Biology is one of the most challenging subjects in the IB program. IB Biology requires students not only to be proficient in the content but also to conduct their research and analysis. Many students can learn the content easily, however struggle with the IA due to its analytical nature.
Want to get a 7 in your Biology IA? Keep reading to find out how!
Overview of the Biology Internal Assessment
Before brainstorming ideas, it’s essential that you familiarise yourself with the IA and its requirements. Your Biology IA should:
- Align with a topic from the IB syllabus
- Be feasible within the time frame
- Allow you to collect sufficient data and have scientific papers written about it
- Be ethical, safe and manageable with the resources available to you
The IA contributes to 20% of your overall grade, and for most people is the difference between a 6 and a 7. This still leaves most of your grade left to your exams.
Want to know how to get a 7 on your exams? Check out our article below!
Brainstorming Broad Areas of Interest
Once you have a few broad topics in mind, do some preliminary research to explore specific questions or problems within those areas. Look for existing studies, articles, and online resources that discuss related experiments. This research will help you identify gaps in knowledge or areas where further exploration could be valuable.
For example, say you are interested in photosynthesis. You should then:
- Research key factors in photosynthesis
- Find articles and studies that discuss photosynthesis experiments
- Note their dependent and independent variables and the outcome of the experiment
Tip: a really helpful piece of advice is to look at Biology IA examples that score a 7 and see what topics they relate to. Having an exemplar to compare to yours will not only give you ideas but set you on the right path.
Refining your Idea
After having a few broad ideas, you must refine them. A good IA always has a clear research question that you can test through experimentation. The topic you choose should also include reasons for conducting research. The more focused your topic, the easier it will be to design a method and collect meaningful data.
Continuing with the photosynthesis example, say you find a lot of research on the plant Elodea:
- You find out that changing the salinity of the solution (salt concentration) affects the rate of photosynthesis
- Clearly state your independent variable (in this case salinity) and the dependent variable (in this case rate of photosynthesis)
- You should also find out why this research is applicable
You must then formulate an in-depth question that has these criteria:
- What independent variable are you changing (and by how much)
- What effect in the dependent variable are you collecting data on
- What are the units of the data you are collecting and how you are measuring it
- The time frame of the experiment
A good IA question will sound something like this:
What is the effect of increasing the salinity of the solution (0%, 1%, 2%, 3%, 4%, and 5%) on the rate of photosynthesis of Elodea canadensis as measured by the number of oxygen bubbles produced in 10 minutes?
This research question tells us:
- What independent is changing (salinity)
- The effect on the dependent variable (rate of photosynthesis)
- The units (oxygen bubbles)
- The time frame (10 minutes)
The research question is also applicable to real life. With rising sea levels, salinity on the shores is likely to increase due to erosion. What effect will this have on underwater plants?
The key to a good IA question ultimately lies in a specific dependent variable and independent variable, and whether it is providing useful information on a certain issue.
The best Biology IA ideas
There are no ‘best’ IA ideas, however some topics are much easier to score a 7. Ensuring you follow the previous steps; your IA idea should already have research that you can reference to strengthen your analysis.
Here are some of KIS’ Biology IA recommendations:
1. Effect of Temperature on Enzyme Activity:
- DV: Rate of enzyme activity (measured by the breakdown of the substrate, such as hydrogen peroxide by catalase).
- IV: Temperature (varied using a water bath or incubator at different temperatures, e.g., 10°C, 20°C, 30°C, 40°C, 50°C).
- Experimental Setup: Create a potato paste (this contains catalase) with hydrogen peroxide. Change the temperature and measure the rate of oxygen production using a gas syringe.
- Rationale: This experiment investigates how temperature affects enzyme kinetics, which is crucial for understanding metabolic processes in living organisms.
2. Impact of Light Intensity on Photosynthesis Rate in Elodea Plants:
- DV: Rate of photosynthesis (measured by the oxygen produced, using a gas collection method).
- IV: Light intensity (altered by adjusting the distance of the light source or using different wattage bulbs).
- Experimental Setup: Submerge Elodea in a beaker containing water. Adjust the light intensities and measure the rate of oxygen produced either via counting bubbles or using an oxygen sensor.
- Rationale: Photosynthesis is essential for plant life, and understanding how light intensity influences this process is key to optimising plant growth in different environments.
3. Effect of Carbon Dioxide Concentration on Photosynthesis:
- DV: Rate of photosynthesis (measured by the rate of oxygen production or uptake of CO2).
- IV: CO2 concentration (varied using different concentrations of sodium bicarbonate in the water).
- Experimental Setup: Place aquatic plants like Elodea in solutions with varying CO2 concentrations, expose them to light, and measure the oxygen produced over time.
- Rationale: This experiment explores how CO2, a critical component of photosynthesis, affects the rate of this process, providing insights into plant responses to changing atmospheric conditions.
4. Effect of Substrate Concentration on Enzyme Activity:
- DV: Rate of enzyme activity (measured by the breakdown of starch using amylase or another enzyme-substrate pair).
- IV: Substrate concentration (varied by preparing solutions with different concentrations of starch).
- Experimental Setup: Mix amylase with starch solutions of varying concentrations and measure the rate of starch breakdown using iodine (which changes color when starch is present).
- Rationale: Understanding how substrate concentration affects enzyme activity is fundamental in biochemistry and has applications in industries that rely on enzyme-catalyzed reactions.
5. Temperature's Effect on Respiration Rate in Germinating Seeds:
- DV: Respiration rate (measured by CO2 production or oxygen consumption).
- IV: Temperature (varied using a water bath or incubator at different temperatures).
- Experimental Setup: Place germinating seeds in sealed containers at different temperatures, and measure the change in CO2 concentration using a gas sensor or chemical indicator.
- Rationale: Cellular respiration is temperature-sensitive, and studying how it varies with temperature helps understand the metabolic rates of organisms under different environmental conditions.
And that’s how you can come up with the best Biology IA Idea. This IA cannot be rushed, so take your time researching and planning to set yourself up for success.
Want more personalized study guidance to help drastically improve your marks? A private tutor can make the biggest difference!
Written by KIS Academics Tutor for IB and QCE, Sameer Baad. Sameer is currently studying for a Bachelor of Advanced Finance and Economics at the University of Queensland. You can view Sameer’s profile here and request him as a tutor.
