?

II. Hypothesis: Your Hypothesis is the order you choose for the fossils.

III. Experimental Design:

A. Materials:
 

  1. two pieces of 8 1/2" by 11" binder paper
  2. two pairs of scissors
  3. glue or tape

B. Procedure:

  1. Take the two pieces of 8 1/2" by 11" binder paper and tape them end to end to make one 8 1/2" by 22" piece of paper.
  2. Cut out each of the 18 fossils from the assemblage and count them.
  3. Organize the fossils on the binder paper so that they depict your explanation of evolutionary change, and give each of them numbers to make it easier to refer to them in answering the questions.
  4. Glue or tape the fossils in place on the paper. Draw arrows -----> in place to show the direction of evolutionary change.

IV. DATA: The Data are the fossils themselves.

V. Questions:

  1. Given no further information is it possible to organize the fossils in any other way? If so, describe the new organization using the numbers you assigned in step 3 of the procedure. If not, explain why not.
  2. Describe the habitat (the environment where it lives) and the niche (the role of the organism in the environment) of the oldest and most recent of the fossils, as well as one from the middle of your timeline (once again, use the number you assigned in step 3 of the procedure).
  3. Name the creatures you described in question two, and be sure to include some aspect of either their appearance or diet in the names.  The names should somehow describe the creature (e.g., spoonbill, snapping turtle, rattlesnake, etc.).
  4. What other information would you need to more accurately place the fossils in order?
  5. Compare relative dating (Not me . . . I don't date relatives!) and absolute dating and describe the merits of each.
  6. Vertebrate fossils are unlikely to take the form we saw in our assemblage. What form would they be likely to take, and what knowledge would be useful in interpreting the fossils?
  7. Describe what specific environmental factors might have acted as selective pressures in the evolution of these creatures.

    The Following Questions are ONLY for the HONORS Class:
     
  8. Research the half-lives (be sure to include them in your answer)of the following elements (indicate their name), explain which is the most appropriate for use w/ fossils hominids (be sure to define a hominid in your answer) dated from 1 to 5 million years old, and explain why (there may be more than one reason) all the others are not appropriate.   After the table, explain how Half-Life works, and how it is used in this process:

    Element

    Half-Life

    Decays to

    Reason(s) for its use, or lack thereof
    14C      
    59Fe      
    131I      
    40K      
    24Na      
    210Pb      
    239Pu      
    238U      
  9. Research the order of the evolution of vertebrates from water to the land (refer to each of the major classes of vertebrates by name) and explain the largest weakness of the collection of fossils given (i.e., to mimic the history of life on earth, what would you have done differently).
  10. Which bone or bones (be sure to use the correct bone names) would be the MOST useful for comparison of these creatures, and explain why. Do your best; I don't want this question to become a bone of contention (Ar, Ar . . .).

VI. Conclusion:

You should know what to do, but in case you have forgotten, you can always check out the Lab Format section of the Staples Science Department's Web Page, or the Lab Section from your Class Rules handout from the beginning of the year..