Results of the textbook meeting

Yesterday's meeting with the textbook rep clarified several tasks (listed below in no particular order):

1. The textbook publisher could create a composite textbook for us, made up of chapters taken from two or more different sources. But this may be more suitable for a survey course than for one that gradually builds expertise The rep will find out whether instructors have used 'composite' textbooks for courses like ours, and if so will put us in touch with the instructors.

2. The textbook rep will find out about on-line genetics activities provided to students with the various textbooks. And we will go through the activities she discovered in one of the textbooks, to find out how suitable they would be for our students (we want interactive activities, where students have to make decisions about what to do and predictions about what will happen).

3. I will dig out our old autotutorial genetics material to see if some of that could be repurposed for this new course.

4. We will look more carefully at the available textbooks, to determine what might be suitable. In particular, is there a textbook that would be OK if it were supplemented with one or two chapters from other sources, or with a week or two of material we have written specifically for our course?

5. We will prepare an email to the authors of existing genetics textbooks, explaining the approach we want to take and asking if they know of any suitable textbooks or other resources. (We'll also give this to the rep.) Here's a draft for us to start with:

Dear genetics textbook author,

We are planning a new genetics course for second-year biology majors, but we haven't been able to find any textbook that uses the approach we think best (described below). So we're contacting the authors of respected genetics textbooks to ask if they might know of something suitable.

After many years of teaching genetics, we feel that understanding the core of genetics has three main components. First, students must understand meiosis and its genetic consequences - how parental genotypes give rise to gamete genotypes, and how random gamete fusion creates offspring with new combinations of parental genotypes. Second, students must understand how genotypes produce phenotypes - how genes and proteins work, the role of environmental variation, how changes to DNA sequences change gene activities, and how, in diploid organisms, different alleles of the same or different genes interact to produce phenotypes. (This last point is perhaps the most important: students need to understand the molecular basis of dominance and epistasis.) Finally, once students have some mastery of both inheritance and phenotypes, they must learn to put these together to understand how phenotypes are inherited.

We have been unable to find any textbook that takes this approach. Traditional (Mendel-first) texts throw students in at the deep end, asking them to start applying Mendelian principles without any explanation of their causes. Even the simplest Punnett square implicitly requires students to figure out parental genotypes from parental phenotypes, to predict the gamete genotypes and proportions these parents will produce, to predict the offspring genotypes and proportions that random fusion of these gametes will produce, and to predict the offspring phenotypes from these genotypes. It's not surprising that students cope by blindly memorizing rules and patterns. Later chapters in the textbooks do teach meiosis and gene action, but most students treat these explanations as independent facts to be memorized, and never really make the causal connections between them and the rules and patterns they began with. (If you doubt this, try asking students why we see dominance.)

DNA-first textbooks give students all the facts of molecular biology before introducing Mendel, but students are unable to use this information to predict phenotypes because the text spent no more than a paragraph on the critical issue of what happens when two different alleles are present. And meiosis is again treated largely as patterns to be recognized, with no emphasis on using it to predict gamete genotypes.

Here's what we think is missing from the textbooks we've examined:

1. Material that teaches students to predict gamete genotypes from parental genotypes. This needn't be a chapter in itself, but the basics should be introduced when meiosis is introduced, and extended when each new complication is brought up. For example, when crossing over or chromosome rearrangements are taught, students should also be taught how to predict the gamete genotypes that crossovers and rearrangements will produce. This teaching needs to be accompanied by appropriate problems. For example: "A man has genotype a1 a2 b1 b2. What gametes will a single meiosis produce? What gamete genotypes will the pooled products of many meioses contain, and in what proportions?"
2. Material (probably a chapter) that teaches students about the causal relationships between diploid genotypes and diploid phenotypes, explicitly incorporating the molecular basis of each effect. (Haploids could also be in such a chapter.) What if one allele produces a functional enzyme but the other produces no enzyme at all? What if one allele of a repressor gene is defective?

We really don't want to write our own textbook, or even our own supplementary chapters. Might you know of any textbook that takes the approach we're looking for. Or perhaps just a chapter or other written material that could fill in the gaps we see?

Thanks very much in advance for any suggestions,

Preparing for a meeting with our usual textbook rep

The Genetics planning committee (or whatever we are) is about to meet with a textbook rep to discuss options for getting a textbook that fits the kind of course we want to teach.

I'll set aside for now the issue of whether we want a textbook at all. I think we need a set of required readings (and maybe activities) that we expect students to complete BEFORE they come to class. These could be chapters of a standard textbook, a collection of chapters from different textbooks that a publisher has put together for us, stuff we wrote ourselves, or ???

Why a typical genetics textbook isn't suitable:

Our approach to teaching genetics seems very sensible to us, but it's certainly not the one most courses take. Genetics courses and textbooks usually start either with some combination of Mendel's discoveries, meiosis and DNA/gene expression, introducing the basics of what's called 'transmission genetics'. They may do Mendel first, or DNA first. Students learn to predict phenotypes of offspring from phenotypes of parents, and vice versa. To do this they need to have memorized 'Mendel's laws'. In this context our current understanding of molecular biology and meiosis is presented as explaining what Mendel found.

We instead want to separately teach the two components of transmission genetics. We will thoroughly teach how DNA sequences determine phenotype, building a solid molecular foundation for such concepts as ploidy and dominance. Separately we'll teach how DNA sequences are inherited (meiosis, gamete fusion, chromosome reassortment and crossing over, etc.). Only once both components have been solidly established will we combine them to teach about the inheritance of phenotypes.

But we can't find a textbook that does a proper job of teaching how genotype determines phenotype. This deserves at least one full chapter, maybe more, but textbooks usually gloss over it, assuming that students who understand how DNA makes RNA makes proteins and what proteins do will automatically grasp the implications for phenotypes, especially in diploids.

So maybe the solution is to use a standard textbook but somehow create this anomalous chapter ourselves, or find it somewhere outside of the usual textbooks.

Improving the match between objectives and assessment

Yesterday one of the biology instructors presented to the rest of the first-year instructors the results of an analysis she'd done.  She wanted to find out whether the 'learning objectives' we developed and are trying to follow match what we actually assess in our midterms and final exams.  The issue wasn't so much about their content as about their level of difficulty, which she scored using the 'Bloom's Taxonomy' scale.

What she found was that our exams ask more of our students than they would expect from the learning objectives we give them.  Even our multiple choice questions are quite challenging, mostly requiring a lot more than simple regurgitation of factoids.  This is good in that we're assessing learning at the level we want, but bad in that we're not telling students the truth about our expectations

The cause of the discrepancy is that we are all relatively new to writing learning objectives. When we wrote them (as a committee) we focused more on content than on what we wanted our students to be able to do with the content.  We knew enough to use 'performance' verbs like describe, list, and explain rather than 'state' verbs like know and understand, but we needed to also use words like predict, interpret and deduce.

The instructor fixed the objectives for us - she went through all of them (about 50!) and rewrote them to reflect what we are actually assessing.  

Word-cloud of the 3491 questions about biology

Here's a Wordle analysis of the 3491 questions posed by my Biology 121 students last year:

And here's a different representation:

Ideas from a creationist

Last night I went to a talk by a creationist, 'Professor' Walter J. Veith, chair of the Department of Zoology at the University of Western Cape, South Africa. It was part of a two-night series called "The Genesis Conflict", with two talks each night (creationists must have a lot of stamina). I couldn't find out who sponsored it, though collection baskets were passed and a lot of people put money in them. There was a big poster at a bus shelter in Tsawwassen - I took a photo of it which I'd like to put here, but I'm afraid I haven't figured out how to access photos that I took with my iPhone (I can copy them to my laptop but then I can't find them).

Veith's mini-biography on the flyer says, inaccurately, that he served for many years as chair of the Zoology Dept. at the University of the Western Cape in South Africa. Apparently he only served for a few months, after which the department pushed him over into the Physiology Dept, where his anti-evolution ideas would be less problematic (see this archive). He's been retired since 2003, and has lots of tapes and DVDs for sale. His current affiliation is Seventh-Day Adventist. Over the next two weeks he's giving another series of 10 talks on the topic of "Reformation Rekindled", which appear to be about how the true spirit of the Protestant Reformation has been squelched by the wicked Roman Catholics.

This talk was titled "The Genes of Genesis". His premise was the old canard that the requirements for life are far too improbable to have arisen by chance, so we must instead infer the hand of a designer. He began by calculating the odds of 300 nucleotides assembling in the right order to encode a specific 100-amino acid protein (2^300 = 1-^127). He then pointed out that this was far larger than the number of particles in the universe, and asked "You decide, chance or a designer?"

He put this question to the audience each time he added another requirement for life onto his list (ribosomes, chaperonins, regulatory proteins,multicellularity, differentiated cell types, biochemical pathways, chromosomal rearrangements, sexual reproduction...). He was quite glib, throwing in enough technical terms and genial explanations to impress the non-scientific audience. He didn't make any other points, just kept pushing the numerical improbability of the origin of life/animals/people.

I especially enjoyed this because I explain the resolution of this 'paradox' in the very first class of BIOL 121. If it were true that 'life' couldn't get started evolving until a fully functional microbial cell had arisen by chance alone, then the origin of life would indeed be a big paradox. But it's not true. We can set aside the issue of that we mean by 'life', and just consider how much chance is required to produce something that natural selection can act on. Before the catalytic properties of RNA were discovered, only entities with RNA-directed protein synthesis machinery were thought to have the heredity and variation needed for natural selection, and these really are much too complicated to arise by chance. But now we know that RNA-like molecules can, in principle, catalyze their own replication. This means that evolution could have gotten started by the chance production of a single relatively simple molecule. Improbable maybe, but not nearly as improbable as a designer.

I think I can improve this BIOL 121 class by introducing it with a description of Veith's talk. This will bring home to the students that

I tried to stick around for the second talk ("Creation to Restoration"). Judging by the first few minutes, it was going to be about how the animals in Eden (vegans all) became nasty carnivores and parasites and pathogens. He had lots of just-so stories ready to go, beginning with how Eden's snakes transformed their salivary glands into venomous fangs, and how roaches in Hawaiian caves evolved eyelessness in 8 months. (The latter appears to confound colonization of Hawaiian lava tubes with Australian cave cockroach evolution.)

When I came out I was pleased to find a flyer from the local Humanists Society tucked under each windshield.

What they learned in kindergarden

I had breakfast with a kindergarden teacher, and we discovered some similarities in our jobs.

In both kindergarden and first-year university, students are learning to function in a new environment. They must discover what's expected of them before they can do what we expect.

In both kindergarden and first-year university, some students are very reluctant to speak up, because they don't feel intellectually safe (they're afraid of saying the wrong thing). We need to find ways to build their confidence, not in being right but in the value of not (yet) understanding. This problem is much worse in university than in kindergarden. That's probably because learning how to do new things is what young children do (they're used to succeeding), whereas high school somehow shifts their focus to being concerned about failing to learn at the expected rate or under the given circumstances.

Teaching Philosophy, Take Two

(Yes, this is a completely different organization that I tried in Take One)

Why I chose to teach first-year students:  Most faculty prefer to avoid teaching introductory courses, but in many ways this is the most important teaching of all.  First, it fills a more urgent need - the inability of the general public to approach the world scientifically is much more critical than the supply of new professional scientists.  Second, it has more impact - first-year students are more open to new ideas.  Third, it's more interesting - first-year courses deal with the big questions in biology, and teaching them pushes me way out of my area of expertise.  Below I describe some specific issues that arise, and my approaches to them.

Learning how to teach:  Like most academics, I initially planned to teach the way I wished I had been taught, but soon realized that what would have worked for future faculty didn't work for the great majority of students.  I then sought out pedagogical expertise, especially from a colleague in the Faculty of Education with whom I still meet regularly.  This exposed me to many innovative ideas, a number of which I've implemented.  But I also realized that, although most of these ideas sounded good on paper, few had ever been critically tested.  The example of the physics Force Concept Inventory convinced me that chances to teaching strategies need to be grounded in rigorous evaluation: science faculty should apply to their teaching methods the same requirements for evidence that they apply to their science.  My involvement with the Carl Wieman Science Education Initiative is now enabling me to begin contributing to this evidence,in the form of a very well controlled experiment testing the effect of written homework on both students' writing skills and understanding of biological concepts.

Teaching how to learn:   Most first-year students' biggest problem is that they don't yet know how to learn.  Despite much excellent teaching in high school, they expect university biology to consist largely of applying their demonstrated memorization skills to more advanced facts.  Because these skills have served them well in the past, students are very reluctant to replace them with what they see as more risky approaches.  To help them experience "not understanding" as a necessary stage in learning rather than as failure, I award marks for posing questions about each week's reading material.  To help them see the value of cooperative learning, I encourage students to consult their neighbours before answering in-class questions.  To help them learn about how they learn,I also explicitly explain the pedagogical issues underlying different class activities and assignments.  To help them learn that understanding is more valuable than rote memorization, all my tests and exams are open-book.

Teaching science as a process:  Initially, first-year students think of science as a body of facts generated by specialists, an attitude that can't be changed by simply telling them "Science is a way of knowing".  To demystify science, and to help them begin to see themselves as beginning scientists, I incorporate new research results into course work, and have students use the same tools for their homework assignments that researchers use for their research (e.g. HapMap, News & Views articles, and text and figures from recently published papers).  Many students also earn 15% of their course grade by reading and reviewing a research paper of their own choice.

Reinforcing relevance:  Students view course work as unrelated to their real lives, needed only for the test and perhaps for more advanced courses.  To help change this, the homework activities have been carefully designed to focus on issues the students care about: cancer risk, the environment, human diversity.  Many students earn 15% of their course mark for community-service learning projects in inner-city schools.  By receiving course marks for what they consistently describe as a "life-changing experience", students learn that the university values their ability to help their communities.