(I have a Wimba lecture on this in some of the Blackboard course shells, so you may have seen/heard this already. But I realized that I didn't put it on the blog, where some people were looking for it.)
One of the goals of BIO 137 and BIO 139, in addition to learning the content of the course, is to teach you to apply the information in new and different ways. That is an example of critical thinking. All of our general education courses strive to teach you critical thinking skills.
When talking to students about developing critical thinking skills, I often show a website that offers a summary on Bloom's Taxonomy. Bloom's Taxonomy is a philosophical framework that helps illustrate the levels of critical thinking. We tend to go through these levels when learning any new concept. First, we have to learn the terminology and what it means. Then we have to be able to use those terms. We have to learn some of the basic concepts, then we learn how they relate to one another. Pretty soon we can explain the new concepts ourselves. Later we can apply those concepts to new scenarios. Eventually we can come up with new scenarios or situations that can use the information that we already know. At the ultimate level of critical thinking, we use information to help us create information we didn't already have. This is how scientific research works - scientists use information to create experiments and then analyze the results for new knowledge.
The verbs or "action words" in that link help me to discuss the wording of essay questions, and ways to approach answering them on exams. A question that starts "define" will be answered differently than a question that begins "compare".
Even multiple choice questions can be constructed to assess students' mastery of different levels of Bloom's Taxonomy. For example, I give the following series of questions on a quiz in Chapter 3:
1. What is a hypotonic solution?
2. What happens to a cell in a hypotonic solution?
3. Which is greater: solute concentration in a hypotonic solution or solute concentration in a hypertonic solution?
4. If the extracellular concentration of sodium decreases, what happens to the cell?
Each of those questions has a series of answer choices that follow it, making them multiple choice questions. The first question is at the level of "define" - the student picks the definition of "hypotonic solution" out of the list of answer choices. The second question isn't necessarily a higher level question either - the student can memorize the effect of each of the solutions that are shown in the figure in the book. The third question starts to get into higher levels - the student is asked to compare two solutions and determine which is greater. The last question is a scenario that the student must recognize is a hypotonic solution in order to pick the correct answer. This analysis is a higher level than the previous three questions.
I think using these questions to illustrate the methods of developing and assessing critical thinking is helpful. I recommend to students that they practice taking their material and putting it into questions at various levels. I also recommend reviewing quizzes and tests from this viewpoint, to see if they are missing a number of the higher level questions or questions of a particular type (compare, for example).
I think Bloom's Taxonomy can be a useful tool in helping students to understand how we learn, and to assess for themselves where they think they are in that process.