Archive for December, 2011

A Question of Content

As we move towards the new AP Biology curriculum set to begin in the fall of 2012, the question of content is a big one.  Visit the Advances in AP web site, and you’ll find the following quote:

“Science is a way of thinking much more than it is a body of knowledge.”

– Carl Sagan

While I find the current curriculum to be excessive in its breadth, the notion that learning biology is exclusively about learning a set of skills does not sit comfortably with me either.  On one hand, I groan each year as I approach animal diversity, wondering when my students’ ability to differentiate among acoelomates, coelomate, and pseudocoelomates will come in handy in the future.  Thus, the decision to remove this detailed information from the curriculum led me to breathe a sigh of relief both for myself and for my future students.  However, when I read the new framework and saw that “memorization of the names of the phases of mitosis is beyond the scope of the course and the AP Exam,” I felt a little taken aback.  In my opinion, students could very well come across an article on cancer, and an understanding of the process of cell division would indeed be very useful to comprehend the article.  Furthermore, while virtually none of my students will go on to become comparative developmental biologists, a good portion are likely to work in the healthcare field, where knowledge of biology relating to cancer is pertinent.   Therefore, while I am grateful that the tightening of the curriculum will alleviate the panic that sets in when a snow day sets me back one day on my syllabus, I am not entirely comfortable with all of the changes to the AP Biology curriculum.

Reading Daniel Willingham’s book, Why Don’t Students Like School has helped me to better understand what is making me a little uncomfortable with the notion that science is all about skills.  He argues that background knowledge is essential for both reading comprehension and for critical thinking.  I find his argument entirely convincing.  I urge educators to dig into his book, but I will highlight a few points here.

With regards to reading comprehension, Willingham emphasizes the importance of background knowledge by asking his audience to read the following passage:

The procedure is actually quite simple.  First, you arrange items into different groups.  Of course one pile may be sufficient depending on how much there is to do.  If you have to go somewhere else due to lack of facilities, that is the next step; otherwise, you are pretty well set.  It is important not to overdo things.  That is, it is better to do too few things at once than too many.

To most, this passage is not easy to comprehend.  None of the vocabulary is difficult, but, as Willingham notes, it is “vague” and “ambiguous.”  However, had you first been told that the title of the passage is “Washing Clothes,” your comprehension would have been much better.  Willingham states that “we interpret new things we read in light of other information we already have on the topic.”  He notes that in the case of “Washing Clothes,” the title “tells the reader which background knowledge to use to understand the passage” (26-27).

For more on reading comprehension, you can also watch this:

Willingham makes a similar argument for critical thinking.   He challenges readers with the following problem involving cards with a person’s drink on one side of the card and their age on the opposite side.  Your task is to analyze the set card set below and enforce the rule that if you are drinking beer, then you must be twenty-one or over.  You must verify the rule is met for the card set below by turning over the minimum number of cards.

Many of us are familiar with this topic, and it is relatively straightforward to pick out the beer card and the 17 card as important for verification of the rule.  It doesn’t matter what a 31-year-old person is drinking.  Likewise, it is acceptable for anyone regardless of age to drink coke.  Interestingly, Willingham points out that when researchers give college students an analogous problem, except this time the task is to verify the rule that if there is a vowel on one side of the card, there must be an even number on the other side of the card, the students aren’t very successful.  Only 15-20 percent of college students figure out how to verify that rule for the following card set:

Why the discrepancy if the problems are so similar?  Part of it, Willingham argues, is that you bring experience, or background knowledge, to the first problem, making it easier to solve (29-30).

At a time when educators are urged to focus on skills, skills, skills, Willingham puts forth a convincing argument that knowledge is a vital piece in attaining the skills that we value, like reading comprehension and critical thinking.  He offers some practical advice to educators regarding content, with the realization that our textbooks are bursting at the seams with both relevant and not so relavent material.  So, what to teach?  Willingham argues that a “minimum target” is for students to graduate with the knowledge required “to read a daily newspaper and to read books written for the intelligent layman on serious topics such as science and politics.”  For core subjects, like math, science, and history, Willingham argues that it is necessary to teach what comes up “again and again” (36-37).

So what is the take away message for a biology teacher?

1.  For my general biology students, I want them to leave with enough background knowledge to be able to comprehend biology-related articles in the science section of a newspaper.

2.  For my AP students, I want to instill an enduring understanding of topics that they are likely to encounter again if they go on to more advanced biology classes in college.

Concept Attainment Genetics Lesson

I got this genetics activity from the 2009 NSTA conference, and it was presented by a representative from the Center for the Integration of Science Education and Research at Texas Tech University (CISER).  The activity employs the concept attainment model.  It leads students to a concept by having them compare and contrast examples that contain the attributes of the concept with examples that do not contain the attributes.  Eventually, students should be able to identify the critical attributes of a concept.  CISER developed a genetics lesson using this method, and it has proven to be an effective, fun way to introduce my general biology students to genotypes.  Here is a link to the lesson:

Concept attainment genetics lesson

I guide students to  categorize a list of potential genotypes into two groups. The items categorized in the “YES” group possess the attributes of a properly written genotype.  Those categorized as “NO” items lack the proper attributes of a genotype.  I give a few examples of both “YES” items, and “NO” items before having students start to guess.  I have adapted this lesson to my Smartboard, and at the beginning of the lesson, it looks like this:

Students then drag the items through the blue revealer cone to see if they are a “YES” or a “NO” item.  Towards the end of the activity, the board looks like this:

Notice the final genotype being pulled through the revealer box.  Once we are finished categorizing the items in “YES” and “NO” groups, the class discusses what makes something a “YES.”  They will suggest attributes of genotypes, like, “there must be two of the same letter written consecutively” or “if only one of the two letters in a pair is capitalized, it must be written first.”  Typically, my students haven’t even been introduced to genes, alleles, or inheritance patterns when we complete this activity.  Once we get to Mendelian genetics, however, they very rarely make errors when using letters to represent dominant and recessive alleles.