Teaching & Learning

What is the best place to start teaching IB DP Biology?

Originally posted on August 20, 2017 @ 9:00 am

Every year I like to think about how I approach the delivery of the DP Biology course. I think about what are the best examples to use to illustrate concepts like the pentadactyl limb, or what is the best way to structure the teaching sequence into a coherent sequence.

This summer I have been thinking about how best to approach the start of the course. I think this is important in my context because I cannot be certain of the biological background of all of my students and I don’t want to make any assumptions about what they know.

I polled teachers on facebook and twitter about this and most teachers tend to start the course with 1.1 – introduction to cells, although other areas like to 2.1 – molecules to metabolism and 5.3 – classification of biodiversity are also popular if not nearly so as 1.1.

My issues with starting at 1.1 is that I think that while there are some essential ideas that are natural to start a Biology course; the functions of life and cell theory, there are others which are not so helpful like stem cells, gene control of differentiation, and evolution of multicellularity. Some of these concepts are tricky to get your head around and do not count as foundational knowledge, in my opinion.

What I want in the start of my DP course is to introduce students to the simplest biological concepts that will go on to serve as a foundation for future learning. I believe the functions of life and the classification of life (“what is life?” and “ok, we know how to crudely define living things, but what types of living things are there?”) are understandings that students should address before going on to look at how living things work.

What I am struggling with is this: the IB’s TSM states that topics don’t need to be taught in order, or that even subtopics don’t necessarily need to be taught in order. We should, as teachers, construct a course that draws different elements into coherent units. Personally, last year, I made a move away from going through topic by topic and tried to link subtopics into themed units. I love thinking about what topics flow well together.

But what if you want to split sub topics? Is this allowable? Obviously you could do this but, with the way the IB has structured the sub-topics each with their own “essential idea”, should you? The issues with the essential idea is that it aims to force all the understandings in that subtopic under a single umbrella. Because the essential idea is examinable, surely all the understandings, applications and skills should be kept together as they serve to illuminate the essential idea.

Personally, I think I may go ahead and chop up 1.1 so that I introduce these:

  • A2: Investigation of functions of life in Paramecium and one named photosynthetic unicellular organism.
  • U2: Organisms consisting of only one cell carry out all functions of life in that cell.

With this from 5.3:

  • U4: All organisms are classified into three domains.

Which will then act as a segway into topic 1.2 the ultrastructure of cells, before going on to consider cell theory and the then the rest of topic 5.3.

Its a little bit pick and mix, but do I run the risk of not covering the essential ideas. To solve that, what I may do is leave the essential ideas  (of these sections) for revision in grade 12. In-fact now I think about it, all the essential ideas would make great revision points.

I could get the students to memorise Allott and Mindorff’s paragraph’s that describe each essential idea and force them to regurgitate them at random points through G12…..

4 replies on “What is the best place to start teaching IB DP Biology?”

Hi Will

Just seen this and I think about this a lot myself. What is the best way to begin the course. For me there are some threshold concepts that I want them to come across soon, at the very least within the first term, such as diffusion, osmosis, surface area to volume ratio, etc. But what is the very best beginning. I like you idea. One year I started with evolution, but I want to leave this till later now as there were some things I couldn’t explain well without some knowledge from other units. But to start with 1.1, 5.3. I like that, looking at biodiversity, the first port of call for a biologist.

What I have done mainly is begin with 2.1 and go through the biochemistry, but with the theme of nutrition, and then add in the lessons on nutrition from Option D. This is because I really like nutrition, I think the students can relate to it well, and it covers the biochemistry that is important.

Hi Christian,
Thank you once again for reading, commenting and interacting online – it is great to be able to virtually discuss teaching biology specifically.

Regarding threshold concepts – I have been thinking about these since you shared your project to map them. I am a little reluctant to go down that road, as I am not sure that they demonstrably exist….but I recognise that it could be helpful to plan in this way.

My worry about starting with biochem and molecular bio is that it could quite quickly lead to cognitive overload as it is quite abstract.

Andrew Carroll (on twitter) catalysed my thinking about this as I think we need to present area with the least propositional knowledge first so as to avoid cognitive overload.

For planning, I think it best to think about which areas initially have the least cognitive load for students because they will have the least *new* propositional knowledge…

Blog post on this coming soon 🙂


Hi Will,

First of all, I can’t thank you enough for sharing your hardwork with the world. In August, I will be teaching IB for the first time and although I have done the diploma programme as a student myself, I was not sure what order to teach the topics/subtopics in. It is a daunting task and I’m so grateful for your resources.

I will certaintly be a regular visitor to your website to get me through this first year.

Thanks again.


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