IB Biology Internal Assessment (IA) Ideas | Owl Tutors

Uncertain how to get started on your Biology IB IA? Jeni demystifies the process of choosing your area of investigation and deciding upon the research question.

IB Biology IA Assessment

IB courses are graded using both external assessment (exams) and internal assessment (coursework) methods, with the weighting being 80% EA and 20% IA. In Biology, this consists of a single individual investigation, which will be supervised and assessed by your teachers, before being externally moderated by the IB. Most students will complete this in the second year of the course and so choosing a topic already covered in the first year might be ideal, as this allows for revision of the concepts involved, increasing your comprehension ready for the EA.  

The Biology IA is an opportunity for students to use the knowledge acquired in their IB studies and apply it to an independent investigation of their choosing, to develop their skills of data collection, analysis, and scientific report writing. An IA is often a lab-based investigation, but can also be a modelling project, using databases or simulations. You will be marked according to the assessment criteria of personal engagement, exploration, analysis, evaluation and communication and it is important you are aware of and deliver material in your report relevant to these criteria in order to score highly. 

The purpose of Science IA is to assess your competence at experimental design and report writing, as these cannot be evaluated easily during EA and are vital skills to develop ready for science-based degree level studies.  A key feature of a successful IA is that it is self-directed and therefore independent, meaning that whilst you can seek guidance from academic staff, you should be making the decisions and showcasing your ability to carry out scientific research – which is an exciting development in your biological education, so embrace it! 

Some students might take this autonomy too far and try to investigate a topic on the limits of the IB specification, which I would caution against. Your research area should be within the scope of the IB syllabus and elongated consideration to decide upon the ‘best’ research question will use up valuable time and is unlikely to translate to Higher marks. It is important though to choose a topic that ignites your curiosity, so follow these suggestions to discover your research question.  

Firstly, brainstorm five mini-themes from the specification that interest you; consider each by making a pros and cons list and seeking advice from a teacher or tutor regarding feasibility; discard and reduce to a short-list of two topics; research both further with suggested academic reading; make notes on these – which will be useful revision, plus essential skill practice; and make the decision – which one are you now excited to focus your efforts on? Finally, formulate your research question, which will be a working version, as amendments might occur once a preliminary investigation has been carried out.  

Listed below are investigation ideas with links to websites which give practical procedures or further academic reading to enable you to formulate your own research project. Remember it is important to have your own idea that is relevant both to the specification and to yourself as ‘personal engagement’ is one of the IA assessment criteria, so it is best to be able to link to a real-world situation that you are interested in and can write about. It is also worth noting that one of the IB learner profile traits is ‘principled’, so while it’s appropriate to seek guidance from a tutor or a teacher, this piece of written work must be your own. 

IB Biology IA Ideas

Factors effecting enzyme activity: explore the effect of pH, temperature or substrate/enzyme concentration on the activity of the enzyme catalase, focusing on the breakdown of hydrogen peroxide under varying conditions. This can be linked to fruit juice production, environmental conditions or climate change. Investigating an enzyme-controlled reaction 

Heart rate in Daphnia magna: the heart rate can be measured by viewing semi-transparent water fleas under the microscope, and it is simple to vary conditions such as temperature or caffeine concentration. Physiological responses like heart rate can be linked with the concept of ectothermic organisms and metabolic rates. Caffeine and heart rate in daphnia 

Osmotic potential in plant cells: various types of vegetable (not just potatoes!) immersed in solutions of salts or sugars can be used for investigation of factors that change water movement, linking to concepts of water potential and osmosis. Osmosis in bell pepper pericarp tissue  

Comparative studies of stomatal density: describing the differences in the pattern and density of stomata in different species or within a species in different habitats. Measuring stomatal density 

Limiting factors of photosynthesis: the relationship between photosynthetic rates and the factors that change them, including light intensity, CO² concentration and temperature can link with plant health and crop production. Photosynthesis experiments using algal balls 

Bacterial antibiotic sensitivity: the phenomenon of bacterial antibiotic resistance is a global health issue which can be studied using aseptic techniques to grow bacteria exposed to various types and concentrations of antibiotics to observe resistance patterns. Aseptic techniques 

Comparing the DNA sequences of humans and chimpanzees: If you would like to avoid a lab-based investigation, consider making comparative analysis of DNA sequences to explore genetic similarities and differences, highlighting concepts of DNA structure and molecular evolution. Differences between human and chimpanzee genomes 

Gene expression and lactase persistence: Investigate the genetic basis of lactase persistence by analyzing the expression of the lactase gene in individuals with different lactose tolerance levels. Lactase persistence 

Studying inheritance patterns in Drosophila melanogaster: examine inheritance patterns in fruit flies by observing traits like eye color and wing shape, relating to concepts of Mendelian genetics and inheritance. Genetics on the fly: drosophila model system 

Assessing genetic diversity in local plant population: Investigate genetic diversity within a plant population using molecular techniques like gel electrophoresis, linking to concepts of genetic variation and natural selection. Gel electrophoresis 

Effect of exercise on heart rate: the relationship between exercise and heart rate can be an engaging topic, using heart monitors to measure heart rate before, during, and after different levels and types of physical activity in human test subjects. This is linked with human physiology, obesity and health. Using heart rate to judge heart health