Do you know that your biology Internal Assessment is one of the best ways to boost your final score particularly if you are on the lower grade?

In biology, students write the Biology IA during their second year of IB Biology SL class. Each student is required to research, design, perform and write up his/her investigation comprising of 6 to 12 pages. According to the International Baccalaureate Organization, each student is assessed by the teacher and moderated externally by the IB.

Writing an excellent biology IA requires an average of 10 hours to conduct an investigation, which provides 20% of the overall assessment for the biology IB score. The performance of the Biology IA is marked against strict common assessment criteria. The criteria are used to grade the IA with a maximum score of 24 points. It includes personal engagement, exploration, analysis, evaluation, and communication. However, some students fail to obtain maximum points because of failing to adhere to these criteria.


Here is a Systematic Guide on How to Write an Excellent Biology IA Worthy of Full Marks

Choose a Topic of Interest

Before beginning to write a biology IA, it is advisable to choose the right topic that interest you. As a student, you are advised to familiarize with the marking criteria because a topic is considered good when it allows you to easily gain the highest score.

When brainstorming topics, try to keep it simple, original and check the available resources. Do not choose a too broad or narrow topic. When the topic is too broad, you cannot be able to discuss and justify a detailed conclusion thus you can easily lose the evaluation points. On the other hand, the too narrow topic can make it difficult to collect sufficient data thus you can easily lose the analysis points.

Stick To the Marking Criteria

The biology IA is graded by using five criteria comprising of personal engagement (2 points), exploration (6 points), analysis (6 points), evaluation (6 points) and communication (4 points). Some students fail to achieve the highest points simply because they do not stick to the criteria. It is therefore advisable for a student to stick to the criteria and use it as a guide for revising and editing the Biology IA.

Outline a Clear Defined Structure

A well-structured IB ensures that you obtain high points because it makes communication simple and clear. It allows your teacher to keep track of your writing. The following is the structure you can stick to while writing your Biology IA.

Research question

  • Formulate a clearly defined research question based on the chosen topic for your IA
  • Make it specific as possible by making it one brief sentence
  • Capture your dependent and independent variables

Background Information

  • Provide the theory behind your investigation and demonstrate your understanding
  • Set the research question into context
  • Use citations to support the biological theory

Hypothesis and variables

  • Provide experimental hypothesis and the null hypothesis
  • Provide dependent variables, independent variables and controlled variables with their respective units
  • Include the impact of each variable

Materials, methods and safety issues

  • List apparatus including their sizes and uncertainty
  • Provide a systematic procedure of conducting the investigation and recording the results
  • Include safety issues along with ethical issues


  • Provide raw data in tables along with calculations
  • Provide processed data using diagrams, lists, tables, graphs, etc.

Data analysis and interpretation

  • Analyze the findings
  • Discuss the impact of the uncertainty and include error bars
  • Discuss the pattern of data based on the research question

Conclusion, evaluation and bibliography

  • Make a summary of the findings and relate them to the RQ
  • Mention the limitation and strengths of the investigation
  • Provide future extension of the investigation
  • Provide relevant references in the bibliography section

Begin Writing as Early as Possible

Writing a biology IA is going to take some time before completing it. In some cases, you may find yourself occupied with several assignments that can be difficult to finish on time. Sometimes you can be stuck along while writing and don’t hesitate to seek assistance with your IB IA paper. We at Writers per hour can help you deliver a professionally written and well-articulated Biology IA paper as per IB Standards within your stipulated deadline.

Here is a List of 20 Topic Ideas that Can Inspire You to Write an Excellent Biology IA for IB

1. Investigating milk spoilage in various conditions.

2. Investigating the effectiveness of various types of toothpaste.

3. Investigating age and speed of reaction. Effect of different altitudes on flowering stages of a plant species.

4. Determining the relationship between weather patterns and different cases of the disease.

5. Examining the accuracy of color vision via online color tests.

6. The impact of River pollution on marine life.

7. Effect of antibiotics on microorganisms.

8. Impact of antibiotics on the rate of seed germination.

9. The relationship between microbial activity and rate of seed germination.

10. The impact of pests on plant diversity.

11. The relationship between temperature and the rate of fruit ripening.

12. Impact of body exercises on heart rate and blood pressure.

13. The relationship between the amount of light and the rate of plant respiration.

14. The impact of isotonic drinks on recovery and rehydration after exercise.

15. The relationship between different light colors and Seedling growth.

16. Determining the effect of glucose concentration on osmosis.

17. Investigating the impact of soil pH and rate of seed germination.

18. Investigating the relationship between temperature and rate of yeast respiration.

19. Investigating the impact of light on vitamin C.

20. The effect of temperature on Staphylococcus epidermidis.


Biology can offer various opportunities for you, and therefore writing an excellent Biology IA can be an avenue for your success. When writing your Biology IA, consider these tips and topic ideas, and in the end, you will be surprised how you will score excellent grades.