IB Biology IA Ideas: 2026 Topics That Actually Work

Moderate ideas (more biology, more thinking)

• Light intensity vs photosynthesis rate in pondweed or leaf disks. Pair your write-up with Notes for C1.3 Photosynthesis.

• Light wavelength vs algal growth (controlled LED colors, growth proxy like absorbance). Strong link to photosynthetic pigments.

• Vitamin C content across fruits using DCPIP titration. Solid data, but be strict about standardization.

• Bioindicators for water quality (macroinvertebrate counts, diversity index). Great for real-world context and ecology.

Hard ideas (high payoff, higher risk)

• Antibiotic resistance in bacteria (zone of inhibition). Requires careful safety, ethics, and methodology.

• Antibiotic production in fungi (inhibition tests). Interesting, but sensitive to contamination.

• Genetic variation in Drosophila or population datasets. Strong analysis, but depends on access to organisms or robust secondary data.

For inspiration on what top-level work looks like, browse IB Biology IA Exemplars or the wider IB Biology Exemplars library.

How to turn an idea into a scoring research question

A high-scoring IB Biology question often sounds like: “How does X (with units and range) affect Y (measured consistently), in Z organism/system, under controlled conditions?”

If you need a model structure, use Sample IB Biology IA: Step-by-Step Example and compare it with IB Biology Internal Assessment Guide.

FAQ

Are “classic” IB Biology IA topics too boring to score well?

No -- classic topics can be the safest path to high marks in IB Biology because they’re measurable and easy to evaluate. Examiners don’t award points for novelty alone; they reward clarity, control, and analysis. A familiar topic becomes impressive when your method is replicable and your evaluation is honest. Add personal engagement by choosing a real context (your local water source, a sport you play, a food you actually eat). Then tighten the research question range and units so it feels scientific, not vague.

How do I avoid choosing an IA that becomes impossible to finish?

Start by listing your constraints: time, equipment, organism access, and safety rules at your school. In IB Biology, the most common failure is planning a “cool” idea that collapses when you can’t control variables or collect enough trials. Do a mini pilot study early to test whether your measurements actually change. If the data barely moves, it doesn’t mean you’re bad at biology -- it means you need a better dependent variable. RevisionDojo’s AI Chat can help you stress-test your variables before you commit.

How can RevisionDojo help while I’m also studying for exams?

Your IA and exams feed each other in IB Biology if you study strategically. Use RevisionDojo Study Notes to write a sharper rationale, then switch to the Questionbank to practice data-based questions that resemble IA analysis. Build Flashcards for definitions you keep using (enzyme denaturation, limiting factors, standard deviation) so your IA writing gets faster and cleaner. When you’re close to exams, use Predicted Papers and Mock Exams to keep your exam technique sharp. If you want direct feedback, RevisionDojo Tutors and Grading tools help you fix weaknesses before submission.

Closing: pick the idea you can finish well

The best IB Biology IA idea isn’t the most complex. It’s the one you can control, measure, repeat, and explain with confidence. Start with a simple system, tighten the research question, and let your analysis do the heavy lifting.

When you’re ready to move from “idea” to “plan,” use RevisionDojo’s Coursework Library, AI Chat, and Questionbank to build an IA that supports your exam prep -- not one that steals from it.