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IB SL & HL Biology Internal Assessment Topics 🧬

The pain of struggling with biology IA ideas is genuine, and we get it. There is so much out there, and you may find yourself in a position where you are caught between two topics and do not know which one to choose for the IB biology IA.

In this blog, our PRO IB team decided to avoid vague “how-tos” and dry theories, so we focused on the main crucial points when selecting a topic for your IB Biology IA. So fasten your seatbelts, because this article will narrow down a couple of ideas you can use for your SL or HL assessment to help you with biology IA ideas.

ib ia help


You can request a custom suggestion of a Biology IA topic from our IB IA experts, or you can spend several minutes of your time, read this article and find awesome suggestions for your next IA.


When it comes to writing the biology IA, finding the perfect topic is really important. In fact, it is THE most important aspect you need to keep in mind when working on your IB biology internal assessment.

Having that said, there is a pool of biology IA ideas you can choose from. With IB IA, there are some particular points you need to keep in mind, such as IB biology IA length, IB Biology IA criteria and more. Before we get to the biology IA topics, let’s quickly go through these points first.

The requirements for internal assessments are the same for three subjects: physics, chemistry, and biology. Internal assessments make up for 20% of the grade and are all about scientific writing and research. The work produced by students is assessed internally by the teacher first, and it is then moderated externally by the IB. At SL and HL levels, the performance is rated concerning a defined assessment criterion which is marked out of the score of 24. Similar situation with IB Economics IA topics, but we will talk about it in another article.

This post was inspired by numerous searches in different Q&As and forums for good Biology IA Topics advice. After numerous searches, I understood that there is a need for updated information for those students who are searching for topic SUGGESTIONS, not theoretical information on how to create a topic for their IAs in ESS or let’s say Chemistry IA topics. So let’s move to the practical part. The one you have searched for, am I right?

Remember! With a tough topic comes responsibility and tough nights without sleep, therefore, choose your topic wisely!

Now that we have that out of the way, let’s discuss the potential IB IA biology ideas and topics for your essay. With every topic that is listed as followed, you would need to look into the basic reasons on why and how you will investigate the topic.

You need to come up with possible dependent variables (also known as controlled variables) and independent variables alongside the experimental setup. Some tips on Critical Thinking essay writing also will be helpful for your understanding. Essentially, you need to consider if you can apply the topic in your regular life and have any personal motivation towards to topic you go for.

IB Biology IA Ideas:

  1. Does our reaction time reduce with our age?
  2. Describe the primary productivity of algae changes for nutrients, salinity, aquatic plants, algae concentration, or other additional variables.
  3. How can we reduce the decaying of vegetables? Can exposure to sunlight, humidity, temperature affect the way and speed vegetables decay?
  4. How can we compare the buffering actions of detergents, juices, yogurt and milk?
  5. How can we compare the respiration rates of wine yeast in different sugar solutions and baker’s yeast?
  6. How do the sudden changes in the position of body affect the baroreceptor feedback and heart rate?
  7. What are the BMI effects on skin surface temperature in different areas of the body and their recovery rate when exposed to cold?
  8. What is the effect of agarose gel concentration on DNA migration?
  9. What happens to dairy products after their best-by date?
  10. What is the impact of river pollution on the lifeline of marine life?
  11. The effect of light and temperature on the ripening of fruit.
  12. Exploring the different conditions and stomatal density.
  13. Exploring the effectiveness of different types of toothpaste.
  14. Biomass and the effect of sunlight.
  15. Looking into global warming: how do oxygen, water vapor, and CO2 (or any other variable) affect cut-off bottle and temperature under simulated sunlight.

2023 UPDATED unique Bio IA questions ideas, especially for you, friends:

  1. Effect of Temperature on Activation Energy Produced during the breakdown of H202 while using catalase enzyme and aluminum inhibitor as a catalyst.
  2. The Effects of Aluminium Chloride on Hydrogen Peroxide Breakdown by the Liver Catalase Enzyme – Experiment Based❗
  3. Evaluate the impact of HDI on moralities that occurred due to lung cancer for top 25 HDI and lowest 25 HDI ranking countries – Based on data collection from a secondary source❗
  4. Effect of concentrations of black tea used as organic house waste on the growth and emersion rate for germination of tomato seeds? – Experiment Based❗
  5. Effect of varying concentration of HCL on the change in mass of seashells and the CO, released during the reaction
  6. Determination of Vitamin C for different juice samples and evaluating its relationship with varying temperature.
  7. Effect of light intensity on the rate of photosynthesis in Canadian waterweed plant (Elodea canadensis) – Simulation-Based❗
  8. How does the growth rate of pinto and green beans differ as they reach their optimal pH? – Experiment Based❗
  9. Effect of volume and pH of carbonated drinks on the Dental Erosion or Decay of Tooth – Experiment Based❗
  10. To what extent do the samples of various locally available brands of treated water differ in terms of the chlorine contents (mg /L) when reacted with SilverNitrate using Titration Method
  11. Effect of different metal ions on the rate of the decomposition reaction of the hydrogen peroxide (H,O.).

Ready to choose a good IB Biology IA Topic?

When choosing the IB IA biology topic, you need to make sure it is a topic you are motivated for. The experiments are long, and the writing part is even longer. It is essential that you go for a topic you are passionate about so it does not look like a hassle but that you enjoy doing it as well.

Here you can find a short video with extra options for choosing the right Bio IA topic.

You can choose any of the topics from the above-listed ones. You can always test different variables and perhaps that will give you the direction you are looking for. Remember, the essay holds 20% of your grade. You definitely need to commit to the essay to the fullest and that starts with focusing on the topic which aligns with your interests the most.

For those interested in writing a Math IA, we have also written an article and provided a list of the best IB Math topics for students who want to succeed.


Moreover, if you decided to ask for expert assistance, you can always call our IB IA writing service, where our expert IB writers will guide you through the process of writing a custom IB Bio IA in a manner of time.

Hope this blog post helped you in finding the topic for IB biology internal assessment you are looking for! And wish you good luck with your writings. May the force be with you, my friend 😉

Vasy Kafidoff

Vasy Kafidoff is a co-founder and CEO at Writing Metier, who has a keen interest in the academic world and technology. He is a cryptoromantic and blockchain enthusiast for more than 4 years now, and he is excited about the way technology shapes financial and educational systems. Check his personal blog to find more tips on writing.

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