My opinion on the new (2025) IB Biology syllabus

Two years ago, we began planning the new IB biology syllabus. Now that we’ve completed our first journey through it, it’s time for an update. Below, I’ll discuss the content load, the overall design and the IAs.

Content load

We were all hoping for a content reduction and I’ve observed many complaints about the new load. What does it look like in numbers? I break down all the course content into short closed questions that my students can use to help them commit it to memory. I have been updating them and you can see my latest version here.

• Last syllabus: 1370 questions.
• New syllabus: 1382 questions (currently)

Let’s consider other data, however. While I managed to finish within the IB-recommended timeframe, I too found it hard to do so under this new syllabus. It seemed I had fewer “extra” lessons for students to think through the difficult Higher Level topics. So, where does the perceived discrepancy originate from?

▸Firstly, this is our first round, and we’re yet to see any official exams. As we do, I’m sure we’ll begin sharing ideas on where we can cut content from what we teach. Cut from areas we may have taught too deeply (just in case).

▸Secondly, it’s hard to design biology curricula nowadays. Biology has become too great (in both ways), and every area has its important aspects. I’ve seen comments, for example, in which teachers complain about content overload but also lament the exclusion of a favourite topic (e.g. the digestive system). We just can’t fit it all in.

First and foremost, we need a balanced curriculum that meets the needs of our globally challenging times. But also as a qualification valid for university entrance, able to compete with others. Therefore, designing biology curricula is a tremendous task likely to leave everyone, even the designers, not fully satisfied.

▸Thirdly, the split between Standard Level and Higher Level is different in this syllabus. I feel the Standard Level course is now much fairer towards students who want to keep a foot in biology but not take it too seriously. On the other hand, the Higher Level is conceptually deeper and harder.

If you choose to study Higher Level IB biology, you must have a good reason; you’re signing away a bit of your life to study. Something that could be mitigated somewhat with different subject choices. If your biology students don’t study, they won’t score highly.

Yet, there’s nuance to discuss here. I like the conceptual focus much more than just adding more topics and more details. The latter can make biology seem rigorous, but generally just adds more peculiar vocabulary to our students’ worlds. It’s not as hard because you can memorise much of it for many exam questions without making meaning.

So, it seems we have a similar load of individual items (per my basic knowledge questions), but the deeper conceptual nature adds more. This is where the understanding arises. But each timetabled lesson can leave us feeling short of time for crucial sense-making exploration. This brings us back to the trade-off the IB has to navigate by creating a competitive university-entrance qualification.

Nevertheless, the designers have succeeded at limiting runaway overload. Deeper concepts are repeated regularly, with feedback loops being a good example.

Students will fare better in this course if they understand fundamental principles of living systems and repeatedly generalise them. (A good thing). Therefore, our lessons must also be arranged around continually conversing with these principles.

Content items are often repeated, too. Take, for example, antagonistic muscles in the topic of muscles (B3.3). The intercostal muscles appear as the official example, and also when we teach the mechanism of lung ventilation (B3.1).

Teaching IB biology is challenging; the content is broad and deep. I’d love to see some content reduction, but this course isn’t impossible either. We must ensure our students make meaning of and enjoy biology at a brisk pace. If you want to see how to do this, without lecturing at students, slide decks or leaving them to explore alone, then read my books, Difference Maker, or Teaching Meaning.

The Sequence Grid

The new grid design isn’t just novel, but also very clever. Key idea: the themes are an organising heuristic and unnecessary for the final exams. Therefore, the grid system gives three choices:

• Follow a sequence that oscillates between levels of organisation: going from molecules to cells, to organisms, to ecosystems in cycles (without extra planning).
• Follow a sequence that ascends the levels of organisation: starting with molecules and cells, then moving to organisms and finishing with ecosystems (without extra planning).
• Create a personalised sequence (with extra planning but which is greatly facilitated by the grid).

Traditional syllabi gave just two choices: follow the sequence or laboriously create your own point-by-point. I like creating my own sequences, but understand that many prefer not to (it’s a lot of work!). Teaching IB biology is a major undertaking and reducing the complexity of our work is a good idea.

I argued in Biology Made Real that the whole organism is where our students will find meaning in biology. Rather than an end in itself, lower levels of organisation, like molecules, offer a perspective to explain what we experience as whole organisms.

Therefore, I welcome the option of a premade sequence that oscillates between levels of organisation (by moving from left to right across the grid). I also welcome the traditional sequence option for those who want it (by moving from lower to higher levels). And I warmly welcome how the grid design greatly facilitates sequence creation. Rather than point-by-point, I can rearrange whole-grouped concepts. You can see my sequence here.

IAs (Internal Assessments)

The change from a 12-page to a three-thousand-word limit is a difference maker. Before, my best students (seeking 7s) would manage to format their work to fit in 5–6,000 words. Having only to mark 3k words has made a positive difference to my workload. I’m thankful.

However, my top students this year, with their 3k word limit, produced IAs that were very different to those of the previous syllabus. With the lower word count, it’s hard for top students to show the “extra” that differentiates their work from others. The research has to be shallower in the introduction, and that then limits what can be said in the analysis.

The difference between IAs that score 5, 6, or 7 is now harder to distinguish. It’s clear that to get the top marks, students must be ultra-concise to fit in their best ideas.

Conclusion

All new curricula bring us challenges, but I can say that I’ve enjoyed this syllabus. Over time, I think these challenges will subside as we move into new routines and gain familiarity. Change is hard, but it can provoke new ideas, perspectives, and improvements.

In the next curricular iteration, I’d also like to see a continuation of the more conceptual nature of biology: less description and more explanatory models that allow students to make meanings and predictions about their worlds. If you want to get your students enjoying and making meaning of biology throughout this tough syllabus – without lecturing or running out of time – then check out my books.