THE DEBATABLE K-T EXTINCTION

Scenario

A senate subcommittee is holding a public hearing to decide whether or not to fund a $50 billion planetary defense system. Are humans at risk of becoming extinct due to an asteroid or comet colliding with the Earth? Evidence suggests that such an event may have caused the mass extinction at the end of the Cretaceous Period. If so, can we prevent history from repeating itself?

Procedure

  1. You will choose a side to support in the hearing. The Pro side must argue the following three points: (1) the K-T extinction was caused by the impact of an extraterrestrial object , (2) such impacts continue to threaten life on Earth and, (3) therefore, we must build a defense system to protect the Earth against such events. The Con side must argue the following three points: (1) there are other plausible explanations for the K-T extinction besides an asteroid or comet impact, (2) large impacts are not a major threat today and, (3) therefore, we should not waste $50 billion on a defense system.

  2. You will become a specialist, choosing a role to play to teach yourself and the class about extinctions and geologic history through a group role playing debate/senate hearing (see Role Descriptions). For this activity, many articles are available in the classroom to provide background information and research materials for the debate. If an article is just used during the class period, you do not need to check it out. Up to three articles at a time may be checked out to take out of the classroom. Never take the last copy of an article. Your group should start by devising a strategy to sift all of the relevant information out of the classroom articles. When this information is exhausted, you may want to pursue further research through the internet or a local library.
  3. Every couple of days, your group should reassemble to discuss the strategy for the hearing by synthesizing arguments from both sides of the argument. Bias and reliability of data should be addressed. It is just as important to understand the opposing view as it is to understand the evidence supporting your side. A couple of days after this project begins, the lobbyists from both sides will provide the teacher with a tentative expert witness list. A couple of days after this, a final witness list must be produced. Both the tentative and final witness lists will be shared with the other side, the senate members and the reporter. As all group members conduct their research, all relevant information should be shared with the appropriate witness in your group. A couple of days before the actual debate, lobbyists should start practicing with their witnesses. The day before the debate, the two sides will be in separate rooms so that they may practice in private. Expert witnesses should have their visual aids to practice with at this point.

  4. The debate itself will last for three days. In reality, senate hearings could last for months but time constraints do not allow for this. There will be set time limits for opening and closing statements, witness testimony and cross-examination by the senate and opposing lobbyists. Students are encouraged to dress for their parts but this is not required. The teacher will videotape the debate and be the official time keeper.

  5. After the debate is completed, the class as a whole will watch portions of each person’s performance. Each person will fill out a self-evaluation in addition to participating in an oral critique of everyone else’s performance. Both the strengths and weaknesses of each presentation will be addressed. Comments during this critique will be respectful and only deal with oral presentation skills and not the content of each person’s portion of the debate.

Role Descriptions

Senator

This is one of the most powerful and demanding roles. Therefore it is probably the most difficult with which to get a high grade as senators must demonstrate a very thorough knowledge of both sides of the issue in their questioning, make sure all debate rules are followed and reach consensus on a thorough, well explained decision. Senators need to be very self-directed individuals who can still reach a consensus with others when required. The senators must research both sides of the issue, listen to all of the testimony given, ask questions when appropriate, manage the proceedings and reach a decision based on the evidence presented during the debate.

Lobbyist (usually Co- Lobbyists)

This position is the "captain" (not dictator) of each side. The overall purpose of this position is to convince the senate to vote for your side. The lobbyist makes an opening statement, presents witnesses and makes a closing statement. Additionally, while the other side is testifying, the lobbyist must listen for weak testimony and be prepared to cross examine these witnesses. This requires sharp listening skills and the ability to think on one’s feet in order to formulate focused questions in a limited time period. Lobbyists must research both sides of the issue in order to aid their own witnesses and effectively exploit weaknesses in opposing witnesses.

Expert Witnesses

These people assume the role of a specialist in some area of knowledge that supports their side’s position. Witnesses determine their area of expertise with guidance from the lobbyist. Witnesses may present their testimony alone or through questioning by their lobbyist. The witnesses should have a very thorough understanding of their field of expertise as interpreted by both sides of the issue as they will be open to questions from opposing lobbyists and senators. Visual aids are required for the witness presentations. These visuals should help organize the entire presentation (essentially function like note cards) and aid others in understanding the material. This role will have the most limited range of research but it will be at a greater depth than the other roles.

Reporter

Like the senators, this person needs to be very self-directed. During research days, the reporter must research both sides of the issue in order to understand the testimony given during the debate. The reporter will take notes during the debate in order to prepare an account of all the scientific evidence presented during the debate. This account will be xeroxed for each member of the class to supplement individual student notes on the debate. The reporter will also interview up to three individuals at the conclusion of the debate in order to shed light on the science presented during the proceedings.