If you feel you want to direct your students into narrow explorations, then you might assign a hypothesis to individuals or to groups.
For example, you could
1. Ask each group (or individual) to list the evidence supporting each hypothesis. Have them weigh the evidence they have listed. Is it strong? Or, is it only partically supportive of the hypothesis?
2. Ask students to debate for or against each of the hypotheses on extinction:
a) Comet or Asteroid Impact
b) Disease
c) Orbital Changes (with climate effects)
d) Supernova
e) Volcanic eruptions
After the students have completed either/or both options above, ask the students to determine which hypothesis is best supported by evidence.
