What I learned about teaching biology this year 17-18

In 2016 I wrote this blog post. My answer to that question is now decidedly, yes. Content is King.

In this post, I want to explore why this is the case and outline what my ideas are now in relation to teaching biology.

The importance of content?

First, I should point out that a re-reading of my 2016 article makes me realise that I never concluded by suggesting content wasn’t king. Like all good questions, the article title helps to stimulate thought and a discussion about where we are at in our beliefs and in defending those beliefs. Really, the argument I was making was that teaching is not all about teaching content, but about teaching content AND encouraging critical thought with that content matter.

Content underpins everything. It underpins thinking. You can’t think without something to think about. It underpins understanding. You can’t understand something that is not represented as a propositional claim at a basic level. You can’t develop “skills” that aren’t grounded in some form of understanding.

When I am talking about content, I am referring to facts or propositional knowledge, statements that are thought to be true and are about the way the biological world is.

Propositional knowledge then must have primacy in teaching biology. To my mind, currently, propositional knowledge can be broken up into facts and concepts. Facts cannot be understood, they can only be known. Whereas concepts can be known and understood.

I think that to achieve deep, flexible, biological knowledge (flexible in the sense that it can be thought about in the abstract and applied in new situations) students need to achieve a conceptual understanding of the major themes in biology.

To do this they must first meet domain-specific examples. From those examples, they can then begin to pull out the commonalities to allow the mind to achieve an understanding of an abstract concept. My post here outlines how I went about this when teaching natural selection this year.

Learning domain-specific facts cumulatively builds to domain-specific conceptual understanding which accumulates in the learner being able to think in terms of these concepts and apply them elsewhere.

The importance of presenting content in the “right” sequence

Related to the idea of sequencing teaching so that we build up to conceptual understanding from specific examples, is the idea that we need to sequence teaching to avoid cognitive overload. To do this we need to think about which areas of the curriculum provide just enough challenge to engage students but not so much so they are overwhelmed.

In teaching biology, I think this is best achieved by teaching those areas with the least new propositional knowledge for the learner. Once the learner achieves mastery of this new knowledge then we can begin to add more.

In this sense, when trying to teach the understanding of the relationship of structure and function we may wish to look at studying the function first of any new example, before looking at the structures that support that function. Developing knowledge of the function of something might contain less instances of “facts” than the discrete structures that build up that function.

Once we have looked at lots of examples of, say, the relationship between surface area and diffusion, students will build up to the understanding of the relationship generally, and hopefully be able to apply this in new and novel ways.

Retrieval practice embedding content for the long-term

Drill and kill, right? Apparently not. My reading this year has convinced me that giving students the chance to practice retrieving information, not only builds their confidence that they can perform, and therefore reduces stress but also improves their ability to retrieve that information and therefore improves its storage in long term memory.

The same goes for learning the language of the subject and so now I try to begin my lessons with a fun low stakes retrieval practice activity. Low stakes in the sense that I do not record results and store them; students are not graded. For this I have prepared a deck of quizlet terms for the DP biology course and I alternate between using these or simply giving students a series of MCQ’s from last lesson, last week, last month and last term.

Interleaving & spaced practice – what might this look like in biology?

A year ago, on the Facebook AP/IB Biology teachers group, I first asked the question of what interleaving might look like in a biology course. I had been hearing a lot about interleaving during meetings and inset training from our DP Coordinator who is a Maths teacher. It seems that interleaving has been studied quite a bit in mathematics education.

When I asked the question, hardly anyone was aware of this concept amongst the biology teachers and I was stumped. I now have some ideas.

Interleaving or spaced practice is the idea that instead of learning all the content for a particular topic at once or in a set of continuous lessons, you space out the learning over time, revisiting topics over time.

In my experience, I have always taught a topic like cell structure and then moved onto the next topic, maybe membrane structure followed by membrane function – and I think that this is true of most biology courses.

In an interleaved curriculum these topics would be spaced out in time. Let’s imagine you have a 60min lesson every day with the same class, so five lessons a week. In an interleaved curriculum you may devote Mondays to cell structure, Tuesday to metabolism, Wednesday to plant physiology, Thursday to animal physiology and Friday to retrieval practice.

You would then teach the content of these units side by side over a number of weeks. It sounds a bit crazy but it has been demonstrated to improve long-term retention of learning and I am also excited by the possibility for the conceptual links you can make by teaching in this way.


Sequencing facts before concepts: natural selection

I have spent a fair amount of time this year reflecting on the application of cognitive science principles in my own biology teaching. There has been plenty written about concepts like interleaving and sequencing in sciences and maths but very little that I have found about how these concepts may apply in biology teaching.

Specifically, I have written up some of my thoughts on sequencing my DP biology curriculum based  on these discussions here.

Some of what I have learned suggests that solid conceptual/abstract understanding can only be developed when novice learners have embedded factual or propositional knowledge in their own mental schemas. In addition, I have tried to think about how principles from cognitive load theory may apply in terms of biology teaching and the sequencing of content.

One example of this has been how I approached the teaching of the concept of natural selection this year for my Y12/G11 mixed SL/HL IB biology class. In the IBDP biology syllabus, this is topic 5.2 and I sequence it after 5.1 “Evidence for evolution” and before 1.5 “The origin of cells”.

I finish the evidence for evolution section by looking at the peppered moth and the changes within the populations studied by Dr Ketterwell, through this online simulation.

In the past, I have taught natural selection by going over the concept of natural selection and then looking at specific examples of it that are mentioned in the syllabus which are antibiotic resistance in bacteria and changes in the beaks of the finches of the Galapagos island of Daphne Major.

This year I sequenced the topic into three lessons (which unintentionally appear to have been interleaved as we are also doing the internal assessment at this point in time and one lesson a week is given over to just the HL students anyway) and taught specific examples of natural selection before finally generalising from these examples to the abstract concept of natural selection.

Lesson 1 – Antibiotic-resistant bacteria

We started with retrieval practice of previous material using a google slide presentation which contained four questions: one using material from the last lesson; another from last week; another from last month and another from the last term. I then asked the students to draw and label a prokaryotic cell. Something that they covered six months ago.

Once completed we moved on to watch some news reports about antibiotic-resistant infections and I asked students to discuss and articulate back to the class what they thought the key message of each of the videos were. These prompted discussion about the general nature of antibiotic resistant bacteria and I used questioning to continue this discussion amongst the class. We also discussed what antibiotics were and why they were used to treat bacterial infections as this was a concept we met when studying the immune system two weeks prior. I highlighted the possible area of confusion for students between the words antibiotic and antibody which I had picked up from examining the previous May session of exams, before going on to explain how bacteria have become resistant to antibiotics.

I then gave the class a past paper question to complete the topic and we reviewed the key points of this question from the mark scheme.

Lesson 2- Finch beak changes on Daphne Major

Again we started with retrieval practice in the same format as in lesson 1. We then conducted a physical simulation as outlined in this practical, where students mimic being finches and collecting food. This was followed by a discussion of the trends we found in the simulation and what this might tell us about birds collecting food in the wild.

We then moved onto exercise 3 from this page and when students had finished the video and quiz I asked them to summarise what happened to the finches in the film.

Lesson 3 – the concept of natural selection

After retrieval practice, we reviewed the definition of evolution we had covered in 5.1 “evidence for evolution” and I highlighted that natural selection was a mechanism by which evolution could occur. I then asked students to think back and name the three examples of natural selection that we had considered in the last few lessons. Once they had written their answers down, I went through those examples and placed them on the board. I then asked students to discuss in pairs the details of each of these examples, before snowballing into a class discussion of the details of each of the three examples: peppered moths, antibiotic-resistant bacteria and changes in finch beaks. While we discussed these I wrote down the key points from each one on a second board with each example in a column so that similar elements from each example ended up in the same row. I then discussed with the students what these key features of each of the examples were and related this to the concept of natural selection. We finished with an example question asking students to describe the process of natural selection using examples.

Review: What if everything you knew about education was wrong?

This Easter holidays I read David Didau’s 350+ page compendium.

Basically, this book is an essential must read for any teacher. It is detailed and covers quite the range of ideas relating to classroom practice. On top of that, it is very well written, with clear and accessible language.

It is broken into four parts.

Part 1 “Why we are wrong” introduces the reader to a few general psychological concepts. Throughout the book, David references Daniel Kahneman’s work “Thinking, Fast and Slow” a lot and I think much of what is written here is sourced from that book, although, perhaps, simplified and certainly written in a much less head scratchy way. If you have read “Thinking, Fast and Slow” many of the ideas about psychological traps and biases will be familiar to you. Still, David is able to show how to apply these concepts succinctly to the classroom setting. He also provides an excellent explanation of effect sizes and the statistical techniques used to compare the effectiveness of classroom interventions before giving some real food for thought as to why this evidence might not be as robust as we think. His critique of Hattie’s work was quite surprising for me and I welcomed the explanation of a concept I had heard lots of people talk about, but nobody has ever explained.

Part 2 lays out what David refers to as the threshold concepts for learning to teach effectively. David unpicks many commonly held myths about classroom teaching and learning and makes an argument as to why many of these cherished ideas are wrong. The key idea here is that learning does not equal the same thing as performance in class. Learning is essentially an invisible process happening in peoples heads and by looking at performance in class we assume that this equates to learning in the mind of the student. Classroom observers look for evidence of “rapid and sustained” learning during class time, however learning, David makes the case for, is messy, non-linear and if it is going to be sustained cannot be rapid. Aside from the difference between learning and performance he covers concepts such the difference between novice and expert learners, the structure of our memory in terms of storage and retrieval strength and cognitive load.

After explaining our cognitive biases and how they apply in education before unpicking many myths about classroom practice held in educational circles, in part 3 David goes on to apply the cognitive concepts from part 2 directly to teaching practice. He gives a clear exposition of interleaving, the spacing effect, the testing effects and the effects of feedback. His writing will prompt you to think about these topics and how they may apply in your own planning and instruction – I know that they certainly have for me.

In the final part, he examines other pet theories in education that we could be wrong about. The first chapter deals with formative assessment and presents a surprising critique of Dylan Wiliams work, with a reply for Dylan Wiliam. There are also chapters on the problems of lesson observations, differentiation, praise among others.

One of the things that I was most surprised about and enjoyed reading was the critiques of the work by very established researchers. The work of both Hattie and Wiliam were picked apart at different points in the book. I am not sure I am fully convinced by the arguments but it was a pleasure to read something that was a little bit different in the sense that I have never come across critical reflections of these, much discussed, in schools at least, concepts before.

I also like the way the book is laid out. Now that I have read it through, I am able to easily go back and find relevant chapters for different concepts again.

This book has given me quite a bit to think about in terms of my curriculum planning and my classroom practice. Despite having just finalised my DP curriculum, I am already prompted by thoughts in this book to review it – particularly in line with David’s thesis that we should plan curriculums around threshold concepts. Doing that first involves identifying them which will probably be the springboard for my next CPD drive. However, I am fully aware that even the threshold concept of threshold concepts may turn out to be an unevidenced and unprovable claim made by education researchers and that my time here will be wasted. Only time will tell!

Why I am not a fan of the MYP

I am an IB educator and I believe in the mission of the IB. When I first started teaching the DP I loved the fact that it gave students a broad education, didn’t narrow down their options, allowing room for changes in future interests and personal directions. Perhaps as someone who took three science A Levels, it reflected a choice that I wish I had had, particularly working as an adult in a society where scientific illiteracy is perfectly acceptable but cultural illiteracy is not!

I loved the fact that while each individual subject may be a little lighter than an A Level (thinking specifically about the sciences here) they still maintain rigour and the challenge to students of taking six subjects plus TOK (which is another subject in its own right), an extended essay and their CAS program is no mean feat.

So, as an international educator and somewhat of an IB ideologue (at least in terms of the mission statement, not so much the ATLS), why would I write a post that is critical of the MYP?

What is the MYP?

The MYP is the International Baccalaureate’s Middle Years Programme and as such is the foundation or preparatory course for the Diploma Program years. It can occupy either 2, 3, 4 or 5 years of Secondary schooling with the final two years being in Y10/Y11 or G9/G10. It is one of three programs offered by the IB: the Primary Years Programme, MYP and Diploma Programme.

It is a curriculum framework that has eight subject groups which aims to provide a “broad and balanced education for early adolescents.”

My experience of working with it has been as a Biology teacher, working within the sciences subject group, teaching grades 9 and 10 in a K-12 school that offers the IB’s PYP, MYP and DP. The course I have built is based on the eAssessment curriculum, more on that later.

The MYP model

The guide for the MYP states:

“The MYP is designed for students aged 11 to 16. It provides a framework of learning which encourages students to become creative, critical and reflective thinkers. The MYP emphasizes intellectual challenge, encouraging students to make connections between their studies in traditional subjects and the real world. It fosters the development of skills for communication, intercultural understanding and global engagement—essential qualities for young people who are becoming global leaders.” (Sciences Guide For First Use January 2015 pg 2)

The model above shares many similarities with the DP model: in the centre, we have the IB Learner Profile surrounded by the ATLs and the MYP concepts and global contexts. These concepts and contexts provide a way of enabling interdisciplinary learning – a major feature of the MYP – thus one of the units in science may be built around the concept of systems, a concept that may be shared with another subject group. The aim of using concepts is to help students to make links between the different subjects that they are studying.

In delivering the MYP teachers are given a framework and a unit planner. They are told what concepts and contexts to teach (they can choose from a list of predetermined) but not what content to teach. This leads it open for teachers to construct their own units tailored to local contexts – on the surface an exciting prospect. I think teachers who love the MYP are initially drawn to this aspect that allows freedom and creativity.

While this is true, I worry that as individuals we suffer from a huge number of cognitive biases that may make us think we know, from our experience in the classroom and our own interests, what is the most appropriate content to cover but may, ultimately be wrong about this.

Effects on learning

The first thing that you notice about teaching the MYP, is that there is no curriculum content. While this is laudable for some reasons, I have grown to deeply distrust the MYP’s ideology for this for the following reasons:

Debatable concepts

The IB has a prescribed list of what I consider to be fairly debatable concepts. So as a biology teacher my units will focus on relationships or systems or change. Now there is nothing wrong with these concepts per se, and I can see why they are used: to try to build interdisciplinary connections.

However, they feel a bit arbitrary. Why should these be concepts that relate to and define the sciences and why do they take precedence over other concepts like information or energy for example?

The selection of general concepts assumes that students can easily build concepts from subject knowledge and transfer these concepts from one domain to another but this flies in the face of evidence from cognitive science.

We know from cognitive science that before learners can generalise a concept they need a good store of domain-specific content (facts) in their long-term memory. Once they have built this, then they can begin to develop domain-specific conceptual understanding. Only once they have mastered this can they transfer that knowledge from one domain to another. For more information on this see Dan Willingham’s “Why don’t students like school?

It is important to note that this takes years! Is it entirely appropriate to take this approach to a curriculum for middle schoolers who are still very much novices when it comes to knowledge and learning?

Novices vs Experts

As noted above the IB assumes that novices learn in the same way as experts; it is what underpins the assumption that you can have an interdisciplinary, concept-driven curriculum.

But the IB also assumes that novices learn in the same way as experts by encouraging students to learn from doing and teachers to set up their classroom inquiry in ways that reflect what experts do.

In MYP science we see this with the criterion B and C assessments and the following guidance:

“In every year of MYP sciences, all students must independently complete a scientific investigation that is assessed against criterionB (inquiring and designing) and criterionC (processing and evaluating).” – MYP Sciences guide

This requirement reflects the philosophy that, when it comes to science at least, students learn best when acting like scientists. Don’t get me wrong, I do agree that developing a solid understanding of the scientific method is very important for students. I am just not convinced that having students carry out their own investigations is the best way to achieve that aim. Domain-specific novices do not think or learn in the same way as experts.


Many authors have written about the effects on knowledge-rich curriculums and their effects on reducing inequality in society (See Daisy Christodoulou’s “Seven Myths About Education“, Lucy Crehan’s “Clever Lands“, and E.D. Hirsch’s “Why Knowledge Matters“). By ensuring a knowledge-rich curriculum schools are able to impact children from impoverished homes to ensure that they are able to become fully engaged citizens when they are older.

Children from poorer socio-economic backgrounds are less likely to have access to books at home and are less likely to be exposed to as many words and ideas in the family home as children from higher income families. This means that schools that serve them must impart the knowledge that will enable them to have a chance of becoming active members of society. In Why Knowledge Matters, E.D. Hirsch explains this at length and I am not going to go further into this here except to say that to my mind, by not imparting a knowledge-rich curriculum the MYP undermines the IB’s wider mission statement. How can the IB aim to create a more peaceful world, if it produces a curriculum model that can be shown to increase inequity?


The MYP can be tested through the eAssessment. The topic list for biology eAssessment is as follows:

Biology eAssessment Topic List – found here

  • Cells (tissues, organs, systems, structure and function; factors affecting human health; physiology; vaccination)
  • Organisms (habitat, ecosystems, interdependency, unity and diversity in life forms; energy transfer and cycles [including nutrient, carbon, nitrogen]; classification)
  • Processes (photosynthesis, cell respiration, aerobic and anaerobic, word and chemical equations)
  • Metabolism (nutrition, digestion, biochemistry and enzymes; movement and transport, diffusion; osmosis; gas exchange; circulation, transpiration and translocation; homeostasis)
  • Evolution (life cycles, natural selection; cell division, mitosis, meiosis; reproduction; biodiversity; inheritance and variation, DNA and genetics)
  • Interactions with environment (tropism, senses, nervous system, receptors and hormones)
  • Interactions between organisms (pathogens/parasites, predator/prey, food chains and webs; competition, speciation and extinction)
  • Human interactions with environments (human influences, habitat change or destruction, pollution/conservation; overexploitation, mitigation of adverse effects)
  • Biotechnology (genetic modification, cloning; ethical implications, genome mapping and application, 3D tissue and organ printing)

A quick scan of this topic list shows something quite revealing. What, exactly does the IB mean by physiology on the first line? This is a large subject in and of itself. I find it strange that the IB doesn’t specify particular types of cells and physiological systems and yet will happily specify “mitosis” or the word and chemical equations of respiration and photosynthesis.

This list has the feeling that it has just been thrown together by looking at the DP course and condensing that with no real thought as to what would actually be taught.

Also, the IB assumes, with the generic topics like physiology that students who have been taught one particular physiological system, like the kidney, will be able to answer questions on the heart. See E.D. Hirsch Why Knowledge Matters Chapter 2 for an explanation of why, in order to be fair, a test has to test a specific body of knowledge.

By having no rigorously defined content, even for the assessment, the IB again, shows a pitiful understanding or knowledge of the evidence from cognitive science about how humans learn. Worse, they willfully put some students and their teachers in line for failure. The fact is if you haven’t studied something and that thing comes up on the test, you just aren’t, as a 15-year-old student, going to be able to answer those questions because you are still a novice in that domain and it is unlikely that you will have learned to think like an expert in 140 hrs of teaching.

The eAssessment course is meant to be delivered with at least 70 hours of teaching in the final two years of the MYP – minimum of 140hrs – just shy of the SL DP course.

Massive workload! Hornets and butterflies

In this post, Joe Kirby writes about hornet and butterflies: ideas in teaching that have either high effort, low impact (hornets) or low effort, high impact (butterflies) – it also makes up a chapter in Battle Hymn.

By its very nature, the MYP is a collaborative project. In fact, one of its huge strengths is that it gets teachers out of their silos and working as a team. But that, collaboration inevitably increases teacher workload. For the reasons that I have outlined above, I think that ultimately, while an asset this collaboration results in low impacts for students.

Some who read this will immediately discount that statement as not chiming with their own experiences. And yes, it can look great when kids are seemingly engaged and enthused but we should not confuse this with learning and as educators, we really need to be aware of our own cognitive biases that may lead us into thinking that something is effective when it isn’t. You can read David Didau’s excellent “what if everything you knew about education was wrong” for more details of that.

But it’s not just the fact that it requires collaboration that increases the workload, it is also the fact that as a framework there is no content, leaving teachers to make content decisions as well. This is incredibly freeing but also, in practical planning terms it pushes the workload up even more and I would argue with little to be said for an increased impact on student learning. Surely a defined and prescribed content list would decrease teacher workload and have the same impact on student learning?

Finally, in its assessment, the MYP is workload heavy. In science, teachers end up having to plan lengthy assessments tasks, with clear instructions that break down the assessment criteria into student-friendly language.

Just planning summative assessments like these tasks, designing and making the supporting materials, is much more workload intense than other systems I have worked with and I am not convinced that it has any more impact on student learning.


I am not writing this to be difficult but I do hope that my thoughts here will lead to some open and honest discussion. I know that certain educational approaches have a lot of emotional appeal. I want to get away fromt this at start talking about what is best for our students rationally.

From Knowledge to Understandings

Recently (when I first started this post at least) I blogged about the best way to begin the DP biology syllabus and I was frustrated by the limitations of the syllabus to be able to pick and choose different assessment statements.

The DP biology course has always been knowledge rich. Maybe not as full as the A Level syllabus to take account of the fact that students are taking six subjects plus a summatively assessed course in Theory of Knowledgea summatively assessed research project: The Extended Essay, and their Creativity, Activity and Service Program.

Now, the IB changed the syllabus to allow more conceptual teaching, by removing the series of statements about students should be able to:… “explain x” and “state y” and grouping knowledge into brief statements under the heading of understandings, applications and skills. However, the structure of the syllabus with the essential idea for each topic tends to hamper the ability to lift assessment statements out and add them to new areas. i.e. mutations and oncogenes in topic 1.6 could be taught with topics 3.1 after 2.6. See the biology guide for the full IB syllabus.

This year, my Diploma Programme Coordinator, asked the subject departments to focus on developing their written curriculum.

It seemed timely to be asked to do this, when over the summer I had been musing about the best place to begin the course and the best ways to break up the different topics – many of the schools I have worked in simply teach the course topic by topic and the IB is keen to point out in the biology guide:

The order in which the syllabus is arranged is not the order in which it should be taught, and it is up to individual teachers to decide on an arrangement that suits their circumstances. Sections of the option material may be taught within the core or the additional higher level (AHL) material if desired or the option material can be taught as a separate unit.”

Over the course of this academic year, I have thought a lot about how best to structure the course to allow the “best” progression of concepts. Actually, I think that this is a process that began when I first started teaching my current Y13s, and I am an exceptionally slow thinker! I do remember reflecting on how to best position evolution within the course and which topics would be best coming before or after it.

But it wasn’t until this year that I have had the time within my working week or the emotional time within my personal life to really dig down and get to grips with writing up my ideas into the formal IB course outline.

I have also been exposed to new ideas about teaching and learning over the last twelve months. Last summer I read Dan Willingham’s book “Why don’t students like school?” which I think I got put onto after reading Michela’s “Battle Hymn of the Tiger Teachers”.

Idea’s from cognitive science have become more and more prevalent on my twitter feed as well as I have started to interact a little more with the #CogSciSci crowd.

All this to say that my thinking has evolved in the last twelve months.

I now know that, generally speaking, content knowledge, concepts and skills are domain specific and that learners have to become fluent with a subject’s facts before they are able to transfer that to abstract concepts and develop understanding let alone build connections with other subjects.

I am also beginning to understand the concepts of retrieval practice, spaced practice, dual coding and the distinctions between declarative knowledge and procedural knowledge and how all this may apply to my subject teaching or pedagogical content knowledge as Lucy Crehan puts it in “Clever Lands”.

Translating this into biology teaching is still not well understood (or so it seems from my vantage point) but conversations like the ones below (propositional knowledge = declarative knowledge) and blogs like this one, are beginning to help me unpack this.

The finished product

The below is the finished course outline that details the units and sequence of the teaching of the course. It is an official document used in the authorization and evaluation process of IB World Schools.

The below is my SOW for the course. It has six tabs. The DP overview shows the number of teaching hours recommended by the IB for each subtopic along with my grouping of them per unit. The Year overview shows the spacing of the units through time for both Y12/Y13. The next two tabs are for the week to week (mid-term planning). The Bio and TOK tabs show the TOK links that I have chosen to focus on the topic and are to support collaborative planning with the TOK team. Finally, the PSOW tab shows the practicals that can be built into the course. The IB mandates a specific number of practical hours for both SL and HL courses.

Final Word

The other effect of this learning for me is that I am now worried about the direction that the IB is taking in its philosophy.

If research from cognitive science is telling us that learners need a solid factual knowledge base before they can build conceptual understanding then what does this say for a course whose syllabus is about “understandings” as opposed to knowledge?

I have not heard anything from the IB that shows that it is reviewing research from cognitive science. Is the IB becoming an ideologically run institution that ignores research that doesn’t fit in with its own paradigm?